Measuring the depth in a hole…

[Okapi]

It is always a problem when you have no surface and no place for a common tool like a kaliper or a depth caliper.

Then last week when I have three particular pieces to modify, changing the Schaublin 38mm. thread by a M40X3 with an insert, and a result which does be in less than a tenth millimeter error, I find the solution with that tool, it's easy to understand how it works, you can use it with a micrometer or just with the moving piece.

You take the measurement in the tool with a classical caliper, and use the micrometer next to make the finish, or you can adjust the micrometer on somethig like a bearing and use it like a normal micrometer.
I hope my explanations are not too hard to understand and will be happy if that can solve a problem for you.

One of the pieces i modify.


The inside view.


And the new tool.


On the lathe.

[kbalch]

Thanks Okapi! I've added your Depth Gauge to our Measuring and Marking and Machining categories, as well as to your builder page: Okapi's Homemade Tools. Your receipt:

Depth Gauge by Okapi

tags: depth gauge, micrometer

[Paul Jones]

I like the design and have considered making something similar but for limited use. I think I may start out with something simpler that won't have the micrometer head attached but will have a pin of the same diameter as the micrometer shank and have the measuring end reduced in diameter. I will substitute gage blocks to measure the gap distance between the moving end and the fixed pin.

[Okapi]

The micrometer head is really not expensive, they come from control department which are going to electronical measurment system.

[schor]

Nice job Okapi. I really like the design.

Is the foot (not sure what you call it) removable so you can interchange it with different sizes as may be required?

[Okapi]

Thanks Schor,
The foot is totally independent then you can use any form you want, this one is fixed but another bar is made in minutes if needed(I have three others made for special applications).
As you need a the beginnig a calibration when it's not just a comparative use, the form is not important, all you want, it's just a basis for the measurment, not a fuctional piece.

[kbalch]

This thread has been moved to the Must Read subforum. Congrats (and thanks) to Okapi for making such a valuable contribution!

[Toolmaker51]

I like it too. Once a common micrometer measurement is made and a cut taken, that measurement becomes somewhat irrelevant. Your tool addresses that perfectly being a comparator, and either re-zeroing to monitor change [reduction]; or calibrate to Jo-blocks validate approach to finished size.
Very good!

[Okapi]

Thanks Toolmaker, I've made a lot of specific supports for special measurements and it always function perfectly with a precision in one hundred for a small price, just a little work for the most appropriate way.
I use too the inverted measure micrometer in the same manner for other parts when measuring a inner space in a hole.