Thread taps

Adjusted

Adjusted

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Feb 8, 2012
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Tacoma, Washington
I am in need of a 1in thread tap but am having very little luck finding anything that big that is not made of an expensive alloy. All i need it for is a project where i am threading into plastic, and I am not interested in spending $100+ on something that can thread forged steel.

Where do you guys find cheap larger size taps? Also, how do you find out the thread pitch - or threads per inch - for something like this?

Thanks
 
U might try harbor freight. I bought a tap and die set and it works really well. Idk about thread pitch though
 
Unless some crazy hard plastic, a fastener will generally cut it's own threads in plastic ( ie nylon lock nuts) , otherwise Id have an industrial machine shop handle it for me for a few bucks
 
agreed, call a few local shops, a head shop would be a good place.

to elaborate on my earlier post, you can gauge the pitch at certain stores. If not, hell, fastenal should have something
 
Buy an ASMT574 (typ black oxide socket head cap screw) in the 1" pitch you need with enough unthreaded shank to get through your material.

Take a pedestal grinder or an angle grinder and put a shallow taper in the leading 3/4-1" of the thread. Then take a cutoff wheel and make 4 cuts symmetrically along the axis of the bolt to below the minor thread diameter. I'd shoot for at least an 1/8" wide to give enough room for the chips to cleanout. Take a jewelers file and clean up the threads to remove burs.

Tada, cheap plastic tap that you can drive reasonably straight.
 
Cheeny23 said:
U might try harbor freight. I bought a tap and die set and it works really well. Idk about thread pitch though
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tried it already, stupid high prices

Jared said:
Can you take the part in? Lowes and Oreillys come to mind.
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wat

AlwaysSomethin said:
Unless some crazy hard plastic, a fastener will generally cut it's own threads in plastic ( ie nylon lock nuts) , otherwise Id have an industrial machine shop handle it for me for a few bucks
Click to expand...

the plastic has a rather thin wall and i dont want to crack it using a dull bolt - might try a machine shop though

Jared said:
agreed, call a few local shops, a head shop would be a good place.

to elaborate on my earlier post, you can gauge the pitch at certain stores. If not, hell, fastenal should have something
Click to expand...

tried it, the bolt is too big to gauge at anyplace ive been, and fastenal is stupid high prices and mainly sells in sets.
 
bggrnchvy said:
Buy an ASMT574 (typ black oxide socket head cap screw) in the 1" pitch you need with enough unthreaded shank to get through your material.

Take a pedestal grinder or an angle grinder and put a shallow taper in the leading 3/4-1" of the thread. Then take a cutoff wheel and make 4 cuts symmetrically along the axis of the bolt to below the minor thread diameter. I'd shoot for at least an 1/8" wide to give enough room for the chips to cleanout. Take a jewelers file and clean up the threads to remove burs.

Tada, cheap plastic tap that you can drive reasonably straight.
Click to expand...

Gon' try dis


Any other ideas? The most common taps im finding are NPT - and that does me no good. Gunna run by an industrial bolt store to see what they say, and grab a bolt like bggrnchvy said to try.
 
McMaster has carbon steel hand taps in both 1" UNC and UNF for ~$18/pc. Should do hundreds of holes in HDPE before wearing out.
 
Adjusted said:
The one at the top left (carbon steel)? http://www.mcmaster.com/#standard-taps/=l59qbt

I tried to measure the thread per inch with a ruler and came up with around 14tpi, however im not sure if I am measuring it correctly (seems like 12tpi is more standard).

Thanks man, had never seen that site - much better layout/info than most
Click to expand...

Yes.

1-12 is UNF and 1-8 is UNC, and are the two standards. You very well could have a 1-14, but I would check it with a thread file or thread gauge before you commit to the tap. McMaster is pretty much an industry staple and their returns are very easy, but you burn a lot of time shipping back and forth unless you're setup for next day.
 
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