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Southbend and Hercus 9” DRO Install

Whoa! Now that’s a tidy solution!
If you have space about the crossfeed screw, then you can do the same on your lathe. If your cross slide is long enough, then you can use it as is. If not, you may be able to extend it in the back by a small amount, to avoid making a new cross slide as I did.

At the time I did this, the 16 x 16mm Sino scales (16 x 19mm with lips) were the smallest cross-section ones that I knew of. These days I know of much smaller cross section solutions, for example a Renishaw non-contact optical encoder with 6mm wide tape, which is 0.15mm thick. Since the ride height is 2.1mm, the total cross section needed is 6mm x 2.25mm for the scale. One of these days I may use that to put a scale inside my compound.

EDIT: I just had a look online at Renishaw's latest offerings. If you are interested in putting the system inside your cross slide, look at the RKLC scale material (part number A6663) and the VIONIC readhead (for example, Part no V2BCZ30A10F). Total cross sectional space needed including the head is 12.25mm height and 13.5mm width. The 12.25mm is 10mm for the head, a 2.1mm air gap, and 0.15mm for the thickness of the scale tape.

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Neevo how's yer install coming ? Any more pics ?
I have moved in to phase 2, which basically means I’ve ordered the DRO. Did it an hour ago.

I went with a SINO which I also have on the mill and works great. I’ve ordered the KA200 and KA300 scales too which are the 3D printed models I have been playing with up until now.

I haven’t drilled the crossslide yet as I was hoping to triple check the scale model was correct first. So when that gets here I’ll do that and I’m hoping the read head mount I have on the lathe already will work as is.
The DRO came in. Great quality for the import versions, feels nice and solid. I have it set up on the bench for now and have been test fitting the small scale.

It’s uncovered a problem. The KA200 scale has small moulded bumps where the seals run in to. So I have a couple of options.

1. Take the bumps off
2. Flip the scale on its side and mount the read head that way. It might actually let me put a tailstock stop in the bracket too.


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Animal is 100% right. And if those are glass scales and not the magnetic type, I'd mount the scale and reader head in the normal orientation with the slot and reader head on the bottom. Glass scales can be real easy to damage with just a scratch on the glass or screw them up with even airborne contamination. Those rubber seals don't stop everything. Even with my Newall magnetic scales, I still mounted them so gravity helps keep them clean and with less chance of any contamination getting inside the scale.
Ok. Then that likely points to removing the bumps. That way I can carry on and plan the original install. I’m happy taking the risk with the warranty if I have to.
I bit the bullet today and took a file to those bumps. Let me get the scale right in to where I needed it and test a few things.

One thing became very clear. It don’t look like I was going to make it work with the 3D printed mount. The read head mounting bolt was right over the top of the bracket bolt.

So I took the step of removing the crosslide assembly so I could get it on the bench and look at it a bit closer:


Adjustment was also really hard with the existing mount. So I thought I’d try some something a little more conventional:


However there isn’t a decent surface under the carriage to mount anything to:


I had to drill the crosslide for the scale mount anyway, so I did that along with milling a nice big flat section:



A quick mock up and it looks like it’s going to work. I’m just waiting on some right angle Alu to make the read head mount.


I also need to put the lathe back together so I can make the 9mm spacers for the scale.
Good thread as I've thought about adding DRO's to my 9A and Heavy 10, but the cross slide designs don't make it easy. I don't think it's in the cards on my 9A as I have alternate cross slides and I don't want to have to move the scale around when I swap them out. My Heavy 10 has a taper attachment, further complicating the issues. I think for both I would only add DRO to the beds and stick with the dial for the cross slides, or just keep running the bed mounted indicators. I've also thought about making an indicator bracket that could quickly attach to the front of the apron with a 2" travel indicator for those times I'm tired of counting cross slide rotations.

On other lathe's I've done similar to yours adding it to the TS side. One thing you can do to keep the TS from hitting it is drill and tap a bolt into the base of the TS and adjust it so it projects out under or beside the reader head enough that it contacts the carriage and not the scale or reader head when the two get too close. I've had plenty of times setting up a job with a center in the TS that I didn't give myself enough room and ran the carriage into the TS, or was sliding the TS in to place and hit the carriage.
The advantage of having the new read head mount to the underside of the carriage is that I can also use it as a tailstock stop. So I’ll make sure it’s sturdy enough for that too.

Currently have 3mm Alu angle on the way. If that’s not sturdy enough I’ll upgrade it to 5mm.
I guess ya don't have a follower rest ?
Correct. I actually don’t even have a steady. Only ever needed a steady once, never a follower.

I think having a DRO will be more a priority than a steady, but if I ever have to put one on. I’ll just drop the DRO off for that. It’ll only be 4 bolts.
I spent today trying to fit up the DRO. It’s not a small job and eventually I found I had to pretty much take most of the lathe apart to do it. Plus then I’d find I needed the lathe to make something to get it all fitted up. But I’m happy to say I have the crosslide and carriage done. I’m just waiting to put the lathe back to make some spacers for the carriage read head.

I have all the scales trammed in and will wait for it all to be done before I do a test run.

Step 1 was to make a bracket for the crosslide read head. I bought some 50mm Alu angle and this worked perfectly.



It’s damn tight in there but it fits great. Plus I did the bolts from the rear so that I could use the nuts on the ends as stops for the tailstock. I’m going to look for some rubber stops to go over the ends or maybe just 3D print some plastic bumpers:



The I set about mounting the display to the mount for the power, motor speed and ELS:


Finally I pulled the whole lathe out from where it’s been for the past 7 years and set about attaching the scale to the back of the lathe. There is a flat section of casting on the back of the carriage that was a perfect spot to mount a section of Alu extrusion. As you can see I just have to make the spacers for the read head and I’m ready to go.


Tomorrow job is putting the lathe back together and making the spacers. Then I’ll do all the display setup before testing it all out.
Question for everyone. What’s the convention for setting up the direction of the axis’? I was going to go with:

1. Crosslide - negative away from me. Set the DRO to diameter mode so I can literally dial in the final dimension I would like.
2. Carriage positive towards the spindle. So I can face the end, zero the DRO, then drive to coordinates based on the dimension I would like from the end? This one I’m not sure about though. I can see it being nice if I need to turn a 20mm section, to be able to just drive to 20mm, not have to go to -20mm
All done. Works perfectly and it’s dialled in perfectly. Couldn’t be happier and think it’s going to be a dream addition to the lathe. Particularly as I tend to work in metric and my lathe is imperial.IMG_0893.jpeg

Did just basic cable management at the back but made sure it’s not dragging on the chip tray to make it a little easier to clean up.


Final step is to set up all the tool library but I’m not going to document that.
Congratulations on getting it done. I am in the same boat as you: imperial lathe but mostly doing metric parts. The DRO speeds things up a lot for me, and also makes my work more fun and accurate. I'm sure you'll find the same!
Nice job !! YA need 2 lathes , at least 2 so ya can make parts fore the other & maybe a 3rd just for a back up .
just sayin