I would not be surprised to hear that the spring had been deliberately removed

… many of the old ‘Tool Room’ guys ridiculed the use of ratchets because there is no ‘feel’

It’s like paddling with your socks on !

MichaelG.

On 13 June 2025 at 21:26 Michael Gilligan Said:

I would not be surprised to hear that the spring had been deliberately removed

… many of the old ‘Tool Room’ guys ridiculed the use of ratchets because there is no ‘feel’

It’s like paddling with your socks on !

MichaelG.

As an old “toolroom” guy I’d second that motion, absolutely no ‘feel’

But if you need a spring, just buy some old mic’s to use for spares, you can pick them up at boot sales for next to nothing.

Andy

At first sight it would seem any ratchet spring from another micrometer would do. However it is a little more subtle than that, and things do not always appear to be as simple as we might think.

Having recently acquired a second-hand 0-15mm Mitutoyo Micrometer with a broken ratchet spring. Enquiries with Mitutoyo require the frame number. As different springs were fitted depending upon which type of ratchet was used, i.e. Metal or Plastic. The spring fitted to a Standard 0-25mm is a lot stronger as I compared the new one for the 0-15 with my 0-25. The spring fitted to my 0-25mm Combi-mike is stronger than the standard 0-25 micrometer. (The Combi-mike has the mechanical digital counter).

While the subject about the sense of feel when using a micrometer is a deep one, and something I know quite a bit about. The purpose of the ratchet is to give a constant force on the measuring surface and thus give consistent readings and promote longevity of the micrometer. Variation will occur when one persons measurement is different from the other, due to his or her “Sense of Feel”.

The best way to hone one’s sense of feel is by using a Slip, or Gauge, (Gage), block. When the micrometer reads the same as the block, assuming it is to NPL standards, then the sense of feel is about right.

Regards

Gray,

On 13 June 2025 at 23:29 Grindstone Cowboy Said:

…

And yes, I agree that one should develop a “feel” for these things, but if it was just a matter of a pound or so, it’d be nice to have it completely working as per brand-new.

…

Rob

In the interest of balance, I suggest most of us, most of the time, are better off with a ratchet.   ‘Feel’ is an acquired skill requiring practice with a set of calibrated standards and not everyone is good at it!  In contrast, a spring provides consistency such that an ordinary Joe gets reasonable measurements from the micrometer without fuss.

I’m very much an ordinary Joe, typically working no better than ±0.02mm (± 1 thou), mostly using traditional fitting methods.  I don’t work to tolerances, or make accurate jigs, fixtures and go-no go gauges!   I don’t match shafts to holes by measuring and cutting metal to 0.005mm.  Rather, I turn shafts slightly oversize, and then reduce them with Emery paper until they fit loose or tight to my satisfaction: the fit isn’t measured!

In a fitting workshop, micrometer may not be relevant, with or without a ratchet.   Though I have one, my micrometer is rarely needed. Even though their accuracy is inferior, most measurements are done with a digital caliper and my mill’s DRO.

Quite interesting to work as an early machinist with good eyesight, a steel rule with ¹⁄₆₄” graduations, marking blue, scribe, and a set of plain calipers.  Results surprisingly good, even in my clumsy paws.   For best it’s necessary to develop a feel for the calipers, which are used as comparators.   I doubt LBSC had a micrometer when he built Ayesha in 1922.   Though I’m sure he owned one later they don’t figure much in his “words and music” – they’re pragmatic rather than precision engineering.

Tool-rooms must be accurate and precise, but there’s little need to meet tool-room standards outside a tool-room!

Dave

You can get a selecion of small springs on Ebay.

RS do a boxed set but £££