[jwettroth]

I developed the Sherline DRO about 20 + years ago after buying one of their machines, completely loving it but being lost without some kind of DRO. I designed the DRO for my own use mostly and put in basic features- mainly position readout and zero setting without having to count dial turns. Other functions of a DRO are kind of gravy and not something that I thought would be very useful.. The main goal that wasn't easy was to keep the cost down to make it an affordable accessory and make it an easy retrofit for the thousands of mills and lathes that Sherline has sold.. This drove the design. I'm proud of the final product and its longevity is a testament to its utility. After 20 years, electronics and sensors have certainly marched on- I'm considering designing something new. I would still like to keep the cost down- a fraction of the cost of the basic mill or lathe, not easy but not impossible. Here a few questions for anyone that would care to comment.

1. The Sherline DRO measures turns of the lead screws- obviously this isn't table position but its pretty darn close. It also has backlash compensation built in that takes out one of the main issues people have with such systesm. The rolled lead screws on the Sherline are very accurate and the short travels don't allow much error to accumulate- overall a pretty nice, cost effective solution. A well maintained Sherline Mill with DRO can maintain a thousandth kind of tolerances with some care. In the intervening yerar, other options have become available, one of the more cost effective and robust ones that I'm considering is magnetic scales. These would have similar resolution to the existing system but would read out true table position- a potential plus. What do you think? I would recommend that Sherline maintains the existing design but make a version with the scales in some compatible way.

2. The display and keypad of the Sherline DRO is absolute minimalism. Color, touch screens are inexpensive and available and the required processing horsepower is also easily available. It should be possible to package an ruggedize a solution suitable for shop use at reasonable cost. I don't think using off the shelf Android tablets, etc is viable long term. Its a good short term solution but an embedded system should have a solid base and operating system that is purpose built. Once you're into the realm of touch screens, etc. a lot of things are possible- its just developing (and maintaining) code. There are a lot of features on DRO's that I've never used- bolt circles, trig functions are not useful especially for a small hobby machine. I would like to include direct entry of a position- datum and storage of some datums- machine zero, etc. What features are useful to you?

[awerby]

I vote yes for measuring true table position rather than the rotations of the screw. But keep it simple.

[ninefinger]

I don't own a sherline, but feature wise, the obvious ones I want / use - switch between metric and imperial, for lathe work ability to change between diameter and radius measurement. And for me, I never really could understand the whole tool programming thing on my big lathes DRO. I found I was typically only switching between 2 tools anyways so I just use the INC or ABS for each. A simple solution for switching multiple tools (say up to 5) would be nice.