truing the bolt face

[SPM]

has any of you tried using a bolt face truing cutter, or is it better to use a lathe? thinking about buying one, i kind of screwed mine up and had to have george at ga precision clean it up for me. SPM

 

[JayIdaho]

My preference is the lathe, using my homemade "LaBounty fixture" in a 4-jaw.

 

[Preacher]

A lathe will give you the best accuracy as long as you dial the bolt jig up perfectly.....

 

[SPM]

i can not seem to find a bolt jig, brownells has been out for some time. i have a homemade mandrel, but my steady rest does not have the roller tips and its a real pain to use. thanks for the replys, SPM

 

[TRECustom]

SPM; I've pretty much been on my own coming up with ways to do this stuff and I always wonder if a real machinist would do it better or easier. Anyhow, for Rem bolts I made up a 1/2" 13tpi r/h thread arbor with a square shoulder that steps up to a .700" dia shank that chucks into my 3 jaw, so that I can drive the bolt to single point the face. Even with the arbor made up tight in the back of the bolt, I added a socket head stop screw that sets in the cocking notch of the bolt, so I can run the lathe in reverse and cut from the firing pin hole going away from me. I can watch the cut better that way. Ground a hawkbill cutting tool that clears everywhere but the tiny cutting point. Chuck up arbor, set live center in f/p hole, fiddle with arbor until I get < 1 mil runout, then set the steadyrest behind the locking lugs and pull the tailstock back. I use CMD Extreme Pressure Lube #3 on the brass steadyrest tips.,can't find white lead). I've never used a steadyrest with roller tips, but I like the brass tips just fine. I think that they dampen resonances and prevent chatter.

Sorry to be so long-winded, but my wife hasn't shown me how to post pictures yet.

Hope this helps, Tom

 

[SPM]

thanks for the replys, i have come to the conclusion that it is more of an operator erroer than anything else. SPM

 

[CentrePunch]

Spm,
Standard bronze or PTFE steady rest tips are much better then the roller variety, the hardened rollers have a tendency to imbed into the surface of the iten being turned and do not elliminate vibration as well as the others.
Turn up a threaded mandrel to suit your bolt shroud thread and also a collar to fit around the bolt lugs with 4 screws through the diameter equally spaced.
Clock up the mandrel untill the threads run true at 2 points.
Screw your bolt onto the mandrel and clamp the collar around the lugs, locate your bolt off the firing pin hole with your live centre and skim the collar.
This will make the OD of the collar concentic with the firing pin hole
Set up your steady on the collar dial it in and hey presto you are ready to skim your bolt face.

Ian.

Ian.

 

[7C15]

Try McMaster Carr they have leaded antisieze. I got lucky some years ago when buying a belt sander off a guy and he had a 25# pail of white lead he wanted rid of so for $1 I came home with the white lead! It sure works great for High Presure lube.

SPM; I've pretty much been on my own coming up with ways to do this stuff and I always wonder if a real machinist would do it better or easier. Anyhow, for Rem bolts I made up a 1/2" 13tpi r/h thread arbor with a square shoulder that steps up to a .700" dia shank that chucks into my 3 jaw, so that I can drive the bolt to single point the face. Even with the arbor made up tight in the back of the bolt, I added a socket head stop screw that sets in the cocking notch of the bolt, so I can run the lathe in reverse and cut from the firing pin hole going away from me. I can watch the cut better that way. Ground a hawkbill cutting tool that clears everywhere but the tiny cutting point. Chuck up arbor, set live center in f/p hole, fiddle with arbor until I get < 1 mil runout, then set the steadyrest behind the locking lugs and pull the tailstock back. I use CMD Extreme Pressure Lube #3 on the brass steadyrest tips.,can't find white lead). I've never used a steadyrest with roller tips, but I like the brass tips just fine. I think that they dampen resonances and prevent chatter.

I use the same setup for opening Rem bolt faces too. May not be the best way, but it works with what I have.

Sorry to be so long-winded, but my wife hasn't shown me how to post pictures yet.

Hope this helps, Tom

 

[Clark]

My brother made a mandrel for truing the bolt face.
He made one with threads that screw into the receiver.

I made a mandrel, that is just a rod drilled for centers on either end and a drilled and tapped for a screw to take the torque. The tang of the receiver can be put between jaws to pick up torque as well.

 

[RIFLE1]

Locating your live center off the firing pin hole is your best option, aside some using an indicator w/ a small tip., I run roller bearing supports behind the lugs and tweak my steady to center the firing pin hole. It takes longer to set up and perform, but no surprises.) One must be very careful not to flare the firing pin hole with the live center when using it for drive support. I've seen quite a few done this way, and there is only one way to fix it, call Gretan or bush it yourself.

Aside from that being said, make sure your bolt face really needs this performed anyway. When you consider that 99.9% of Rem bolts, for example, have some fairly dramatic curve to them to start with, and the bolt changes position in the race under the dynamic forces exerted on from firing due to bolt bore tolerances, the bolt face has to be really out of whack to be of a measurable detriment to the system as a whole. If you can insert your bolt in your action with the striker unit installed,considering it is taken for granted that lugs are already lapped into suitable contact and the receiver has been faced) and you can only measure 0.001" or so from side to side of the bolt face referenced to the receiver face, it could be considered a waste of time, or at least it is by many old world smiths. Sometimes perfect is only perfect, not an increase in performance.

Just one more opinion,...

Chris

 

[Clark]

What am I doing, I posted about truing the receiver face.

This is bolt face on a VZ24 Mauser was made for 8x57mm, but I opened it up for 300 Win mag.