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

[Richard BrickwoodParticipant @richardbrickwood17062]

Morning all – I’m stumped! I have a Chesterton 369 Height gauge but the first main calibration starts at 2″ below which are vernier calibrations from .9-.2

I can’t work out how to measure a height under 1″ – except by subtracting (say) 2 from 2.750 to get 0.750 – which is a bit tedious in reality.

Is there a better way of achieving an accurate sub 2″ measurement?

…or anywhere I can get a Chesterton manual (not just the how to read a vernier scale paper)

Richard

[Richard Brickwood]

On Richard Brickwood Said:

…or anywhere I can get a Chesterton manual

Put the item on top of a 1″ 123 block. Put the scriber arm under the main arm. At some point the whole sliding assembly will hit the base, so the design of the instrument imposes a minimum reading.

If you want a Chesterton manual, ask Father Brown.

If you want instructions for a Chesterman height gauge, searching google for ‘chesterman height gauge instructions’ gives some helpful results. Searching ‘images’ shows some useful pictures of the device in use.

As well as reading this thread from its beginning, you will find a couple of older threads from this forum that include some pictures. You will find a YouTube Video by Oxtools that discusses the item.

Chesterman 369 height gauge

Lollipop maybe?

The link to the instructions/brochure in the first thread appears to be dead, but someone here may be able to re-upload the document.

You will also see that at some point the name Rabone was associated with Chesterman, so that would be useful in your research.

 

 

[Andrew TinsleyParticipant @andrewtinsley63637]

Machine DRO sell cranked scribers. I purchased a Mitutoyo twin column non worker which was also missing the scribe. Machine DRO supplied me with a generic carbide tipped replacement for not a lot of money. Not worth making one for the price.

Oh and I fixed the electronics, so all working as it should.

Andrew.

[Howard LewisParticipant @howardlewis46836]

With regard to reading the vernier.

The normal belief is that the dimension that you read will be within a thou. The difference between one pair of lines and the next pair coinciding will hardly be discernable, even with a magnifier.

Remember, the vernier part will differ by 49 or 51 divisions from the 50 on the main scale, so the resolution between one line and another will be VERY small.

You can either use the Height Gauge to measure, or scribe directly, of use a DTI, preferably a finger clock. Zeo it on the object to be measured, and then clamp it

Build up a pile of gauge blocks (slips) until the clock reads Zero again.

No gauge blocks? Make up an adjustable assembly.

Take a piece of bar and face the end to a fine finish. (NO central pip).  Reverse in the chuck, cut to a little under the length that you want to measure, by at least 1/2″. Face, and drill and tap with a suitable fine thread (ME 40 is good, giving a fine adjustment )

Make up an adjustable length gauge with the same size thread, knurl and face the head,

Make a thin, knurled locknut

Assemble the three components

Adjust until the clock reads Zero and lock.

Either use a Micrometer, or calliper, to measure the length.

Or even exchange the scriber for clock, and use the Vernier Height Gauge to measure the length of the adjustable length gauge. Although, this would be the same as using the Height gauge directly.

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