drill size

[maverick13]

Hello guys,

I need your help for drill sizes.

I'd want to buy the drills used for the most common screw sizes for automag parts. I think they are 6-32 / 8-32 and 10-32.

Here in France, imperial drills are almost impossible to find, so I'm going to look for them on the web.

Could someone tell me the drill size I have to buy for these screws, and the taps needed to repair threadings or tap holes for these screws ?

Thanks

[luke]

6-32 tap: #36 drill
8-32 tap: #29 drill
10-32 tap: #21 drill

[maverick13]

Thanks !
I hope I'll find these on ebay !

[luke]

http://www.mcmaster.com/#standard-drill-bits/=rpf0nt
http://www.maritool.com/Cutting-Tools-Drills-HSS-/-Cobalt-Jobber-Length-Drills-118%C2%B0-Split-Point/c78_140_361_195_196/index.html

[maverick13]

Thanks.
It seems maritool ships worldwide, I'm going to look at their shipping costs.

[maverick13]

What kind of tap would you recommend ?

[luke]

You would need hand taps, both links above will have them.


Maritool is a great company to do business with.

[maverick13]

Are these the good ones ?

http://www.maritool.com/Cutting-Tools-Taps-Taps-for-Aluminum-Sprial-Point-Plug-Taps/c78_148_271_272/index.html

[Laku]

Try looking from RC car parts shops, they might have something like that.

Here's a set in Finnish RC car shop includes all you are searching.

http://www.hobbypeople.com/shop/index.php?main_page=product_info&cPath=34_124_333&products_id=15483

[maverick13]

Thanks, I'm going to look if I can find it in France

[luke]

Are these the good ones ?

http://www.maritool.com/Cutting-Tools-Taps-Taps-for-Aluminum-Sprial-Point-Plug-Taps/c78_148_271_272/index.html

It's a good tap but it's not a hand tap. I didn't realize Mari didn't carry them, LMK if you can't find what you need in France.

[luke]

BTW "hand taps" are a specific type of tap, not a generic term. ;)

[maverick13]

Ahhhh the knwoledge of the professional is always precious !
Thanks again for your help to both of you.

[brokeass_baller]

I'll add a question to this. what size bit would I need to tap 1/8 NPT? And doesn't it have to taper? Got any tips?

[luke]

I'll add a question to this. what size bit would I need to tap 1/8 NPT? And doesn't it have to taper? Got any tips?

Drill R.
The tap is tapered not the drill.

[brokeass_baller]

So does that mean I have to leave a little bit of untapped space behind the threads?

Thanks for the info.

[luke]

So does that mean I have to leave a little bit of untapped space behind the threads?


I don't really understand the question(?)

It's pretty simple, drill and tap. There really are no tricks or strategies except if you tap the hole too deep the tapered fitting will loose it's ability to seal, go to shallow and it limits how far you can screw the fitting in. Use a liberal amount of tapping oil or WD40 (In aluminum)

[brokeass_baller]

Ok. that's basically what I was asking; you don't want to tap too deep. Thank you very much, Luke!

[luke]

No problem..

[BLachance75]

If you have problems finding what you want let me know. I can get them for you and will ship them to you.

[maverick13]

Thanks a lot, it's very nice.
I highly apreciate.
If I can't find them, I'll come back to you.
Thanks again.

[ElPanda]

if you have never tapped anything before just be careful that you dont let the chips build up in the tap flutes/below the tap

there are two general kinds of taps; gun taps and spiral fluted taps

gun taps will push the chip below the tap, useful when tapping through holes where you have the help of gravity in clearing chips out of the hole, they are also somewhat stronger than spiral taps because they usually come in a two flute style in the sizes you are looking for

spiral taps will push the chip above the tap (or out of the top of the hole) as you tap, this is useful when tapping blind holes (non-through holes) so that the chips dont have the opportunity to build up in the way of the tap. They are weaker than gun taps but have a solid place in the industry for a reason.

also be very careful with that 6-32, they are notorious for breaking as a 32 pitch in that small of a diameter is relatively coarse, you are relying on a smaller diameter tap to remove more material essentially. We usually dont even allow our designers to incorporate 6-32 threads into a design unless absolutely necessary. Even drilling one size oversize those taps can be a PITA for any small production run.

you probably wont have any problems, just take them slow and if you feel the chips building up just remove the tap, clear the chips and go back in until the hole is done.

[maverick13]

Thanks for this very detailed explanation.

At first sight all tap I found are gun taps.
I'll look if can find spiral fluted tap for tap handles.

[luke]

there are two general kinds of taps; gun taps and spiral fluted taps


And then there are form taps which are my favorite, no chips, no pecking, much faster operations and stronger thread too boot.

[dboggs79]

And then there are form taps which are my favorite, no chips, no pecking, much faster operations and stronger thread too boot.

Agreed. Surprised they haven't caught on more.

[ElPanda]

And then there are form taps which are my favorite, no chips, no pecking, much faster operations and stronger thread too boot.


.

formed threads ftw