Crush washers for threaded muzzles. CHEAP!

[imarangemaster 315]

I have an AMD65 brake headed my way to put on those lovely 14mmL threads I found under my shroud. I looked around for crush washers to index it correctly. Dinzag is out, but you can get 5/8" AR10 crush washers from Midway USA, etc for about $4 and shipping, usually about $6 shipping. Then it dawned on me: Many spark plugs have 14mm threaded shanks that screw into the block. plugs that are non-taper seated have very nice, compact 14mm crush washers on them. Ran by O'Reilly's Auto parts and got a lawnmower plug for $2. When you look at a plug, usually the first number tells you if it is 13 mm or 14, on a car plug. 14 mm RN45Y. The 4 denotes 14mm thread. Lawnmower is a little different, but 4 still means 14mm. Mine was something like an 844-1.

 

ANyway, should be good for about most of a half turn to index your threaded brake,

Edited October 28, 2010 by imarangemaster

[Stansplace 414]

I was gonna do that, but discovered the detent pin. That's the way I went.

[imarangemaster 315]

Detent is the way to go if you cut the shroud all the way back to the FSB. Some 14mm L flash hiders and brakes can not accommodate that long of a threaded area, though. That's why folks use locktite when they cut the shroud only half way. Crush washer is a better alternative when the shroud is not cut all the way back.

[imarangemaster 315]

Here is a picture of the AMD65 brake using a 14mm spark plug crush washer to index it. Cut the shroud back half way using a hose clamp as a guide and a dremel cut-off wheel, smoothed it a little with a safe side file, opened up the inside of the crush washer at tad with a round file, to let it go on easier, then screwed the AMD65 brake down with my hand until snug. Finally took a wrench and turned it half turn to line up. Washer worked perfect. Touched it all up with some rustoleum high temp stove paint.

[Stansplace 414]

That looks good, I was gonna go that route, but my problem was on one of my SAR 1's and it already had a detent pin hole but the detent pin and spring were MIA so I just made one. If I do a Saiga in X39 I may go this route instead of modding or changing the FSB.

 

I even posted a thread questioning where to get a crush washer but Nalioth showed me the error of my ways. Good info either way.

 

Keep us posted about how it holds up at the range.

[oxyehho 8]

awesome! Thx for the idea and the pics!

[Klassy Kalashnikov 1,393]

Awesome idea, I really like it.

[imarangemaster 315]

If I had one with the hole for the index pin, I would go that way too. Unfortunately, if you cut the Saiga shroud back all the way to the FSB (actually even more than about 1/2 way) the threads are too deep for most 14mm L flash hiders and brakes. Neither my AMD65 brake or the Tapco M16A1 style birdcage type FH could thread much deeper than this is.

Edited November 2, 2010 by imarangemaster

[CPE1704TKS 24]

Then it dawned on me: Many spark plugs have 14mm threaded shanks that screw into the block. plugs that are non-taper seated have very nice, compact 14mm crush washers on them.

 

Believe you can also use oil pan drain plug crush washers.

Edited November 6, 2010 by Mikey

[Stansplace 414]

Then it dawned on me: Many spark plugs have 14mm threaded shanks that screw into the block. plugs that are non-taper seated have very nice, compact 14mm crush washers on them.

 

Believe you can also use oil pan drain plug crush washers.

 

I tried the oil pan ones, they don't crush enough to be of any use. At least the ones I tried didn't.

[imarangemaster 315]

The nice thing about spark plug washers is that you can get almost a full turn of crush from them. Mine turned snug by hand just shy of being correct. I used a wrench to turn it 1/2+ turn, lined up sweet and is VERY tight. No lock tight.