Thread gauge

[Sergeant Pluck]

Can anyone recommend a relatively inexpensive thread gauge?

[Chris N]

For which thread size?  Metric or imperial?  Measure the outer diameter to give the size, then check pitch with something like this: http://www.axminster.co.uk/axminster-metric-imperial-thread-pitch-gauge-prod23483/

This is useful site for checking various thread sizes: http://www.gewinde-normen.de/en/index.html

[Sergeant Pluck]

For which thread size?  Metric or imperial?  Measure the outer diameter to give the size, then check pitch with something like this: http://www.axminster.co.uk/axminster-metric-imperial-thread-pitch-gauge-prod23483/

That's the sort of thing I was looking at, but I wasn't too sure if something at that sort of price range would be of adequate quality to be useful, hence the query. Metric is what I'd use most but I might as well have a tool that can do both.

[Chris N]

We use Kennedy ones from Cromwell at work: http://www.cromwell.co.uk/KEN5181010K and they seem fine.  I'm not sure where the one I use at home came from but I've not noticed any inaccuracies from either.  In practice you're comparing two rows of grooves (one on the gauge, one on the screw) and if they don't line up it's immediately obvious.  Try against known threads to see what the difference between correct and incorrect pitches.

[zigzag]

i was caught out recently by buying 10mm axle nuts instead of required 3/8" - they are pretty similar!

[LittleWheelsandBig]

Particularly since 10mm axles can be 1mm pitch or 26 tpi.

[wajcgac]

For which thread size?  Metric or imperial?  Measure the outer diameter to give the size, then check pitch with something like this: http://www.axminster.co.uk/axminster-metric-imperial-thread-pitch-gauge-prod23483/

That's the sort of thing I was looking at, but I wasn't too sure if something at that sort of price range would be of adequate quality to be useful, hence the query. Metric is what I'd use most but I might as well have a tool that can do both.

Those are screw pitch gauges.

A thread gauge is actually one of these - for internal threads and works on a simple GO/NO GO principle (GO end will go in and NO GO shouldn't by more than 1.5 turns iirc).

http://www.cromwell.co.uk/index.php?q=0&p=browse&c=05010301&ss=thread%2Bgauge

and a screw calliper gauge or screw ring gauge for measuring external threads

http://www.cromwell.co.uk/KEN3610170K

http://www.ebay.co.uk/itm/NEWALL-THREAD-CALIPER-GAUGE-0BA-U-B-/250640284083. You will need a an equivalent setting plug gauge to correctly set the gaps as they are adjustable

These will also check the effective diameter of the thread and will be more accurate than a pitch gauge alone.

Unfortunately you will need a separate gauge for each thread size so not the cheapest option.

I've mentioned this only because you may not be aware of what is available and these may or may not be more suitable for your application.

I am not wishing to appear as a pedantic sod

[Sergeant Pluck]

I am not wishing to appear as a pedantic sod

 

No, we like this sort of thing here - thanks for the corrections and info!

This is just for bike fettling purposes to help me sort through a pile of odds and sods (a few of which are Imperial) and just to have for those random times when I feel the need. So the screw pitch gauge  that chrisn has linked to might do me.