Gunsmithing Muzzle Break Timing

[cuutter]

Is there a formula for calculating the amount to be faced off the break in order to get it timed correctly? I can figure the pitch of the threads and dia. of break just don't know how this information tells me what to face off. I appriciate any help on this.
Thanks
Wayne

 

[BOLTRIPPER]

Re: Muzzle Break Timing

gunsmithing class don't start till Randy gets here ....or Roscoe, or George.....or ............

 

[DAVETOOLEY]

Re: Muzzle Break Timing

or Dave

divide 1 by the pitch, this gives the distance traveled in one turn. Then multiply that by the percentage of one turn needed.

Example: 3/4-24TPI 1 divided by 24 gives you .041" per turn.
Eye ball the percentage of rotation needed. 50% or 180 degrees would require you take off .0205" off the shoulder. 90 degrees would be about .010". Best to sneak up on it as it's easy to over shoot. On my manual lathes I set up a travel indicator on the carridge and then cut about 2/3 off the first go around, then sneak up on the rest of it.

 

[300sniper]

Re: Muzzle Break Timing

divide 1 by your thread pitch to get the decimal number of the distance traveled by one full rotation. divide that by 360 degrees. that will give you the amount that needs to be removed from the shoulder for each degree. multiply that by the degrees you need it to rotate.


for example, say you have a 5/8-24 muzzle brake and need it to rotate another 15 degrees.
1/24=.0416" thread pitch
.0416/360=.0001" per degree
.0001x15=.0015" removed from the shoulder
(to avoid doing math on a 24tpi, .001" per 10 degrees is what i use)


or a 16 tpi barrel to receiver thread to rotate 15 degrees.

1/16=.0625" thread pitch
.0625/360=.0002" per degree
.0002x15=.003" removed from shoulder

 

[cuutter]

Re: Muzzle Break Timing

Hey thanks you guys. I guess I was over thinking it.
Thanks again
Wayne

 

[krlemas]

Re: Muzzle Break Timing

Here is how I do it; on a 28 pitch brake you divide 1 by 28 that gives you .0357 that tells you that if you remove that much thread off the brake it will rotate 360 deg. now divide the .0357 by 360 that gives you .0000992 that tells you that for every 1 deg you want the brake to turn you have to remove that much. Now I figure the circumference of the brake a 1" brake is 1 X 3.1416= 3.1416" so if you divide that by 360 you get.0087 that means that for every 1 deg rotation the outside of the brake moves .0087". Now I put a screw in the rear scope base mount hook a string and pull it the full length of the barrel on center, over the brake and then measure how much it has to rotate with a caliper then divide that by .0087 and that tells you how many deg it has to rotate multiply that deg. by .0000992 and that tells you how much you have to remove off the threaded end of brake. I always stop short and then remove it with 600 wet sandpaper on a very flat surface a LITTLE at a time. I do this on my lathe with the compound set on a angle so I can remove .0001 at a time when I get close.
This is the math and other then this you have to guess and I always seem to guess wrong so I use the math.
Hope this makes since.

Ken
NRA Life Endowment Member

Sniper I was typing while you had already posted so it looks like you had already provided the information....sorry

 

[AXEMAN]

Re: Muzzle Break Timing

see, id do it differently. start by measuring the checkbook, divide that by roscoe or one of the other smiths phone number and there you go, lol.


now i am glad i am good at math after i see what you guys have togo through. much respect for the machinists. i know we dont see the work and effort you put into doing this stuff, but the end results are nothing short of art work

 

[Goin'Hot]

Re: Muzzle Break Timing

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AXEMAN</div><div class="ubbcode-body">see, id do it differently. start by measuring the checkbook, divide that by roscoe or one of the other smiths phone number and there you go, lol. </div></div>

Now that's funny right there!

 

[He Shoot Me]

Re: Muzzle Break Timing

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Goin'Hot</div><div class="ubbcode-body">

see, id do it differently. start by measuring the checkbook, divide that by roscoe or one of the other smiths phone number and there you go, lol. </div></div>

Hah! Or, use plan C. Walk into your local drive line shop with your rifle and new brake in hand. Mind you, YOU WILL be getting some very strange/concerned looks as you approach said shop, but all will fine as long as you have cash in your free hand.

-Pat

 

[wnroscoe]

Re: Muzzle Break Timing

Cutter, don’t forget, never remove enough material so the brake times up exact while in the lathe, leave approx 1/16 of a turn for tightening.

As mentioned above 1 divided by thread pitch equals the amount needed for one complete revolution. I always cut short and try to sneak up on the desired dimension. It does suck to go past it.

 

[x ring accuracy]

Re: Muzzle Break Timing

Sneaking up on it still means cut, check, cut some more, check, cut a smudge more, check, and then start cutting! Timing a brake in my opinion is more tedious than any other operation.

 

[jimmyrjessie]

Re: Muzzle Break Timing

The math provided above is your best choice for sure. If that does not work well for you you can also thread the brake on all the way see how much it needs to turn. Then back it off half way or so stoping the brake at the same position as it did when bottomed out and take a measurement (say .270) with a pair of calipers. then rotate the brake to timed position take a secod measurment (say .241). now sbtract first measrment from second and you should be real close (= .029 The numbers are just an example) On a side note you should still leave a little to sneak up on it. hope this helped.

 

[eddybo]

Re: Muzzle Break Timing

That is one of those why didnt i think of that ideas, thanks.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300ultramag</div><div class="ubbcode-body">The math provided above is your best choice for sure. If that does not work well for you you can also thread the brake on all the way see how much it needs to turn. Then back it off half way or so stoping the brake at the same position as it did when bottomed out and take a measurement (say .270) with a pair of calipers. then rotate the brake to timed position take a secod measurment (say .241). now sbtract first measrment from second and you should be real close (= .029 The numbers are just an example) On a side note you should still leave a little to sneak up on it. hope this helped. </div></div>

 

[Bronco]

Re: Muzzle Break Timing

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: eddybo</div><div class="ubbcode-body">That is one of those why didnt i think of that ideas, thanks.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300ultramag</div><div class="ubbcode-body">The math provided above is your best choice for sure. If that does not work well for you you can also thread the brake on all the way see how much it needs to turn. Then back it off half way or so stoping the brake at the same position as it did when bottomed out and take a measurement (say .270) with a pair of calipers. then rotate the brake to timed position take a secod measurment (say .241). now sbtract first measrment from second and you should be real close (= .029 The numbers are just an example) On a side note you should still leave a little to sneak up on it. hope this helped. </div></div> </div></div>

Seems like I run across this all the time.
I was working with an "old" machinest and we needed to counter sink for a screw. I got the screw and started to measure how deep and he grabbed it and stuck it on the depth control of the mill ran the stop down on top of it and was ready to go. Worked great.

 

[cuutter]

Re: Muzzle Break Timing

Thanks again guys for the help.
Wayne

 

[dreamdrummr]

Re: Muzzle Break Timing

Not to hijack the thread, but Eddybo, I tried to send you a PM but it says you are full... can you please send me a PM? Thanks, jimmy