Tap and Die thread question

[Martin S.]

I am having trouble seating a breech plug.  I thought I might buy a tap and die and "chase" the threads.

I ordered a 3/-16 bottoming tap, but it also is denoted as an "H3".  I didn't know about H3 until just now.  I researched it, and it says it is basic plus .0010 to plus .0015.

So, I tried to put it in my barrel, and it seems like a tight fit and I don't want to screw up the threads.  It seems like the tap is too large?

Rice barrel, if that matters.

Can anyone tell me what size tap I need?

This is what I bought.

https://www.amazon.com/Drill-America-Qualtech-High-Speed-Threading/dp/B00FXJY1MQ/ref=sr_1_4?crid=2HZBEOT9U44NQ&keywords=3%2F4-16%2Bbottoming%2Btap&qid=1707101882&sprefix=3%2F4-16%2Bbottoming%2Btap%2Caps%2C118&sr=8-4&th=1

Can anyone tell me a good tap for a Rice barrel 3/4-16?

[Clark Badgett]

Fit the plug to the barrel, not the barrel to the plug. The Rice barrel probably has it right.

[Ky-Flinter]

Martin,

As they come out of the box, a bottoming tap won't actually cut threads to the bottom of a hole, or in this case to the shoulder inside the barrel breech.  To cut all the way to the shoulder you'll have to grind the face of the tap so it has full threads all the way to the face of the tap.

I would assume Rice threaded the barrel to standard 3/4-16 size.  If that is the case, your 3/4-16 H3 tap will remove about .0010 to .0015 of steel, making a standard 3/4-16 breech plug fit looser.

I'm curious, Rice barrels generally come with a fitted breech plug.  Are you installing a different breech plug?

Ron

[Martin S.]

Clark, your information is good.  I should be working on the plug side, or not at all.  I really don't want to ruin my barrel.

Ron, yours is good as well.

The plug is from Rice.  I didn't take it out, but the man who inlet my barrel did, (he needed to, nothing against him) and now I am trying to put it back on.  I can get it on, but there is still about 1/8" to turn until the witness mark lines up.  When I try to do that, the barrel twists in my wooden vise.  I have a steel vise on order.

I guess I am afraid to really crank on it, for fear of either denting the barrel or the plug.

I thought there might be some obstruction in the threads, so my intent was to run a tap and die over both parts to clear any obstructions, and then I thought it would go together like it should.

The Amazon site does not say anything about "H3", and I had no knowledge that an "oversize" tap even existed.  I thought a tap was a tap.

Perhaps I need to wait until I get my metal vise and crank a little harder.

I do have the Rice barrel "holders", that I think are made from aluminum.  Also the Rice breech plug tool, which does not seem to work well for me, perhaps I am using it wrong.

Any suggestions are appreciated.

[Steeltrap]

Before you run this tap down the barrel, compare your breech plug to the pic below. I just finished a drill\tap for a 50 cal in 5/8-18. If you look at the pic you can see where I've filed off the first 2 to 2.5 threads so the plug cones into the barrel. You DO NOT want to reduce the diameter of the plug face below the diameter of the base of the tap grove. (I hope I've said that so you can understand it). You just want to "cone or taper" the plug via removing the plug threads.

When I tapped the barrel I used a "regular" tap followed by a Flat Bottom Tap (FBT) which I had ground off 95% of the taper. That makes the initial "getting the tap" into the hole a bit touchy, but it threads the hole all the way to the bottom.

As stated above, the plug is much cheaper than the barrel. So it's cheaper to mess up a plug than a barrel.

Before you screw in the plug use a dab of anti-seize to prevent galling.

As to the use of an H3 tap, I'd likely not use it as (even though it's just black powder) you don't want any more play than necessary in the plug\barrel connection. That may be over cautious, but......

And should you find it necessary to use a tap, make sure you use lots of oil or a tap cutting fluid. LOTS!! Place a container under the muzzle of the barrel to collect the oil\fluid that runs down the barrel.

FWIW I buy my drills\taps here:  https://www.victornet.com/tools/Hand-Taps/86.html

[rich pierce]

Nowadays barrel makers really crank the breechplug home. A better vise should be the easiest solution. Like Steeltrap above I commonly do a tiny bit of filing based on what I see after painting the plug with magic marker and advancing it as far as it goes with a good effort. A little needle file work and future removals and returns of the breechplug become less of an ordeal.

