Electronic vernier accuracy

[yetloh]

Am I right in thinking that this cutter also had a 1/4" shank? If so that may well have been the cause of the initial chatter which led to the disasster. I hate them. 1/2" shanks are so much more rgid and worth every penny extra.

Jim

 

[Steve Maskery]

You are right. This was a 1/4" cutter with a 1/4" shank. I do use 1/2" shank cutters where possible, but on this occasion I used what I knew was an unused cutter.
I'm having a replacement collet personally couriered in from the USA in just over a week

 

[Robbo3]

I use Dial Calipers as digital are too fiddly.

Very useful for accurate measurement especially if your eyesight isn't as good as it used to be.
The bottom two measure 10mm for one turn of the needle with each small mark being one tenth of a millimetre - more than accurate enough for any type of woodwork. The nylon ones are for general use & the metal ones for use on the lathe. One word of warning, round off the sharp corners of the internal legs if you use them on rotating wood.

The top pair measure in 64ths for the odd time when I need imperial & saves making a mistake with the size conversion.

The second pair from the top measure 5mm per rotation, which although more accurate, you have to take great care to see if the needle is in the 0-5 or 6-10 range.

 

[Phil Pascoe]

For quick gauging of turned work I use a set of Lidl open ended spanners. The 13mm is about 1/4 a mil oversized, so they're accurate enough for woodwork, and of course the error is always topside.

 

[Inspector]

......and difficult to use when 8 foot long

Work had a 10 foot Mitutoyo but it was a true vernier calliper, not digital. it was a two person job to use. :wink: Once over 40" or so you usually need help to measure things

Pete.

 

[Racers]

You can’t compare a printed tape to a digital caliper they are totally different things.

Pete

I'm well aware what verniers are, I have a digital and an ordinary one. I was commenting about not being surprised they vary. Some makes obviously better than others.

But it’s a digital measuring system it shouldn’t be wrong.

Pete

 

[Phil Pascoe]

......and difficult to use when 8 foot long

Work had a 10 foot Mitutoyo but it was a true vernier calliper, not digital. it was a two person job to use. :wink: Once over 40" or so you usually need help to measure things
Pete.

I spoke to an old guy one day who told me he was part of the team that cleared out the old Holman's workshop in Camborne when it finally closed down (they made large scale mining equipment).
They found a 108 inch micrometer. How accurate/inaccurate it was who knows? :?

 

[rafezetter]

......and difficult to use when 8 foot long

Work had a 10 foot Mitutoyo but it was a true vernier calliper, not digital. it was a two person job to use. :wink: Once over 40" or so you usually need help to measure things

Pete.

I'm sorry, a TEN FOOT vernier calliper?

 

[Inspector]

Yes and we also had an inside micrometer that by adding sections totalled 10' too. They didn't get a lot of use. They also had a coordinate measuring machine with a 10'x20' or so table along with a couple smaller ones of 5'x10'. A portable coordinate machine, a probe on the ends of an articulating arm that could reach a radius of 4'. And a Laser coordinate measuring machine that could measure 100' radius with a readout to 0.0001" subject to temperature and air movement. Aerospace has nice toys.

 

[Jacob]

......and difficult to use when 8 foot long

Work had a 10 foot Mitutoyo but it was a true vernier calliper, not digital. it was a two person job to use. :wink: Once over 40" or so you usually need help to measure things
Pete.

I spoke to an old guy one day who told me he was part of the team that cleared out the old Holman's workshop in Camborne when it finally closed down (they made large scale mining equipment).
They found a 108 inch micrometer. How accurate/inaccurate it was who knows? :?

I'd hazard a guess it was for surveying movement in mine works e.g. height of a tunnel. Accuracy wouldn't matter too much as long as it precisely measured any change in height at chosen spot points, and you used the same bit of kit. Just a guess.
Surveyors do something similar by attaching a calibrated sliding scale over a gap to see if it moves. Or simpler - attach a slip of glass, which will break if there is any movement.

 

[johnnyb]

The toolroom gauge room was kept at 20°c. It was always busy in heatwaves!

 

[Phil Pascoe]

Work had a 10 foot Mitutoyo but it was a true vernier calliper, not digital. it was a two person job to use. :wink: Once over 40" or so you usually need help to measure things
Pete.

I spoke to an old guy one day who told me he was part of the team that cleared out the old Holman's workshop in Camborne when it finally closed down (they made large scale mining equipment).
They found a 108 inch micrometer. How accurate/inaccurate it was who knows? :?

I'd hazard a guess it was for surveying movement in mine works e.g. height of a tunnel. Accuracy wouldn't matter too much as long as it precisely measured any change in height at chosen spot points, and you used the same bit of kit. Just a guess.
Surveyors do something similar by attaching a calibrated sliding scale over a gap to see if it moves. Or simpler - attach a slip of glass, which will break if there is any movement.

No, it was for cylinder bores.

 

[Lons]

But it’s a digital measuring system it shouldn’t be wrong. Pete

Is that not a bit naive Pete?

I have 3 of the things and the same one can vary when used on the same bit of material, they also vary when you close them which is why there's a zero button. Also for use because the metal jaws expand and contract.
I also have a Mitutoyo non digital, definitely more accurate but not as easy to use as I have to put specs on to read it these days.

I guess you probably get what you pay for as well!

I know it's not the same comparison but we have digital clocks and timers and they aren't always accurate either.

cheers
Bob

 

[MusicMan]

I accuse Pete of irony, not naivety

 

[Lons]

I accuse Pete of irony, not naivety

:lol: :lol: I feel for him Keith.
I do the "irony" in our house, or at least I iron my own shirts these days after once complaining they still were creased after the missus had done them. #-o

 

[Just4Fun]

I also have a Mitutoyo non digital, definitely more accurate but not as easy to use as I have to put specs on to read it these days.

I am in the same position. I have various older tools which never got used and I have a couple of cheap digital verniers that I use all the time because I can easily read them. To me that is worth more than a minor loss of accuracy.

 

[Gerry]

As a day job I calibrate and repair verniers every day.
The reason you are getting a different reading is usually due to a burr raised on the tip of the measuring anvils.
When you close the jaws to zero the caliper the burr is introducing an error. A few strokes of a fine stone is usually all that is needed to remove the burr.
The stainless steel is quite soft and knocking the pointed end of the jaws quickly burrs them.

Gerry

 

[Steve Maskery]

Thank you. I'll check.