Hi, not sure what you mean a 'decent indicator' (not DTI as in dial test 'indicator&#39? Anyway Mitutoyo are a decent brand.

Tony

Edited By Tony Pratt 1 on 24/03/2022 14:34:46

Edited By Tony Pratt 1 on 24/03/2022 14:35:32

If you want it for setting up work in a 4-jaw, don't get a digital one – buy an analogue one. If you're using it for actual measurement, then a digital one is a good choice.

To avoid confusion on the left is a dial indicator, on the right is a dial test indicator (DTI):

The dial indicator is intended to make precise measurements with the plunger moving axially. Using it to indicate while applying a side load is inaccurate.

If the greater movement of a dial indicator is needed to centre work in a lathe chuck then the technique being used is wrong. One can get well within 0.5mm by aligning the jaws on the chuck with the concentric rings on the chuck body, or by eye against a lathe tool. Or just note where the DTI touches and where it doesn't and adjust according. Then fine tune position using the DTI; I normally aim for less than 0.02mm total runout. I only use a DTI for aligning parts in the lathe chuck. I find it to be fast and accurate, given the correct technique.

Andrew

PS: I acknowledge MikeK beating me to it

Edited By Andrew Johnston on 24/03/2022 16:15:54

I have both, but only use the lever type DTI for centring, they are much easier to use. Also, I am suspicious of the accuracy of the plunger type used in a horizontal attitude, the slightest bit of friction and the tip can loose contact with the workpiece.

The long travel of the dial indicator can be handy for setting square stock in the 4-jaw as you can leave it in contact and there is enough movement for it to rise over the corners, can't do that with a lever one unless you keep moving it out of contact and back again.

I use whichever suits the job in hand as sometimes the shape of the work gets in the way of where the mag bases can be fitted or if setting up say a flywheel to turn the second side then both get used, one for concentricity and the other to eliminate wobble

A Vernier? (It seems popular with calipers)

Incidentally, Gauge vs. Gage provides written proof that English and American are different languages as Starrett UK and US use different spellings in their catalogue / catalog.

Brian G

Clock on the left. Finger indicator on the right.

Surely they both have a zero ref that can be used. Either by adjustment of the stand so that the fixed zero can be used or by turning the adjustable one on the outside. You can then measure movement from that zero.

Thank You, Andrew

MichaelG.

Yes I agree with what Mike Hurley says. Lot of the cheaper stuff these days is quite serviceable for home shop use. I have a ridiculous blatant imitation Mitutoyo DTI and mini magnetic stand with single-knob locking (hydrualic) that cost about $20 delivered. Ridiculous. But it has given at least 5 years of good service so far. All I use it for is truing in the lathe or checking things for straight and parallel etc mounted on a scriber block on my plate glass "surface plate" and occasionally truing motorcycle crankshafts.

When you think of it, China is full of factories full of machinery working day and night that all need to be set up with dial indicators so they can't be using total junk to do all that work with. They would never get it done. Might not be as good as a Starrett Last Word or Verdict or Swiss Interapid in a professional setting, but they get the job done.

Edited By Hopper on 25/03/2022 10:26:19