How can you measure the thread size of a bolt?? - Third Generation F-Body Message Boards

grafx · 04-05-2002, 03:04 PM

I ordered a set of speed bleeders for my car but the ones they sent me are a different thread size for the replacement calipers I purchased, needless to say I ordered them by make and year instead of bleeder size. They offer 3 different thread sizes for the same size bleeder 10mm. I need one with a courser thread than the one they sent but I'm not sure if it's the 1.25 or 1.5, how can I measure it??

rezinn · 04-05-2002, 03:07 PM

Go buy two bolts from anywhere in those thread sizes and see which fits.

grafx · 04-05-2002, 03:10 PM

yeah I thought of that just thought maybe there was another way. Do they make some sort of guage to measure thread size?

Black 91 Z28 · 04-05-2002, 03:27 PM

I think they make a flat plastic gauge that'll tell you about the bolt. I'm not 100% sure but I think you can get them at a local hardware store.

Looks like these.

http://www.atlanticfasteners.com/technical/gauges.html

David

92 RSS · 04-05-2002, 03:37 PM

If you know of a machine shop locally, go there and they could measure it for you. Or go to sears, they have them too.

Ed Maher · 04-05-2002, 04:03 PM

Thread pitch is measure by TPI (threads per inch) for standard hardware, or (on a limb), thread spacing for metric. So a 1.25 pitch metric bolt will have 8 threads in 10mm.
You can use a knife or any thin straight edge to count teeth.