Why bore the barrel completely?

[Drew M.]

Although there are many discussions regarding the best method to install a breech plug into a cannon barrel, none seem to mention leaving a portion of the breech-end metal untouched by drilling or boring.  Would it not be best to bore the barrel without exiting the breech area while trying to add a convex surface to the rear inner bore to prevent stress?  This would seem to reduce the chance of the breech end failing versus a welded/plugged version.  I am sure there is a reason why this has not been explored but I was not able to find it.  It seems a simple and safe manner to bore the cannon barrel.

BTW: I recently got an Ames Manufacturing Co. lathe - with the spindle center 6" above the bed and 54" between the spindle and tailstock.  It is from ~1900 and weights at least 1200lbs.  If any of you can share some info on this lathe, I would appreciate it.  The very robust design is not like the jeweler Ames Lathes I saw on the excellent UK lathe website.  It looks more like an oversized Star/Seneca Falls lathe.   

[Rickk]

breech plugs are installed when using heavy walled steel tubing as a basis for the barrel or barrel liner.

If drilling the bore yourself, you would do as you mentioned, stop drilling and leave the breech as part of the barrel.

[CU_Cannon]

You are fully correct about the strength of cannons from solid stock vs. tubing.  The biggest reason many people go with canons from tubing is the fact that it is much easer (notice I said tubing not pipe there is a difference).  Deep hole drilling and boring can be quite difficult and time consuming.  In general large scale cannons are built from tubing and smaller scale cannons from solid. 

The lathe you have sounds like it is ideal for cannon work.  If you are going to drill your bore from solid remember that you will need a lathe twice the length of the barrel you plan on making.  This is due to the length of the barrel and the drill.

Welcome, you have come to the right place.  There is lots of info here.  Don’t hesitate to ask questions. 

[Cat Whisperer]

Drew -  WELCOME to the board!

What flavor of cannon ball chucker are you favoring?  Range, bore diameter, use (competition or urban redevelopment)?

[m223]

Congratulations on your purchase Drew. I have not used that particular lathe before but I'm sure it will suite your needs. Both Rickk , C.U. and yourself are correct. It is best to avoid the breach plug if possible. I pretty much just finished up my first small cannon. I too have access to a large lathe but I am limited to how deep I can bore the barrel. I do not have the money to by really long drill bits, and boring bars have their limitations. I do not know how much experience you have running a lathe , but in my humble opinion I have found the morse taper bits to run more true than straight shank style. Be sure to check the run out on your stock first, face it off, and center drill first before drilling. Even after all of this you will most likely find your hole will be a little over sized. That is why most people drill undersized and then finish up with a reamer or boring bar. Be advised most boring bars only go so deep before chatter sets in. So you may need to make an extension for your reamer , or buy a long one to match your long drill bit. So in my case if I want to supersize my artillery I will be looking at a breech plug. Welcome to the forum and happy machining.  Tracy

[dominick]

B

TW: I recently got an Ames Manufacturing Co. lathe - with the spindle center 6" above the bed and 54" between the spindle and tailstock.  It is from ~1900 and weights at least 1200lbs.  If any of you can share some info on this lathe, I would appreciate it.  The very robust design is not like the jewerler Ames Lathes I shown on the excellant UK lathe website and looks more like an oversized Star/Seneca Falls lathe.   

  Hi Drew, Welcome to the forum.  You may want to try Lindsay Publications  www.lindsaybks.com/   They have re-printed several old turn of the century books and technical manuals on lathes and early machine eqiupment. Good luck with your projects.  Dom

[Drew M.]

Drew -  WELCOME to the board!

What flavor of cannon ball chucker are you favoring?  Range, bore diameter, use (competition or urban redevelopment)?

I am planning a USA 37mm WWII anti-tank gun replica for parades, Memorial Day services, and New Year's(I live in a shrinking rural area).  I have a BATF approval letter for my design to mount a BP cannon on a WWII 37mm anti-tank gun chassis (antique design looking like a WWII vintage artillery piece).  They instructed that the piece (smoothbore) not use fixed ammo, and use an antique ignition source to not be classified as a destructive device.  See www.g503.com's artillery section for these guns and the reproductions.  I would prefer to make the M1 (57mm)/6pdr anti-tank gun as it is more appropriate for my Dodge M37 3/4 army truck, but I opted fr the smaller 37MM being there will be a learning curve and the 57mm is more complicated to build.  BTW: I started out making the small BP kits such as CVA pistols and rifles, then US service rifles (M1/M14(M1A1), then a Browning M1919 (semi) & M2 tripod.

