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Armor/AFV
For discussions on tanks, artillery, jeeps, etc.
M18 57mm Recoilless
NeilUnreal
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Joined: January 31, 2002
KitMaker: 80 posts
Armorama: 0 posts
Posted: Sunday, March 03, 2002 - 07:38 AM UTC
Hi-

My Dad collects model cannons. I scratchbuilt him a model ship's cannon in brass last year for his birthday. This year, for something different, I'm going to scratchbuild him a model of an M18 57mm Recoilless in brass at 120mm scale. Does anyone know of any good references either online or in print?

-Neil

p.s. This seemed like the best forum for this, since there isn't one titled "Small Arms and Artillery."
Kencelot
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Florida, United States
Joined: December 27, 2001
KitMaker: 4,268 posts
Armorama: 2,804 posts
Posted: Sunday, March 03, 2002 - 09:45 AM UTC
What an elusive one there. I was able to find mostly literature on that Neil. Here are a couple of sites of it. Not the best but...I did find one of interest...that is if you are looking to buy one. LOL Maybe if you contact the guy spoken of in the second link here, he may get you a picture of it. Who knows. The last site here may have the schematics of it. The list was so long that it might take a little bit of time to locate it. They do charge a bit though...only a couple of bucks.

http://www.rt66.com/~korteng/SmallArms/57m18.htm

http://www.mil-veh.org/archives/97-02/0281.html

http://www.e-gunparts.com/webcontents/military.htm

Good luck. :-)
210cav
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Virginia, United States
Joined: February 05, 2002
KitMaker: 6,133 posts
Armorama: 4,557 posts
Posted: Sunday, March 03, 2002 - 08:48 PM UTC
Neil--there is a future for people who can create brass barrels. Just what kind do you do?
DJ
NeilUnreal
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Joined: January 31, 2002
KitMaker: 80 posts
Armorama: 0 posts
Posted: Monday, March 04, 2002 - 06:26 AM UTC
Thanks for the resources. I'm finding information rather scarce.

I picked the M18 because it is complex and unusual enough to make a nice looking model, but simple enough to be do-able between now and the birthday. Also, my dad was in an armored cav. regiment when I was younger and I remember him talking about recoilless rifles. (He transferred to Signal Corps, so maybe my next model will be a field telephone!) The model will be mostly brass, with some parts -- like the tripod legs -- in steel, for strength and variety. I picked 120mm scale for the simple reason that it best fits the metal stock I have on hand!

I've never really turned any model armor gun barrels at 1/35 or 1/72. I've done some pretty precise tapers (e.g. Morse taper, sail-era ship's cannon) at shorter lengths. The main issues in turning longer tapers would be part deflection at the end away from the lathe head, and center drilling of the bore.

Handling deflection is mainly a matter of experience and creative setup. I'm not an expert, but I've had a bit of luck "sneaking up" on tapers -- i.e. start with no taper, then gradually work a taper into the entire length of the part. If I were going to turn a lot of tapers, I'd want to try to rig up either a follower or steady rest that could be angled along with the lathe head.

The long, thin bore (especially in a "grabby" material like brass) is tougher -- I'll do some research. Obviously I need to solve this problem for the M18. A key element will be determining what diameter of drill bit is required for scale, since a complete index set of boring length bits would be overkill!

Just out of curiosity, I've noticed that after-market barrels are a hot item. Why are kit manufacturers so bad at supplying good barrels? Is it just carelessness, or is it the limitations of styrene?

-Neil

p.s. I don’t build many car models, but last year I made a working 1/24-scale u-joint just for fun. I think 1/35 engine parts would be feasible. I've got also got an ongoing 1/144-scale Soyuz 19, for which I turned the crew capsules by hand using gravers. I just finished winding tiny bits of magnet wire onto the service model to simulate the radiator. Actually, I did it twice -- I got the pattern wrong the first time, arrrgghh!
210cav
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Virginia, United States
Joined: February 05, 2002
KitMaker: 6,133 posts
Armorama: 4,557 posts
Posted: Monday, March 04, 2002 - 07:41 PM UTC
My personal preference is to place an after market gun tube on the vehicle. Kit supplied tubes are usually two piece affairs which often have a decided seam running down them after glueing. I tried any number of ways to eliminate the seam without success.
DJ