Tapping Barrel For Breech Plug

[Zoar]

I have looked high and low and bought several books with titles that clearly indicate they are "gun building - muzzleloaders" and the part about the breech plug says---Unscrew breech plug etc etc and then how to RE-insatll it!!!

I want advice on procedures to TAP a barrel, make a breech plug, etc, not how to disassemble a muzzleloader and RE-assemble! Why are so many gun "building" books misnamed?!? These should be named GUN repair and assembly of kits or existing guns, and not gun building!

Can anyone steer me toward TRUE MUZZLELOADER BUILDING! books and I especially need advice on the breech plug and tapping a barrel. I have TWO 50 caliber barrels that I bought as MUZZLELOADERS. They are both rifled but are NOT tapped for a breech plug. And I need a source for a breech plugs for 50 cal barrels. Thanks!

 

[rich pierce]

This is machinist work, to be done on a lathe, by someone who knows how to do it.
1) Square up the end
2) bore to correct diameter for small dimension of the threads, to correct depth
3) Cut the threads on the lathe

If you want to make a breechplug, you have several choices- 2 piece or 1. If 1 piece, saw out the correct size piece of steel, chuck it in the 4-jaw chuck of your lathe, turn the plug part round to the exterior thread diameter, cut the threads to the correct depth and pitch on the lathe.

There are old-timey ways of doing both without sophisticated machinery but they still require specialized tools and skill and experience.

Breechplugs can be bought at any muzzleloading supply place for builders- the big real ML shops and the online places- Track, many others.

I don't mean to upset you more than you are already but it seems you plunked your money down on those barrels before you had a clear plan or any books that satisfy you, and it sounds like you're new to the game. That's a big chaw for a beginner. Might sell those barrels and start with a more manageable project. Or not- but remember, it's supposed to be a hobby and fun.

 

[paulvallandigham]

Track of the wolf, among others will charge you a reasonable fee to thread and fit a breechplug to your barrel. You might contact them to hire them to do this work for you. Unless you are a skilled machinist, I do not suggest trying to do this yourself. :thumbsup:

 

[Zoar]

Rich---Sage advice. I hear you and while I have done some machining myself and own a company with a small machine shop (doing unrelated work to gun building) I know the breech plug work requires more than just a conceptual understanding. I guess I wanted a book to give me good advice on this vital aspect of the work. I know how to drill and tap etc.

I didn't pay much for the 2 barrels (like $15) and I have put gun KITS together before. I wanted to investigate the next step----more of a true build.

I can buy a barrel with a breech installed and maybe I should just do that until I can peer over someone's shoulder and work with someone who is tapping a barrel for a breech plug. Or maybe send these barrels out to someone who will tap them and install the breech plugs.

Thank you for your wisdom and perspective. It is appreciated.

 

[Zoar]

However, the big question remains: does anyone have a recommendation for a good book(s) for actually BUILDING (and not disassembling/assembling) Muzzle Loader Pistols and Rifles?
Thanks!

 

[bioprof]

There is a small paperback booklet that was written in the late 1950's or early 1960's on how to build your own flintlock by McCrory (I think that's how it's spelled). It was written before there were good sources for parts like we have today, so it explains how to make your own breech plug and how to breech a barrel by hand. However, it is very basic and doesn't go into a lot of the technical details. I've seen copies for sale on the online auction by the bay that bans the listing of some gun parts.

 

[hotsparks]

I agree with bioprof, the McCrory booklet (The Modern Kentucky Rifle) describes ML making as it was in the 50s/60s and was my "bible" for quite a while. TOW still carries it for under $10. I've hand tapped some two-dozen barrels, one this afternoon, and never needed a lathe. One tip I have learned that makes it go so much better. Modify your drill press, i.e., usually meaning enlareing the hole in the table and baseplate, and possibly the benchtop unless you have a full size press. Carefully align and clamp the barrel on the exact centerline of the press chuck, and plumb. Fix the modified tap in the chuck and hand turn the tap...NEVER, EVER, EVER TURN THE PRESS ON!!! For safety sake, unplug it before you even put the barrel in place (don't ask). This arrangement starts the tap, and threads, plumb and on centerline. Also use a good cutting fluid and remove the tap often to remove the shavings...cuts friction and makes for much smoother threads.
John

 

[mckutzy]

what kind of a modified tap are u referring to, if i may ask? With a standard drill there will be a space even if a bottoming tap is used, if a flatbottom hole drill(a standard drill with the tip ground off to make a flat tip) was used that would eliminate the space. am i correct. :hmm:

 

[Zonie]

Just my opinion but I think the bottom of the breech hole should be "flat", not the cone left by a standard drill bit.

