Close to 1/8 NPT

Sep 21, 2004 10 Replies

I'm trying to hook up a new (to me) air chuck. The air line fitting looks like it should be 1/8 NPT but its not. Just slightly smaller. An 1/8 NPT nipple will start about 1 thread.



Any good guess as to an air line fitting just smaller than 1/8 NPT? The tapped hole is down inside the chuck and impossible to measure.



Karl


1/16 - 27 straight maybe

Unless it's just a bad thread, it's probably an RPT thread, pretty common on European (Festo) and Japanese (SMC) pneumatic components. One turn before the fitting fetches up is pretty typical when trying to insert a male 1/8 NPT into an RPT female.

Ned Simmons

It might be 1/8 NPT straight thread, more or less what you get if you run an 1/8 die in so far you run out of taper.

To the others posts; its definitely not 1/8 NPS or 1/16 NPT.

Here's a thread I haven't heard of. I just looked ALL though McMaster Carr. Didn't see a listing for this (RPT) anywhere. So, anyone know where to order one?

Karl

I get them from SMC. If a straight adapter to 1/4" tube will work for you, I've got a couple here. SMC p/n KQH07- U01 Email me your address and I'll drop one in the mail. It's a push-lock type and will work with nylon, HDPE, and hard urethane 1/4" OD tubing, probably copper as well.

Ned Simmons

Indeed. I keep adapters in the truck as I do a lot with Festo.

Gunner

"In my humble opinion, the petty carping levied against Bush by the Democrats proves again, it is better to have your eye plucked out by an eagle than to be nibbled to death by ducks." - Norman Liebmann

What's that Lassie? You say that Karl Townsend fell down the old rec.crafts.metalworking mine and will die if we don't mount a rescue by Tue, 21 Sep 2004 19:31:23 GMT:

Some kind of JIS thread? ( Japanese Industrial Standard)

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