a little hole gauge i made

[refinery mike]

This is a little hole depth gauge i made a little while ago. It has already come in handy several times. Notice the brass mechanism for gripping this rod, (second half of picture). That works a whole lot better than just a grub screw. Which moves the rod as you try to tighten it.
The second picture demonstrates that the gauge is exactly one inch tall, so i can measure the depth with a vernier and just subtract one inch. Of course it could be done in metric.
Now i know they make hole micrometers but in my entire life i have never wanted to know the depth of a hole down to a ten thousandth.
Hope someone out there can use this as well.

By the way I know there are a million good ideas out there, time for you guys to start posting them. they may be old hat to you but an eye opening discovery to others.

[RSG]

Nice job Mike!

[gravy]

I really like the rod clamping arrangement.

[Inspector]

Your tool is good for getting a depth in an awkward location but with slight changes could be made to hold a dial indicator for quick and direct readings. Search Dial Depth Gauge for examples if you aren't familiar with them.

Pete

[Lew Hartswick]

I just use my thumbnail a length of wire and a 6" scale.
...lew...

[refinery mike]

Lew you make me laugh. You are right i have never needed to know how deep a hole was that your method wouldn't work just as good. But which tool looks cooler laying in the draw of your tool box???
To tell the truth i saw that way of gripping the little pin and i just had to make something to try it out.

[stevec]

Mike, I just got a mental flash of a Kennedy box, small drawer open and several finger nails lying there, sorry Lew, couldn't resist, you know the next drawer down was full of bits of wire.

[RichD]

Here's a Depth Gauge I made. Simple turning and knurling.
The rod is 1/16" diameter. One end pointed. One end square-flat.
Same collet design as Mike's.
Very handy for small hole depths, grooves and shoulders.
RichD

[mklotz]

I use the OP's method of locking the measuring rod too but I add another little refinement that may be of interest.

Note that a small button has been formed on the end of the pin on the end opposite the lock nut. Before drilling the hole for the measuring rod through the base and pin, assemble as shown with a washer holding the button proud of the base. Lock the washer in place by tightening the lock screw. Then drill the hole for the measuring rod



Now, to complete the assembly, remove the washer and insert the measuring rod. You'll note that the button stands proud of the base. Simply pressing on the button will lock in the measurement until you can withdraw the gauge from some awkward location and reach the knurled knob to lock the measuring rod.



Once you've built your depth gauge you need some means of measuring the extent of the rod. Fiddling with the calipers to read the measurement after setting the gauge gets to be tiresome. I remembered that I had bought one of those digital indicators at HF when they were on sale for some ridiculously low price.

I quickly (re)discovered that digital indicators, like digital VOMs, are lousy at indicating trends. They're really only good for making 'stationary' measurements.

I dug it out of my toolbox where it had been languishing and made a tiny button tip for it out of brass. (It's worth having a 4-48 tap and die on hand so you can make DI accessories.) Then I made a sleeve that attaches to the indicator 'shaft' (the part fixed to the frame) with a nylon-tipped setscrew. Said sleeve has a through hole slightly larger than the movable stem on the indicator.

Here are the component parts



With the sleeve attached, set the instrument on a flat surface and zero the indicator.



Now, to read the depth gauge, simply stick it in the hole.



The last picture shows the thing clamped in the vise but that was only because I don't have a third hand to hold the camera. Normally, it's held in my left hand with the depth gauge in my right.