No wonder I have trust issues!
- Thread starter Dadam
- Start date
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The left one I bought from a tool stall in Leeds Market in the late 2000s, cost about £6. I never had a reason to doubt its accuracy. I mislaid it around the new year so bought another at Toolstation. This was a Minotaur branded tool for £14 in a nice plastic case and it certainly feels well made so I was happy enough.
I was measuring the seatpost of a new bike so I could design and 3D print a clamp to hold the mudguard. The measurements didn't seem quite right. Thought maybe the post tube wasn't properly round, or I was measuring in different places. Then my old one turned up and didn't agree with the new one. Now I know why.
On the left caliper the bit measures 5.51. I think there's a smidge of parallax in the photo as it looks about 5.50 but to the careful eye it comes up between the 5.50 and 5.52 marks. Either way you can see it's around 5.5mm as the bit is labelled. The right one measures about 5.35. Way under.
Yes both are inexpensive tools, but they're still supposed to have a reasonable degree of precision, or you might as well use a plastic ruler.
I was measuring the seatpost of a new bike so I could design and 3D print a clamp to hold the mudguard. The measurements didn't seem quite right. Thought maybe the post tube wasn't properly round, or I was measuring in different places. Then my old one turned up and didn't agree with the new one. Now I know why.
On the left caliper the bit measures 5.51. I think there's a smidge of parallax in the photo as it looks about 5.50 but to the careful eye it comes up between the 5.50 and 5.52 marks. Either way you can see it's around 5.5mm as the bit is labelled. The right one measures about 5.35. Way under.
Yes both are inexpensive tools, but they're still supposed to have a reasonable degree of precision, or you might as well use a plastic ruler.
Punkawallah
Veteran
Don’t fret. The French did their sums for the length of the Metre and got them wrong. Took them years to fess up. Some would say accurate to a tenth of a millimetre -was- a reasonable degree of precision.
They did but most people tend to agree on it these days. Depends on the application whether +/- 0.1mm is reasonable. Fitting of parts is often not one of them.
sevenfourate
Devotee of OCD
- Location
- Lowestoft, Suffolk
All I’ll ever use at work / for anything remotely serious at home. For all the reasons you’ve stated and more….. 👍
EBAY LINK: https://ebay.us/m/R6bLjz
EBAY LINK: https://ebay.us/m/R6bLjz
Psamathe
Über Member
Confess: I never got on with reading vernier. Metric ones I can manage but recently wanted to check my disc (brakes) thickness so recovered my Dad's old callipers and they were imperial and afraid I didn't manage. Age late 60's so well familiar with imperial though do use metric by choice these days.
If you are using an inaccurate measuring device it only matters if you give the measurement to someone else. If you pay £14 for a caliper it is likely to be as accurate as a tape. Many years ago we used to have slip gauges (iirc) for checking accuracy of tools for machining.
Yes that's true but the 2 decade old unbranded £6 caliper is spot on, so I guess my expectations were coloured by that.
In the use case I describe the measurements had to transfer to a CAD program.
sungod
Well-Known Member
does it read 0 at 0 ?
if not, it's probably had it as there's no sign of any scale adjustment
if it does read 0, check if there's a lot of play between the slider and scale - with play, the jaws might become skewed wrt each other, which'd cause reading error, there may be some screws to adjust the amount of play, often at the top of the slider either side of the locking screw
if not, it's probably had it as there's no sign of any scale adjustment
if it does read 0, check if there's a lot of play between the slider and scale - with play, the jaws might become skewed wrt each other, which'd cause reading error, there may be some screws to adjust the amount of play, often at the top of the slider either side of the locking screw
Yes, the only thing that puts me off though is the number of fakes about. How do you know you're getting the genuine article?
It does read 0 at 0. Good advice though cheers. It generally feels well made though, purely by feel it seems better made than the more accurate one.
gbb
Squire
- Location
- Peterborough
A bit OT, but on T at the same time..It often occured to me after all my working life in engineering, maintenance and a substantial part if it in the tools...while I used vernier frequently, I never learned...or needed to use them beyond 0.5mm increments. It occasionally bugged me...but managed quite well without it.
slowmotion
Quite dreadful
- Location
- lost somewhere
I saw a review of the wide range of bootleg Mitutoyo degital calipers floating about. There was a section on how to recognise them from the way they were packaged. The general drift of the reviews was that the accuracy of the fakes wasn't too bad but the battery life and build quality of the digital ones were pretty bad compared to the real deal.
It's out there on Youtube somewhere.
Dogtrousers
Kilometre nibbler
You need to buy a large number of vernier callipers and average the result. But because more expensive ones can be expected to be better than cheap ones, you should probably make it a weighted average. 
I've got a nice pair of vernier callipers that belonged to my dad, (along with some other things like gauge blocks and stuff). I almost never have any need to use them though.
I've got a nice pair of vernier callipers that belonged to my dad, (along with some other things like gauge blocks and stuff). I almost never have any need to use them though.
