I Need Help with Gauge Block Calibration

You're about to calibrate a precision reference gauge block using a laser interferometer and you don't know how to hold the block in place??!!

Normally gauge blocks would be 'wrung' onto a grooved surface table and then BOTH sides would be measured to get the length without any errors from a twisted, warped or non-parallel gauge block, as you will be measuring down to an accuracy of micro inches, you will, of course, need a temperature controlled calibration room together with all the necessary equipment...

Overall you are talking of an investment of many tens of thousands of dollars/pounds etc...

So for a few hundred pounds / dollars it would be advisable to buy the correct gauge block holder you will need.

John.

I agree, calibration must be done between 68 and 73 degrees Fahrenheit or you will not get an accurate reading. You also need a regulated amount of humidity lower than 50%. It may be cheaper to send them out and have them calibrated. We send ours to

The L.S. Starrett Company

24500 Detroit Rd.

Cleveland, Ohio 44145

I am sure you can find a qualified company close to wherever you are located.

sorry, after posting I reread the question. They can also provide you with an appropriate holder for the blocks. www.starrett.com If you have never attempted this experiment I would advise having an experienced person with you to doublecheck and make sure you reduce possibility for error as much as possible. We have an old model linear measuring machine that has had a laser installed on it. If you can set something like this up, it would be very helpful for clibration and measurement. It just has the laser mounted on the stationary end and the sightglass/target mounted on the moving end of the table. Very useful!

Hi !!!

I wish to add to what is contributed by "GURU" Electroman & Heart Cooks - Brain

• For Calibration set up if being designed by you you would need a Robust Granite Comparator stand and on the column of of the comparator you would need to mount your laser equipment.
• Which make of laser do you propose to use ?
• For your information SIOS - Germany offers similar equipment
• You can also see IBB - Germany Metroscope which uses Laser for calibration of length standards
• For calibration of Gauge blocks you would need to check flatness of two opposite working faces of the Gauge block and also check the parallalism
• What is the budget of uncertainty of measurement for your calibration set up?
• In any case as already conveyed by other contributors, this would be a costly proposition for you if you do not wish to commercially exploit further
• Please elaborate more if you wish specific reply with regard to holding arrangement

I believe comparator should be available near your place, incedently we produce these type of comparators with Granite base and can offer if you furnish mounting arrangement of Laser equipment.

Udayan

udayan121049@yahoo.co.in

Pull down Gauge Block using Vacuum Fixture.

Best Regards.

JM Harrower.

FNB Metrology South Africa.

If you have access to a set of traceable master gauge blocks you can use optical flats & monochromatic light, eg sodium light, VERY cheap way of checking a suspect gauge block against a master block, just need to know how to interpret the fringe patterns, old fashioned way, cheap, accurate & quick, especially to just quick check the "tool-room / work-shop" blocks to see if they are too worn to be serviceable.

Brien.

1: What resolution are you required to measure at?

2: Hell use a Keyance system. Simple, resolution 1/4 lambda. IE, if you are using 653 nm light, the resolution will be 653/4 nm, to a first approximation. If ~ 162 nm is acceptable, then a low cost Keyance system will work.

3: No one will set up to measure and calibrate gauge blocks when you can have it done with the installed equipment base.

4: White light interferometers are generally +100K US. Laser interferometers are also in the +100K US range. If you have the budget, go for it. If not, contract to have it done.

I've tried to find the auxiliary tool for the gauge block in so many sources including at www.starrett.com as Heart Cooks Brain had suggested. but still, i can't find any appropriate tool to use. the problem is-as i know that, laser interferometer is rarely (or even never been) used for this kind of measurement. koster interferometer is commonly used to do this measurement.

as we know, laser interferometer can be used to measure flatness, straightness, and DISTANCE. i use this laser distance measurement to calibrate the length of gauge blocks, which means that i need an auxiliary tool to hold the blocks

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