Aluminum vs steel blocks for scale install

[rronald]

Nice install. I have the same lathe and I was curious how much space you lost between the carriage and the tailstock. I currently have a iGaging scale on my cross-slide but I mounted it hanging off the back of the cross-slide so I didnt limit how close the tailstock could get to the carriage. I also have a custom carriage lock that mounts between the bed ways (under the carriage) so where you have the readhead mounted might be an issue for me. I’m hoping I can find a replacement scale that is slimmer if I go back to the traditional mounting location like you have.

The Aikron slim magnetic scale (AUMS) is 9mm thick. I had that configuration for a couple of days and then came to my senses. I drilled and taped the tailstock to take a screw so that I'd have a bumper between tailstock and carriage (that isn't the scale). So, I probably have lost about 11-12mm of travel between the two.

I measured this AM. The exact distance lost is 11.27 mm between tail stock and carriage. Well worth it!

 

[u2fletch]

I got my DRO scales and mounts installed and successfully powered it all on yesterday.

For the z-axis reader mount, I started with the metal angles and long piece included with the scale/mount from Aikron. Then printed an orange plastic piece to space this the right distance from the carriage. It worked fine
View attachment 469256
However, I'd drawn up the part in Fusion 360 and it was designed to only need machining on one side. So, after the plastic protoype proved the shapes and sizes, I used my printNC to cut the part from aluminum. I suspect the plastic part would have worked just fine, but the aluminum one does look nice.
View attachment 469257
For the x axis reader mount, I had cut a piece of aluminum with the bandsaw and drill press. Pretty easy to do with hand layout. For the scale, I printed a bracket to attach the back bolt and brace the side (picture is taken from above). Part worked on the first attempt.

View attachment 469260

However, I'm not quite satisfied with this part. Two reasons.

First, I suspect that for this use the ABS plastic might not be the best material. It's almost 4" long and the coefficient of thermal expansion for ABS is pretty high compared to steel and cast iron. So the part may tend to expand in a Texas summer.....which may move the scale.
Second, I'm blocking the end of the T-slot with the part. Granted that I don't even know why I want a T-slot there, but I'm sure there are good reasons for it. If I do remove some material to allow access to the T-slot, the remaining section will be fairly thin.

So, I will likely redo this part in aluminum too. But, it will probably be a month or more till I get some 1" by 3"aluminum stock to cut it.

Unless you have a setup where you need absolute repeatability from day to day the ABS should be fine. As long as the part is not flexing in between operations. It’s the relative motion that needs to be stable.

 

[u2fletch]

Nice install. I have the same lathe and I was curious how much space you lost between the carriage and the tailstock. I currently have a iGaging scale on my cross-slide but I mounted it hanging off the back of the cross-slide so I didnt limit how close the tailstock could get to the carriage. I also have a custom carriage lock that mounts between the bed ways (under the carriage) so where you have the readhead mounted might be an issue for me. I’m hoping I can find a replacement scale that is slimmer if I go back to the traditional mounting location like you have.

I probably lost an inch of travel. The read head bracket has a raised area around the mounting bolt to act as a bump stop. So far have not used a setup where that lost travel is an issue. Most operations have my chuck in the tail stock and that has plenty of reach.