-
Hi.
I\'ve been building a 1/3 scale 1874 gatling gun in .22LR which is based on plans by D&E model drawings and thought I\'d share my progress. I made a fair few parts when I first started the project a few years back, but a change of career meant I didnt have access to metal working machinery for a while. I\'ve now got a bit of a workshop set up in my garage so will endeavour to get further on with the build.
I\'ve finished a lot of the components and have made rough castings of most of the other parts. As I machine the castings, I\'m gradually going to start being able to assemble some of my parts together.
I\'ll get some photos uploaded on here as regularly as I can.
-
Here\'s the main base to the gun. It\'s made of 6mm thick brass sheet. I\'ve turned up two collars and pressed them into the base. The blue wheel is a prototype part I made, but it will be replaced eventually when I have machined up the brass wheel. There are 3 small stainless screws in the wheel that hold it onto the collar. This has been sitting for a while, hence the tarnish.
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo.jpg)
Here\'s the cast wheel:
(http://i847.photobucket.com/albums/ab36/pmercer1975/37074352.jpg)
(http://i847.photobucket.com/albums/ab36/pmercer1975/ecb2c5a5.jpg)
-
Here\'s the main shaft. it doesn\'t look all that pretty but the finish isn\'t that bad:
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-40.jpg)
Here\'s a key for the gear hub. You can see where it fits on the photo below.
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-41.jpg)
Here\'s the gear hub
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-42.jpg)
Here\'s the driven gear. I decided to buy the gears rather than make them.
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-43.jpg)
Here\'s it assembled.
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-12.jpg)
The gear hub screws onto the main shaft, so when it turns one way it is fine, but if you rotate it the other direction, it unscrews. I\'ll either loctite it or add another keyway at some stage.
-
This is the start of the barrel group.
Here\'s the bolt carrier that the bolts fit into. It\'s got tape round it to protect it whilst I was lapping the bolts in. In the bolt hole nearest you can see where the black marker pen hasn\'t worn off. I won\'t drill important holes with a drill again now I know what happens. Milling bits from this point on I think. Mind you, this is the same idea as the bolt on the Sterlings having a flute down them for crud removal. The hole to the left of no1 hasn\'t been lapped in yet as I\'ve only finished maching 5 bolts.
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-49.jpg)
Here\'s the pan. This is the casting and hasn\'t had anything done to it yet.
(http://i847.photobucket.com/albums/ab36/pmercer1975/49043715.jpg)
Heres the breech ring:
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-31.jpg)
This is the shaft:
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-26.jpg)
Here\'s the front shaft. I suddenly realised after making this part that I had better check the overall length of my gun to keep it legal. I subsequently had to make a longer front shaft....
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-55.jpg)
-
More of the barrel group:
The blue pan is a prototype as I\'ve not cleaned up the brass casting yet.
(http://i847.photobucket.com/albums/ab36/pmercer1975/fbcb0dda.jpg)(http://i847.photobucket.com/albums/ab36/pmercer1975/adb6fe80.jpg)
Here is the breach end of the barrels. I\'ve still got to cut the chambers, screwcut them and cut an extractor groove.
(http://i847.photobucket.com/albums/ab36/pmercer1975/2ef27485.jpg)
Here\'s the muzzle end of the barrels. I still need to cut and taper the length of the barrels.
(http://i847.photobucket.com/albums/ab36/pmercer1975/30418062.jpg)
-
Here\'s the top cover.
(http://i847.photobucket.com/albums/ab36/pmercer1975/295cb97d.jpg)
(http://i847.photobucket.com/albums/ab36/pmercer1975/7705cb65.jpg)
-
Here\'s the cascabel plate and plug.
(http://i847.photobucket.com/albums/ab36/pmercer1975/42f57b1a.jpg)
The rear isn\'t finished yet. I need to machine a thread onto it to match the receiver once it\'s made
(http://i847.photobucket.com/albums/ab36/pmercer1975/5875361b.jpg)(http://i847.photobucket.com/albums/ab36/pmercer1975/aefa5439.jpg)
-
This is the oscillator assembly:
Here\'s the oscillator pin:
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-57.jpg)
Here\'s the oscillator knob:
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-56.jpg)
Here\'s the oscillator adjusting screw:
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-28.jpg)
Here\'s the oscillator cap:
(http://i847.photobucket.com/albums/ab36/pmercer1975/photo-53.jpg)
Here\'s the assembled unit:
(http://i847.photobucket.com/albums/ab36/pmercer1975/e1da00e0.jpg)
-
Nice job with your progress and castings. It won\'t be long before you are test firing your gun now.
-
Thanks. At the moment, a lot of the parts have a dull tarnish on them, which added to the fact that I\'ve not got a proper finish on any surface yet means my work looks shoddy. As time goes on, I\'ll start to get proper finishes on all parts.
-
There is plenty of time for polishing after it is done. I have done enough prototyping and projects in the past to realize that somethings don\'t always work the way they are supposed to and need some re-machining which means repolishing again. Good luck!
-
I\'m in awe.
I admit that I haven\'t visited the site for a while, simply because the projects here are so far beyond my skill level that I can\'t contribute anything. But I had to come back out of curiosity.
Rethink: despite my inability to contribute tech suggestions, I _can_ give praise, and my jaw drops when I see home casting and machining like this.
Carry on, our new Gattling-wielding overlords!
-
Did you use Petrobond sand for your castings?
-
I built some of the parts out of wax on a Thermojet machine and then sent them off for ceramic casting. Basically they add sprues etc then dip the parts in liquid ceramic. Once the ceramic sets they melted out the wax and filled the voids with metal. The ceramic is then chipped off.
