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9/22/2017 12:11:25 AM
Posted: 3/6/2006 6:39:56 AM EDT
I've removed both the FSB and gas chamber from my "post ban" SAR1 and purchased replacement parts to make it evil once again (new gas chamber with bayo lug).

While I am replacing everything I want to make dead sure everything is TDC with the barrel and may need to drill new "slots" into the barrel for the pins. My pins measure .120". Will my #32 drill (.116") be the right size for the size pins I am using to achieve the proper press fit?

Also, when aligning the gas chamber and FSB on the barrel does anyone have any tips on making sure they are top dead center?
Link Posted: 3/6/2006 6:54:50 AM EDT
im still half asleep but i think
its #31 and 1/8x1/2 pins

as for making shure they arnt canted just eyeball it
you will know if they are off
Link Posted: 3/6/2006 11:59:37 AM EDT
1/8 = .125

My pins are .120, so I assume the next drill size down (#32) will be fine.

I was hoping for a better method of finding TDC. I don't eyeball my FAL builds nor my AR builds. My AK should be no different.
Link Posted: 3/6/2006 3:04:42 PM EDT
a #32 bit is .116 and .120 is a #31 like socandyman said.
Link Posted: 3/6/2006 3:25:37 PM EDT

Originally Posted By kidcaos:
a #32 bit is .116 and .120 is a #31 like socandyman said.

That answers nothing I asked.
Link Posted: 3/7/2006 10:54:11 AM EDT
you want .004-.005 between your pin and bit

when you drill a hole it will be .001-.003 bigger than your bit
and you want a .002 press fit

so your bit would be correct for the pins you have

i was just going off what i have used in the past
most people dont have the correct pins and to buy them and wait dosnt make much since when you can get 1/8 from any hs store
Link Posted: 3/8/2006 3:13:29 AM EDT
Gotcha, thanks!

I originally planned to just use .125 drill rod but since I was already placing an order with K-Var I went ahead and ordered the original size pins.

I remeasured my pins and it turns out they were .1215". So I used a .120" drill and they fit perfectly.

I also used a Dewey 1 piece cleaning rod laid down the center of the barrel to line up both the gas chamber and FSB. If they're both not TDC they sure are damn close.
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