Gene beggs on chambering

Get one of Nat Lambeth's Micrometer Reamer Stop from PTG. Makes it very easy to get the right depth. It attaches to the reamer so the tailstock can be moved repeatedly without having to be put back in the same spot each time. Set it to give you a short chamber, cut to the stop contacts the barrel. Then measure the chamber depth using a HS gage and a depth mike, or other favorite method. Dial in how many .001" you need on the stop and cut until the stop contacts the barrel. Once set it is very repeatable. I chambered five 7.62mm NATO EPVAT pressure test barrels this week using a stop on a reamer I set up months ago, when I did ten barrels, all 15 have exactly the same HS measurment.
I am sure Rustystud will be along to add more info to this.
 
MilGunsmith said:
Get one of Nat Lambeth's Micrometer Reamer Stop from PTG. Makes it very easy to get the right depth. It attaches to the reamer so the tailstock can be moved repeatedly without having to be put back in the same spot each time. Set it to give you a short chamber, cut to the stop contacts the barrel. Then measure the chamber depth using a HS gage and a depth mike, or other favorite method. Dial in how many .001" you need on the stop and cut until the stop contacts the barrel. Once set it is very repeatable. I chambered five 7.62mm NATO EPVAT pressure test barrels this week using a stop on a reamer I set up months ago, when I did ten barrels, all 15 have exactly the same HS measurment.
I am sure Rustystud will be along to add more info to this.
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Yes sir, I have one of Nat Lambeth's MARS reamer stop setups and it works great. I got mine from Nat but I understand they are made by and available from Dave Kiff at PTG. An ingenious design and well made piece of equipment there.

Gene Beggs
 
alinwa said:
Gene,

Could you describe how you run the reamer and how you gauge depth of the chamber??

This is the sort of stuff that's hard for the new guy to visualize....... you don't just drive the reamer in "about yeahh" using gtrial and error... ;) ... so could you tell us WHEN to stop the reamer and how you know?

thanks


al
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Mornin' Al

The first part of your question, "Could you describe how you run the reamer?"

At this time, I do not use a muzzle flush system although I believe it is the best way to go, especially if you chamber a lot of barrels. For now, I still use the ream and clean method, holding the reamer with a nine inch tap handle, chambering at 60 rpm. I'm very careful to keep the crosslide out of the way so there is no chance of the reamer grabbing and crashing the tap handle into something or injuring my hand. I curl my fingers around the lower handle of the tap wrench and place my thumb against the top handle which I believe keeps the pressure as symetrical as possible. I've developed a technique that does not require starting and stopping the lathe after each cut.

Let's say I've just finished a cut and feel it is time to clear the chips and blow out the chamber. I leave the machine running and take my right hand off the tailstock feed, hold the tap handle with my finger tips at the end of each handle and after the lathe has made a couple more revolutions, simultaneously release both handles. The reamer and tap handle then rotate with the barrel. Unlock the tailstock lever, slide it back out of the way and with the lathe still running catch the tap handle near the center and carefully withdraw the reamer from the chamber. I blow the chips off the reamer and swish it around in a wide-mouth plastic jar filled with odorless mineral spirits. The chamber is then blown free of chips and we are ready to go again. The lathe is still running.

Dip the reamer in cutting oil and carefully insert it back into the chamber with the lathe running. If you have not tried it, this procedure may sound scary but I assure you it is safe and easy. Slide the live center back up to the reamer leaving just a little gap before making contact but, DO NOT LOCK THE TAILSTOCK LEVER AT THIS TIME. With the tailstock free to move, carefully advance the spindle until it contacts the reamer and begins to push the tailstock back. Watch the feed dial and stop it on zero, then lock the tailstock lever. Back the tailstock feed out slightly so the reamer doesn't start out in a bind, then catch the tap wrench handle as it rotates. Again, this sounds scary, but believe me, it's safe and easy; sort of like getting in time with a jump rope. With the tailstock backed off slightly, the tap handle stops rotating immediately with only slight finger pressure and with the tailstock dial zeroed as described above, you know exactly where the reamer will start cutting; you also know exactly how much you are feeding. I usually cut the entire chamber with the finish reamer. On the first cut, I run the reamer in until the shoulder is engaged. After that, I take about .200 cuts until I get near finish depth. I've never had a chip ringed chamber and I've never worn out a finish reamer.

Al, the second part of your question was; "How do you gauge chamber depth?

As the chamber gets deeper check your progress by placing the headspace gauge in the nose of the bolt and insert into the chamber. (Yes,, stop the lathe for this) The gap left between the bolt nose and cone is how much further you have to go. Eye ball it until you get down to about .070 then carefully measure the gap between the tenon shoulder and receiver face with a thickness gauge. Let's say the gap is .065. That means you must run the reamer .065 deeper plus about .002 more to allow for crush.

Hope this helps. It's a lot easier than it sounds and much easier to demonstrate than describe.

Later

Gene Beggs
 
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I insert, advance and remove the reamer a bit differently. The graduated dial on my tailstock is one turn equals .100". Nice for referencing. I use the saddle as the "stop" for the tailstock, clamped in the position I want.

