digital caliper - floppy wheel

[PerranOak]

I bought one of those calipers with a digital scale - I know but I couldn't resist.

The wheel that moves the jaw up and down is very loose: I nearly sent it back but then I remembered that I used one a few years ago and it was the same.

Is this a "feature" rather than a "bug"?

 

[Mottie]

I bought one of those calipers with a digital scale - I know but I couldn't resist.

The wheel that moves the jaw up and down is very loose: I nearly sent it back but then I remembered that I used one a few years ago and it was the same.

Is this a "feature" rather than a "bug"?

No. I had one like that. Bought if from Aldi or Lidl I think for £7.99. CBA to return it so chucked it in the bin.

 

[Lower]

I bought one of those calipers with a digital scale - I know but I couldn't resist.

The wheel that moves the jaw up and down is very loose: I nearly sent it back but then I remembered that I used one a few years ago and it was the same.

Is this a "feature" rather than a "bug"?

Its normal. It allows you to move the jaw without the thumb wheel dragging and creating resistance.

 

[just pumps]

Normal on cheap calipers.

 

[Old Salt]

Its a thumb wheel on a caliper not meant to be used as an adjustable

 

[PerranOak]

Yes, it's funny as it does seem to be purposely made that way?

 

[Burnerman]

Most of them do that to some degree.....always worth measuring twice, zeroing after each try.
My biggest moan with these things is that if you disturb them, they often switch themselves on so when you really need it the battery is flat. A right PITA.
John

 

[ibruceuk]

The wheel is supposed to slip, it is a method (albeit crude) of ensuring consistent pressure without being too much and potentially causing a crushing force on the item being measured. If it was a toothed wheel for example the measurement would heavily depend on how much force the user put on the wheel to adjust as there would be no 'clutch effect'

 

[RandomGrinch]

The wheel is supposed to slip, it is a method (albeit crude) of ensuring consistent pressure without being too much and potentially causing a crushing force

I'm afraid I would have to disagree!
I believe the wheel (often referred to as the 'drive wheel'), is there to offer a precision, slow motion movement to allow accurate measurements.
By being effectively a gear for slowing down movement, it is actually creating a mechanical advantage - enabling a larger crushing force to be applied to a delicate object!
A true clutch mechanism is used on a micrometer, where as you get nearer to the object being measured, you use the end wheel and tighten to a standard '2 clicks'.

 

[TeaAndBiscuits]

No. I had one like that. Bought if from Aldi or Lidl I think for £7.99. CBA to return it so chucked it in the bin.

You chucked a caliper in the bin because the thumb wheel was slightly loose?

 

[Mottie]

You chucked a caliper in the bin because the thumb wheel was slightly loose?

No. I must have read the OP wrong. When I took a measurement and locked the jaws to read it, the jaws still had movement and therefore you couldn't get an accurate reading. As I said, cost £7.99 from Aldi or Lidl (can't remember which one) and CBA to return it so I just binned them.