30 dgr bolt nose clearance

J

johan teughels

Member
how do you guys measure /cut the bolt 30 dgr bolt nose clearance and end play when chambering a new barrel for a glue in action
 
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Mine is a flat bolt face. I did it the same way I do the counterbore on a Remington.Measure from the face of the action, and recoil lug if it has one, to the face of the bolt, subtract around .005 to .008 for the clearance.

I know it is difficult to get a regular set of depth mic's on the action face in a glue in, I have a set that is cut off on one side in order to get close to the center.

The important thing is to give it enough clearance so there cannot ever be any interference, but not so much as to uncover the web of the case.

Assuming they are all the same, mine measures .587 inch.

http://benchrest.com/attachment.php?attachmentid=19194&stc=1&d=1489405102
 

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Bolt Nose Clearence

I use I fine piece of lead.And measure it..like a bullet a squirt,or plumbers use fine lead wire to pack joints,you could probably also use that stuff they check bearing clearences in rod and main bearing.plasti-gauge.I shoot for .006".010"clearance.
bill
 
Lead works great but for the occasional one off you can use several layers of tape on the front face of a lug. One thing you didn't mention is if you have a barrel on the action now. If so make a long piloted CB gage. Take some 1" round stock, I used brass, turn a 2" long pilot, caliber of your choice and finish up with a 30 degree angle out to full diameter. It a mirror image of your counterbore. Part it off, square up the face, drop it into the existing barrel and take a measurement just like you were measuring the HS. With the shallow counter bores on custom actions getting a close fit isn't as important as it used to be.
 
When I did the very first chambering job for a bolt gun and it had to be a glued in action, Butch loaned me the necessary tools to accomplish the job. Before I returned the tools I duplicated them.This is one of them.

I had to bug him a few times asking for details how to use the various tools, he was patient. Thanks, Coach.
 

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NezRongero said:
When I did the very first chambering job for a bolt gun and it had to be a glued in action, Butch loaned me the necessary tools to accomplish the job. Before I returned the tools I duplicated them.This is one of them.

I had to bug him a few times asking for details how to use the various tools, he was patient. Thanks, Coach.
Click to expand...

that is what i was thinking to make. other idea is to use a a ball from a bearing )prox 1" ore 250 mm and a a tube that fits on the sholder so i can measure on the barrel that i want to duplicate

i
 
johan teughels said:
how do you guys measure /cut the bolt 30 dgr bolt nose clearance and end play when chambering a new barrel for a glue in action
Click to expand...

If you are planning on doing several barrels you need to make the necessary tooling that allows you to do an actual measurement from an older barrel taken from that action..

If you are going to do just one you can start the indention and just by looks get close to the proper depth but not to full depth.

Then remove the barrel from the lathe and with the bolt in the action, screw the barrel in as far as it will go. Then measure the gap between the action face and the barrel shoulder. Re indicate the barrel and take this amount off the 30 degree surface plus about 0.010".

If you feel safer sneaking up on it, just take some off then reindicate the barrel and take a lesser amount off than what your measurement above was. You may want to do this several times till you get confidence in the process. The final measurement of bolt nose clearance to barrel cone should be about 0.010".

If you have just chambered that barrel, how did you determine the headspace?



.
 

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This is what I use. I have one that is 18tpi and another at 16 tpi. Nez's picture of the valve type tool for bolt nose clearance at 30 or 25 deg. You can also use your headspace gauge. The vertical lines are used to copy where the old barrel info and transfer it to the new barrel. It is easier for me to screw it on and use one hand to measure instead of a sleeve that takes 2 hands.

zsok5x.jpg
 
Hal D. said:
Like most, I've made up my own tools, but I'd pick one of these up if I hadn't.



http://www.pmatool.com/pma-woolums-accuracy-barrel-micrometer/
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that is the idea i got

i got symilar tools like the ones jackie uses

i think that a ball is more accurate too measure but then i might be wrong and make like a bunch of you guys make me a 30 dgr tool

look way more userfrindly then a ball to measure a barrel that sits horizontaly in a lathe
 
JerrySharrett said:
If you are planning on doing several barrels you need to make the necessary tooling that allows you to do an actual measurement from an older barrel taken from that action..

If you are going to do just one you can start the indention and just by looks get close to the proper depth but not to full depth.

Then remove the barrel from the lathe and with the bolt in the action, screw the barrel in as far as it will go. Then measure the gap between the action face and the barrel shoulder. Re indicate the barrel and take this amount off the 30 degree surface plus about 0.010".

If you feel safer sneaking up on it, just take some off then reindicate the barrel and take a lesser amount off than what your measurement above was. You may want to do this several times till you get confidence in the process. The final measurement of bolt nose clearance to barrel cone should be about 0.010".

If you have just chambered that barrel, how did you determine the headspace?



.
Click to expand...

in do not want to take out the barrel from the lathe untill the chamber is completly finished
for a bolt in i screw the action on and measure the gap like you do
 
The problem I see with the ball to measure with is if the angle's aren't exactly the same, the depth will be different. I have measured some barrels that were done with the ball and they had some variation, and more than I would ever want from a safety aspect.

I also like to measure the distance with a piece of lead. I have a roll of lead wire from fly tying that works great. It is .015" diameter.

Joe Hynes
 
liljoe said:
The problem I see with the ball to measure with is if the angle's aren't exactly the same, the depth will be different. I have measured some barrels that were done with the ball and they had some variation, and more than I would ever want from a safety aspect.

I also like to measure the distance with a piece of lead. I have a roll of lead wire from fly tying that works great. It is .015" diameter.

Joe Hynes
Click to expand...

yes you are probably right about the ball i will make a 30 dgr piece
 
johan teughels said:
in do not want to take out the barrel from the lathe untill the chamber is completly finished
for a bolt in i screw the action on and measure the gap like you do
Click to expand...

After you cut your tenon and chamber using whatever measuring adapter you decide to use, trial fit the bolt by just holding it up against the end of the barrel tenon with your go gage in the chamber. It is easy to make sure you have at least enough clearance.
 
SGS said:
After you cut your tenon and chamber using whatever measuring adapter you decide to use, trial fit the bolt by just holding it up against the end of the barrel tenon with your go gage in the chamber. It is easy to make sure you have at least enough clearance.
Click to expand...

good idea
 
I cut the cone until the bolt just closes and then measure the clearance with a dial indicator on the back of the bolt then cut the cone for .005"-.008" clearance, easy.
 
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