For the remainder of the parts I used a machine that builds parts out of polythene. Same post treatment though.
-
I\'ve cleaned up the casting of the Pan. It was fairly easy to clean up, but time consuming as I wanted to keep the edges crisp and not round any edges off.
(http://i847.photobucket.com/albums/ab36/pmercer1975/32586e4c.jpg)
If you look carefully, you can see some pitting from the original casting. I\'ll fill these small holes in with silver solder. They won\'t affect the running, but don\'t look too nice.
(http://i847.photobucket.com/albums/ab36/pmercer1975/c4df8a08.jpg)
Ok, so I\'ve attempted to fill the holes with silver solder. Now to clean off the flux and the surplus metal. You can see a reddening on the brass which I can only assume is the copper coming to the surface due to heating up.
(http://i847.photobucket.com/albums/ab36/pmercer1975/be165978.jpg)
I still need to machine the Center hole to final diameter and clean up the recess where a large extractor washer fits.
-
Ok, so I went downstairs to machine the last few operations on the pan, and can\'t find the chuck key for the lathe. Typical. I bored the center hole out though, so at least it fits onto the assembly now. I didn\'t get a photo of it as it\'s not quite finished yet.
Here\'s a photo of the Pan, the bolt carrier, the main shaft and driven gear. It\'s a fairly good start to the barrel assembly being completed. I put the five finished bolts in the assembly as well as three inert .22 rounds.
I noticed that the bolts dont all slide into the Pan nicely, so a bit of additional filing is required, but I wont do that until I\'ve got all 10 bolts done and rotate the pan for best fit. I also noticed that the .22 rims catch on some of the grooves of the pan, so some additional filing will be required for that as well.
I also marked out the barrels where they need to be turned down with a taper. When I\'ve got my chuck key back I\'ll finish the barrels as well and fit them.
(http://i847.photobucket.com/albums/ab36/pmercer1975/7237cafc.jpg)
(http://i847.photobucket.com/albums/ab36/pmercer1975/7f0ab1ab.jpg)
(http://i847.photobucket.com/albums/ab36/pmercer1975/e798de2e.jpg)
It\'s nice to see some of these parts assembled at last. I couldn\'t find the stainless M10x1 bolt I\'m sure I already made, so I quickly threaded a steel M8 bolt to hold the assembly together.
-
When I started building this gun I modified all the dimensions to allow a .22LR to be the caliber of choice. I then carried on manufacturing parts.
One day I realised that although I thought the gun would be long enough to be legal, I\'d better check. Anyway, it came up short. It needs to have a barrel length of at least 12\" and an overall length of at least 24\". At this stage I hadn\'t made the barrels so the easiest solution would be by extending the front of the gun, ie the BARRELS (unmade) and either the SHAFT or the FRONT SHAFT. For some reason, at the time, I decided to remake the FRONT SHAFT, but now I\'m not too sure.
The central shaft is split into three:
The MAIN SHAFT is not seen and goes inside the BOLT CARRIER, PAN and BREECH RING.
The SHAFT is the long section that goes between the BREECH RING and the BARREL RING (brass disc on right hand of picture) and screws into the MAIN SHAFT
The FRONT SHAFT is the section to the right of the BARREL RING and is supported in the RAIL FRONT which isn\'t shown. The FRONT SHAFT screws into the SHAFT and traps the BARREL RING.
In the pictures below;
The top picture shows how long the SHAFT and FRONT SHAFT should originally be. Below it is a barrel that is of the length I need it to be but positioned so that you can see how the front of the FRONT SHAFT and the front of the BARREL relate to each other and also the BARREL RING.
The bottom picture has had the extra long FRONT SHAFT fitted and the BARREL positioned correctly to give some idea how the BARREL RING now fits in. The BARREL RING is a lot further from the front of the gun now.
My question is this: Should I use this extra long FRONT SHAFT to solve my problem, or should I make a longer SHAFT? The main difference would be where the BARREL RING ends up. By design, it should be nearer the front of the gun than it currently is.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/a38dd012.jpg)
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/11eeefc1.jpg)
-
Nice work pmercer, your bolt extractors are looking great too. Did you custom grind the cutting tool from an end mill, or make one from scratch?
I have a bit of advice that you will find out soon enough when you start cranking away with it. The shaft needs to be tightened extremly tight where it goes through the barrel plate, pan and the bolt carrier or the alignment will change on you. The better solution would be to drill the parts for dowel pins to keep everything in alignment after you finish the other bolts and get everything aligned just right. I don\'t know why they didn\'t use hex stock for the rear part of the shaft in there design to start with.
bruski
-
Pmercer, have you got to the stage of a test fire?
-
Bruski
As I was assembling these parts the other day I thought there was a risk of movenent when its working. Great idea about a dowel pin - I\'ll definitely do that.
The other thing I noticed at the rear is that the DRIVEN GEAR is woodruff keyed to the GEAR HUB to prevent it turning - however the GEAR HUB is screwed to the MAIN SHAFT which is fine when cranking the gun forwards, but if you reverse the handle, as you may do to clear a stoppage, it unscrews. Maybe I\'ll locktite the thread on.
Steve, the parts shown are the only parts finished so the gun doesn\'t fire yet.
-
Very nice work Pmercer. I haven\'t been on the site for some time. The problem that people had mostly with the D&E is to get it to fire all the time due to all the bolts are at some stag of cocking at one time causing the gun to be difficult to crank. Then when the firing pin springs were lightened the gun didn\'t fire. The RGG gun cocks one bolt at a time making it much easier.
