After my month long search and postings I bought a JEC Brake. In speaking with jason told him i was threading the barrel myself. He mentioned you need to indicate off the rifle bore and not the od of the barrel because they are seldom concentric and the brake is precision made. The light clicked on it made alot of sense, didnt think that one out. Next call was to Pacific Tool and Gage to purchase a range rod to place in the rifle bore to indicate it in. Never thought about but i could have ruined a perfectly good barrel. Wanted to post this to maybe help someone else . I am sure everyone has a buddy that can thread a barrel and most would indicate off the OD Thanks to Jason at JEC
Gunsmithing Threading Barrel for brake
- Thread starter kish
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Only a garage mechanic would indicate off the OD and then thread. I make my own, done a number of them. I usually make them oversize, thread and fit it to the barrel and them, with it mounted, indicate in the OD of the barrel and turn the brake to match the barrel.
No need for a range rod...simply use a test indicator inside the bore. Cut and thread the tenon, fit the brake...indicate OD like mentioned above and turn brake to match barrel or a few degree taper to bore. Just did this Vias(1/2-32) on a M70 in 300 WSM. Blue is Brownells cold blue polished with steel wool.
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Never done anything like this before on a rifle just trying to learn, I was worried about indicating off of the bore not getting a good reading because of the rifling. Are the rifling lands all the same height or do you indicate off of the major dia?
Did order the range rod after pinning out the barrel, wanted to place two indicators on the rod one close to the end of the barrel and one about two or more inches down to ensure it was running true. Did pin check the barrel last night, a .2560" pin went in the crowned end about 3/4" and stopped. the .2550 pin slipped in all the way with no interference. is this normal ? This is a factory barrel
I shoot for the major diameter. Its very possible for the rifling to be different dimensions...never know what you get on a factory barrel. Work at it and get it best possible...that's all you can do. The range rod will work too...never can have enough tooling, lol.
My issue with range rods is if you dial it in perfect, then take the rod out and put it back in, check your reading and it will likely be off again. I never liked that which is why I moved to direct indicating, super easy once you do it a few times.
Not to say range rods don't do the job, they do, you must need a lot more tooling to use them if you work with every caliber.
Galaxy S3 on tapatalk
Not to say range rods don't do the job, they do, you must need a lot more tooling to use them if you work with every caliber.
Galaxy S3 on tapatalk
The thing I hate about indicating on the bore itself is needle bounce. Kinda hard to keep it tight with the needle dancing everywhere.
I have not noticed a marked repeatability issue with range rods.
I will use gage pins frequently as well.
I have not noticed a marked repeatability issue with range rods.
I will use gage pins frequently as well.
What do you mean by "needle bounce"?
I assume you are not spinning the chuck around quickly while indicating... I spin the chuck by hand in neutral extremely slowly until it gets to the next groove. It does help to get the bore close to start with, I always stick the live center in the bore when Im tightening the 4-Jaw, this way it starts off pretty close to center. If you are starting with the bore out by more than the sweep of the indicator you could be at it awhile.
Once you get the direct indicating method down I 100% guarantee you will be able to do it much much quicker than with a range rod. I say this because with a range rod, you can never get your pivot point at where you are indicating from. With direct indicating, you set the barrel stick out so that with the indicator all the way in the bore, the tip is at your 4-jaw pads. Now when you are adjusting the actual chuck, you are adjusting it at the measurement point. This way when you adjust the outboard spider, its not throwing your chuck inner adjustment all out of whack. Kind of hard to describe what Im talking about.
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