Ght centre height gauge

[Bjorn_B]

Took a long, long time. But at last I have got a proper centre height gauge! As I had a mishap with the leadscrew handwheel (handle jammed against an oilcan and taper pin sheared). I ordered a leadscrew thrust bearing conversion from hemmingway. As a treat I allso ordered the ght centre height gauge kit. Could have made it from scraps, but knowing myself I will never get it done that way. Anyway, here it is. As someone wrote, a wonderfully over engineered piece of kit.

[ths]

A very useful addition Bjorn, and a nice job of it. Cheers, Hugh.

[Graham Meek]

Hello Bjorn,

You have made a good job of the centre height gauge, time spent making these little aids is soon repaid many times over. 

In all fairness I think somewhere along the line someone has added some embellishments to GHT's original design. I made my version to GHT's words and music, (shown below) about 30 years ago now and would not be without it.

My best regards
Gray,

[Bjorn_B]

Thanks for your kind comments. I have some projects under the belt by now, but this is one of the things I just did not get round to, been using all sorts of temporary sollutions for years 

[sshire]

Bjorn
Nicely done! And simple.
For those with absolutely nothing to do, here's the one that I built. I saw something similar (commercially done) 3-4 years ago but have no idea where.

A .50" ground drill rod with a .25" reamed center hole. The .25" ground drill rod is the calibration surface. A Horrible Fright indicator was cheap enough to dedicate to this device.



With the device in a 5C collet, the indicator is zeroed. The .25" rod is then removed.



The cutting tool is positioned under the indicator and the height is adjusted to -.125" (the center of the .25" calibration rod: the lathe center)



Once calibrated, I just keep switching tool holders on the QCTP.  Centering 15 tool holders takes very little time.

[mklotz]

Very innovative, Stan.  Plus it provides a simple way of quantitatively setting tools (e.g. cutoff tools) slightly above center to counteract deflection when in use.  I may steal your design.

My approach is crude, though effective.  I machined a block of steel to such a length that, set on the compound, its top surface is at center height.  Running my NIST-certified thumbnail across block top and adjacent tool top tells me when they're at the same height.

[sshire]

And I thought I had the only certified fingernail. I use mine with the center finder (pointy end; no power) to pick up a center punch mark. Amazing how close one can get.

[mklotz]

Torturers long ago learned to pull out fingernails to encourage confession.  That says a lot about how well supplied with nerve endings the nailbed is.