Hi guys. I just wanted to get the general opinion on the correct way to set and use a height gauge.

Lets say for example I want to scribe a line on a block at a known height.

I have put the height gauge on a surface plate, and then put a gauge block next to it. I swing the height gauge finger over the gauge block and drop the height until I can just feel it rub on the top of the gauge block as I swing the height gauge over it. I am doing this using the under face of the height gauge finger. I then adjust the vernier on the height gauge to calibrate it. Is that the right way to calibrate the height, or should I do it until the point strikes the side of the gauge block and then back off slightly.

I can then set the desired height on the height gauge and swing it across the face of my item scribing the line.

Is this the correct way?

Presumably the scribed line will be offset by half of the radius of the end of the height gauge scriber. As the height gauge was zero'd on the underneath surface of the finger but the line was scribed at the point. Does this matter, I can't gauge what the likely difference would be.

How do people care for their height gauge fingers, do people regrind the points, and if so is there a preferred method.

If doing it using my method, then the flatness of the underside of the finger, having the finger mounted horizontally, and having a point ground at the very bottom of the finger with a small radius are all key to getting an accurate measurement out of it.

Sorry if this is a dumb question, but i've searched online for help on how to use one, and they don't cover these specific questions.

Thanks

Graham

Cheers guys. The finger on mine doesn't go down to the base. I'm presuming at some point it had the old cranked finger replaced with a straight one. I stick a 1 inch gauge block under it and calibrate it at the 2 inch mark.

If I use the fine adjusting knob on the height gauge to slowly drop the finger down until it touches, its quite often tricky to actually determine the point at which it touches, and I guess you could have the same effect when zeroing to the base. You could crank it a thou too far and actually have lifted the front of the height gauge up, or alternatively what you think is touching is actually slightly above base. You loose all feel for the "touch down" point when using the fine adjustment. This isn't just a calibration thing. It would be exactly the same if you were using your height gauge to measure the height of a block and needed to touch down the finger on the top of the block.

This is on a chesterman height gauge with has coarse adjustment by disengaging the head from the feedscrew and sliding the whole head up and down, or fine adjustment using a knob on the base to spin the feedscrew. If I attempt to touch down onto a gauge block using the coarse adjustment, the head drops back into the nearest thread in the feedscrew which moves the head.

If I get the height gauge close to the right height using coarse adjustment, then press down on the base and use fine adjustment to drop the finger onto the top of the item being measured, I can kindof feel it touch, but not definate enough for it to be repeatable to the thou.

I suppose I could try getting it to what I think is touching, then if I can slide the gauge block in and out from under the finger, but not feel any noticeable up and down play when I try and rattle the gauge block, that would probably work.

I guess its all in the technique.

Do i have a 40 year old gummed up height gauge that has "lost its feel".

My height gauge has been at the back of my tool cupboard since I acquired it. And Ive only just tried to start using it. Can you tell

Graham

I was just thinking aloud. I haven't ever tried sharpening the end of my scriber in the height gauge. It had occurred to be if the end was dull, or badly radiused, or not ground correctly, I could actually be scribing a line somewhat above my zero reference.

i.e if there was a 5 thou radius on the end of my scriber, all, all my scribed lines would be 5 thou greater than any height measurements made using the under side of the scriber.

Thanks for everyones suggestions. They've been really useful.

Ive actually just been out and had a look at the height gauge again, with the intention of measuring it up for a new cranked scriber however as you can see from the photos, its designed to have a straight scriber and by the looks of it, designed not to measure anything below about 40mm. I guess I would place small items on a 1-2-3 block to raise their height.

You can see here on a 2" block, its reading 2", so no need to manually add numbers as I originally thought.

Calibrating the metric side with a 50mm slip.

Calibration is done by loosening the screws on the vernier plates, which are slotted and adjusting them to suit.

Jason,

A massively exagerated illustration, but if the scriber is blunt, you will scribe a line higher than you wanted to.

Maybe on a blunt scriber it equates to a tenth, a thou, maybe 10 thou I have no idea.

Graham

Clive,

It is a wedge type scribe point, not a round one. It doesnt come out well in the pictures. Heres a closer view.

If I mount the scriber below the clamp bar it still does not reach the table. If it was designed to reach the table, the scale on the height gauge would start from 0. As it is the scale starts at 1.5 inches. If I put the height gauge to 1.5 inches, the top of the clamp bar is 1.5 inches from the table. There is only approximately +/- 1mm adjustment in position of the scale, so theres no way it can work any other way, than with the scriber mounted in the top of the clamp bar.

Graham