I was also considering a punt gun design.  The punt gun is basically a over-sized shotgun ~6' in barrel length (0-4 gauge/1.5-4"i.d.) used previously in the US for bird hunting and still used in the UK.  Being it shoots shot and not a shell/bullet - the pressures are reduced as is the barrel thickness.  Also, the punt gun barrel taper nicely matches the 37mm profile. 

Lathe length - maybe does not need to be 2x the barrel length.  Why not attach the drill bit to round stock sections (maybe using pucks (nylon) centered on the drill bit shaft to reduce flexing for long lengths while inside the bore)?  That way you drill in a set distance then add the drill drive-shaft extension section.  For max boring length - you would need lots of short extension sections to add to keep the distance between centers as much as possible - yes a pain but doable.  Then again, it may be better to farm out the boring to a well equipped shop depending on their competence and the $$.

Thank you for the encouragement.  I'll post the project's progress over the Winter.

[Drew M.]

My new old lathe - remember it is 6' long overall and the ways are 12" apart.  This is not a little lathe!

[Double D]

I am planning a USA 37mm WWII anti-tank gun replica for parades, Memorial Day services, and New Year's(I live in a shrinking rural area).  I have a BATF approval letter for my design to mount a BB cannon on a WWII 37mm anti-tank gun chassis (antique design looking like a WWII vintage artillery piece).  They instructed that the piece not be rifled, not use fixed ammo, and use an antique ignition source to not be classified as a destructive device.

We have always taken a stand that discussion o fthese types of guns were out side the scope of the board.  We have also stated that should anyone provide a copy of the letter from  ATF authorizing the construction of the gun we would allow discussion of that piece.  So be for there is anymore discussion on this gun please send me a copy of you ATF letter. You can scan it in and send it as an attachment to an email. Hurry becasue we are all interested in this project.

Now don't be put off by that.  We have done it before.  Powderkeg's 10 guage signal gun is one example. Wes got the letter and sent it to us.  We then watch Wes build the gun.  Not only did we learn how to build a signal cannon we learned the proper way to approach ATF for approval.
 

Punt guns have also been allowed on this board for sometime as there is not any other place for them on Graybeard's.

BB is bowling ball on this board, B-B would be littl;e steel pelets

[m223]

Hey Drew , that is a neat looking lathe. It sounds like you have a good grasp of machining a deep bore. If you have the desire and material by all means make it happen. Please get D.D. a copy of that A.T.F. approval letter. I and many others would like to follow your progress on this.  Thanks     Tracy

[Drew M.]

DD,

I appreciate the forum and your policing of it to keep it working no nonsense place to share information.  I am building a BP gun (BTW - I mistakenly kept typing "BB" instead of "BP" - for black powder in a few posts - sorry for the typos).  IMHO the carriage/chassis design it is mounted upon should not matter for its inclusion upon the forum - however you are the boss and I will strike all references to it if you wish. 

Likewise, the pre-1898 cannon barrel design sharing a profile of a more modern designed gun did not change its definition from an antique design for BAFT. (I included photos of punt guns and the 37mm AT with my clarification (approval) letter and told them I planned to use the gun at local events and the annual PA Fort Indiantown Gap "Battle of the Bulge" reenactments (Januarys).) 

I understand your concern that my design would be a DD in BATF's view and my information could lead others into legal problems and commend you for it.  I hope that after reading the BATF letter these concerns will be alleviated.  If not, I won't hold it against you to delete my previous posts and asking me not to mention it further.  I would prefer to be a forum member in good standing. 

Sincerely,
Drew M.

 
 

[Cat Whisperer]

Drew - 

WELCOME to the board!

We're off an running on the right track.  Looking forward to providing all the information and encouragement (we get fun out of watching the projects too) within the limits of this board.  There are several members that play with Class 3 stuff, which is OK if posted on the other GBO forum. 

Your approach to BATF is right on the mark - write the letters asking first.