Bill
-
\"Each part is simplified as with the original Gatling system which was a Marvel of Simplicity\". Quote by Douglas Schneider included with the plans for his gun.
I am a simple man, I thought. This looks like a good project. It is within my skill level, tools and budget. Since I had this thought I have spiraled down into the depths of a ggun addict, buying tools, materials, reading the internet, and thinking of nothing else except gguns. Beware the evils of the D&E gun.
I, too, have encountered every problem that everyone else has with the firing of the gun. I reached the point where I had two guns ready to test fire. Insert a round, turn the handle and nothing.
I have built and rebuilt enough parts to make several more guns. I have worked and reworked parts to destruction. I have spent three times my original budget. I have some new tools (which is always good). I have new experience and a constant headache.
What I do not have is a ggun that will fire two rounds in a row. I have not completed the gun. It is ready for the yoke. I have it on a temporary wood stand for testing. If anyone is interested I can identify the problems and explain the steps I took to solve them.
-
YES, we are interested as I know that I am anyway. I know that the firing pins need to be perfectly true when soldered into the hammer shafts or they will drag enough to slow and weaken the strike on the rim. A heavier spring doesn\'t hurt either if you are willing to bore out the bolts a little more.
bruski
-
I didn\'t realise there were issues with the D&E gun firing. When I bought the plans they were the only company that I could find selling them. I\'ve gone too far with it now to even consider stopping or changing to a different design.
I would be very interested in hearing what problems you had and the solutions!!
-
Pmercer,
Your post has already mentioned three of the problems, the cutter, the bolt carriage and the pinning of the barrel assembly. I have many more. I will start with the cutter because it can be separated from the rest of the parts.
The cutter was an intimidating little thing as I have not made a cutter before and of its size. I made several out of oil hardening drill rod. I cut them on the mill using a dividing head. I had to buy a 40-1 dividing head for this project as my rotary table was 90-1. I had no way to sharpen them so I cut them to size, hardened them and touched up with a stone. I made the radius on the lathe with a file. I made a radius gauge by drilling a hole in a piece of brass and cutting it in half. The first cutter I made was the best.
I had only made 10 bolts at this time so I sacrificed one for a test cut. After ruining several bolts I stopped. The radius portion of the cutter worked good but the shaft portion dulled fast and burnt the bolt. I could not make a cutter that would make both cuts on two bolts in a row. I stopped working on the ggun and went to the internet.
I started looking at small tool and cutter grinders and found the Quorn. I started gathering materials and bid on the castings on ebay several times with no success. One day at Harbor Freight I was looking at the mini mills. The costumers at Harbor Freight love to take any part of a machine that will come off. I remembered a comment from the internet that it was possible to make a tool and cutter grinder by converting a mini mill. The manager had a returned mill and I bought it.
I modified the mill so it would rotate in three axis. I made end mill holders to sharpen the ends. I made a three axis holder using 5C collets. I made a rotary table with a 5C collet holder. I made an air bearing to sharpen the spirals. I still plan on making a Quorn.
Using this I made more cutters. I ground them from broken HSS end mills. It was then that I saw that it would be much better to make a single cutter and use an end mill to cut the shaft portion of the bolt. I was able to grind a radius cutter to the correct size. As it was HSS I have not had to sharpen it yet. I can only get one sharpening before it would be too small.
I divided the cutting of the extractor into two stages. I made a fixture to hold the bolts so I could index them and make multiple bolts at a time. I would cut the shaft portion first and then cut the radius portion. As the fixture was already centered all I needed to change was the end mill to the cutter. The bolts were already cut to final length.
I divided the cutting into two stages because I could not get a bolt to the correct length to touch the round and the correct length to clear the barrel and eject a round in one pass. I am sure it is possible but I could not do it. I tried adjusting the spacing between the bolt carriage, pan and the barrel ring. I made partially completed bolts to use as gauges. The sequence that worked was to get the three parts in place and tightened. Place a round in the barrel. Use a bolt without the extractor and trim a little off until it fit against the round and everything would rotate with no interference. This is the length of the bolt to the point of the extractor. Next I cut the extractor groove on another bolt a little deep so it would not touch the rim of a round. This is a guess at this time because what I was trying to find was the depth of the shaft cut. I placed a round in the pan and brought the bolt up to it. I measured the distance from the top of the extractor to the shaft of the round. I then cut the shaft portion of the extractor using this measurement. I repeated the process until the round rim would fit in the extractor groove and the extractor would fit over the round.
The last step was to fit the extractor into the space provide by the barrel. I used the same bolt to determine the correct length of the extractor. It must fit into the barrel space without touching the barrel. Then I put a round in the pan and inserted the bolt and turned the handle and observed for any interference. The extractor must come over the top of the rim of the round, then the shaft must push the round into the barrel and set into the barrel space. All this was done without the firing pin. I repeated this for each bolt when I encountered another problem. The round would constantly catch on the barrel and stop the action.
As this is not connected with the cutter I will stop here. Check out GatChat and the Gatling group on Yahoo. I did not take pictures as I did not have a camera. (I can not find the spell check).
-
Bruski,
I followed the suggestions and made the first set of pins by soldering. I did not like them so I made the pins I now use out of one piece. The springs I have tried are from MSC.
1. .240 x .026 x 2
2. .300 x .032 x 2
The springs mentioned on the yahoo group are that worked are .300 x .032 x 1.75 also from MSC.
I have more on the springs later.
-
Steve, Did you have any other problems with your gun firing on all ten? I am wondering if there might be a problem with the cam followers or the rear cam getting damaged from the beating of the larger cartridge?
bruski
-
There is cordite at the end on the barrel. I just achieved rapid fire. I was able to fire three rounds in a row.
