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View Full Version : Crazy Scherr-Tumico dial indicator....



J Tiers
09-17-2011, 09:12 AM
Possibly it wasn't S-T who did it, but.....

0.01mm indicator, S-T rebadged, made in UK. Jams up when you tighten the backplate..... fine when its loose.

The maniacs put it on with FLATHEAD screws, and all I can figure is that they are slightly out of alinement, and when tightened, they wedge the case enough to jam the plunger.... which would not take very much at all.

JCHannum
09-17-2011, 10:25 AM
Dial indicator backplates are often swapped from gage to gage depending on application. There is supposedly some standardization, but mounting holes and screws can vary. It is more than possible it is not the original backplate.

J Tiers
09-17-2011, 12:24 PM
Dial indicator backplates are often swapped from gage to gage depending on application. There is supposedly some standardization, but mounting holes and screws can vary. It is more than possible it is not the original backplate.


probably even more chance than that...... I'd say "probable" it isn't original..... although it might be an OEM alternate type. Usually the ones sold with the indicator are either plain flat ones, or a "loop" type. This has a stud dead center in the cover.

As soon as I find some M2 screws (got lots of M3, M4, even M1.5, no M2) it's getting counterbored and fixed up with proper cheesehead or pan head screws.


The real issue is using flatheads, which will put a wedging action on the indicator case (which is no more than a ring of metal) if there is ANY misalinement.

What kinda maniac does not KNOW that?

J Tiers
09-17-2011, 08:44 PM
Well, I seem to have been wrong..... There IS some effect of the screws, but even with that corrected there is still a problem.

The problem really is in the manufacturing of the indicator. The forcing in of the two bearings at the time of manufacturing actually cracked the housing of the indicator. And it made the whole housing slightly un-square. It is a QC "leaker"

When you tighten ANY back on it, the housing is moved just enough to bind up the plunger.

Since both portions have cracks, it is unlikely that abuse caused the issue.

Rats, I could use a metric indicator, but this one didn't cost me much. I'm not even sure what it did cost, it came with a load of other stuff. The H&W level alone would have been worth far more than the entirety of what I paid, so even if this thing is NFG, there isn't an issue.

You can just see one crack directly over the left bearing in the picture. It looks like a fine hair, but it is a crack apparently right through, and there is one over the right bearing to match.

If I don't tighten the back too much the indicator still works, but..........

http://img.photobucket.com/albums/0803/jstanley/S-T_crack.jpg

aboard_epsilon
09-18-2011, 07:00 AM
make a thick cardboard gasket for the back ..

then the cardboard will compress on one side rather than it distorting the case.

all the best.markj

J Tiers
09-18-2011, 10:07 AM
make a thick cardboard gasket for the back ..

then the cardboard will compress on one side rather than it distorting the case.

all the best.markj


That's about what I planned to do, although cardboard might shed bits......Haven't decided what to do on it, if anything.
Basically it has been "surveyed out" of the "good" indicator stock for the moment. I have plenty others, although no others with mm dial calibrations.

I was, however, interested that it was an OEM reject that apparently didn't get rejected.
The UK manufacturer QC didn't manage to reject it, and Scherr-Tumico apparently accepted their QC pass.