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View Full Version : Darn clever piece of barreling tooling



Boyd Allen
01-31-2016, 11:42 PM
Check it out.
http://www.pmatool.com/pma-woolums-accuracy-barrel-micrometer/
Comments?

Dave Tooley
02-01-2016, 10:32 AM
I have three of them for various diameter and length tenons. I use direct reading tenth micrometer thimbles. I'll never go back to a depth mic with tape wrapped around the gage to center it. I made individual buttons with appropriate angle to measure the counter bore/cone depth. For the new guys make your own. It's a good learning process. If you can't measure accurately you can't cut/ream accurately.

Butch Lambert
02-01-2016, 11:10 AM
The photo says 2006, but I built mine in about 1999. If you look at the picture and feature 2 of these. I did the slip on one time but discarded it. When I said 2, I mean one threaded 16TPI and 18TPI. Remington and for custom receivers. The valve looking tool is for bolt nose measurement. I have one each for the different nose angles and a similar but different one for a Remington. The vertical lines will align closely with your old barrel lettering. It enables you to letter the new barrel without having the receiver for reference.
http://i48.tinypic.com/zsok5x.jpg
I use the small thimble Mitutoyo micrometer heads as does Dave I believe.

Boyd Allen
02-01-2016, 11:12 AM
Dave,
As always, thanks for the comment, but take a closer look. The genius thing about this tool is that the designer substituted a large diameter bearing ball for an angle specific truncated cone insert. The same tool without the ball is used for headspace, with the ball, assuming that you are cutting the correct angle, the large ball will land on the cone (once the headspace gauge is removed from the chamber), and let the smith make cone depth comparisons, using the same ball for all cone angles.

Butch,
Your index lines for accurately transferring lettering locations is a really good touch. It seems that someone could make simple nuts, marked the same way to use with the tool that I put up a link for.

Boyd

WSnyder
02-01-2016, 02:01 PM
Greg Walley in the past has shown a method of using a bearing to measure cones but not in combination with the tenon tool.

http://benchrest.com/showthread.php?86603-cutting-a-cone-for-a-Panda-action

CMaier
02-01-2016, 04:33 PM
i used to have shinny steel balls,

but as time went by they dulled,

then flaked.


In the end i was left with







BIG BRASS BALLS!

mwezell
02-01-2016, 05:05 PM
I made a similar tool for this job, some time back. I opted to use an indicator on the top but a mic would work just as well. With a digital indicator or mic, you can simply zero it out on the original barrel and work back to zero on the new one.

WSnyder
02-01-2016, 07:04 PM
The type with an indicator was actually patented at one time. Badger ordinance sells a copy of the original Anderson gage.

http://www.badgerordnance.com/media/bo_media/200-11.pdf (the patent number on Badgers data sheet is incorrect)

The original and expired patent: http://www.google.com/patents/US5170569?dq=device+for+measuring+headspace#v=onep age&q&f=false

More info: http://www.practicalmachinist.com/vb/gunsmithing/measuring-chamber-depth-lathe-204370-print/

mwezell
02-01-2016, 07:34 PM
The type with an indicator was actually patented at one time. Badger ordinance sells a copy of the original Anderson gage.

http://www.badgerordnance.com/media/bo_media/200-11.pdf (the patent number on Badgers data sheet is incorrect)

The original and expired patent: http://www.google.com/patents/US5170569?dq=device+for+measuring+headspace#v=onep age&q&f=false

More info: http://www.practicalmachinist.com/vb/gunsmithing/measuring-chamber-depth-lathe-204370-print/
Mine is similar, by coincidence, but I'm not selling them anyway.

WSnyder
02-01-2016, 08:16 PM
I only mentioned it for the sake of history. Patent is long expired so anyone can manufacture them just as Badger is.

mwezell
02-01-2016, 08:47 PM
I only mentioned it for the sake of history. Patent is long expired so anyone can manufacture them just as Badger is.

It's totally unnecessary, but I very much like the digital indicator instead of the dial simply for the convenience of being able to zero it. I think it would be a nice feature if the PMA tool used a digital mic stem as well, but they can be considerably higher priced, for a good one. That said, it really doesn't have to be a very expensive one for this application. If you desire more precision in this measurement, a depth mic would still be hard to beat. I doo like that this type of tool makes a rocking hs gauge easier to deal with though. On many of my hs gauges, I can put an o-ring on them for a snug fit in the chamber that also centers it up and prevents it from rocking.

The PMA tool looks very nice and I'm sure it would make a nice addition to the tool chest of anyone doing much barrel work..especillay on coned breech barrels like we use so often.

Dusty Stevens
02-01-2016, 10:56 PM
I bought one from pat at the nationals. I already had a few homemade ones with dial indicators. It works very well.