On another forum, the moderators humored my questions about ballistic coefficients (because they were professionals in that business) of CAST bullets but addressed the questions even though the forum was on SWAGED bullets.  There are some common topics.

Your machine has the basics!

I've considered boring a tube 2/3 the length of the lathe bed - by building a holder for the boring bar that will hold it near, then in the middle, and then on it's other end as the boring goes deeper.  Let me look for the pictures.

[Double D]

Drew,

I got you letter and forwarded a copy to CW.  Here is what ATF said you requested a determionation on.

This refers to your letter to the Firearms Technology Branch (FTB), Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), in which you ask about the legality of mounting a replica, 1850-70’s era percussion-cap-ignition, black powder muzzle loading shotgun (punt gun) on a “replica 1941 USA M3 37mm anti-tank chassis...” Your letter was forwarded to FTB’s new location, Martinsburg, West Virginia, for reply.

You describe the shotgun as having a stee’ barrel approximately 3-1/2 inches in outside diameter at the breech plug and a taper-down to approximately 2-1/4 inches at the muzzle, with an inside diameter of approximately 1-1/2 inches. Further, you state that the weapon is smoothbore and incapable of firing fixed ammunition.

ATF's Repsonse was:

It appears that the described muzzle loading weapon uses an antique form of ignition system and meets the definition of an antique firearm. Based on the cited statues, as well as the intended construction and use of the weapon, FTB has determined it would be precluded from classification as a “firearm” or “destructive device.” However, if it were capable of using fixed ammunition, this determination would be subject to review.

ATF says it okay to discuss the shotgun punt gun. We say it's okay to discuss the punt gun.  We don't care what you mount it as long you make the gun the focus of the topic and keep the talk of the vehicle to a minumum.

Now you say you are making  BB gun.  Define BB?

[Cat Whisperer]

Ahhh the game is a-foot!

What are you planning on using for projectiles?

More importantly, you'll have some respectable velocity, hence range, with this - WHERE do you have to shoot it?  I'm in Virginia where 50 yard shots at deer are the rule.

[Drew M.]

Where to shoot? Yes, that is becoming a problem.  When I and another buddy built our last guns we used my wife's uncle farmette's apple orchard as a slight downhill slope with a wooded hill on the other side - maybe 200yds to the hill base.  No much of a decent shooting area.  There are lots of Civil War reenactors in the area (Gettysburg is not far - I need to get suggestions from them).    The Gap reenactment should be fine.

[Drew M.]

Well, I got a 40" long 3" o.d. unknown steel round stock (files easily so not hardened) to play with for gun drilling.  Here's what I've learned so far from talking to local machinists on the idea of drilling the steel: steel flakes off the drill bit will bunch up and will need frequent cleaning out, the drill needs to be kept cool to avoid wearing out the tip quickly, drill at a slow rpm, and they feel the project is not possible without high tech $$ machinery.  They all suggested DOM tubing instead to save $ vs machining and labor costs on the solid steel stock.

On the plus side (and back burner), I got my M3 37mm trail arms sections formed (2x4" on one end and 4x2" on the other with a taper over the 8' length).  The trail arm halves need to be butt welded together after the internal gussets are added.

[GGaskill]

Why not attach the drill bit to round stock sections (maybe using pucks (nylon) centered on the drill bit shaft to reduce flexing for long lengths while inside the bore)?

Referring back to an earlier post, the problem with simply adding sections of bar to an extension is that the drill must be removed from the hole to remove chips.  This step cannot be omitted if you use a twist drill as eventually the drill will bind in the hole and be impossible (or extremely difficult, at least) to remove.   See page seven of the cannon making class report about one way to make a drill extension.

The best way to drill this type of deep, blind hole is with a gun drill or a spade drill, each of which uses a high pressure oil feed to force the chips out of the hole along the shaft of the drill (which is smaller than the drill head itself.)  (A spade drill can have different cutting heads so that the hole can be mostly drilled with the least expensive style and the bottom of the hole profiled with a special shape such as rounded corners.)  Besides requiring the high pressure coolant pump, etc., this is a messy process.  If there is any kind of a machining base in your area, try to find a shop with a gun drilling machine and have them do the work.

By the way, what dimensions are you trying to achieve?