[Metrology] Damage Indicator?

[Holescreek]

I have searched here and generally the web and was unable to come up with a conclusive answer. Will tapping (with a hammer) a piece of stock while an indicator is in contact with the stock damage the indicator? For example truing up stock in a lathe chuck.
Is the answer the same for digital and dial, test (lever type) and drop indicators?
Does "shockproof" have any effect on the instrument's survive-ability?

Short answer. NO! No damage will result to the indicator as long as it has plenty of travel. Now you've read it on the internet, it has to be true. Merry Christmas!

I have never, or even ever met another machinist that removed the indicator point from a part when tapping it into tram.

 

[Tony Wells]

I'm kind of like Wreck. That's what the $9.95 ones are for. I still tend to pull the stem off the part if I hit the stock very hard, but if it's that far out, your hammer is not going to help anyway. Plus I use a deadblow or plastic faced mallet to tap a piece when I need to. Really can't remember when the last time I had to use a hammer on a part, even when setting a steady rest. The hand usually is enough, since you're really not chucked tight at that point in the game anyway.

The shock resistant models are more durable, but they do cost more, and there are other interal parts that are easily damaged so I wouldn't beat on the stock while using them either. I've got some nice ones, and some utility grade indicators.....and use them as such. I do not strike the part using a DTI in any case, other than perhaps my palm.

I have seen some people strike the same side of the part as the indicator is running on, I suppose thinking this may lessen the shock, but it seems to me that the bounce-back from the blow is not a lot less than the strike itself, and still doesn't do the indicator any good.

 

[maker of things]

Thanks for the feedback all, an yes the idea was to use the hammer to hit the stock, not the indicator. I'm talking about a light bump with a non marring face, not a 20 oz ball pein at full swing. I only have a few years inexperience as a self learning person who has machines. I have been leaving my HF and Shars 1" indicator on the part and tapping the stock when the indicator shows the most travel (so away from the instrument). Two of the devices seem to have developed "hitches" in their movement that I attribute (possibly incorrectly) to jarring the rack and bending some teeth. I want to buy a nice Mit or Starrett and don't want to wreck it due to improper use. The Mitutoyo user manual states "do not displace spindle quickly" and Starrett "avoid shocks to contact point and spindle".

I have poured over a few metrology books and did not find one reference (that I can recall) to specifically avoid the practice nor any literature that specifies what "shockproof" means.

Generally, it sounds like in fact I am following general practice and if my 9.99 indicators in fact are damaged it's either due to the low quality of the mechanism, or I was more enthusiastic in my efforts to adjust than my memory recorded I guess it would be worth taking them apart to see.

 

[middle.road]

I too will have to go with no. If you examine how fine the gearing mechanisms are in them you might not want to shock them.
Back when I was designing inspection gaging, we'd use indicators and mic barrels. Never could make them 'gorilla' proof.
It's amazing how mangled the insides of an indicator can get. And those designs used the lever style to lift the point.
Then there was the tightening of mics so hard that the threads on the barrels would be shot.
Couldn't get line personnel to use the smaller knurled 'clutch' knob...

 

[uncle harry]

I believe the OP is referring to tapping the part into tram, not bashing the indicator with a hammer. Totally different process. One is work, the other is fun! It is completely acceptable and actually standard practice to tap a part into alignment with the indicator needle or point touching the part, that's what they were designed for. It is of course a lot cheaper if you completely miss parts of your indicator.

In a bad year I might repair 300 or so gauges at work with the majority being indicators. The worst thing you can do is drop them - and it happens a lot.

The worst thing that happened to a Starrett indicator that I loaned to a friend was when he stepped on it. He replaced it with one of better quality.