After my last post I changed directions and experimented with the firing pins. I used the 4mm non rotating pins first. I filed the end to a rectangular shape about half the area of the round end. I had less misfires. Then I used a 5/16\" x 1/8\" bearing instead of soldering a steel end. This made a much smoother action. I attached the bearing with Locktite and by peening over the shaft. I had to enlarge the groove in the cocking ring to match the size of the bearing. Less misfires again.
I have tried brass and UHMW plastic for the ends of the pins. I like the plastic but have not found a way to keep it attached it to the shaft. It keeps coming off. The bearings work best.
I am trying to find things that work so I can do a rebuild. I have not fired 10 shots in a row. I am using .22 shorts.
I am sure that most of the firing problems I am having are because of the bolt carrier. The holes may be over sized. They may not be in true alignment. They may not align exactly with the pan and barrel ring.
I have enlarged the hole in the bolt to a Q drill to allow for the spring. I have made the firing pin retainer and the spring retainer of UHMW plastic. I like the way the plastic feels but it is difficult to remove a small amount of material because it is made to resist abrasion. It cuts well but is very difficult to file.
I have hardened the end of the pins and the ejector portion of the bolt. I have tried using a bearing instead of the lug on the bolt. It works well but the holding peg keeps breaking because of the firing force. Other builders say they have done a lot of filing, fitting and polishing. I am assuming that they are doing the same things I am doing. I have done everything I can think of, I have one idea left to try and then I will decide if I am going to do a rebuild. I talked a little about the bolts. I have a lot of trouble getting the bolt to eject after getting it to fire.
You will need to make some kind of bullet trap in order to test fire while you are building.
It is possible to make this gun as other people have been successful. It might just be beyond my skill level?
-
When I encountered the firing problem the first thing I did was to rebuild the cams. Mr. Schneider had said that the cams needed to be machined following his instructions or there would be jambing. I made the cams out of brass and steel. They were not the problem.
I have no experience with larger calibers. The cams are held in place with screws. The rear cam takes the force of the shot. I would think there are only two ways to make them stronger, that would be to add more screws or to solder them in place?
-
My bullet trap is a double walled ice chest filled with clean sand. Does the job without leaking sand onto my shop floor.
-
Lots of good chat here. ;-) Hard plastic can be tricky to file, but it will generally sand with sand paper.
I\'ve pretty much finished playing with my CAD models. I\'ve had to lenghthen the SHAFT, FRONT SHAFT and BARRELs. I didn\'t model the height adjuster screw but may do so. Also, the odd nut and bolt are missing.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/gatlingguncomplete.jpg)
-
Pmercer,
Will you describe your lapping process for the bolts and the bolt carrier?
-
Lapping BOLTS into BOLT CARRIER.
Tools: marker pen, file, sandpaper, large tub of patience.
I machined my BOLT CARRIER so that was the most accurate part with nice straight \'bolt holes\'. My BOLTS were cast so they were never going to be 100% perfect. For this reason all lapping was done on the BOLT, not the BOLT CARRIER.
I filed the bolt surfaces as straight as possible and then clamped them in a vice. I then used a strip of sand paper which I looped round the bolt and pulled back and forth. This enabled me to get them nice and smooth, and by doing it this way I ensured that I didn\'t put any flat edges on them. I paid good attention to the bolt body around the recoil lug although I have done little work to the lug itself. I\'ll do that later to make it fit perfectly in with the BODY and CAMS.
I then put marker pen all over the BOLT and also all in the \'bolt holes\'. By doing this I could see where I was getting interference. At first the BOLT would only go into the BOLT CARRIER a short distance. I removed the bolt and put it back in the vise where I used a strip of sandpaper to work the area where contact was made. Perceverence meant that slowly the bolt went in further and further. Eventually the bolt was a lovely smooth fit with no resistance.
-
HI, Your way is probably the right way of lapping in the bolts. Another way is to put a little bit of rubbing compound or valve grinding compound in each hole and work the bolts in and out until smooth as a babies bottom. bruski
-
Hey Bruski, I finished them off with valve lapping compound. I forgot about that. It works very well that way.
-
Because it\'s cold outside in the garage/workshop, I decided to work on a components that I could do inside. I decided to do some work on the BASE PLATE. The BASE PLATE bolts onto the top of the TOP COVER to allow the BROADWELL DRUM to be fitted instead of using a stick magazine.
The BASE PLATE was one of the components that I decided to cast. In hind sight......
This is the underside of the BASE PLATE. In this photo you can see the sprue where it was cast (I\'ve already cut it off and placed it back in position for the photo). You can also see where holes should have been cast. Most of them are almost all the way through, but one of them you can only just locate.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/IMG_1301.jpg)
This is the top of the BASE PLATE. In this photo you can see the two slots that the KEY,SHORT and KEY,LONG slide into. Well, they should slide in. The slot that the round of ammunition drops through is very well formed, but the flashing disguises that.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/IMG_1302.jpg)
I\'ve cleaned up the BASE PLATE and KEY,LONG and they now fit together nicely. The surface looks awful, but is very flat and has been finished with 150 grit so far. I\'ve not cleaned up the hole that the round of ammunition drops through as once the BASE PLATE is bolted to the TOP COVER there may be a slight mismatch. I\'ll finish the hole off once both parts are bolted together.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/3c638e4a.jpg)
Here\'s the BASE PLATE and the KEY,LONG. You can see that the end of the KEY,LONG is rounded, whereas the end of the slot is square. I\'m not sure I like this so may modify one or the other. On the flip side, this joint wont be seen once the BROADWELL DRUM is in place.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/78e34bda.jpg)
Here you can see the cross section of the two parts.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/25cde63d.jpg)
How did I get the two parts to fit? The slot was nowhere near as well formed as I\'d hoped. I used a small needle file, a small dremmel with a modified cutter and lots of patience. In hind sight, I should have bit the bullet and machined this part from solid. I decided to cast it as I knew I wouldn\'t have access to a mill when I came to machine it. As it happens, I\'ve got a big pillar drill and a compond table so I could well have machined it at home. I\'m considering machining some of my other parts that I already have castings for, since machining a casting is a nightmare and very hard on cutters because of the ceramic on the surface.
