Thread: Pipe Clamp Compilation.

Just for others who are looking to do some pipe clamps but perhaps daunted by the pipe changes (i dare say some stuff was changed before i was born) and there are quite a few younger than me nowadays, and so as to find everything in one post.

***Even if you have purchased a newer type of Irwin clamp as Kyle and others have mentioned elsewhere, You'll have no need for threading information, however the actual pipe information will most likely apply. The downside or limitation to this style of clamp leads to the next comment.

*** From Bushmiller and others, The threaded styles of clamps can be extended by the use of double ended collars between the heads. IF you have a thread cut on both ends of your tubing. Using conection / collar along the lines of this union joint.

From wikipedia about the BSPT thread;

"The size number was originally based on the inner diameter measured in inches of a steel tube for which the thread was intended, but in the modern metric version of the standard is simply a size number."

British standard pipe thread - Wikipedia, the free encyclopedia - here.

Most of the time these days even the steel suppliers are dealing with only the ND or DN (nominal diametre) or NB (nominal bore) in Australia. The above has and seems to create a bit of confusion and communication where the crossover happens. "Just get a bit of ol' 3/4 gal waterpipe, she'll be right..." they say, is kind of there, but when you ring the suppliers and ask for the same and get something along the lines of " We only do metric now, nothing suits your purpose".

So using the chart on the wiki link above you can see the 0.75 (inch) thread, or 3/4 bspt, is 14 threads per inch, 1.814mm pitch, 1.041 inch or 26.441mm thread major diametre, so thats the thread, finer details of the angles and shapes etc. are in the link also. Continuing to use the chart we move across to the recomended pipe for this threading, DN of 20, OD of 26.9mm or 1.06 inch with a thickness of 2.6mm. (So the old 3/4 ID expressed water pipe is externally 1" OD....)

What a drama eh, we ask for what we think is right (and one time it was 3/4 "internal dia." pipe), and now isn't in context (because we now measure the OD ), then get told the context we're using isn't compatible with current systems of measurement (imperial 3/4 ID used as an OD reference to measure metrically an OD wont work), do a bit of digging and get some research done, and find out they had what you asked for, but neither knew what the other was talking about. No wonder some give up. I almost did.

So in a nutshell. 3/4" gal waterpipe is sold as DN(or ND or NB) 20 Medium grade (or 2.6 wall or a "blue" colour code, not to be confused with "blue" uncoated steel) Gal pipe. And the threading used is 3/4" BSPT.

Note: "Blue" or untreated/coated steel can also be used and is ever so slightly cheaper than the Gal, the Gal is a personal choise.

Whew. So got my 4 Carba-tec clamp heads @ $12 or so ea, now i got my pipes @ $38 and dropped em off to my BIL (ex plumber) for threading @ $zip (worst case 6pack goldies). Hopefully this week i'll have a piccy of some nice 1100mm pipe clamps an 86 bucks spent.. Cheapy solution to finish my benchtop so i can reassemble my lathe and sort it out to get back into turning.

For completeness, i'll add some stuff, there are a couple of cheap options for threading die's and handles, ridgid do a ratchet handle the Oo-R to suit the die commonly currently found on ebay the link to it may decay Ebay Ridgid die so the part # 66330 is the 3/4" 14tpi hss die to suit the handle.

This seems from what i've seen the most common purchased solution to cutting the thread, also Trefolex cutting paste (or aerosol) as the lubricant.

Some of this stuff wont apply to everyone, your mate at the steel shop is an old boy, or he's switched on, or you have a sample clamp head, or your brother in law is a plumber, or your next door neighbour has an old set of threading dies, or you can buy em prethreaded. I just wanted to see all the info in one spot or post along with the relevant explanations. It might help others.

Neal.

PS: not associated with any of the companies, or items, or people within.
PPS: I used Earlybird Steel in Brisbane, and checked out others whitch had what i was after on their websites when i knew what i was looking for. They were closest to me. Really hope this helps someone/anyone else out. Happy Clamping.