Bolt face and lug truing

K

KenG

Guest
I looked at a gunsmiths website that frequents this site and I saw an interesting fixture for dialing in the bolt for truing, it looked like it was similar to a spider but for your bolt. It looked pretty interesting and like maybe a better system then using your firing pin hole for a reference just wanted to see if anyone has seen better results and if it's worth building a fixture like this when truing up a bolt.
 
Ken

The problem with using the firing pin hole as a center is the darned things, more times than not, are not that true in the middle of the bolt body.
I don't true many bolts any more, because I don't fool with factory actions that much. I used to screw an attachment into shroud threads and use that to chuck on, running the lugg end in a small steady rest.
If you are going to do a lot of bolts, having a good fixture that allows you to true the body while holding the bolt secure enough is a big plus......jackie
 
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Brownell's has in stock the bolt truing fixture made by Cliff LaBounty. I have been using one for a few years and it has served me well.

Don
 
I currently have a fixture that screws into the back of the bolt (I have made several for different actions) but my area for concern is exactly what you point out, there is no guarantee on how the firing pin is centered in the bolt. The idea of a spider on the front of the bolt would fix this problem and also adjust for any conial movement in the bolt as it spins in the lathe allowing a zero runout setup. When the bolt is dialed to zero runout the lugs would be trued then a steady rest would be installed to clean up the bolt face. I was just wondering if it's worth it to build this for any gains it might buy me. I guess as I write this I'm realizing I'm going to end up building one because I'm seeing the advantages of doing it this way. I guess I was looking for an expierienced smith to tell me using the firing pin and dialing in the bolt works great and there is no need for this bolt head spider gizmo. I saw it on Bryant Customs website by the way.
 
4 Independent Jaw chuck, ball bearing support

rest placed as close as possible to (the working necessarry room needed) the rear of the locking lugs will give one all the space/time/room to work on the bolt accuracy bumps/lugs/face/nose at the same time. One can't ask for anything more.

Shoot well
Peter
 
I made up a very simple spider to engage the bolt nose and allow me to indicate the bolt body true for facing the back of the lugs and turning recess's for and finish turning sleeves. I got the idea from Greg Tannel's bolt sleeving video. Obviously, the spider must be removed and the steady rest set up to true the bolt face and nose.

I hope the pictures are clear enough to help. This is a simple setup.

Scott Roeder, Hubert, NC
 

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Great, yep that looks simple enough. Does the face of your bolt butt against the front of the jig or is the pressure from your set screws enough to hold everything in place on your live center?
 
Bolt Face and Lug truing

The Front of the bolt rests against the inside of the spider. The inside diameter only needs to be about 1.010". The bolt lugs run about .990 and there should not be much adjustment needed.

Scott
 
Another way to true the lugs is to hold the bolt nose in a 4 jaw chuck, run the tail stock with a center in the other end. Adjust the 4 jaw until an indicator runs zero while moving it up and down the bolt body. This will get the cleanup cut perpendicular to bolt body. You'll also be surprised how many bolt bodies are banana shaped.

Dave
 
The only true bolt is

One bolt, one setup, one set of cuts = one trued bolt.

Shoot well
Peter
 
Bolt Zeroing fixture

Hey Scott Roeder.
Just turned up one of your bolt truing fixtures. Made it just like the picture. Works great ! Thanks for sharing. Not too proud to pick up on someone else's good ideas.
Rich Quigley, Clinton Township, MI
 
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