Manual Measuring Tools

[Steve1]

Just a warning to anybody reading this thread and decides to buy electronic calipers.

The cheap ones will be accurate enough, but are battery hogs.  I believe because they consume some power, even when off, to maintain the zero position.  I have a set of Mitutoyo calipers that go many years between battery replacement.  Leave them on, or shut them off when finished -- does not matter.      Also have a cheap set of calipers that collect dust because I gave up trying to keep a working battery in them.

 

[ChuckM]

Snip.
The cheap ones will be accurate enough, but are battery hogs. 

I make it a habit of removing the battery from a device when it's going to be idle from use for a long period of time. Battery erosion is often seen in idle AA or AAA batteries.

 

[rvieceli]

Just a heads up. Mitutoyo calipers are one of the most counterfeited items on the internet. Make sure you buy from a reliable source.

Ron

 

[Packard]

I just bought a $21.00 digital caliper from Amazon.com.  I brought it to work where we have reference blocks to check our measuring instruments and it has been right on the numbers.  I reads in imperial, metric and fractions.

I cannot comment on the durability at this point, but right now it is working fine.

 

[mino]

I just bought a $21.00 digital caliper from Amazon.com.  I brought it to work where we have reference blocks to check our measuring instruments and it has been right on the numbers.  I reads in imperial, metric and fractions.

I cannot comment on the durability at this point, but right now it is working fine.

I would say $20+ is about where the "normal" ones start, it is similar over here just in €.

Quality ones here go for €40 or so for the basic versions (no USB/Bluetooth or other fancy stuff).

You are lucky to have reference instruments to check against. This allows to risk a cheaper buy and return if not accurate enough.

 

[Packard]

I just went online to see what a pin gauge set or a block gauge set cost.  Pin gauges are cheaper at $75.00 going up to 1/4".  Block gages go for about double that. 

Our set goes up to 1.000" so I don't even want to know what that cost.

A feeler gauge is just about $7.00 and is useful for checking accuracy.  Clearly, it cannot verify accuracy for larger sizes, but a good indicator nonetheless.

 

[mino]

I just went online to see what a pin gauge set or a block gauge set cost.  Pin gauges are cheaper at $75.00 going up to 1/4".  Block gages go for about double that. 

Our set goes up to 1.000" so I don't even want to know what that cost.

A feeler gauge is just about $7.00 and is useful for checking accuracy.  Clearly, it cannot verify accuracy for larger sizes, but a good indicator nonetheless.

The problem with calipers or any other length measuring thingie is you need a complete set. The same calipers can be accurate at 1" while very much off at 3".

Over here "basic" digital calipers from a reputable company go €40 or so. Calibration of the same calipers goes €30. It is a lot of work to do for the calibration service guy.

I have one tape measure calibration protocol next to me, and for a 5 meter tape measure it includes a reference measurement each 200mm for a total of 25 measurements. Tape cost $30. Calibration $20.
[cool]

If I wanted to get a reference measures set and build a thermally controlled chamber to use it I would be in the $10k investment or so. Maybe more.

There is real value in buying "certified accuracy class" kit as you can skimp in the calibration costs most of the time and get a generally more accurate measure for the price. But it is always good to have at least one reference measure which you do get calibrated so can check other measures against it.

 

[Packard]

I am not allowed to keep my personal caliper at the office.  It is not officially calibrated.  I could have it engraved with "not calibrated; do not use for quality assurance", but it is easier to take it home.

Our company is an ISO certified manufacturing facility and all measuring equipment has to be certified yearly.  Most of the measuring equipment is certified by one company.  We self-certify the weighing scales with certified weights.  But the optical comparator and the tensile testing equipment is certified by the manufacturer.

It does mean that I can check the accuracy of my  personal equipment and that is useful.

 

[Steve1]

I am not allowed to keep my personal caliper at the office.  It is not officially calibrated.  I could have it engraved with "not calibrated; do not use for quality assurance", but it is easier to take it home.

Strange policy.

Where I worked, the company annually would come around the offices to pick up and calibrate measuring equipment.  If an employee has calipers in his desk, it seems pretty obvious that he must sometimes take measurements as part of his/her job.

 

[Packard]

We have about 20 balance beam scales that we use for counting parts and they are labeled "for parts counting only".  Also to comply with our ISO cert.  Those signs probably save us $4,000.00 a year. 

It is just expedient.  And we are able to get away with it.  And it does not impact our quality in any measurable way.

 

[mino]

We have about 20 balance beam scales that we use for counting parts and they are labeled "for parts counting only".  Also to comply with our ISO cert.  Those signs probably save us $4,000.00 a year. 

It is just expedient.  And we are able to get away with it.  And it does not impact our quality in any measurable way.

And it is fine as far as certifications go. The point of such standard requirements is to ensure accidental misuse is avoided the ISO (an other) standards leave it for the organization to choose a way how to (provably) do so.

Obviously, easiest is to not have an uncalibrated tool around. But marking is generally seen as fine too as long as it is easy to follow/understand for the employees and the policy is clear enough even a newcomer (or auditor) will be able to follow it.

I am not allowed to keep my personal caliper at the office.  It is not officially calibrated.  I could have it engraved with "not calibrated; do not use for quality assurance", but it is easier to take it home.

Strange policy.

To the contrary, it is the only (practical) policy that can ensure unverified measuring tools do not end up being used in production either by intention/convenience or by accident.

The only other is banning uncertified/uncalibrated tools altogether.

Not following such standards can lead and lead to from equipment seemingly randomly malfunctioning, dying earlier due to a wrong tolerance etc. etc. It is not self-serving.