Question about inside calipers

[BladesIIB]

Based on this thread and another one about measuring ID with gauge blocks I am going to do a quick video about using a variety of tools for
Measuring ID. Maybe it will offer some insight. The whole picture is worth a thousand words thing. I have round and straight leg calipers so you can see both in action, as well as vernier caliper, telescopic gauge and inside mic. Will try to get it posted Wednesday evening. Have an event tomorrow.

 

[mikey]

Thanks, practicing without a known reference only helps with repeatability.

What about an outside diameter reference?

I take it you're asking for something of a known, stated diameter so you can check your technique. Pin or plug gauges would suit that need. Cheapest way to go for that is to look on ebay for "partial pin gauge sets" and look for good ones like DoAll, Tesa and the like. If the pin says it is a specific diameter then it will typically be that diameter within 0.0002" or so.

This is not the same as knowing/testing to see if the measuring tool you have is accurate. For that, you need gauge blocks.

 

[KevinM]

Yes, I am checking my technique. I ordered a ring gauge and will use endmills (thanks for the idea BladesIIB) to check both my equipment and technique. I make small engines and getting the bore to piston clearance is what is most important to me. Accurate size is not as critical as long as it is consistent and will give me the correct clearances but 0.0002" accuracy would be great.