breeching barrel without lathe

[The German]

I am hoping somebody can tell me how to breech a barrel without a lathe? I have a barrel and want to install a 5/18x18 plug. I assume zero tolerance bottom tap can be used but how to "bore/drill" the hole with a " square" end.

 

[paulvallandigham]

It can be done with a milling machine using an End mill.

 

[Zonie]

I am hoping somebody can tell me how to breech a barrel without a lathe? I have a barrel and want to install a 5/18x18 plug. I assume zero tolerance bottom tap can be used but how to "bore/drill" the hole with a " square" end.

In my opinion, with GREAT difficulty.

Not only is obtaining and maintaining the proper alignment with the bore a real problem but the nature of how a drill bit cuts adds to the problem.

Anyone who has used a twist drill to enlarge a hole in a metal part knows that the drills twist causes the bit to want to pull into the hole, rapidly.

When done in a lathe or a milling machine the mechanical strength of the machine can control the drill but the relatively weak arms on most humans will find it a real challenge.

There's also the issue of the shape of the bottom of the drilled hole.
Ideally, this surface will be a flat bottomed hole perpendicular to the bore.
As most drill bits have a 'drill point' they leave either a 118 degree or 135 degree cone at the bottom of the hole.
This shape doesn't lend itself to making a breech plug fit without gaps as it should.

Tapping the hole isn't a real problem as a taper tap will pretty much align itself with the tap drilled hole and modifying a taper or plug tap to a bottoming tap can be done with a grinder and a cup of water.

 

[The German]

The small problem - have no mill either....

 

[roundball]

One alternative is to send the barrel to Dennis McCandless, Custom Breeching machine shop in Los Cruces, NM...he's made 4 custom patent breech plugs for me so far, quality is perfect.

 

[rich pierce]

Large gun works like the Henry Gun Works used special borers which had a pilot that fitted the bore to drill the breech to the correct diameter and finish the shoulder. I'll see if I can find the photo. They had some sophisticated, specialized tools that achieved the desired specs simpler and faster than could probably be with a lathe back then.

 

[zimmerstutzen]

Breeching a barrel without a lathe is certainly more difficult, but not impossible, after all colonial frontier guns smiths did it. If the bore is centered, it is easier. With an off center bore it is very hard.

A twist drill can be used but a reamer can make it easier. Lots of cutting oil and a large crank on a brace helps. Just as some chamber reamers have bushings on the front to keep them centered in the bore, that would be preferrable. But it is very expensive to have the tools made.

I gave done it but it takes a great deal of patience. it is far easier to take the barrel to a machine shop and have them bore it to threading size. Threading is easier

 

[The German]

I was wondering if anybody tried to drill with a 3764 bit and then using a endmill ( hand held) to cut the hole square

 

[jerrywh]

You can buy a droll with a pilot on the end. Try McMaster Carr. If not , there are companies that will make you one.

 

[zimmerstutzen]

I used a 37/64 bit, but used a end mill to square the shoulder. I turned the end mill slowly with a brace as well.

 

[Bubba45]

It can be done with a floor mounted drill press.Slow an easy and be sure every thing is squared up with spindle and drill bit .

 

[Vaino]

Using a floor mounted drillpress, I put the bbl through the table hole, clamped it in a V-block, centered the bbl's bore w/ the spindle and clamped the V-block to the table. Drilled the hole, ctsk the hole and ground a flat bottom on the same drill and cut the ctbre flat. Lubed the tap, pressed the "on" and immediately pressed the "off" and while the spindle was coasting, started to tap. Unchucked the tap and finished on the bench. Had a flat bottom tap which is used to "clean up" existing threads and cut the threads to the flat. This can work only if the bbl is short enough to fit vertically in the DP and when a swamped bbl is used, it has to be shimmed in the V-block so the bbl is perpendicular. An end mill shouldn't be used in a DP...the spindle is not stable enough. As Jerry said, a piloted ctbre makes it much easier seeing it not only cuts the hole but also makes the ctbre flat. Have done 2 the above way, but now buy the bbls already breeched....Good luck...Fred

 

[Birddog6]

After reading all of these posts, IMHO, take it to someone & have it bored & tap started properly. It would be one thing if you were going to do a bunch of them, but if you are going to do ONE barrel, I would take it to a place, have it done correctly, & be done with it. Instead of buying tools, rigging up multiple configurations of of holding the barrel, & using machinery that is not designed for doing the job correctly or safely, etc. Or at the bare minimum, have it drilled correctly & breech seat cut, tap started centered & then you can tap & fit the plug by hand if you wish to do so.

:idunno: Just seems like a practical approach, but everyone has dif. ways of doing things.

Keith Lisle

 

[Bill Hall]

I agree with Birddog. I had to breech a barrel that I cut down to 26" to make a rifle for my daughter. I worked at a machine shop, but I was a sheet metal guy, so I spent many days searching for tools and drills and such in all our bins, trying to find the right combination that would work. I brought some of the doo-dads to a machinist and asked if it what I had would work. He said "Gimme that thing and I'll give it back to you in the morning". He cut the recess on a cnc mill in a few minutes and it was done. I did thread it myself by hand, since I felt confident about that operation.

Now, I did get it cut for free by a friend, but I'm willing to bet that it would still be cheaper to have it done by a machinist, rather than investing in some expensive tools, especially, as Birddog mentioned, if it's a one time deal. And they can get it dead nuts perfect. Bill

 

[Vaino]

I agree ....take it to a machine shop. I did 2 bbls as described but you have to keep your wits about yourself while doing it otherwise it's easy to screw it up. In my younger days I did everything and having been a tool and diemaker, this operation was not at all difficult.....Fred

 

[Roy]

I've done them with out a lathe... think it was part of my learning process. :v I have a lathe now... and then, but the point was for me to learn how to do it with out one. Want to be a gunsmith, sort of have to know how to make the gun. Only thing that I haven't done so far is hammer forge a barrel.

Lucky for me I had to start out building a gun with a Douglas barrel that didn't have a breech plug, and then a pistol that I used a section of rifle barrel that wasn't threaded.


You have to drill out the barrel to whatever the tap needs to get a full thread, use a reference as a stop point. The drill bit will follow the bore. Tap the barrel first using a starting tap then to a bottom tap. Fairly simple, but takes more time to fit the breech plug...

 

[B.Habermehl]

Using a end mill to bore a square shoulder is a disaster in the making. They will suck into the hole and cause all sorts of he.... The angled seat the pilot drill leaves is just fine. Fit the end of the breech plug to match. Think of the plug and seat in a globe valve. On board ship they need to hold back 1200 psi superheated steam indefinately. Not just miliseconds like a breech plug does.

 

[bob308]

i did 2 in my old blacksmith post drill it worked out quit well. ut i use my lathe or mill now.

 

[sbhg]

http://www.mcmaster.com/#counterbores/=8um80o
You should be able to use one of these.

 

[44-henry]

I've bored lots of holes using end mills in the lathe. I use them the same way that you use a boring bar and have never had any problems, in fact, it is actually a pretty common trick.