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View Full Version : Need help - Is what I want to do feasable.



Vincecam
8th January 2014, 09:34 PM
I am a garage hobbiest and I have a Hafco HM46 Mill.
I would appreaciate comments on the following:-
I have purchased DRO with 3 scales for each of the X,Y and Z axis. I will put the Z axis on the headstock bed.
Generally, the spindle height is first set on the headstock bed and then locked off. Fine adjustment on the spindle is done on the quill, which is still technically on the Z axis. (remember I am an ametuer so terminology may not be quite right)
Can I put a small scale and read-head on the quill and have a switch which can alternate readings on the monitor's Z reading between the headstock position and the quill position. This way I can have position 1) - Headstock reading, and switch position 2) - Quill position. Is this possible.
Does anyone make or sell this modification. The signals from the sacles are digital so a simple electrical switch could not be used???
I would very much like opinions.
Thanks
Vincecam

Driftabout
9th January 2014, 07:51 AM
Have you seen this post? MD45/HM46/RF45 DRO Install as requested.. (http://www.woodworkforums.com/f65/md45-hm46-rf45-dro-install-requested-169053)

I suspect that each scale has it's own calibration, but then I 'm guessing. More detail of your gear might help others

You could just fit a single stand alone DRO or digital caliper to the Head as it I locked and the quill used for actually adjusting z. Could you use offset function if you intend to move head?

variant22
9th January 2014, 09:40 AM
Can I put a small scale and read-head on the quill and have a switch which can alternate readings on the monitor's Z reading between the headstock position and the quill position. This way I can have position 1) - Headstock reading, and switch position 2) - Quill position. Is this possible.

Some DRO monitors have dual inputs for a single axis. I think that might be the path of least resistance if you want to glass scale the Z and quill. I did not know about them when I purchased my DRO (link above is my install). I have a simple digital vernier type scale for my quill and a glass scale for my Z.

Either that or you could buy a Serial Port Switch box and switch between two distinct scales. I am assuming that the DRO scales have a Serial port as their output connector. It looks like they do, but I am not near the mill to check.

cba_melbourne
9th January 2014, 05:45 PM
It depends on the DRO that you are using. Some better or newer DRO's can automatically add up the readings of two scales, and display the sum of both scales as if it was just one scale.

For example, on my X3 mill I have two z scales. One reads the quill position, the other reads the head position along the column. I use a low cost kit DRO that you assemble yourself. It is a Shumatech DRO-550 (Home Page | shumatech.com (http://www.shumatech.com/)). It is really a joy to use, I use the quill to set the coarse position, and the head to make fine changes (the X3 mill does not have a graduated fine feed on the quill). To make a measurement, I just release the quill clamp and the cutter speeds upwards to let me access the workpiece. Then down again close to the cutting position, lock the quill, drive the head to exact cutting position and continue. All the wile, the DRO shows always the exact position on the z display, as if there was only one scale. Absolutely no need to switch between scales. The DRO integrates the two scales into one single z-display.

Have a look at the operator manual that came with your DRO. Or check the backside of your unit, DRO's that have this feature would have more scale inputs than just the usual three (x,y and z).

Big Shed
9th January 2014, 06:52 PM
I guess that's where a 4 axis DRO comes in handy:)

Steve Bedair's Grizzly G6760 Mill (http://bedair.org/Mill/6760mill4.html)

Vincecam
10th January 2014, 11:02 AM
Many thanks to all.

really appreciate your input.

vincecam