How to correctly use a height gauge

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Andy, I understand what you are saying, however the numbers 10 to 50 are not directly depicting the measurement, but are showing the number of divisions of every fifth of the Vernier scale, and you will see the Vernier scale covers 49mm, therefore each division is 0.98mm apart, which gives you the 0.02mm resolution.

The one I have was at one time, owned by Vickers Eng. South Marston, and was last calibrated in their calibration department on the 1 / 2 / 84 with its next one due on 1 / 2 / 87. If it was good enough for Vickers, I'm sure it meets my needs. I have checked the calibration in the best way I can, and it looks very good to be correct.

Regards Nick.

[Gareth ThomasParticipant @gareththomas76772]

Thank you Bill and Dave for your inputs. Things are now beginning to dawn on me that I have perhaps asked too much from my measuring techniques and the instruments I use. After using a vernier height gauge I bought myself a digital one in order to get away from all the arithmetic (and mistakes!) but I still seam to have a lot to learn.

Using the height gauge and a 'finger' Mercer Type 301 DTI I thought the measurements would be a doddle by touching the bottom and top of the hole with the stylus and reading the height gauge. Ni eve! Following the input received from yourselves I have adopted the following method:

1) with DTI attached to height gauge zero Mercer clock with about 0.005" (0.127 mm) deflection of the stylus on a gauge block of a known dimension. The height gauge is also zeroed and ABS zeroed. Raise the height gauge and adjust the height gauge to zero the Mercer clock on the lower edge of the hole. Note height gauge reading and zero the height gauge. Now place a piece of round bar in the hole and wedge it to touch the top of the hole with a piece of Plasticine. Then bye again adjusting the height gauge to zero the Mercer clock on the top of the round bar I have got a hole size. Magic! Also using the ABS button on the height gauge I have also an ABS dimension to the hole top edge as a check for the hole size. I am now more confident of my measurements. Don't forget to add the gauge block dimension to the ABS dimension!!!!

Thinking about it, the way the Mercer DTI reads has perhaps led me astray, the needle only rotates clockwise whether the 'finger' is raised or lowered. Pesky thing!!

Regards Gary

[Howard LewisParticipant @howardlewis46836]

Gareth,

You have a PM

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