How to chuck a bolt body ???

My standard method has been,first put the cute lightening hole in the bottom of the knob while it is straight,with a Bridgeport.

Then I cut about 70% through the bolt handle,from the top,right where I want the bolt to bend over the receiver rail.

That makes a nice spot to wave an oxy-acetylene torch.Its thin,it heats quick,and I have a hinge to bend the bolt handle body down with,.I still have the original root to bear against the rail to clock the rotation.And,I have a nice,open Vee on the top to fill with weld.That cut gains a little length,the outside bend radius.

I won't bother you with the electrode I would make for the EDM machine by plunging a 5/8 ball mill into some graphite to burn down the ball.I don't have access to EDM any more.

And,I still 5think bolting some 4 or 41/2 in deep aluminum soft jaws on your chuck and boring them to fit the bolt body would work to open your bolt face.
 
I looked at my options and went with this setup:


The sleeve is actually cut into two pieces directly under the bolt, so it isn't visible.

It wasn't perfectly aligned when I chucked it, but it was close enough so that the adjustment between my chuck and spindle (roughly .020") was able to accommodate it easily with a TIR that was ~0.0003 inches. It worked so well, actually, that I popped a second one in and opened it (in the pic with the straight bolt handle) to WinMag specs. The metal is clearly harder than most, but I didn't have any issues with the carbide tools and the interrupted cuts ... I did keep my mouth closed, though, in deference to Clark :D

Thanks to everyone for offering their suggestions ...

Saands
 
Hi, Clark,

I wasn't making pretty jewelry either, but if you don't care what the result looks like, I think a lot of "men" would prefer to take their guns elsewhere. If a guy wants a weld job done by the local tractor shop, he will take it to the local tractor shop, not pay a gunsmith.

Jim
 
Saands,
There are a couple things I noticed about your pic:
1) You are cutting with a 60 degree Carbide insert with chip breaker tipped profiling bar or boring bar.
2) Your bolt fixture is made from ~ 3" Aluminum round stock.
3) Your ways are flat.
4) Your jaws on the 3-jaw chuck don't match.
5) You have not cut or bent the bolt yet.

And you say the fixture is two piece, and the chuck is adjust through.

I could see how buying a bar like that could save me some time and do a better job.
 
I double clicked the pic and blew it up.
The chuck jaws match,the lathe has a vee way
Adjustable 3 jaw chucks are common,and very nice.You can dial them in like a 4 jaw.

One thing to watch working inside a small dia like that with inserts,they have minimal clearance for cutter edge strength,watch your heel clearance.I also suggest I hope your tool nose radius was very small.Corner radius in the bolt face could be a problem,.If you have a diamond wheel,you can make some real useful special tools out o a dull micrograin insert.

Good job!!You got her done.

If you do not have any,check MSC,Travers,Enco,etc for aluminum soft jaw inserts .
 
Years ago I ground a tool to open the bolt face of 91/30 Mosin Nagant to 45/70.
I was surprised at the constraints on that tip.
It is like a cork screw to get in there.
 
Insert was actually a 55 deg diamond shaped tool ... and yes, the insert has a smallish radius (0.008" IIRC) ... but after I dialed in the threading routine for the barrel threads, I made a shoulder lapping and bolt face lapping adapter that screws into the threads and guides/holds a lap perpendicular to the face or shoulder. This lap sneaks all the way into the corner of the bolt face so the radius that I have on the bolt should be smaller than that of the tool that cut it.

The bolt in the pic was the second one I did ... it wasn't any easier or more difficult to do than the bent handled one, it just didn't occur to me to take a pic until I had already unchucked the first one.

I actually have soft jaws (even have an EXTRA set of 4" ones), but for the life of me, I couldn't figure out how to get the relief cut into the back side of them to accommodate the bolt handle (recall that I don't YET have a mill) ... so I didn't try that route. Oh ... it just occurred to me that not all soft jaws are pie-jaws ... the full pie style is the only kind I've ever used and are what I had ... now that I'm opening my mind a bit, I think I see what you are saying :cool:

Saands
 
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I made a lathe fixture to hold welded bolts, so i could clean up the intermediate weld from extending the bolt handle length.

You can't see it, but the bolt body is in a V notch in the Aluminum plate.
 

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  • MausersBoltHandleFistureDSCF0033.jpg
    MausersBoltHandleFistureDSCF0033.jpg
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Here is my bent bolt on the 330



I bent this one by cutting about 40% of the way through the handle about .125" from the root. I heated with oxy-acetylene and pushed it over. I am mounting my scope on a Farrell one piece base and this bend clears it easily, even with a flip-up lens cover in place. It is coming along :)

Saands
 
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