#1
·
Jan 3, 2006
I need to drill and tap some 1/2 NPT holes, anyone know the drill and tap sizes?
I asked the tool guy at Sears and he just looked at me like i had boobs on my forehead. :scratch:
#4
·
Jan 4, 2006
most taps have the proper drill bit size stamped into them FYI
#6
·
Jan 4, 2006
When I got my 1/2 NPT tap, the recommended drill bit size listed was 23/32. I had no luck finding that size so I used a 11/16.
#7
·
Jan 4, 2006
The correct bit for any tap should be 90% of the tap size.
NPT requires an 50% increase adjustment since it is measured differently than drill bits.
Therefore, 1/2 * 1.5 (50% increase) = 0.75
0.75 * 90% (tap to drill bit conversion factor) = 0.675
Drill bit sizes in that range
21/32 = 0.6563
11/16 = 0.6875
23/32 = 0.7188
11/16 is the closest and the correct size for that tap.
#10
·
Jan 4, 2006
Gadfly said:
I asked the tool guy at Sears and he just looked at me like i had boobs on my forehead. :scratch:
Do you? Pics?
#12
·
Feb 18, 2009
ok...so I think I can find the 11/16 drill bit....where can I find the tap?
#14
·
Feb 18, 2009
wow, so much for trying to own some one.
They dont have that there anymore.
AND i meant like a local chain store. Lowes, Homedepot, Sears, etc.
0
Reply
#15
·
Feb 18, 2009
I just got the tap and drill bit from
http://www.wttool.com/
I only needed to do a few holes so I didn't really care about getting very high quality, but their the tap and drill worked great for me.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.