Need help measuring a groove

[scot]

Hello All,

I hope this is the proper place for my question.

I need to measure the depth of a groove located in a pocket. Can you give me some ideas?

The important measurement is the depth of the groove from the bottom of the pocket. I am currently using a dial caliper and this is questionable.

Thank you, Scot

 

[strokersix]

Perhaps a dial indicator with a small tip?

 

[scot]

Thank you strokersix!

We have an indicator and a selection of tips, works like a charm.

 

[CITIZEN F16]

Perhaps a dial indicator with a small tip?

On a stand like this one:

 

[michiganbuck]

a dial caliper may be good for +- .001, a dial indicator perhaps +- .0005 or +- .00025, a machined or ground bar gauge like a homemade JoBlock perhaps +- .0001 or so with striking the bar gauge with a tenths (or less) indicator.

but you have to watch the corner radius if that is an issue. You don't want your gauge to rise up bumping into a corner radius.

 

[TGTool]

On a stand like this one:View attachment 345871

I can't read the name plate so I'm not sure exactly what one like that is. Just from appearance it looks like one a friend of mine asked me to get for him years ago. I don't remember where, but Enco or equivalent. I sent it on to him and thought no more about it. He died a few years later and his significant other gave it back to me where it sat on the back of the bench for several more years. I pulled it out for a specific task, checking Alfa valve shims, and could NOT believe what crap it was in details. The fittings were so loose that you couldn't effectively set a zero with the fine adjustment. It would go all over the place as you tightened up the locks. I finally sleeved the fittings and installed a post from ground stock and it's now a fairly usable tool. I know you take this inexpensive stuff "for better or worse" but this was much worse than I took it for. Posthumous apologies to my old friend since I could have done that before I passed it on if I'd looked more carefully.

 

[CITIZEN F16]

The stand is a Vector looks like they don't exist anymore. The indicator is a Teclock those are Japanese and about $100 now, they are decent. I also have a bunch of attachments to put a .0001 on a height gauge. I make pretty small parts.

 

[jccaclimber]

The place I work now had the MSC version of that stand, looks near identical though. It was also a total POS. The end of the shaft was so rounded you couldn’t bolt it down firmly and the mount moved a couple tenths if you bumped it. A skilled hand could work it, but it took some care. Not great for generic inspectors. We ended up getting a new one from McMaster Carr. Much nicer, and repeatable. Mitutoyo also makes one which I assume is reasonably nice.

 

[CITIZEN F16]

The place I work now had the MSC version of that stand, looks near identical though. It was also a total POS. The end of the shaft was so rounded you couldn’t bolt it down firmly and the mount moved a couple tenths if you bumped it. A skilled hand could work it, but it took some care. Not great for generic inspectors. We ended up getting a new one from McMaster Carr. Much nicer, and repeatable. Mitutoyo also makes one which I assume is reasonably nice.

Even though the maker is no longer in existence, that stand I have is decent. I would not call my beat up hands with sausage fingers "skilled" by any means. Other than slapping a cheap indicator on it I don't see how someone could make a bad one, but you never know these days.

 

[ezduzit]

This can be easily measured using a blade mic or pin gage with standard mic.

 

[Mechanola]

No tolerances on the drawing, a joke

 

[jccaclimber]

How do you know there isn’t a global or decimal place based tolerance not in this screenshot?

 

[Mechanola]

I do not know. You’re right, didn’t think of that possibility.

There could be more information such as to the finish of the groove’s edges and gorges, the allowed radius of the internal step. Nothing the like is sketched.

 

[Toolmaker51]

The indicators suggested are good initial checks. However first tries don't always achieve satisfactory readings. So, these offer means different enough from normal gauges to be reliable corroboration.
FlexBar Repli-Putty,
Cerrometal (low temperature bismuth alloys),
Small Vee-block with pin gauge (use as a depth mic). Use 2 pins, 1 small enough to miss corner radii, compared with 1 at groove width and what ever depth it reaches. Simple test with indicator or height gauge for result.

 

[guythatbrews]

Sometimes I use a little steel ball to check this sort of thing. Lots of precision sizes available and very cheap for 100 or so.

You could use a 1.5mm ball and check distance above bottom of pocket with a unimike. Checking with a DTI is a bit more difficult, and damn near impossible unless you use a flat tip. Which creates its own issues.

Of course you have to make the assumption the bottom of the groove is flat. May not be an issue depending on tolerance.

Checking with balls is handy and can be a pretty cheap way of getting around a problem. I keep a range of sizes handy.