Muzzle brakes that don't blow off

[grit]

After the recent thread, I figured many would enjoy seeing how brakes are installed. I'm installing one now. I'll offer some photos and explanations. If you have any questions, I'd be happy to answer.

For starters, here is a finished brake, blended and polished to match the factory Sendero barrel. I built this brake to suit the customers wants.

 

[grit]

Here, I have a barrel through the headstock of the lathe, preparing to install a brake.

 

[grit]

Here's a closer view. I have cut an inch off the barrel, and refaced the end. I cut from the center out to not push a burr into the bore. This is important for the indicator rod. You will notice aluminum L's between the chuck jaws and barrel. I have finished dialing the barrel in. I start with a .001 indicator, and finish with a .0001 indicator. I indicate in two places on the rod to dial in both ends of the barrel.

 

[grit]

Here is the indicator rod with removable bushing. The rods are tapered. You choose a bushing to precisely fit the bore, then slide the rod in until the taper stops it. It is critical there are no burrs on the bore, and the bore is clean. There are several ways to dial in. They all work if you understand the possible shortcomings.

 

[grit]

Here is the outboard end of the head stock. The four opposing screws are called a spider. This allows both ends of the barrel to be dialed in. The barrel has an aluminum collet around it to prevent marring, and to aid dialing. The action is temporarily installed to mark the top flute, for brake timing.

 

[grit]

Here is a photo of the aluminum L's in the chuck. These allow the barrel to pivot when dialing in, and prevent slipping and marring. The brass tipped screws (they are .22 shells) are in the spider. This makes for a short pivot point, prevents marring, and aids dialing.

 

[grit]

This is the brake the customer supplied. I believe it is from Center Shot Rifles. The next steps are to turn the barrel to diameter, thread the barrel, time the brake, recheck our dial in, cut the barrel crown, install the brake, drill the brakes bore hole, double check our bore hole alignment and size, chamfer the edges, cut the taper on the brake, blend the brake, and bead blast. If that isn't a run-on sentence... As you can see, some thoughtful person labeled the top of the brake to keep the gunsmiths world right side up .

 

[grit]

I forgot two steps. Gotta feed the horses and get a pepsi . I'll photograph and post more as I go.

 

[grit]

In the first photo, I've taken a light pass and set a micrometer stop a few thousandths short of my desired tenon length. When I get to diameter, I'll back the stop off a few thousandths and pull the cutter out for a nice shoulder. The second photo is turned to the correct diameter.

 

[grit]

I've taken a light threading pass and am verifying my thread pitch is correct.

 

[webs]

Does the final step include JB Weld?

 

[grit]

Does the final step include JB Weld?

You'll have to wait and see !

 

[grit]

I set the compound the same angle as the threads. Advancing the thread depth with the cross slide minimizes cutter contact and chatter, for a smooth thread cut. This is my first test fit. The brake just starts to thread. From this point I will advance the crosslide, rather then the compound, .001 per pass until the brake threads on completely. The goal is resistance free threading with minimal clearance.

 

[grit]

I took .003 from the first test, where it started to thread, to final thread depth. Out of curiosity, I put an indicator on the brake. With the brake threaded on half way there is .002 movement at the indicator. If you did the math, you might figure there is under .001 play in the thread fit. You could shoot the rifle like this without clearance issues or the brake blowing off.