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What drill bit/tap size do I need to install Ace stock on Draco?
7/17/2011 1:10:00 AM
I ordered the stock and adapter and its on the way, just wondering what size tap and drill bit
are needed for the install. Thanks
are needed for the install. Thanks
7/17/2011 11:53:02 AM
It's a 10-32 tap.
That will need a #21 drill bit, (which is something weird, like .1259 (ETA: Looked it up .159") or whatever in inches, not sure there's a fractional equivalent) although most places will sell the bit right with the tap.
Remember, use LOTS of cutting oil, and go SLOW, and only do ONE QUARTER TURN at a time before backing out to clear the chips.
The trunnion steel is some pretty hard stuff. And as long and tiresome as it may seem tapping that trunnion 1/4 turn at at ime, it's not nearly as time consuming as trying to pull out, or shatter a broken tap, then welding up the hole, grinding the weld flat, and trying again, or just abandoning the tap in there and grinding that flush. 
7/17/2011 2:20:20 PM
Originally Posted By AJ_Dual:
It's a 10-32 tap.
It's a 10-32 tap.
That will need a #21 drill bit, (which is something weird, like .1259 (ETA: Looked it up .159") or whatever in inches, not sure there's a fractional equivalent) although most places will sell the bit right with the tap.
Remember, use LOTS of cutting oil, and go SLOW, and only do ONE QUARTER TURN at a time before backing out to clear the chips.
The trunnion steel is some pretty hard stuff. And as long and tiresome as it may seem tapping that trunnion 1/4 turn at at ime, it's not nearly as time consuming as trying to pull out, or shatter a broken tap, then welding up the hole, grinding the weld flat, and trying again, or just abandoning the tap in there and grinding that flush.
I'm just buying the parts, I'm having my dad do it for me
I don't want to screw it up lol. Thanks7/17/2011 3:07:25 PM
The number 21 bit is for aluminum, the correct bit for the steel trunnions is a number 18(.1695)
Using the #21 will make it easy to break the tap
Using the #21 will make it easy to break the tap
7/17/2011 3:30:24 PM
Originally Posted By Urban_Ops:
The number 21 bit is for aluminum, the correct bit for the steel trunnions is a number 18(.1695)
Using the #21 will make it easy to break the tap
The number 21 bit is for aluminum, the correct bit for the steel trunnions is a number 18(.1695)
Using the #21 will make it easy to break the tap
Good to know.
7/17/2011 3:49:58 PM
So use an #18 bit and a 10/32 tap?
7/17/2011 7:13:18 PM
Yes, a # 18 bit and a 10/32 tap.
I always buy gun flute taps rather than the el cheap hardware store hand taps, stronger and easier cutting on through holes.
Here is a good ref chart, normally use a slightly larger bit for steel
http://www.shender4.com/thread_chart.htm
I always buy gun flute taps rather than the el cheap hardware store hand taps, stronger and easier cutting on through holes.
Here is a good ref chart, normally use a slightly larger bit for steel
http://www.shender4.com/thread_chart.htm
