Installing a breech plug?

[Kurt]

Can a breach plug be safely installed using a tap, by hand, without the use of a lathe? Perhaps a lathe is needed to make it flush and aligned with the flats? Thank you.

[rich pierce]

It has to be bored out to the minor thread diameter of the plug. Up to a square face. Then 3 taps can be used. Starter tap with a lot of taper. Then a starting tap that has been ground off at the tip. Then a finishing tap.

[Kurt]

Thank you, Rich. I had a suspicion it was more complicated than I was supposing.

[whetrock]

I have done two by hand without a lathe, but I would say it is hard. Like Rich said, you have to have three taps. Or you can start with one and just grind the tip off in stages as you go. Regrinding taps is a little tricky.
The hardest part of the task is drilling the hole and keeping things aligned so that you don't end up with the hole out of alignment with the bore, and you don't end up with loose threads and a loose, wobbly breach plug.
It's also helpful to have or make a cutter that will fit just inside the cylinder of the finished threads so as to cut a shoulder for the plug to mate up against. That cutter cuts the shoulder 90 degrees with the cylinder of the threads.

Back in the old days they did all this by hand, but they were also using iron barrels and coarse threads, and a different type of tap, that partially cut and partially swaged threads. The drill and perhaps the starting taps as well were made with a pilot on the end that kept them aligned with the bore. (There are photos of some of these old tools in some of the reference books.) The breach plugs were also iron, made with a die that used the same principles.

With modern steel barrels, the taps cut rather than swage, the threads are relatively fine (which, provided you are working with modern metals, makes for a superior joint). So the threads need to be right. There's not a lot of room for error.

[Kurt]

Thank you, whetrock.

[mikeyfirelock]

I’ve done it but it was a long time ago. ( did it by hand).  I’d take it or send it to someone who does this regularly,

[whetrock]

I agree with Mike that taking it to a machinist or gunsmith with a lathe setup is a perfectly reasonable plan.

That said, let me add another detail. I meant to mention that when doing this by hand without a lathe, I think it is helpful to drill the hole 1/8"-1/4" deeper than you want the final hole to be (that is, longer than you want the breach plug to be), and then plan to trim off that extra length and square up the breach before you seat the breach plug. The extra length gives you a little throw-away material to work with as you hand start the tap. This helps because it's easy for the first few threads or so to be a less than perfect as you try to get the tap to grab. Even once it grabs, you often still have to adjust the angle so as to get it aligned with the bore, so the first few threads are often more loosely formed than you want. So, if you give yourself a little extra and plan to trim it, then once it is trimmed, you will have perfect threads all the way to the edge of the breach opening.

Having this extra length for the hole at the beginning also helps you avoid having your starting tap reach too far into the bore. If it reaches too far in, it can scratch the sides of the bore. You have to plan to avoid that.

I hope what I've described is clear.

I use a similar plan when making ramrod tips, and when lock bolts, or jags/worms, or anything with a threaded shank, as well. I make the threaded section just a little longer than needed, and that way I have extra to work with. I'm talking about cutting threads by hand, without a lathe. If the tap or die doesn't start straight, I can work with it and get it going straight. Then trim off that throw-away bit as planned. I imagine professional machinists may have a name for that throw-away margin I'm talking about, but I don't know what it is.

[Joe Stein]

I've done a few without a lathe, but I used a drill press and one of those vises that will adjust in two axes. The drill press that I used had a table that would pivot to vertical. I would get the table perfectly parallel to the quill of the press and the jaws of the vise parallel as well. Make sure that the travel of one axis of the vise travels in and out perpendicular to the quill. Get or make a round bar that fits the bore of the barrel with a close slip fit. Chuck the bar in the drill press chuck and slip the barrel onto the bar. Now comes the finicky part. You have to adjust the drill press table so that the fixed jaw of the vise just touches the barrel, and the barrel is sufficiently within the jaws of the vise to not slip when you drill and tap the bore. Loosen the chuck. If you have done everything right there will be no sideways pressure on the bar. Everything will be lined up. Remove the bar,  and proceed with the drilling and tapping.
It helps to have extra hands, but spring clamps and big magnets can suffice.

[Birddog6]

Can a breach plug be safely installed using a tap, by hand, without the use of a lathe? Perhaps a lathe is needed to make it flush and aligned with the flats? Thank you.

I have done it & Never again. Takes 3 taps & I used 4. Issue I had was starting it straight.
I ended up with a tube sleeve over the end of the barrel to hold my tap straight, as it is
easy to cock.  It was a Real PITA. Took me Days. If it is not straight you encounter more issues as it gets close to finish as not the barrel is not exactly 90 deg to the plug & its a
dang mess....  Last 2-3 I sent to a machine shop & had them done.  At that time, the
lathe I had was too small to do them.
If you do one, you best be a guy with LOTS of patience.

[Kurt]

It does sound like doing it by hand would be more than I would want to tackle.

I attempted communicating with someone recommended to do the job, but based on that, I have become discouraged with the project entirely.

All advice and replies here are very much appreciated! Thank you.

[Daryl]

Did it by hand a few times and wasn't a problem. I've watched Taylor do quite a few using his big, floor mounted drill press.
I just took my time and did it right. Others here have given the procedure.

[whetrock]

So what are you wanting to work on, Kurt?