I\'ll do a write up on using cast parts in a fresh thread and put a link to it here:
-
Barrels. What an ass ache. I bought my barrel blanks a long time ago. They were something like 500mm long and 25mm diameter. I skinned them down to something like 12mm OD and 420mm long and machined each end and left them. They can be seen on the first page of this thread. I did all 10 barrels in one 8 hour night shift at work. ;-)
It should be noted that I am fairly compentent on a lathe having used a harrison M300 for years. This is a new Chicom lathe and I\'ve hardly used it. Also most of my insert tools don\'t fit in this lathe which is annoying so I\'m having to grind tool steel up.
I\'m now at the stage where I need the barrels finished. Yesterday I went down to the garage with all 10 barrels and a whole day free. Once I start on the lathe I\'ll generally go non stop all day, so expected to have finished all 10 by the end of the day. That was 10 tapers to cut and 10 screwcut operations. Easy.
Like Hell. I decided to offset the tailstock to do the tapers which meant the fixed steady and the moving steady were out of the question, meaning lots of vibration and lots of swearing. In the end I found that I can do the whole barrel length in one cut if I had an rpm of 200, a slow feed and a 0.1mm cut. Each cut takes 24 minutes, Yep, you read it right, twenty four minutes. I\'ve never had to do such a ridiculous cut!! I managed to get the taper done on one barrel in 6 hours.
Today, I decided to use the fixed steady and cut the barrel to within 0.6mm of the final taper diameter. I took 0.2mm cuts at 500rpm and a nice high feed rate. I placed the steady all the way to the right allowing me to cut about 60mm of barrel. I then moved the steady 60mm left and turned down to within 0.6mm of final taper diameter. Once I\'d done the whole barrel like this, I then did 6 cuts at 0.1mm / 200rpm / slow feed. I finished my second barrel in about 3.5 hours which is a large improvement.
Normally I\'d be very annoyed at having to stand watching a lathe for 24 minutes, but I\'ve got so many other parts to make, I\'m just spending the 24 minutes working on other parts on the bench next to the lathe.
Has anyone else found that the barrels have been harder than they thought???
-
You experience mimics mine exactly, long, skinny and prone to chatter. Had to take light cuts, slow feed with very sharp radius tools. Ended up with a reasonable finish but require a lot of filing and sanding pre-polish. I remember about 16 or 18 minutes per cut.
I also noticed that the barrels varied in hardness. I made 12 barrels, 0-9 and x,y. I used takeoffs and have (1) Winchester, (3) Springfields, (1) Sears and (7) Ruger 10-22\'s. The Winchester, Springfileds and Sears were Gun Show refugees and the 10-22\'s were bought from the classified on Rimfire Central. I averaged $17.75 ea for the 12 barrels.
I have noticed a difference in the machining quality of the barrels, some cut smooth and easy and some not so much. Even the Ruger barrels varied a lot. My group at work has a Niton XRF Gun that can sample chemistry non-destructively. When we shot the barrels with the Death Ray Gun they all were alloy steel but some were leaded which would explain the ease of machining. The hardness also varied significantly.
nitewatchman
-
I did my 3rd barrel today. Wish I\'d done a 6 barreled gun now instead of a 10 barreled one. lol.
I\'ve done a write up on how I turned the barrels. It can be found here (http://www.gatlinggunforum.com/forum/viewtopic.php?f=5&t=156).
I bought my barrels from Numrich I think. They were all blanks and the same but it was easier for me to order them all in one go as I had them sent to a friend in NYC and then he shipped them over to the UK for me.
They machine fairly well, dont seen to case harden (thankfully) and they\'ve been sat for 4 years, untreated in the garage since I skinned them down and there\'s no sign of rust on them. I wanted stainless barrels, but couldn\'t find any at the time. These must be some sort of chrome vanadium ??? and although not as shiny as stainless, do have a nice dull shine to them.
A couple of posts up I said I\'d put in a link to a casting discussion but am unable to edit my posts. It can be found here. (http://www.gatlinggunforum.com/forum/viewtopic.php?f=5&t=155) I struggled to say what I meant but hope you get the idea. :-)
-
Nitewatchman, is the finish on all your barrels the same or have you treated them in some way? Thinking back, I toyed with the idea of sourcing barrels from all over but decided I wanted one source in case they finished differently.
I finished turning my 4th barrel today and started on the 5th. Still got all the threads to cut and also got to chamber them still. I won\'t chamber them till much later though.
-
The mechanical polish is very similar on all the barrels but I do have concerns about matching color if the barrels are blued. I have had this problem in the past on rifles I have built from military bolt action receivers. Some components particularly on the US 1903 and 1903A4 Springfields would come out tinted green or red if held in the light.
I guess I will just have to wait and see. If the color varies, one solution would be to iron plate the barrels in the same fashion that Winchester Arms used on their early Stainless Barrels. The barrels were polished, plated and then hot blued resulting in a deep black uniform color.
