G0762 Benchtop Mill — Z-crank 0.118" Per Revolution?

[Rex Walters]

I'm a recent owner of a Grizzly G0762 benchtop mill. Overall I'm quite happy with it, but a question came up in another thread regarding the Z-axis head crank: was it 0.100" per revolution or 0.125"?

I never use the head crank for anything other than gross positioning. I use the dial on the quill (with the feed knob engaged) for precise positioning in Z.

So I pulled out an indicator to answer the question, but now I'm more puzzled than ever. I've measured umpteen times, and the answer keeps coming out to 0.118" per revolution (or 3 mm).

Is it really possible that despite inch dials in X and Y as well as Z (on the quill) that the gearing is metric for the head crank? Not only is it annoying, it makes creating a dial for the crank difficult. I'm starting to regret only buying a two axis DRO....

Nothing special about the setup, just a 0 to 1" dial indicator:

Any comments or suggestions for creating an inch dial for the crank will be appreciated.
--
Rex

 

[Holescreek]

Standard 3mm thread pitch.

 

[tmarks11]

That is not abnormal in machinery coming from Taiwan and China.

Maybe you can Ebay your 2 axis DRO and get a 3 axis one. The convenience and precision is worth the extra $$$.

 

[epj]

I have a 2 axis DRO. I fitted a digital scale on the quill to serve as the Z axis. Not quite as good as a real DRO, but it is a million times better than the scale on the hand wheel. Only cost about $35 from eBay.

 

[tmarks11]

In the absence of a DRO for the mill head, just use a dial indicator on a magnetic base. Attach the magnetic base to the head, with the dial indicator probe on the part, and use the dial indicator to read-out how much the head moves.

Even when you can trust the dials on a mill, this is more convenient (since you don't have to count rotations) and accurate (since it accounts for backlash). I do this on my lathe all the time when I need to move the cross slide or carriage by a precise amount.

Personally, I would shop for a 3 axis DRO. Life with it is so much better.

 

[kennyv]

I have a 2 axis DRO. I fitted a digital scale on the quill to serve as the Z axis. Not quite as good as a real DRO, but it is a million times better than the scale on the hand wheel. Only cost about $35 from eBay.

did You use this for full z axis travel ? Can you post a pic and link you spoke of thanks
I have a PM25MV that has a fine digital z axes feed (quill only) but not for full column Z travel. I am thinking about using a 12 dig caliper to and modiphy for this use looking for ideas.

 

[epj]

I have a picture on my iPhone if I could figure out how to post it. Mine is a 6"'and covers the 5" quill travel.

 

[epj]

 

[wrmiller]

Nice. I have the same one in black on my quill.

 

[kennyv]

Sorry I chimed in perhaps posted in wrong place. Forgive me brothers .... However like to give a quick shout throw one thing out there if someone catches post thanks .
I have A PM25 MV little dif set up than the Griz . My model came with quill travel down feed DRO (fine adjustment ) but not Full Z travel on column . I was thinking of adding in addition to fine feed DRO. . Like to see a pic of someone who may have put Z depth on the side of column . Or a mod like wise thanks