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Accuracy...

Posted: Tue Sep 12, 2006 8:49 pm
by mark.f
Being tired of measuring things with a crescent wrench and a ruler, I decided to invest in some good calipers.

I just bought a decent pair off McMaster, (± 0.001" accuracy, 0-4" range...), and they weren't at all expensive. My friend was trying to talk me out of it because he said they cost all of this money. But, I needed them anyway for an upcoming project so I figured I'd knock em out while I could.

Most of their use is just gonna be normal stuff like for Chemistry, (getting the lowest percent error out of everybody in the course), and various machining endeavors. But, for spudding, I guess they would be useful for making piston valves, moving parts, and maybe measuring bores to make sure they'll be the right size before I buy em!

Another thing I'm curious about is the difference in bore between 2-1/2" ASTM D2466 pipe and 2-1/2" conduit pipe. I've heard the I.D.'s are different before, but I'd like to see. The Home Improvement near me has 2-1/2" conduit, and I've got the ASTM D2466 on my tennis ball cannon.

That's it! Besides boilingleadbath and all you other people with access to metal shops out there, anybody else have some calipers or micrometers? Wanna form a Metrology club? :roll:

Posted: Tue Sep 12, 2006 9:03 pm
by jrrdw
Building my cannon with a 25' tape measure, but i do have 2, 1" frame micrometers, 2, i don't know what kind/make of venear calipers, much like you discribed, 2, feeler gauges, spark plug gaper, 2, squares a 3' one and a 1'

Posted: Wed Sep 13, 2006 12:57 am
by sgort87
Never underestimate the power of eye-balling! But yes, calipers are nice to have as well.

Posted: Fri Sep 15, 2006 5:54 am
by mark.f
Just got em in last night. So far, I've just been measuring bullet calibers.

Posted: Fri Sep 15, 2006 8:57 pm
by frankrede
sgort87 wrote:Never underestimate the power of eye-balling! But yes, calipers are nice to have as well.
That was a good one.