I'm currently using a lot of brakes by Harrell's Precision- which are 9/16" thread, tenon length is only .500 max- but thread pitch is 32. The fine threads allow a greater number of threads for engagement, and fine threads are less subject to loosening from vibration than coarse.
The threads do not align the brake to the bore (though they certainly need to be precise). This is done by the shoulder on the brake (typically the rear of the brake, but a shoulder can be internal to bear against the muzzle if needed) being torqued against the barrel shoulder. Both of these surfaces must be machined at perfect right angles to the bore. Assuming you're trying to fit this brake to a factory-threaded barrel, you need to determine the class of thread fit (2A or 3A) by contacting the manufacturer or using wires. Then, the threads could be cut with an appropriate tap.
This is all about clearances. Typically, a brake should bee bored to have 20 to 30 thou clearance over bullet diameter. Any more than that, costs some efficiency. Obviously, the tighter the clearance, the less room for misalignment error.
A flash hider could be threaded by a monkey with vise grips, crooked as hell and there won't be a bullet strike. The longer the muzzle device, and the smaller the clearance, the greater the precision required. An 8" suppressor with tight baffle clearances requires absolute perpendicularity so that baffle strikes do not occur. You must have some way of ensuring that the hole you're drilling/tapping is perpendicular to the brake shoulder- which is why this is best done on precision machinery (lathe or mill).