Micrometer Blues

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, I've had the same problem with a Moore & Wright 0-13mm mic.

Very difficult to see the markings without a magnifier and then had to look at it at a slight angle from the left.

Well this morning I've cured the problem by removing the sleeve and taking a smidgen off the head end of it while holding it in my collet chuck and then refitting it back onto the mic and placing the datum line in a more central position. I then had to loosen the screw holding the thimble and tuning it up slightly to bring the zero mark back in line with the datum line when the mic was closed to zero.

I can now read the mic clearly seeing the marks just with my normal glasses on and looking at it face on. Much better.

Personally I don't see how this can affect the accuracy of the mic, because there has been no interference with the measuring components. In my mind it is no different to shifting a zero point on a DRO.

Regards Nick.

[David ColwillParticipant @davidcolwill19261]

How about removing the thimble and mounting it in the mill with the 0 facing upwards, then with a small end mill (1.5 – 2mm ) milling a hemisphere into it in line with the zero line. This will allow you to see where you are without too much hastle. You could even do this by hand with a file.

Regards.

David.

[David ColwillParticipant @davidcolwill19261]

Err next time engage brain! This will only work at one point per turn of the thimble. Doh!!!

David.

[Mike PooleParticipant @mikepoole82104]

Before everybody starts machining their mics, check that it is not adjustable like this Moore and Wright. The thimble position can be adjusted by the black nut shown on the spindle here, the thimble is released by unscrewing the ratchet. This probably doesn't apply to Nicks 13mm mic as it is a compact thimble and likely to be like the Starrett I pictured.

Mike

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Mike, my 13mm one has a cone on the ratchet that engages into a corresponding split cone in the spindle, which opens it out into the hole on the one piece thimble.

Regards Nick.

[Simon Williams 3Participant @simonwilliams3]

Seems like it's Easter Egg Holiday Micrometer Modifying Friday!

In between toasting hot cross buns, I too have been modding my micrometer.

Here's the sleeve dismantled:

The brown crud on the inner is dried oil. Carburettor cleaner is wonderful stuff…

And here it is after taking 8 thou off the LH end of the scale sleeve and re-assembling it.

I did it by holding the sleeve into a 12 mm collet and popping it into the T&C grinder so I could control the amount of metal removed. Is it fixed? – time will tell!

Now, why has the toaster caught fire…..

[KWILParticipant @kwil]

Since we are talking metric mics, better to have written "0.2mm off" !

[Tim StevensParticipant @timstevens64731]

You can solve the real problem without affecting the notional 'accuracy' using a chain-saw file. Remove the barrel (just unscrew it all the way) and carefully file a notch in the edge at the zero position. Don't go mad – leave enough of every scale mark so that no confusion there can arise. Tidy up any burrs with wet & dry wrapped round the same file. This will only give you the extra visibility around the zero position, but that is the only place where confusion of this nature can arise – isn't it?

Or have I joined the ranks of 'don't understand' ?

Cheers, Tim

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Tim, I think I prefer both Simon and my solution, looks much neater me thinks.

Regards Nick.

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