Looking for 0.001" resolution carbon fibre digital calipers

I recently searched for 0-6” carbon fibre (cheapo) digital callipers priced typically within the price range £5 to £15 but could only find, perhaps not unreasonably, units having a resolution 0.010”. Anyone know if they are available offering 0.001” resolution within a similar price bracket or is this expecting too much?

I think the bold bit's key. I don't know its modulus of elasticity or owt like that, but I wouldn't expect carbon fibre to have the rigidity to work to a thou with any reliability.

Carbon Fibre can be very rigid indeed, and interestingly you can control the rigidity of the part in each axis by manipulating the way it's laid up...

But I do find it extremely unlikely that carbon fibre that rigid can be manufactured for £15 profitably...

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Yes … most unlikely !!

A few months back, I bought some cheap ‘carbon fibre’ tweezers

Most of then were broken when they arrived … presumably because the mailer that they were in had gone through the franking machine

Inspection showed them to be some sort of brittle plastic ‘reinforced’ with chopped-strand rovings of carbon fibre, in lengths too short to be useful.

… the complete antithesis of a fully ‘engineered’ filament-wound product.

MichaelG.

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Edit: __ Temus fugit !! this photo is a year old :

Edited By Michael Gilligan on 07/11/2022 17:12:31

General thought inspired by the photo shown on Page 581 of the Model Engineer No. 4702, 21st Oct - 3rd Nov 2022 where the author refers to the use of an inexpensive digital caliper for use in a DRO lathe application.

Zoro offer a "Senator Polycal Digital Caliper" at £15.99 inc. VAT with a resolution of 0.01mm / 0.005" but this appears to be polycarbonate like the similar (identical?) M&W one. I wasn't impressed by the claimed accuracy of +/-0.02mm / 0.008", but even a Mitutoyo caliper costing 10 times the price doesn't claim to be more accurate, so I guess it is in the nature of calipers.

Brian G

I wonder how resistant to abrasion the jaws are? I wouldn't like to use them on anything harder than wood.

For the application in mind i.e. a lathe DRO (See ME 4702), the jaw hardness is irrelevant and can in fact be sawn/ground off as they would simply get in the way.

Chronos do a steel one but you'd have to shell out a whole £22..

Chronos Electronic Digital Caliper 6" / 150mm

..they claim 0.01mm /5 tenths resolution, 0.03mm / one thou accuracy..

You only need the slider and the electronics. I used the bits from a set that the plastic case had broken, and 3D printed a replacement housing.

Works well as a cross-slide DRO.

PS Get a set that retain the zero when they switch off. The ones that reset to zero when you switch them back on are a pain as a DRO.

Edited By Peter Cook 6 on 07/11/2022 23:04:34

Just found these at RDG;

Dasqua Plastic 150mm caliper claims 1/2 a thou.

Amazing! Well done - I'm seriously tempted, just to play with it and see if it's really any good.

Just gotta get the Expenditure Appropriation through now...

All I can say is why, why, why?

Tony

Hmm, I don't see any accuracy claim, just a "graduation" of 0.0005".

Assuming this means a resolution of 0.0005" then the accuracy can not be 0.0005" because of the quantisation error of +- 0.0005" plus all the other error sources.