A Different Twist to Benchrest Barrel Fitting

Multiple Methods same goals...

Bnhpr:

I have been chambering barrels for 35 plus years. I have changed my methods about that many times also.

Co-axial alignment, concentricity, even throat transition, proper fitting case to chamber, no chip or unneccessary tool marks are the objectives.


It should not matter how one gets the job done as log as he does get the job done.

There are some fine gunsmiths who post here daily and they politely agree to disagree.

I will say that I learn something new every day. I really appreciate folks like Micky Coleman, Mike Bryant, Jackie Schmitt, Dave Tooley, Butch Lambert and many others sharing their wisdom. It is a great resource to learn form others successes and failures.
Rustystud
 
Anyone here know Middelton Tompkins?

If you do, you know his reputation as a shooter in highpower and long range.

Mid holds a reamer with a pair of vice grips.

He also holds buttplates together with drywall screws.

Master craftsman?

No.

Accurate gun builder with proven performance?

Absolutely!
 
NesikaChad said:
Anyone here know Middelton Tompkins?

If you do, you know his reputation as a shooter in highpower and long range.

Mid holds a reamer with a pair of vice grips.

He also holds buttplates together with drywall screws.

Master craftsman?

No.

Accurate gun builder with proven performance?

Absolutely!
Click to expand...


Excellent point.

I was told early on here, by someone whose user name is the same as their real name, that only the end result matters.
 
Now, to counter what I said about Mid. (Love that old cuss BTW)

Nesika gave me a 65K dollar CNC lathe to chamber barrels with. I spent the better part of a year modifying that machine and working with the manufacturer to taylor the software to suite my needs.

It'd turn threads fitted to each action and cram a reamer in a barrel in 10-30 minutes depending on what cartridge you were doing.

It'd also hold total indicated runout to under half a tenth.

Honest!

Gotta love six hundred pounds of oil pressure and through coolant reamers!

David Kiff is a Jedi when it comes to tooling.

Lots of ways to skin cats. Mine was probably the most expensive way but it sure works good and is quick.
 
butch, he's probably still indicating to 50 millionths on a part that if lucky maybe has a surface finish of 63 at best good luck. george
 
George, your a hoot! Why don't you get that old ambulance cranked up and come shoot with us in Texas or maybe we could meet at a match in Arkansas. I hope you have a good year.
Butch
 
butch, arkansas might be possable need to find dates shoulder's a little sore yet won't be shooting right away. george
 
Bnhpr said:
Excellent point.

I was told early on here, by someone whose user name is the same as their real name, that only the end result matters.
Click to expand...

Very good point.

NesikaChad said:
Now, to counter what I said about Mid. (Love that old cuss BTW)

Nesika gave me a 65K dollar CNC lathe to chamber barrels with. I spent the better part of a year modifying that machine and working with the manufacturer to taylor the software to suite my needs.

It'd turn threads fitted to each action and cram a reamer in a barrel in 10-30 minutes depending on what cartridge you were doing.

It'd also hold total indicated runout to under half a tenth.

Honest!

Gotta love six hundred pounds of oil pressure and through coolant reamers!

David Kiff is a Jedi when it comes to tooling.

Lots of ways to skin cats. Mine was probably the most expensive way but it sure works good and is quick.
Click to expand...

And... may I ask, how do those guns shoot?

With all due respect, why would you use a CNC machine and then "ream" the chambers?
 
Butch Lambert said:
George, your a hoot! Why don't you get that old ambulance cranked up and come shoot with us in Texas or maybe we could meet at a match in Arkansas. I hope you have a good year.
Butch
Click to expand...


yes, yall come down this year and shoot. may even get me out of the house to shoot closer than 10hrs:D yall just gimme a call when you want to do it.
 
4Mesh said:
Very good point.



And... may I ask, how do those guns shoot?

With all due respect, why would you use a CNC machine and then "ream" the chambers?
Click to expand...

Because a reamer is still the best tool for the job :).

Bill
 
Because a reamer is still the best tool for the job :).
Click to expand...

Really? Please explain..........I would think a well set up CNC machine could hold much closer tolerances and not suffer any of the misalignment issues we all cope with in using reamers.......
 
Well this is an IMHO, and it is coming from running cnc and manual machines, mills, lathes, grinder for almost 30 years now.

