Lathe Tool-height Setting Gauge

[davidpbest]

I finally got around to making a lathe tool height setting gauge. I got tired of breaking carbide inserts because the tool was never at exactly the right height. Here are some photos - in 316 stainless, 38mm diameter. It’s based loosely on what I saw done by Tom at Ox Tool on YouTube:


The height adjustment screw is 1/2-20, it’s locked in the base with a set screw, and the upper sleeve has a nylon-tipped set screw to lock it in position once adjusted.




I copied the swing-out top off the Hardinge version so I can check tool height against either against the bottom of the swing-out top, or by feel against the top surface of the main body.







I use it in conjunction with a 1.5” square bar (precision milled) to span the carriage gap.



It’s very easy to discern the height of the tool relative to the reference point - my finger can detect a difference of under 1/1000th. Or the height gauge can be rotated around to test if the swing-out top clears the tool.





This is how I adjusted it to the lathe spindle center line. 3/4” end mill backwards in the chuck, checked for zero TIR. TDC referenced to zero with indicator.



Carriage is moved so indicator is over the tool height gage with a 3/8” gage block stack on top - then the tool height gage is adjusted by (turning the base) to read zero, then secured with set screw. I've posted a video of the height adjustment method here if anyone is interested: https://www.flickr.com/photos/davidpbest/34194462773/in/album-72157682262435431/



Hope this is helpful to someone - one of the most functional additions to my lathe, and has really helped - especially with part-off tool height setting.

 

[MonkMan]

Very nice David, Thanks

 

[Bob Korves]

Nice job, David, and I have thought of making that same setup for my lathe, just never get to it. I mostly end up using a 6" rule pinched lightly between the cutting edge and the work, check for vertical, quick and dirty. For some jobs that is not good enough and I really should copy what you made exactly...

 

[BFHammer]

Nice project David, very well executed. Thanks for sharing!

 

[brino]

Hi David,

Thanks for sharing this project; and you did it with great clear photos and text showing everything very well.

The square bar to bridge the gap is smart, it means you could use it with almost any machine, just make the bar to suit.

It is much appreciate!

-brino

 

[ddickey]

How's that solid post working for you?

 

[davidpbest]

How's that solid post working for you?

Works great actually. Has really helped with surface finish on some things, and parting-off in particular. Details on that can be seen here: https://www.flickr.com/photos/davidpbest/albums/72157684102384825

 

[jbolt]

Nice work David. The fit and finish looks great.


I'll add a couple more examples of tool setting gauges.

These only reference the tool from the underside of the gauge but a spacer bar is not required. The only downside is setting some boring bars can be difficult.

The first one was made from scrap aluminum and some all thread. The flat for measuring is milled to the center line of the hole. The gauge is set to the lathe center line using the hole with centers in the spindle and tail stock. This has been my go to gauge for years.



The second one was made from a magnetic base, two 1/2" optical posts and a fixed 90 degree clamp from Thorlabs. A flat was milled on the horizontal post. Gauge height is set using 123 block and an adjustable parallel.

 

[davidpbest]

Thanks for posting Jay. I like what you've done (as always).

 

[JimT-72]

Quality work David, well done!