Thursday, June 9, 2011

DRO installation on Real Bull Mini-Lathe from Henry Thomas

An excellent installation on a mini lathe.

The challenge in mini lathe is the space constraint.

Thanks for the photo, Henry, it will be a great help for our budding installer.

Here is an unedited email from Henry :


Just thought I would send some pics of my successful installation of your DRO on my Real Bull bench top mini-lathe. While it may seem overkill to mount a DRO on such a small hobby lathe, properly set up with lapped beds and ways, this is a very accurate and capable lathe, which I use for a lot of R&D work. So I wanted to add a DRO to improve my productivity. I had considered using calliper type scales, but didn't think they would be robust enough. In the end your package turned out to be only marginally more expensive. The biggest challenge was figuring how to get it all to fit, so I am really happy with how well it actually turned out.

My goal with this installation was to make minimal changes to the original appearance and operation of my mini-lathe. It has a pretty compact work space, so I didn't want the scales interfering with any of the slide movements. Below you can see how installing both the X and Z scales under the carriage has achieved this.

For the cross slide I milled out a 20 x 20 mm bar.

This is attached to the cross slide in the channel where the feed screw is located. It connects to the 120 mm X-scale under the carriage.

The X-scale is mounted under the carriage to a bracket that backs onto the same bracket that connects the carriage to the Z-scale. The other end is bolted to the under side of the apron. I had to mill a notch out of the X-scale bracket to clear the half-nuts, which protrude slightly below the apron.

Even though space was tight, I was still able to mount covers over both scales.

The Z-scale bracket spacer required a slot to be milled out to make room for the cross slide bracket.

Here you can see the Z-scale mounted to the bed and the bracket attached to the milled spacer (from above) which is attached to the back of the carriage.

I had to mill all the parts from scratch, which took a bit of time, but nothing was particularly difficult. The carriage travel is limited by the lead screw covers, but I added a stop to prevent the cross slide over-running the X-scale.

Kind regards,