Smiths Square Number Impulse Tachometer

Post any technical questions or queries here.
Post Reply
jackPDX
Posts: 17
Joined: Mon Oct 11, 2021 2:17 am
Location: Portland Oregon, US

Smiths Square Number Impulse Tachometer

Post by jackPDX »

I just picked up an old square number Smiths impulse tachometer. It is missing the nuts for the mounting studs and I'm having a hard time figuring out the correct thread size.

An 8-32 seems like it wants to start but only goes a turn or two. As the studs are not in perfect shape I don't want to force anything.

Anyone know what the correct thread is on these studs? Metric maybe?

jack
User avatar
iain1967s
1275 Cooper S
Posts: 1844
Joined: Sat Jun 10, 2017 12:46 am
Location: Cambridge, MA, USA
Been thanked: 7 times

Re: Smiths Square Number Impulse Tachometer

Post by iain1967s »

I think it’s the same 3BA as the oil/temp type gauges?
See here: viewtopic.php?p=285413#p285413
jackPDX
Posts: 17
Joined: Mon Oct 11, 2021 2:17 am
Location: Portland Oregon, US

Re: Smiths Square Number Impulse Tachometer

Post by jackPDX »

Thank you!

Also the US links in the prior post are much appreciated.

jack
Post Reply