finndogg54

Hey yall, I was hoping that someone could tell me where to find a drill bit size "R". Or if maybe it translates to a standard size. This is what ISSPRO recommends to drill with before using the 1/8" NPT on their pyrometer. According to the packaging on the tap it says use with a 11/32 bit. Can anyone enlighten me on the subject?

jwb600

ive got a tap dril chart I go by that tells me what size the letter drill bits are.
you may be able to get one from a hardware store. I know ive got a bunch of them from when I was in college for machining

WolverineRam

Drill bit "R" is .339" in diameter. Hope that helps

danc46

It's smaller than the Q drill bit and larger than the S drill bit.

t-boe

I used a 21/64" bit. It's .328" so it's about as close to a "R" .339" as your going to get without actually having to find and buy one. An 11/32" is .343" so it's a little bigger.

finndogg54

Thanks T-BOE

Billm2004

Sorry, but i though it was funny

Boris-MC1

Diesel Manor has the whole tap kit and individaul tools for pyro installation

I am not affiliated to DieselManor in any way other than a customer.

boris

bkrukow

Ime a CNC Machinst and run 1/8-27 NPT threads literaly every day. We use zerks with that thread on the parts we build. If ya want it to seal properly use the letter "R". Anything larger will leave less than suficiant threads and increase the likelyhood of it leaking or striping out from weak threads. Smaller would be better but still not advisable. Drills are cheap. Find a hardware store and spend the couple bucks and get the proper drill.

mjsandt

When I installed my COmmander, Qaudzilla recommended a 21/64, and the package the tap came in also said 11/32. I followed Quads advice and used 21/64, and it worked good, but was a pretty tight squeeze when I started to run the tap through, but it worked out.

M Sandt

cameroneod

I couldn't find an "r" bit locally. Ended up drilling it a bit smaller and just going to town with the tap. Worked for me.

P.J

I used a 21/64th's for mine too, only took me a week of looking to find one.

Oddly, I found it in the LAST place I looked (Joke) at SEARS for less than $4.00.

Used it on two installations now.

JyRO

I'm heading to Lowe's today to buy a 21/64ths, and some anti-sieze.