Questions on Timing a FH or Comp with a lathe...

AR/M4 AR Technical Discussion
1

A few questions for those who do this… GotM4, if youre online. :smiley:

  1. How many degrees to "proper time do you typically leave on a comp before final toqrue?
  2. How many degrees does milling a millimeter typically take out?
  3. Would you recommend the use of rockset for this timing method?

Estimates based on your own full hand-tighten torque will do if thats how you do it before going at it with torque wrench.
I have the FC556 in mind but inputs on whatever each of you guys use will be much appreciated.

2

I can run a milling machine but I don’t mess with a lathe, Drew at WAR Rifles does my lathe work and any milling that’s far above my head. A mans got to know his limitations.–Clint Eastwood. :wink:

FWIW there’s a formula for how much to take off per revolution of turn needed. I do use a tiny bit or Rocksett and about 15-20ft lbs or torque when attaching this way.

3

If you are not using a crush washer your comp/fh needs to be about 30 degrees before top dead center, it also matters how much torque you wont on your muzzle device torque to…AD

4

Very true… In which case, I would feel more comfortable trying it out myself on a mini mill over pestering a lathe operator. Im a bit of a control freak and notice the slightest tolerance differences by eye.
Would you know off hand or have a link to said formula?
Also, how many degrees do you personally leave on before proper torquing?

5

Thanks! Your post came up just as I was typing mine. Will set that as my max torque, probably + a dab of rockset… What do you think?