I have a 1956 stamped .243 Winchester Model 70 Bull Gun that was built in the Winchester Custom Shop around the time or just before the .243 was commerically released. This gun has a stainless barrel that is matt finished with a deep black color the matches the receiver quite nicely. This is by far the most accurate gun I have ever owned. It has fired 5 shot groups that measured under .18\" at 100 yards, (one small ragged hole). I used to shoot this gun regularly in reduced range High Power Matches until I got too old and fat to compete.
nitewatchman
-
Hi,
When bluing when it comes out green the temperatue is too low and when it comes out red it is too high. Some metals act at different temperatures. Especially heated metal.
-
Cold outside today so did some more work on the BASE PLATE. I managed to get the KEY,SHORT fitted to it. There seemed to be a lot more work on the short key compared to the long key.
I still need to drill a few holes in the BASE PLATE but there\'s no rush for that.
One thing that is dawning on me, is that there is no method of securing these keys in place. I suspect they\'ll come loose when firing. If they do, I\'ll have to fit a detent to them.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/f7c4ecf7.jpg)
Oh, I also did some more work on the 5th barrel. It\'s all turned down, but still needs some TLC with sandpaper. This one is about 0.2mm under diameter which has annoyed me slightly.
-
I\'ve not done much on the Gatling recently as I\'ve been tied up with work. I\'ve now got 2 weeks off so aim to get all barrels completely finished. I\'ve turned no6 down and made a good start on no7.
-
7th barrel finished being turned and going to continue with the 8th after lunch. The end is in sight!! I\'m looking forward to getting them screwcut so I can assemble them. :-)
As far as getting the same colour on different metals, I hadn\'t thought about getting them plated first. I don\'t think I\'ll need to do that, but it\'s certainly something worth remembering for future jobs. I intend to do a 7.62 Gatling at some stage and I suspect I\'ll end up with barrels from different suppliers on that.
-
8th done!
-
Phew. All 10 turned down and tapered now. I just need to polish the hexagonal sections on 2 of them and screwcut them all. I\'ll get some pics up soon. :-)
-
Ok, all 10 barrels done now. I\'ve screwed them all into the BREACH RING by hand. I need to make up a tool to tighten them up still. I need to crown the barrels still. I also need to chamber the barrels but won\'t do that till later in the build.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/2737f60d.jpg)
Here the barrel assembly is almost complete. After previously deciding to alter the position of the BARREL RING I need to make a new SHAFT and FRONT SHAFT to the correct length.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/1ef379da.jpg)
Here\'s the rear of the BREACH RING. I need to cut a groove in the rear for the extractor claws of the bolts to fit into.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/d70a089b-1.jpg)
Here\'s the muzzle end of the barrels. I intend to lap the bolts into the BARREL RING so that they are a snug fit. I\'ll do that over the next few days with any luck. There will be a 5mm gap between the BARREL RING and the hexagonal section.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/1aadd6b9.jpg)
-
I lapped the BARRELs into the BARREL RING today. Here\'s the finished result. I\'ve still not cleaned up the crown.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/c2dfd2cd.jpg)
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/50c82db7.jpg)
I think one of the next parts tp make is the body. I love machining brass, but there\'s a lot of screwcutting to be done on it.
-
The plans I have show two breech rings, one grooved, one plain. I grooved the barrels and used the grooved breech ring. Later I found that the groove would allow the extractor to bend and sometimes break when test fired. The groove also allowed the brass to expand into the space of the groove and not eject. I then made a second breech ring without the groove and replaced the grooved ring. I had a little trouble with alignment of the barrels but this solved the problem of the bending. It made for a much tighter fit and I liked the look of the plain ring.
The groove in the barrels left so small a piece on the barrel that it broke off when fired. I removed it and cleaned up the barrels.
I made my bolts to be able to be used in any position. On my rebuild I am going to follow your lead and fit them into only one position. I made bolts by silver soldering the lug and by turning the lug. I prefer turning in one piece.
I hope you do not have the misfiring problems I have had.
-
I made the front shaft round at first and used brass strips to tighten it. Since I had to remove it many times I put a flat on it. Then I made one out of hex ss and just used a socket to install and remove.
On a rebuild I am going to make the shaft one piece with threaded sleeves for tightening. The shaft will be a larger diameter but cannot be seen. It will have key ways.
-
Here\'s a picture(below) so all can see what we\'re talking about. This only shows the BARREL, BREECH RING and BOLT.
I also had a print with a grooved BREECH RING and a grooveless BREECH RING. I assumed the grooveless one was just an extra print in the same way that some other parts have half finished prints as well as completed prints.
I can see that a grooveless BREECH RING can be used, but the barrel still needs a cut out of it for the extractor part of the bolt to go into. If there isn\'t a cut out on the barrel at least, the extractor would stop the bolt going fully into battery.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/breechringgroved.jpg)
This picture(below) shows the bolt in battery and a round of ammunition in the chamber. As far as I can work out, the whole of the case is supported other than the part where the groove is which is very small (2.5mm long and about 1/3 of the circumference). Is this too much to be unsupported?
I dont see how I can support the extractor any more without a lot of work. One way would be to counterbore the barrel only on the side of the extractor and use the barrel to support the extractor. I dont think this would be viable though.
When you grooved the BREECH RING, did you also groove the BARREL, or was your barrel set further forwards so the cartridge wasn\'t supported all the way round at the rear?
I can also see the small slither of the barrel that you were saying breaks off. I\'ll make sure I remove that if I do it this way. (Thanks)
I\'m wondering if the barrel missalignment maybe weakened the extractors somehow on your first version? I\'m definitely going to pin the BREECH RING, PAN and BODY before I fit it in the BODY.