[okawbow]

When I became interested in building a muzzleloader in the late 1960’s, the few books and writings on building only touched lightly on breech plug installation. Tap some threads about 1/2” deep or a little more and screw a bolt in until it wouldn’t go any farther, cut the bolt off and weld on a tang. No mention of fitting the face of the plug to a shoulder. I wonder how many guns made like that are still around?

[Kurt]

whetrock, I was thinking of building, or having built a Fowler barrel for a rifle I currently own. It is a bit of a "flight of fancy" in that I don't need it, and wouldn't use it much, but I kind of like the idea of taking a gobbler with a flint fowler.

[2 shots]

 i have used  TRACK OF THE WOLF  a few times. they do nice work at a fair price but shipping these days is high.  if you ship it wrap well and then wrap it again. i made a pcv tube with one screw off end cap and put heavy foam on both ends, [ also wrap the barrel tight to the tube]

[Steeltrap]

I did the last two flintlocks I've built. Now, I will state up front that a long time ago I worked in a machine shop that built very large turbines and compressors. All I did was drill 'n tap on a drill press that would likely not fit in your living room. (Which explains why I got bored and left for college)

I tapped both using these two taps. The one I purchased as a Flat Bottom Tap, but I ground it down to have no taper at all.


I aligned the drill press table with the drill chuck. I checked this for "straightness" using a wooden dowel rod of the bore size and simply pushed the dowel in so I'd see no left\right in\out movement. Then I chucked up the proper drill size and with a lot of lube, slowly drilled the depth I wanted. IIRC just over 1/2". I used big clamps as I don't want the barrel to slip during the drilling and tapping.



Now, I did not use a flat drill to put a 90-degree angle so the face of the BP would mate against it. I simply thought there would be too much of a chance for the drill to run out and I didn't want to invest in another bit with a pilot on the front.

So, what I did was, using a fine file and a transfer agent, filed the angle of the BP to match the angle of the drill. And yes, this takes time (the entire procedure takes time....if you're in a hurry...don't do it.) But eventually with care I got the transfer agent to meet the "bore ridge" and seal all the way around.

If you miss the alignment flat you're "aiming for" you can drill a bit deeper....but that will require using the FBT and get that deeper. I got a good seal on both "first time" so a little luck came my way.

To me, it's not overtly difficult. And I did enjoy the process.

[Herb]

Can a breach plug be safely installed using a tap, by hand, without the use of a lathe? Perhaps a lathe is needed to make it flush and aligned with the flats? Thank you.

  Is the barrel already drilled and tapped for the breech plug, or do you need to drill the barrel for the breech plug?

[Herb]

Kurt, I have a tutorial about this.  Go to Tutorials- Gunmaking Tools and Techniques- Metal Shaping, page 2 "Fitting a Hawken Breech Plug by Hand" by Herb, June 21, 2010.

https://www.americanlongrifles.org/forum/index.php?topic=10970.0

[Scota4570]

My experience is that starting the tap by hand usually goes in cockeyed. 

I usually start the treads with a 60* boring bar and finish them with the barrel in the lathe.  The tap centered in the tail stock center to finish the threads.  I also make the bottom of the hole 90* to the line of the bore so the plug can mate up to it better. 

If I did not have a lathe, I'd pay the barrel maker or seller  to cut the threads in the breech and fit the plug myself. 

[Steeltrap]

Kurt, I have a tutorial about this.  Go to Tutorials- Gunmaking Tools and Techniques- Metal Shaping, page 2 "Fitting a Hawken Breech Plug by Hand" by Herb, June 21, 2010.

https://www.americanlongrifles.org/forum/index.php?topic=10970.0

Very nice writeup. I'm pretty sure I read your tutorial before I did my first one.

Also, I failed to mention that when I did my rifle barrel, in addition to the heavy duty C clamps, I also placed a piece of 2x4 under the muzzle and to the floor. (You can sort of make that out in the second pic) I did the same for the pistol barrel except it was short and didn't require turning my benchtop drill press sideways like I had to for the longer rifle barrel.

[Leatherbark]

I've done it a half-dozen times or more.  First you need to make sure your plug threads are a fuzz longer than your barrel threads. Plus, like in the pictures above drilled straight.  I use an end mill in the drill press for the last part to square up a nicer flat shoulder for the plug to tighten against.  Plus, I have a ground a flat face on the bottoming tap to get the last thread as close to the shoulder as possible. Now timing the tang to the correct flat is much easier on a new barrel that has no dovetails or underlugs.  This makes the chore much easier.

 All you have to worry about is where the makers mark will be. When you have to time the plug rotation and tightening to a specific flat is when things get complicated and a lathe will uncomplicate it.  But with your thread depth of at least 1/2 inch there is a narrow window of opportunity as far as removing steel from octogen part of the back of the barrel. If you screw up and have to make a complete revolution to get everything timed and tight, you might be starting all over to get the thread depth back to normal. Then your client's barrel (usually me) will be 41-11/16ths inches long instead of the 42-inch barrel he wanted.

What all the above means is if I had a reliable guy up the road who had a machine shop and knew how to do this without me having to hold his hand, I would farm it out in a heartbeat.

Bob

[ColonialRifleSmith]

Can a breach plug be safely installed using a tap, by hand, without the use of a lathe? Perhaps a lathe is needed to make it flush and aligned with the flats? Thank you.

It's not as difficult as it sounds. I've breeching all my barrels by hand for many years. I've never had an issue.