Picking up at the assumed cut with the reamer, when I reach the end of the advance I want, and the barrel makes a full turn, I immediately back the reamer off using the tailstock wheel one full turn (.100) keeping the reamer against the dead center. I then unlock the tailstock and pull it back again keeping the reamer tight against the dead center as it comes out and clear. I clean pretty much as Gene says, but I give the chamber a short blast of cheap carb cleaner to cut the thick oil some before I blow out the chips. I think/hope this helps clear everything out.

Re-oil the reamer and the inside of the chamber, I push the tailstock back against the locked saddle giding the reamer in. I know it's still .100 away from making contact, and I then advance into the next cut. I usually don't cut more than .100 at a time (unless it is taking the small amount out after drill and bore), sometimes only .050. All depends on how much I feel on the reamer handle.

By moving the tailstock gently back against the saddle, and using the dial on the tailstock, I've had no trouble reaching the exact depth I want.

I use a Sinclair brass turning handle on the reamer. I agree with Gene about even pressure holding the handles.

I'm a little anal about cleaning as I go. I caught a chip with a reamer years ago, made a nice groove around the chamber. Damn!

Thanks for the great thread Gene!
 
My system for accurate advancing of the reamer is not high tech but it works very well. I have a dial gauge with a magnetic base on it and a tail stock quill with a piece of aluminum clamped on it... a dog on the reamer is pushed by the tail stock.

magneticbasedialgauge-0.jpg


chambering-0.jpg
 
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Mr. Beggs and other smiths,

I want to extend my appreciation for what this generation would call and "epic" thread!! Rarely in this day do you find so much honest information given with so little ego, this is one of the most refreshing reads out there right now, IMO. I'm starting to try to get into working on my own rifles, albeit not BR but hunting this thread has been a valuable asset to me for future reference and I thank you guys!
 
Got to spend the last day and a half with Gene in His shop and chamber as He describes in this thread.

Had some excellent instruction and tips along the way. It works like a champ!
Well worth the trip. Thanks again Gene for all the help and see You Soon.
John Stark
 
if you go look at jackie's method you will simplicity at its best.
instead of trying to make precise cuts/tops with the reamer,cut just past flush with the go gauge, then come back and make simple
face cuts to the end of the bbl and shoulder to set the head space.
there is nothing wrong with the method gene and others use, it is just simpler to
use jackie's approach.
 
Steady rest........... Chambering

Gene,.....very well done,and thanks for taking the time to write it up...... the only thing I add to your method is a brass wire around the chamber end to act as a gimbel....... I thought I was one of a few...who sometimes uses a steady rest......til I found out Kelbys,Hart,Lilja,Obermeyer, prefer it......and now I find out many others use this method..... the beauty of the steady rest is ... it does not inflick a barrel to bend if it not straight......
Both methods...thru the headstock and steady rest are about as good as the guy doing the job.......
bill larson
 
Steady rests

Butch Lambert said:
Kinda confused about your comment
" it does not inflick"
Why would chambering in the headstock do this?
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Butch...... with an outboard spider.... and no gimbel mount at chuck..... it is very easy induce/inflick.... stress/bend barrel......while dialing in the muzzle bore. It don`t take much..... finger pressure will do it.......
bill
 
B.Larson said:
Butch...... with an outboard spider.... and no gimbel mount at chuck..... it is very easy induce/inflick.... stress/bend barrel......while dialing in the muzzle bore. It don`t take much..... finger pressure will do it.......
bill
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If, in a steadyrest setup, the chuck jaws have induced a bend between themselves and the steadyrest you could induce workhardening in the barrel because as it rotates it is continually flexing.To eliminate this possible problem the barrel must be chucked so the barrel is not in a stressed condition by using something like a heavy copper wire between the jaws and the barrel.

In a through the headstock setup if you have induced a bend (curve) there is not a flexing problem since that curve is static and is rotating in space with the spindle. This will not induce any stresses like the steadyrest method could.


.
 
steady rest chambering

JerrySharrett said:
If, in a steadyrest setup, the chuck jaws have induced a bend between themselves and the steadyrest you could induce workhardening in the barrel because as it rotates it is continually flexing.To eliminate this possible problem the barrel must be chucked so the barrel is not in a stressed condition by using something like a heavy copper wire between the jaws and the barrel.

In a through the headstock setup if you have induced a bend (curve) there is not a flexing problem since that curve is static and is rotating in space with the spindle. This will not induce any stresses like the steadyrest method could.


.
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Like I said Jerry.......... either method.... is about as good as the man doing it........ that`s why...Kelbys,Obermeyer,Hart,Lilja, and mid Tompkins use the steady rest.....
bill
 
B.Larson said:
Like I said Jerry.......... either method.... is about as good as the man doing it........ that`s why...Kelbys,Obermeyer,Hart,Lilja, and mid Tompkins use the steady rest.....
bill
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Bill,
Are you saying that these people do it this way and it is the only way? Do you want a list of people that do it in the headstock? Winners have been chambered both ways. You pick your own poison.
 
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