03-20-2023, 01:39 PM
As far as "eyeball" estimates of how far off your brake is from timed (ie, tdc), I would say estimating by degrees of the circle, 15, 30, 45, 60* are relatively easy for the eye to see. Based on 30-60-90, 15 is 1/4 of a hex flat... and so on.
To move the brake on a 5/8-24 threading, every 15* is a thickness of 0.00174", 45* is 0.0052".
So if you tighten up your brake and it is (for example), 15* past tdc, you need a shim of 0.005" to set it back to straight... but that's not torqued. You need a shim some X thou's MORE beyond 0.005 so that when torqued to your desired inch (or ft)-lbs you are timed. How much is that extra? Idk, but probably on the order of ~0.005 more (just a guess). I think I read somewhere that going 15* was an acceptable amount of torque... but don't remember exactly.
Another thought. If your barrel mfr could always start the thread pitch at the same spot on the barrel circumference, and the same spot on your brake, you would know pretty much that they both would time to tdc when mated up. If that "mate-up" was finger tight at, say, 15* before tdc, then torquing to tdc would put you there... that sort of logic. May be too hard to get mfrs to do this however. And would not apply to using any other barrel... just brain storming here.
To move the brake on a 5/8-24 threading, every 15* is a thickness of 0.00174", 45* is 0.0052".
So if you tighten up your brake and it is (for example), 15* past tdc, you need a shim of 0.005" to set it back to straight... but that's not torqued. You need a shim some X thou's MORE beyond 0.005 so that when torqued to your desired inch (or ft)-lbs you are timed. How much is that extra? Idk, but probably on the order of ~0.005 more (just a guess). I think I read somewhere that going 15* was an acceptable amount of torque... but don't remember exactly.
Another thought. If your barrel mfr could always start the thread pitch at the same spot on the barrel circumference, and the same spot on your brake, you would know pretty much that they both would time to tdc when mated up. If that "mate-up" was finger tight at, say, 15* before tdc, then torquing to tdc would put you there... that sort of logic. May be too hard to get mfrs to do this however. And would not apply to using any other barrel... just brain storming here.