DRO's - Printable Version

DRO's - Printable Version

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RE: DRO's - PixMan - 03-10-2012

I'll have to get some photos of the DRO setup on my dad's Victor. It's a old Mitutoyo unit, and although it came fitted to the machine I did have to reinstall the Z axis scale.

The machine doesn't have a taper attachment, but I believe the scale can be (and in my case, has been) placed in such a manner that it won't interfere. The scale for the cross slide is placed further aft of where the one on Ed's machine is located. It can be anywhere as long as the reader head moves within the scale housing, is aligned to stay in the middle of the slot, and stays there within the limits of travel of the cross slide.

On my dad's machine, which was "bought" used (a gift really, just paid shipping), the placement of the long scale was wrong. The machine had a junky 3-jaw 10" scroll chuck on it since Day 1, apparently. The carriage had never been moved any closer to the spindle nose because the cross slide wouldn't go past the chuck. When I replaced the chuck with a new 10" Pratt Burnerd Super Precision, still no problem. When I fitted a Royal 5C lever style collet closer, well then it was "Houston, we have a problem." The carriage could now move 4" closer to the spindle nose, but with the scale mounted very low and behind the rear way I didn't notice that very first time we ran the carriage to the spindle (and in anytime we made small parts), the reader head bracket had hit the scale mounting bracket and was knocked out of alignment. It worked fine for a couple of years, I guess, but then one day the Z axis readout numbers stopped moving. The reader head had worn right through the die-cast metal, then finally the ribbon cable.

Given that the AT102 scales were now obsolete, I hit Ebay and bought a 100mm new-old-stock scale for $75 (I think) and swapped the new reader head into old 800mm scale. Now I initially thought an 800mm scale was about 200mm too short for a 16 x40 machine. However, once I removed the scale and checked travel, I found that the factory limited the carriage to just about 800mm. The scale proved to be mounted wrong, being in a position that crunched at the spindle end, but had 100mm of unused travel at the tailstock end. I laid out the new holes, drilled and tapped the M6x1.0 holes and realigned the scale in it's correct position. All that takes is a long-travel indicator on a mag base, riding on the carriage.

I'll get a photo of the repositioned Z axis scale later this weekend, but for now here's a crappy photo where you can see how the X axis scale is mounted toward the far end of the cross slide. It works perfect, and is out of the way of the carriage lock and nay swing of the compound slide.

[Image: 2011-01-30_13-05-39_467.jpg]

RE: DRO's - EdK - 03-10-2012

Ken,

I wouldn't mind seeing a picture of the X scale read head mounting scheme. I assume there is a bracket attached to the back of the lathe holding the read head in place.

Ed

RE: DRO's - PixMan - 03-11-2012

Ed,

Here's a few photos. A better view from the top first:

[Image: X-scale_top_right.jpg]

From the right side, low view from the right side rear of the lathe:

[Image: X_scale_low_right.jpg]

From the left side, better showing the bracket holding the reader head:

[Image: X_slide_rear.jpg]

A broader view from the lower right, where you can see how I moved the Z-axis scale about 4"/100mm toward the spindle to solve a problem:

[Image: Z_slide_low_right.jpg]

A closer view of the brackets for the Z-axis scale. Though not visible from these views, the reader head bracket for the long scale had initially been fastened to the carriage's lower rear way clamp. I moved to using holes on the major carriage casting for greater rigidity and security.

[Image: Z_scale_low_rear.jpg]

RE: DRO's - EdK - 03-11-2012

Thanks Ken.

I'm tempted to redo the mounting on my cross slide scale. I overcame the carriage lock problem but my cross slide lock is still blocked by the scale. I'll have to take a few measurements and see how far back I would need to move the scale to gain access to the cross slide lock.

Ed

RE: DRO's - DaveH - 03-11-2012

Ken,

That is really well photographed and shown

DaveH

RE: DRO's - Bogstandard - 04-05-2012

Ed,

Yet another link, this one to get around your cross slide locking problem.

http://www.atfreeforum.com/chesteruk/viewtopic.php?t=389&mforum=chesteruk

John

RE: DRO's - EdK - 04-05-2012

(04-05-2012, 07:49 AM)Bogstandard Wrote: Ed,

Yet another link, this one to get around your cross slide locking problem.

http://www.atfreeforum.com/chesteruk/viewtopic.php?t=389&mforum=chesteruk

John

John,

Thanks for the link. That's just the ticket! Your cross slide lock mod looks like it will work perfectly on my lathe.

RE: DRO's - Bogstandard - 04-05-2012

Ed,

It should work on anything that uses a dovetail slide, and there is method in my madness.

Personally, I don't like the normal method of locking up a gib with a grub screw, as most gibs are locked, as it will have a tendency over time to actually deform the gib strip. By coming from the other side, as I have done, the strip should remain perfectly straight.

I have yet to do the same mod to my topslide (compound), as I want a very easy method of locking it up for when I am facing off, plus also, I have a DRO wacked over the top of the gib locking screw on that as well.

John