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/breechringgroovedwithbullet.jpg)
In this picture, I have added the pan and the rim stop. The rim stop limits how far forward the bolt goes (as well as the FRONT CAM)
(http://i847.photobucket.com/albums/ab36/pmercer1975/gatling%20gun/breechringgroovedwithbulletandpan.jpg)
I thought about turning the BOLTs in one go, but chickened out and had them cast. I didn\'t fancy making up the cutter for the extractor!!
I\'ve not silver soldered anything yet. It\'s one skill I\'ve not got although I might need it at some stage..... Its definitely the way forward if you want nice machined surfaces. My way entails lots of hand finishing. :-(
I think looking back, I\'d have made the main shaft out of hex bar and used a breaching tool to make the central hole on all my center holes. I may also turn a hex on the front bar in order to enable me to tighten it up. (thanks). ;-)
-
I did not think I would have to take the barrel assembly apart so I tightened the barrels into final position as the plans showed and cut the groove on the lathe. A trepanning tool would work well here but I am not going to use the groove on a rebuild.
After I removed the sliver on the barrel and reassembled the threads here were visible and touched the extractor. I put the grooveless ring in a dividing head and milled out this portion of the threads.
On a rebuild I will put the barrel assembly in the mill on a dividing head and mill out the portion for the extractor instead of using the groove method.
See my earlier posts about the extractor length and the cutter. I am about 50% complete on a Bonelle tool and cutter grinder, quorn owner\'s group, yahoo.
There is a very good article about silver solder in the book by Kozo Hiraoka, \"The Pennsylvania A3 Switcher\". If I follow these instructions everything works well, if not disaster.
I had a problem with the center line of the gears on the body. I used the soldered body and followed the instructions. I bored the drive shaft tube first and then soldered. After assembly I found that the gears bound. I corrected this by making a new cocking ring with the center hole offset by the amount of the error. I have since made several cocking rings and experimented with bearings.
-
I used the soldered body. I bored the drive shaft tube first and then soldered.
On a rebuild I would use a solid tube and then bore it out. This would assure the position of the center line of the gears.
On a rebuild I would make two oscillator brackets and use one temporary for the front of the body. I would mill them flat after soldering so as to have a datum for measurements and a flat to clamp into the the mill vise. Remove the front bracket after all milling and fitting.
On a rebuild I would consider making the body a larger diameter as I had trouble with the threads for the cascabel plate. I cut a little too deep and the thread showed through in the groove I milled for the body side rails. The instructions say to cut a flat for the rail and they also say to radius the rail on one side?
I am sure you cast the body.
-
I have experimented with ways to lessen the spring pressure on the crank handle and stop misfires.
By using the 4mm square firing pin I was able to make a rectangular pin and have the pin strike the rim in the same place each time. I turned the pin one piece. I used a solid end and a bearing.
In stead of using stronger springs I tried to lessen the friction. I used bearings on the end of the pins and cut the cocking ring to match the bearing. I used bearings on the shaft. I used a thrust bearing in the cocking ring. I tried to use UHMW plastic for the end of the pins but I could find no way to get it to stick. I made cocking rings out of UHMW plastic but they would not hold up to the thrust. I made laminated cocking rings out of brass and UHMW plastic with the same results.
Before I stopped on the ggun and started the Bonelle I made a cocking ring with a curved linear ball bearing. Works good but need to change dimensions.
I have tried to measure the force required to crank the handle so I can have some better reference than my hand but I have not found a scale with the amount of range needed.
The best combination was with a UHMW plastic cocking ring, thrust bearing and a bearing on the firing pin. This worked well until it destroyed itself. I tried to work within the given dimensions so that other parts did not need to be changed.
When I start a rebuild I am going to use all the experiments that worked and change the dimensions and materials if I can solve the cranking pressure problem.
-
[
Although ive not had any issues as far as turning the mechanism yet, I\'m beginning to worry that I will.
It\'ll take some inventive mounting for me to mount the barrel assembly in my dividing head and be able to mating out the relevant sections, although I think that is the best idea. At first I didn\'t see the problem with the extractor rubbing the threads on the breach ring. Another solution would be to extend the outer diameter of the groove to take off the entire edge of the barrel and threaded hole.
I have got a cast body, but will still have to mill out the holes for the shaft. I\'ve also got a large lump of brass to machine a body if need be.
I really don\'t want to have to make another cocking ring although cleaning up the casting is a lot of work so I guess it may be easier long term if need be.
I redesigned my cascabel plate so that it used the same threads as the cocking ring. I thought it made sense.
Unfortunately, I didn\'t allow enough machining on the cast parts and I\'m having to juggle dimensions for the thread in the body. I may have to remake the cascabel plate.
I like the idea of utilizing bearings and will try and do that still. I think all the places youve suggested i\'ll try straight away. Do you have links to the bearings you used? I\'m learning a lot and will utilize a completely different design on my next Gatling!
Once ive worked out what size I\'m making my body thread, I\'m going to start machining that. I guess that\'s when I\'ll realise what problems I\'ve got. I can see a lot of lapping of parts In the future.
-
pmecer,
A better way to bore the extractor holes would to be use the lathe. While making the Bonelle I had to bore two paralel holes. My lathe has a flat cross slide. I made a t-nut table to bolt onto to the cross slide. I will make a longer t-nut table and mount the barrel assembly and the dividing head on it. The barrel ring will be held by a steady rest.
I will not use the grooved ring as I am sure it was only for grooving the barrels. This way the barrels will not have to be removed once bored.