Boring a chamber sounds like a great way to do it...people have tried it. The back end where it is bigger would work the best, but it is the least important :)...the real heart and soul of the chamber is the neck and throat, and on say a 222 think on how tiny, and how far it hangs out the boring bar would be to make the MOST critical part, the throat...and it is buzzing around on an interrupted cut cutting the lead.

Most any gunsmith who has worked a cnc job shop has spent hours daydreaming on this issue....I Think a boring bar could be made the shape of the cartridge with a bit of clearance, this would be stiffer by far. BUT still the cats meow would probably be to ream the last .05" or so of depth after the bring was all done. Burrs in the throat are the biggest issue I hear from guys that have tried to finish a chamber by boring.

Dave Kiff the guy who makes my reamers...does ALL the hard work for us...he gets all the radii and angles just right, that little gem of a reamer cuts what 20 dimensions at least all at once.

Tapers and close tolerance holes even in the cnc world are still cut mostly by....reamers, maybe today they are carbide reamers with high pressure coolant coming out of holes right in the flutes...but still reamers, and still mostly made just like one was made when Pope was in short pants :).

Plus a decent CNC lathe of any size costs $25,000 or more, and the beasts have the habit of toasting mainboards that cost $1000 or more to exchange for a repaired one. And even more expensive little electronic/mechanical farts now and then. A cnc lathe of any size and quality needs 40-80 hours a week of work that pays $100 an hour just to keep it in feed and water :).

Bill
 
I agree with Bill

I have a small Hardinge CNC tool room lathe that has a control that reads in .00000". It's an awesome lathe...... but every once in awhile it just decides to eat a part for no apparent reason. Sure makes me glad that I don't have a customer's new barrel in there when that happens.

But then, the spindle on my little Hardinge is too small (5c collets) and I'm not too sure how I'd control the set up to cut to 50/1,000,000. It'd be a B**** to try to inform the machine where the centerline of the Z axis is to 50/1,000,000". Dang, I sure like to type all of those zeros...... it's just soooooo cool. The stock roundness and finish of most of of the things that I machine in the Hardinge makes it hard to dial anything in to any better than .0005". The needle on my Intrepid has a bad case of the jitters, reminds me of my hands back in the days when I'd wake with a bad hangover.

Still, I do dream of cutting chambers with the cnc.

Shelley
 
ShelleyDavidson said:
I have a small Hardinge CNC tool room lathe that has a control that reads in .00000". It's an awesome lathe...... but every once in awhile it just decides to eat a part for no apparent reason. Sure makes me glad that I don't have a customer's new barrel in there when that happens.

But then, the spindle on my little Hardinge is too small (5c collets) and I'm not too sure how I'd control the set up to cut to 50/1,000,000. It'd be a B**** to try to inform the machine where the centerline of the Z axis is to 50/1,000,000". Dang, I sure like to type all of those zeros...... it's just soooooo cool. The stock roundness and finish of most of of the things that I machine in the Hardinge makes it hard to dial anything in to any better than .0005". The needle on my Intrepid has a bad case of the jitters, reminds me of my hands back in the days when I'd wake with a bad hangover.

Still, I do dream of cutting chambers with the cnc.

Shelley
Click to expand...

you are not going to hold 50 millions on a lathe that's why they grind parts your ind. jumping is from surface finish not much you can do about it unless your prepared to grind or lap for finish. george
 
reamer X bore

I have paid a lot more money to have less fun. Have seen many different ways to chamber creating oversize chambers with bellies like fish,throats that were so uneven that part of the lands much less grooves not being cut. Just think like a barrel. Can we not control only one end at a time. May everyone find a way they like,with the results expected by them.
 
I remember reading a few years back when 1000yd shooting was getting popular that there was a father and son team that were building their own rifles and using CNC to cut the chambers.

I know nothing about CNC lathes except I've seen some amazing tight tolerance parts with amazing intricate internal turnings that are down to .250" bore and over 3" long...........I have no idea how this is done, but somebody is doing it...

I still say, EDM, if it was economically feasible would be the way to go.........
 
If you know anything about plunge or wire EDM, I think the feasibility is a long way off. I think that it has been mentioned before, The push off on a tool to single point a chamber would be hard to overcome. Remember that you would be cutting the throat also. I don't know if your finish would be as good as a good reamed hole.
Butch
 
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