A flat bottom allows the breech plug to be installed right against the end of the bore while a coned hole will either need a coned breech plug to match it or it will have a gap between it and the bore.

This gap will not seal the breech, allowing hot gasses to pass back thru the threads.

This is one of the reasons that the best way to breech a barrel requires the use of a lathe that can cut the 90 degree shoulder needed.

As for modifying the tap, I'm guessing that it has been ground back to create a bottoming tap so it can tap full threads right up to the 90 degree shoulder.

 

[paulvallandigham]

If you drill the barrel with the standard angled drill bit, you can often clean it up and square the shoulder using a milling machine's end mill reamer in your drill press. Otherwise, use a lathe so you can square that shoulder.

Because bottoming taps are so expensive, most machinists simply buy a cheaper, standard, tapered tap, and grind it down to make a bottoming tap from it. Most of the metal you have to remove is already removed with the tapered tap, and the bottoming tap will simple expand the cuts on the bottom threads right against the shoulder. Use lots of Tap Oil, and take 1/4 turns, and back the tap out to clear the chips.

Take your time, and go slowly at this last part of the tapping process. The teeth on the tap will do the cutting; you don't need to force them. The last thing you want is to ruin( Tear) the threads on those forward most threads that go right up against the lands and grooves. :thumbsup:

 

[Vaino]

I've drilled and tapped 2 bbls...one straight and one swamped but no longer would even consider doing it, seeing I buy breeched bbls. First off, a sturdy drill press is req'd w/ a large enough hole in the center of the table and a table height sufficient for whatever length of bbl is being worked on. I clamped the bbl into a large V-block w/ the bbl hanging down thru the table hole {the swamped bbl had to be shimmed so it was vertical} and using the existing bore as a pilot hole, the drilling started. Once the drill found center, the V-block was clamped to the table. Drilled to depth, cleaned up the bottom of the hole w/ a flat bottom drill. Ctsk the hole, chucked a regular tap, turned on the drill press to full speed, immediately shut it off and while coasting, brought the tap into the hole. Removed from the drill press and continued tapping in the bench vise and finally used a bottom tap against the shoulder. Everything worked out fine. One word of caution...using a milling cutter in a drill press can ruin a lot of work and I wouldn't do it. If I did a lot of breech threads, I'd use a counterbore w/ a bore sized pilot in a lathe, ctsk and then run the tap in. Sorry for the long winded post...Fred

 

[Zoar]

Wow guys. Thanks!

First I have one of McCrory's Books--"Lock, Stock & Barrel" and find it very useful. I will get his other book mentioned above.

Also, the advice about the modified or squared off tap is EXACTLY the kind of advice I was needing! Thanks. I will get one.

I was tapping a part with one of my employees earlier this morning that was 1/2 inch (diameter) 13 threads per inch. We used our vertical milling machine, unplugged, but used it to make everything perfectly centered and rotated the tap by manually turning the belt! He used many of the techniques you guys described, but NOT all---clearly there are a few key matters very specific to tapping a breech plug and you guys have been very helpful to bring those to light.

 

[Zoar]

I've ordered the Building a Kentucky Rifle by McCrory. I've also ordered a breech plug 5/8 18 thread for the 50 caliber rifled barrel. And of course whenever I visit TOW I always need some other things so the bill is always more than I expected.... Boy, this flintlock thingy sure is addicting...

Good stuff here on this forum. Thanks again, guys.

