Rifling?

[cannon man]

I have been wondering how to cut rifling in my barrels can anyone shed some light on this for me?

[Double D]

Suggest you go to www.abebooks.com and look for Howe books on gunsmithing.  He tells how to make a rifling machine in the book.

It involves making deep hole scrapers and tooling that rotate as the cutters as the go in and out while increasing there depth of cut every pass.  It's actully fairly straight forward equipment.  I have seen both commercial machines and custom built machines. 

P.O. Ackley built all his own machines from hot roll steel and store bought gears.

[GGaskill]

Check out this thread on the Practical Machinist gunsmithing forum.  Not so much plans as ideas and pictures.  The cutters and cutter box are special work but if you get to the point of needing them, you'll have learned enough to make them.

DD,
  You mention Howe; here is a site with Howe and a number of other old time books online:  Archival gun/gunsmithing books

You might want to add it to the References section.

[cannon man]

thanks guys

[CU_Cannon]

I have thought of trying to build a rifling machine such as this for cannons.  From the looks of the pictures it would not be all that difficult to build.  Are there any differences between the operation of rifling machines for small arms and those used in cannons?  Also how did they finish the rifling at the breach of the barrel?  It would seem to be a difficult spot since the rifling tool can not pass all the way though the barrel.

[Michael Az]

  Also how did they finish the rifling at the breach of the barrel?  It would seem to be a difficult spot since the rifling tool can not pass all the way though the barrel.

Just thinking out loud, but I wonder if a relief would be turned at the breach end for the rifling to end? In other words a radiused groove would be cut and the rifling cutter would end its cut in the grove. After cutting the rifling, the bore could be lapped with a brass or copper plug to remove any burrs.
Michael

[Double D]

Are there any differences between the operation of rifling machines for small arms and those used in cannons?

 

Yes, think big, bigger, biggest!!

Also how did they finish the rifling at the breach of the barrel?  It would seem to be a difficult spot since the rifling tool can not pass all the way though the barrel.

 Don't need to finish it, thats the chamber, the projectile doesn't go down the far.

[GGaskill]

In other words a radiused groove would be cut and the rifling cutter would end its cut in the groove.

The cutter cuts on the pull stroke so the cut ends when the cutter exits the muzzle.  When you do a blind barrel like a muzzle loading cannon, the cutter needs to be spring loaded so you can push it down the bore to begin each cut, so you really don't need any special construction in the chamber area.  Some part of the shot will have to expand to take the rifling in any case since it needs to be sub-bore-size to be muzzle loaded.

Are there any differences between the operation of rifling machines for small arms and those used in cannons?

I would think the major differences between rifling a small bore (less than 1/2 inch) and a cannon barrel would be at least two:  the grooves would be a lot deeper (.010" minimum vs. .004" or less) which would mean many more strokes of the rifling head, and the grooves would be wider which would mean the head would be harder to pull since you are cutting more metal.

[GGaskill]

There is also some discussion and a few pictures of the rifling process on R. C. Hubbard's Recreating the Ellsworth Gun web page.

[guardsgunner]

CU,
   Making a rifling machine is fairly simple with the basic parts being a pair of breaings, a rack and pinion gear (McMaster-carr del.'s next day) and a piece of shafting. Mine is much like the one GG linked to.Making the machine was the easy part. The more guarded secret is the how to, do's and dont's.
   GG is right about the tool pressure on the larger radiused grooves like that of the 3 groove Parrott rifles. This would be difficult (depending on size, .5 ok 3.0 no way ) to do without some heavy duty eqp at home..There were many styles of rifling used in the Civil War.; everything from 1/8 wide poly grooves to the 15 x15 that I built would be easy to cut. Choose wisely.
   The spring loaded hook style cutter body takes a little time but are not hard to make. I have not tried to do a blind hole of a muzzle loader yet because My interest has been more to the obscure civil war breech-loaders. I am not so sure but I think that I would make a liner and insert it. Sooner or later I will get there and find out.
   IF you  have  thought about rifling something for very long give it a try. If you look in the right places you should be able to make a machine for around a $100. (manual).

RCHJr.