Any tricks for measuring the inside dia of a shallow bore or pocket?

[mmcmdl]

Kinda look like these ?

 

[dbb-the-bruce]

Turn a piece of rod to a couple of dimensions, like .998, .999 & 1.....

I tried this (sort of) as I had a chunk of 1" drill rod that measured at .999. But I overshot and then it was hard to figure out by how much other than using plastic shim once it was off the lathe. I think a tool that will let me cover a range easily is the way to go.

 

[dbb-the-bruce]

Kinda look like these ?

Looks great to me. How do we exchange addresses?

 

[mmcmdl]

Incoming pm . They will go out tomorrow if PP is recieved before 8 am . I have a few more boxes going out . How's that for service ?

 

[RJSakowski]

For a .050 deep counterbore, I would make a disk around .75" in diameter and .050" thick to sit in the bore. Then I would fit gage pins to the gap. Th3e bore diameter would be the sum of the two diameter. It should get you within a thousandth. For deeper bores, I just use two gage pins but it would be a pain to try to manage two pins in a shallow bore,; hence, the disk.

 

[dbb-the-bruce]

For a .050 deep counterbore, I would make a disk around .75" in diameter and .050" thick to sit in the bore. Then I would fit gage pins to the gap. Th3e bore diameter would be the sum of the two diameter. It should get you within a thousandth. For deeper bores, I just use two gage pins but it would be a pain to try to manage two pins in a shallow bore,; hence, the disk.

Yeah that could work nicely. Maybe I'll make a few disks in 1/4 increments and keep them with my pins.

 

[benmychree]

Ask yourself why does the feature need to be overly accurate?

 

[Winegrower]

You can’t use a cheap inside caliper to make a transfer measurement?

 

[erikmannie]

What about pin gauges?

 

[Larry$]

I did recently by a full set of pin gages from .25 to .06 - They have made checking and matching smaller holes *MUCH* easier. really glad I got them.

A couple of years ago I bought sets from .011 to .500 in under sized by up to .0002. I use them more often than I had expected. By using two pins in a bore I can get to .999 - .0000 to -.0004. I just made a "sort of" gage pin @ .900 +- a fuzz by turning it a bit over size then using my home made tool post grinder bringing it to as close as I could measure. So now I can bore measure accurately (enough) to 1.4". All done by the feel of sliding two pins into the bore. Since using the smallest pins is very difficult I decided not to go to a full 1", that and my smallest pin is.011 which is really fragile and would make the first step up from the new gage pin jump too much. I'm thinking now I should make several more larger pins. You can also buy individual large size (to 1") pins. Class Z ( 0.0001) about $14 each @ McMaster-Carr. Or you can get a pair of go-no go pins for 1" @ about $100 for the pair. Ring gages are even more expensive.