 

[mazo kid]

I have drilled/tapped 4 pistol barrels just like Fred suggested. These were not really pistol barrels with the faster twist, but cut off rifle barrels (and one 22.cal barrel). All came out nicely, haven't done any rifle barrels though. Depending on the caliber of the barrel, you will probably not have much of an angled shoulder to square off in the plug area. You can also taper the end of the breech plug to match if you don't have a flat drill; use inletting black or lipstick to fit the plug.

 

[rich pierce]

The Henry museum in Pennsylvania shows specialized tools such as Fred indicated above to bore out barrels. A boring tool with a pilot for the bore was used to square up the shoulder before tapping. And the tap also had a pilot to fit the bore. Looks like everything could be done by a workman standing at a vice with the right tools. I will say I have done this on a drill press but you really need to be sure you have everything lined up and immobile.

 

[zimmerstutzen]

Exactly what mazo said. I have installed breecch plugs on perhaps a dozen rifle barrels. Never used a lathe. Although if you get a barrel woth an off center bore, a lathe bored breech would be better.

I have drilled them out by hand and tapped by hand. It takes two or three separate taps so you can tap to the bottom.

I used soot from a candle flame as the carbon blacck to check the breecch plug face for proper taper and seating. There is a cutting tool that is sort of the opposite off a counter sink that tapers the outside of the breech plug face to matchh the angle of the drill you would use to drill the breech. I got mine at a second handd tool shop years ago. Sure made the task easier. Alot less hand filing.

For instructions, you are better off getting a machinist's text. The one I have covers the various types of thread, gives all thhe dimensions for the drill andd threads, etc.

I don't think your belieff that a gun building book would include it is unreasonable, but some tasks involved are woodworking and some are metal working annd some are carving. You would expect a gun building book to have instructions for using a bandsaw, samee for tapping is a specialized skill that machine shop apprentices learn. It isn't hard, but requires some knowhow and technique, that can be learned by reading.
I had a jig of sorts set up on my work bench for tapping the threads.

There is a specialy used and surplus tool supply place near here and that is where I get my taps, hack saw blades, files, emery cloth etc. The taps were $6.00 for two and I paid $1 for one with a broken lead tooth. I ground that one down (slowly) to make the bottom tap. I don't thread my breech plugs, but buy them already done. Figure threading one side of the arrangment was enough.

I did some work on a 40 cal. gun once that had a 1/2 inch hex screw plug for a breech plug. If the barrel was removed from the stock, it wasn't all that hard to remove the breech plug. Odd arrangment, but seemed to work.

 

[Zoar]

Indeed.

I bought a breech plug from TOW earlier today for one of the 50 caliber barrels. I agree that tapping the barrel is enough for the first time.

Luckily I have access to a small machine shop but none of the guys are gun builders so while I have access to general knowledge and access to a vertical lath, drill presses, fantastic clamps & tools to secure the barrel firmly---I want to get specific gun barrel tapping advice and the info on this thread is very helpful.

 

[Len Graves]

I agree with all who have said"Let the pros do it"
with the proper tools. I guess this brings up a question in my mind. How did the old timers do it? I know they made their own taps, and screw plates for other stuff. did they have lathes with which to counter bore for threads? Was there any standardization? Lots of questions come to mind. I know some of you fellers will have answers.

 

[zimmerstutzen]

a few of those early hand banged barrels had breeches forge welded into place out of metal from the barrel end. Not a good idea.

 

[hotsparks]

No, they didn't...except in the later period when there became 'specialists', such as barrel makers, most smiths didn't even have water power for "power tools". Everything was done by hand. Imagine drilling a breach for tapping by hand. Smaller holes in metal, and almost all holes in wood were done with a bow drill (imagine a Scout starting a fire with a bow). Files were made by hand by upsetting the surface of an iron bar. You already mentioned that most smiths made their own taps and screw plates (not to mention their own fasteners). Not to mention that in the earlier period, most smiths made their own barrels from iron skelps. Interestingly, not many made their own locks, there seems to have been a lively import trade in English and European locks. Point is, look at the excellent work they turned out, comparable or better than what we do today with all of our "advantages"...and we blanch at doing relatively simple tasks today. My method is, study it, find out as much as you can about it (like here), and go for it! All you can do is mess up, we old-timers call that 'gaining experience'..LOL
John