[Long Ears]

Sounds like your setup is a little light for what you need done. If you have only 1/8 turn to go it will go without any alteration to the threads. They are tight machine threads not the homeowner version. If your inletter took it out it will go back perfectly. get a 30' long piece of steel water pipe for a handle on that breech plug wrench and a good vise and it will go easy. Don't file threads it will go. just sneak up on the witness marks slowly, back off 1/4 turn then tighten a little. Do this a couple times and it will seat perfectly. Bob

[Long Ears]

What area do you live? Someone close may be able to help you though some of this. Most are. pretty good guys on here. Bob

[2 shots]

 please , use the right tools. get a barrel vise.

[smylee grouch]

Also use some graphite grease on the threads. 

[J Shingler]

Yes today's plugs are tighter than needed but it will go. Not with a wood vice though. Also have a couple inches of the breach sticking out of the vice. In other words don't clamp on the breach threads. Then that tool you got from Rice is made to put a pipe on it for leverage.
Jeff

[bptactical]

Also use some graphite grease on the threads. 

Or at least some type of lubricant be it anti seize, oil or grease. With a certain “Ugga Dugga” it should pull up.

[JTR]

And note this important comment from above.

"In other words don't clamp on the breach threads."

[Jerry V Lape]

I make my own barrel vise for each size barrel.  I drill a large hole in a block of hardwood 4x4 then saw it down the middle.  Partially fill the cavity halves with bondo; wrap the barrel with seran wrap; clamp the barrel between  the halves to form a female mold.  Dont clamp the barrel too close to the plug end as you don't want to increase pressure on the breech threads.  once bondo is set pull the barrels and unwrap. Use this as your barrel vise in a strong bench vise. 

[t.caster]

Many large vices have teeth in the jaws that will scar the h#@$% out of the barrel! I have mine lined with .060" brass sheet. Much friendlier.
I use either a 10" or 12" adjustable wrench to tighten/loosen the plug. One of the jaws is ground to a taper like the lug on the plug.

Please don't ever use a pair of pipe wrenches to remove a plug like one of my customers did! Those scars never did heal!

[Steeltrap]

I have one of these https://www.brownells.com/tools-cleaning/gun-tools/fixtures-blocks/barrel-vise/ and it works very well for modern and octagon flintlock barrels.

For octagon barrels I place a 3/16" strip of maple on the bottom and top of the barrel before tightening down the 4 bolts.

This tool is more of a luxury than a necessity. A good set of blocks and a decent vice will get you to the same place.

[bama]

For starters, Jason at Rice barrels knows how to properly fit a breech. There is nothing that needs to be done to the threads in the barrel or on the plug. Take the money that a tap and die of that size would cost and buy a good 6” machine vice, a set of barrel clamps which Jason also sells. Mount the vice to a solid bench that doesn’t move. Place the barrel clamps as Jason instructions indicate. Lube the breech plug with a little anti seize and put the plug in. The last turn to line the witness mark up will be tough going, Jason sells a breech plug wrench that works great to help with this. It’s worth the money. A wood vice is inadequate for the job. Get the proper tools for the job or get someone that has the proper tools and have them to put the plug in for you.

[duca]

So Martin how did it go???

[Dennis Glazener]

Great advice from Jim you will thank him if you follow is advice. With correct tools the job is not a problem and  good tools will last you a lifetime.
Dennis

For starters, Jason at Rice barrels knows how to properly fit a breech. There is nothing that needs to be done to the threads in the barrel or on the plug. Take the money that a tap and die of that size would cost and buy a good 6” machine vice, a set of barrel clamps which Jason also sells. Mount the vice to a solid bench that doesn’t move. Place the barrel clamps as Jason instructions indicate. Lube the breech plug with a little anti seize and put the plug in. The last turn to line the witness mark up will be tough going, Jason sells a breech plug wrench that works great to help with this. It’s worth the money. A wood vice is inadequate for the job. Get the proper tools for the job or get someone that has the proper tools and have them to put the plug in for you.

[Martin S.]

Sorry for the late update.

I have the barrel clamps sold by Rice.

I have ordered a large enough machine vise.  It was supposed to be here in January (ordered late November).  Then I was told mid February, now told I might get it in March.  I am disgusted.

So...I think this situation will resolve itself with my new vise, if it ever gets here.

Thanks for all the suggestions and help.

Martin