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Need a barrel OD ground

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dgeesaman

dgeesaman

Member
Nov 14, 2019
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Hershey, PA
I have a barrel of particular interest that was machined for a clamp-style receiver at 16mm. It was not machined well and this surface is wavy and inconsistent by a couple thou.

I’d like to put this barrel in my RAW which needs to be .625 (+0/-.0005) diameter. So I assume the only good solution that keeps the length is to OD grind down to .625 and hope for 90-95% cleanup. (To be clear I only want the receiver end ground - not the whole length)

Suggestions who can do this? The local machine shops might but they aren’t barrel people. Bonus if they can machine the port and chamber too.
 
dgeesaman said:
I have a barrel of particular interest that was machined for a clamp-style receiver at 16mm. It was not machined well and this surface is wavy and inconsistent by a couple thou.

I’d like to put this barrel in my RAW which needs to be .625 (+0/-.0005) diameter. So I assume the only good solution that keeps the length is to OD grind down to .625 and hope for 90-95% cleanup. (To be clear I only want the receiver end ground - not the whole length)

Suggestions who can do this? The local machine shops might but they aren’t barrel people. Bonus if they can machine the port and chamber too.
Click to expand...
A manual machine job shop can easily do this. You have all the right call outs with dim and tolerance.
 
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Grinding requires doing so on a Live and dead center spinning blank via bore. If bore hole is not exactly center of blank you may have an issue.
Most grinding fixtures I've ever seen dont have a 4 jaw chuck that would allow O.D. run out to be adjusted, tho such chucks and adjustable run-out type fixtures do exist for Lathes.

Being so close to spec size wanted already is going to be tough .... Wish you the best in getting someone to take this on :oops:
 
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Motorhead said:
Grinding requires doing so on a Live and dead center spinning blank via bore. If bore hole is not exactly center of blank you may have an issue.
Most grinding fixtures I've ever seen dont have a 4 jaw chuck that would allow O.D. run out to be adjusted, tho such chucks and adjustable run-out type fixtures do exist for Lathes.

Being so close to spec size wanted already is going to be tough .... Wish you the best in getting someone to take this on :oops:
Click to expand...
I forgot to mention that using tubing mics I did confirm the ‘wall’ thickness to be uniform within a few tenths, which is to say it’s well centered at the very breech end.

Also I don’t mind losing a bit of the end. If they want to overbore, machine center, or turn down 1/2” for grinding, that’s a lot better than losing 4-5” of length.

I do wonder if a lathe with grinding attachment will work. I hear they’re a mess to use but for doing barely more than a spark-off it might be ideal.
 
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dgeesaman said:
I forgot to mention that using tubing mics I did confirm the ‘wall’ thickness to be uniform within a few tenths, which is to say it’s well centered at the very breech end.

Also I don’t mind losing a bit of the end. If they want to overbore, machine center, or turn down 1/2” for grinding, that’s a lot better than losing 4-5” of length.

I do wonder if a lathe with grinding attachment will work. I hear they’re a mess to use but for doing barely more than a spark-off it might be ideal.
Click to expand...
It’s going to be tough to find a shop to grind it properly and or not mess it up. Properly meaning the right machine to do the job. Crosman, Daystate ect do have custom center less grinders for this. A lathe grinding attachment can do it but would definitely still need a good follower on the opposing side of the wheel.
 
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Airgun-Revisions said:
It’s going to be tough to find a shop to grind it properly and or not mess it up. Properly meaning the right machine to do the job. Crosman, Daystate ect do have custom center less grinders for this. A lathe grinding attachment can do it but would definitely still need a good follower on the opposing side of the wheel.
Click to expand...
My mind goes to an engine rebuilding machine shop that can grind cranks and cams.
 
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dgeesaman said:
I have a barrel of particular interest that was machined for a clamp-style receiver at 16mm. It was not machined well and this surface is wavy and inconsistent by a couple thou.

I’d like to put this barrel in my RAW which needs to be .625 (+0/-.0005) diameter. So I assume the only good solution that keeps the length is to OD grind down to .625 and hope for 90-95% cleanup. (To be clear I only want the receiver end ground - not the whole length)

Suggestions who can do this? The local machine shops might but they aren’t barrel people. Bonus if they can machine the port and chamber too.
Click to expand...
That is normally a straight forward job for a machine shop, find a gunsmith shop. Most shops are set up to thread barrels either chamber end or muzzle. We do that all the time here altho it makes it easier if the barrel can be removed from the action. Set in a four jaw chuck and centered. Much the same as treading the muzzle for a brake or silencer.
Good luck on the project
 
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Motorhead said:
As with nearly all one off machining jobs your paying for mostly SET-UP time, as the actual doing happens very quickly.
Click to expand...
Customers need to understand that. Production and single jobs are two different bears. What also adds to the time is the experience to not mess the part up. We only have one shot so it needs to count.
 
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