Bolt thread 6mm 14-15tpi

[The Natural Philosopher]

You sure its not 3/8"?

[Syd Rumpo]

1/4" UNC 20 tpi.

Cheers

[Dave Plowman (News)]

Depending where it was made, might be American Course? The head is a good guide for that - will be imperial AF.

[Syd Rumpo]

FWIW, that's what's usually used for camera tripods, so should be easy to check.

Cheers

[tabbypurr]

It's nowhere near 9.5mm. Vernier calipers say 6mm.

NT

[tabbypurr]

How is a bolt with 14-15tpi going to be 20tpi?

[tabbypurr]

The head's 4mm allen.

NT

[The Natural Philosopher]

Well punk, we have to decide whether this is a bolt made to a completely novel specification, or whether you have made a mistake.

Given the cost of tooling for an entirely new thread.....

[tabbypurr]

Dia & tpi don't match any UNC screws, it's coarser than those.

Since I seem to be going nowhere, I'm now wondering how to insert them then add some kind of extension to give another inch or so. Maybe I should consult the spam folder.

NT

[GB]

I hadn't quite realised that the prongy bit was so visible. Can't you prise it out and put something else there? With a standard thread, ofc.

[Syd Rumpo]

Measured on my monitor, across the threads is 39mm. If that's really

6mm, then 1/2" or 12.7mm would be 82.5mm on the monitor. I set my calliper to 82.5mm and count 10 threads in that distance, so either it's 20 tpi or it's not 6mm.

Cheers

[tabbypurr]

I took it out & measured it for the 3rd or 4th time, and some of you were right, I had repeatedly misread the inch scale and it's 20tpi, so UNC.

Thank you to everyone!

NT

[Adrian]

I find it hard to believe this is a dibnah thread. Surely the seat wasn't made in the US?

[The Natural Philosopher]

As I said., a process of probability assignation is useful: To construct a machine to make both a spire nut and a bolt to an entirely non standard thread is simply massive in return for no discernible benefit whatsoever.

Ergo one or other of the measurements must be wrong. Diameter is a lot harder to get wrong than TPI.

[Dave Plowman (News)]

Depending on thread diameter, some metric bolts are pretty close to AC at a casual glance. To the point where a nut will sort of 'fit'.

[tabbypurr]

As I suspected Staples HQ is in the US. So we get chinese chairs specced there.

NT

[tabbypurr]

That's what I realised. At some point.

NT

[GB]

Isn't this exactly the same issue that comes up time and again? People convince themselves of one set of events and then tie all of the conflicting information into knots to correspond with their incorrect mindset.

It's what let the Air France crew keep their aircraft in a stall from

30,000 feet into the ocean, fighting the computer which would have resolved the issue nicely. Or the issue with the roller coaster.

[The Natural Philosopher]

Er no. The computer would have done something nasty since it was being fed false information from a pitot head

Or the issue with the roller coaster.

>

[GB]

Ah, was that it? I forget some of the details. I certainly remember them fighting to keep the nose up far too high, so as to maintain the stall. I don't think the computer could have got it wronger.