The body should have some sort of flat to use as a datum for mounting and measuring. I made mine out of centerless brass. I made the dimension to the gears wrong so I had to make the hole in the cocking ring off center.
The cocking rings are easy to mill. I could not find the cutter called for so I used the closest one I could find. After changing the firing pins I made several more of different sizes.
I got the bearings from vxb.com and mscdirect.com. As I used several different sizes as I changed things the part numbers would not be of use. I am going to use a needle bearing for the front shaft. This will require the rail front to be larger. I did not have the CD plans when I first made this so I made my jig out of wood. I will use a three piece thrust bearing for the main shaft. One race will be recessed into the cocking ring. The bearings and the other race will be in the bolt carrier.
I will use a sealed bearing for the main shaft to turn that will be set into the other end of the cocking ring. I am going to use bearings in the drive shaft, will have to make the tube larger. Other sites I find useful are grizzly.com, shars.com, surpluscenter.com, littlemachineshop.com.
I tried bearings on the bolts. This made the action smoother but there was not enough material on the bolts. They would break after a few firings. I would like to use these bearings but it will require that the whole firing parts be redesigned.
I put bearings on the end of the firing pins. I turned the pins out of 4mm stock, pressed on the bearing with locktite and then peened over the top. They have not come off. I used the 4mm square stock so I could make non rotating pins and shape the firing end to a rectangle. This helped a lot with the misfires. ( I needed a 4mm square hole for another project so I used my broach. It cut well in the brass firing pin retainer but I broke it in two with the steel part.)
I made the linear bearing using balls from MSC and a 1/16th ball mill. This works but needs to be refined.
I like you drawings, what program do you use. I need to learn how to use 3D.
I am sure someone has made this ggun but in the posts I have read no one has said their gun will rapid fire a full 50 round magazine without a misfire.
-
Steve,
I\'ve read your posts many times and will certainly be using a lot of your ideas and suggestions. I\'ve not managed to do any work on my Gat in months but do think about it a lot. ;-)
I use Magics which is a CAD tool mainly for repairing files rather than designing parts. I\'ve got a full version from a previous employer but there are disks available from the manufacture that have a sample version on them - all the functions you will need will be available. ;-)
I need to spend some serious time sitting in front of my software making sure I\'ve incorporated all the modifications that I need to.
I\'ve also just invested in some new tooling - a quick change tool post and a live Center in preparation for the next stage.
Hopefully I\'ll get to do some work on it soon.
-
Hey, Pmercer.
I have been waiting for you to post again. Hope you are well.
I have not worked on the ggun since I started on the Bonelle tool and cutter grinder. I am about 80% complete.
I have used my converted mill for sharping many times. The grinding wheel is horizontal and I can see the grinding action. This is good because it requires less adjustments. The wheel on the Bonelle is vertical and I cannot see all of the action. I feel this may be a major problem when I am finished.
Have had many other things to do. I am repairing a house so I can rent it. Made a few other tools for use with the ggun rebuild. I have been thinking about using chrome plating on the firing pin parts.
Have not decided to start on the rebuild yet.
One problem with the main shaft parts was that they needed to be pinned or keyed to keep the parts from moving. I found a Rhodes shaper, slotter so I bought it to use for the interior slots or key ways. I have an Atlas 7\" shaper but the slotter is vertical and is easier for some slots. I have used it several times for small interior key ways, nice machine. I am going to use key ways on a rebuild.
One thing I did not mention before when I talked about making the main shaft was it\'s length. The slack in it\'s length will affect the fitting of the bolt length and add to the misfiring problems. More on this later.
I found that Google Sketchup 8 was a free 3D modeling program. I downloaded it an have made several drawings of the machines I was building. It is easy to learn and to understand. It seems to be a complete program and a professional
version is available for sale.
Check out this site, metallmodellbau.de. This guy does beautiful work.
-
What ever happened to Pmercer and his gun? It was 3 years now since the last post and the gun was nearing completion. Quite a few builders seem to fall off the earth after getting a large percentage completed.
-
I\'m still here. I moved in with the GF and didn\'t have access to my shop for a long while. I\'ve now built a shed/workshop in the back garden and have all my tools there. I will get some more of this GG done soon I promise!
-
I\'m still here. I moved in with the GF and didn\'t have access to my shop for a long while. I\'ve now built a shed/workshop in the back garden and have all my tools there. I will get some more of this GG done soon I promise!
Glad you are still around and have not given up on the gat gun. I also moved, out of state, and am just now getting my new shop operational. I can relate to what you are going through.
George
-
Just thought I’d check in on this site. I’ve still not managed to get any further on in the build, but it is still on my to do list. Would love to come on here one day with a finished GG
-
Just thought I’d check in on this site. I’ve still not managed to get any further on in the build, but it is still on my to do list. Would love to come on here one day with a finished GG
“If the starter fails, you need a push.
Then it feels so good when running.â€
Cutter 2019
-
I got all the finished parts of the GG out today to refresh my memory about where I was with it. I can’t wait to start work on her again!
-
I got all the finished parts of the GG out today to refresh my memory about where I was with it. I can’t wait to start work on her again!
WOW Great to have you back again !!
-
I got all the finished parts of the GG out today to refresh my memory about where I was with it. I can’t wait to start work on her again!
Glad to hear your running again.
If you need any help, I’ll be happy to
donate a few hours.
-
Glad to hear your running again.
If you need any help, I’ll be happy to
donate a few hours.
Great ! He needs his house painted.
-
Great ! He needs his house painted.
I think he’s in England somewhere, so
if I get a first class ticket, I’ll paint