Measuring Inside Diameter With Various Tools - Calipers to Inside Mic

Having trouble getting the same accuracy measuring Inside Diameter (ID) as you are measuring Outside Diameter (OD), then this video is for you. I can't pass "feel" through the video but these techniques should help you develop your own feel for measuring.
Accurate measurement is the key to most machining tasks whether boring on a metal lathe or on your milling machine or just measuring parts for fit. You want to make sure your measurements are accurate.
The video has the following sections for the different tools - Where listed multiple times, they are measuring a different size bore:
Overview of all the tools - 1:35
Mitutoyo Digital Vernier Calipers - 3:45
Inside Spring Calipers - 6:15, 11:45, and 17:30
Telescopic Gauge - 9:05, 13:05 and 20:40
Mitutoyo 1-12" Inside Micrometer - 9:50, 13:45, and 22:00
I hope this helps you master your "feel" in accurate measurement.
Thanks for watching!

[@paulgreenlee190]

Really enjoyed the video, I am certain that it helped a lot of hobbyist like me understand the method of using these inside measuring tools.

[@BladesIIB]

Paul, glad it helped and thank you for the feedback.

[@texaswoodworks8853]

Great info. Really enjoying your channel.

[@BladesIIB]

Thanks, as always.

[@rsb2842]

Nice video easy to understood very helpful

[@BladesIIB]

Rohit Bhatt - Appreciate the comment. Glad to hear the video was helpful.

[@robotech]

I have a set of telescopic bore gauges I bought for $15 from Amazon and they work just fine.

[@BladesIIB]

robotech - that is great. My telescopic gauge set is over 40 years old. Made by Suzuki, I don’t think they even make measuring tools anymore. They still work perfect.

[@Chris-ut5ih]

For the inside mic, can you make adjustments while measuring the piece or would you recommend always taking the mic out and adjusting it like how you’re doing in the video? Also to be sure I’m completely straight with both sides of the mic, I would look for the largest number (or drag) in one direction and the smallest in the other direction (largest # in left/right direction & smallest in up/down direction)? Sorry it’s hard to explain my question without actually showing it.

[@BladesIIB]

@Chris-ut5ih - Thanks for the questions. If the hole/bore is large enough you can make adjustments in the hole. Just be sure the mic is angled enough to allow an adjustment without wedging and t in the hole. For your second question I will do my best to answer what I think you are asking. There is only one drag you are feeling for and only 1 number you are trying to get to. The back and forth as you stand the mic up in the bore is to ensure you are measuring the center and largest part of the bore. You just keep feeling for the edges until you are sure you have the center then get it where the mic passes through the center with just enough “feel” that you know you made contact. Then you measure that with a calibrated mic and get the same “feel” to see the correct size. You can also calibrate your inside mic to read directly but I find this just takes longer each time you change the barrel on your inside mic and I prefer to just use an outside mic for the actual size.

[@dankalicious007]

I think I had that exact same chuck. Is it a 10” 4J independent?

[@BladesIIB]

Erik- yes this is the 10” 4 jaw from PM. If you ordered one with your TL likely the exact same one. I ordered this with my TL.

[@dankalicious007]

Exact same chuck! I have worked mine like a rented mule, and I’ve never had a single issue.

[@marcosferrer8071]

How you should measure an inside diameter if the tolerances is in the range of +-0.001

[@BladesIIB]

@marcosferrer8071 - Great question. The inside mic is the most accurate of the tools I am showing in this video, although for smaller holes you should be able to be as accurate with the telescopic gauges. Both of those are measured using a mic that is rated to .001" but you can read between the lines to get a good estimate on .0001". If that is your tolerance you may want to consider a go, no-go gauge or some type of digital bore measuring tool.

[@fernandohood5542]

Can a verneir be used instead of a micrometer?

[@BladesIIB]

Fernando Hood - Great question. I guess it all depends on what you have on hand and what accuracy you need. A micrometer is generally considered more accurate than a vernier.