Sherline Saddle Digital Readout

 

This article describes making a saddle digital readout for a Sherline lathe.  After making the DRO for the Sherline crosslide from a digital caliper I wanted the same function for the saddle. As with the crosslide DRO, I wanted to know where the saddle actually was not how many turns the lead screw had taken.

After some searching I found that the "iGaging 6" 150 mm Digital Readout / Read Out DRO w Remote Magnetic LCD display" was just the right length - the 6" refers to the travel not the length.

 

I only had to make 3 simple pieces to mount the DRO unit on the lathe. First I had to make a spacer block for the left hand end (when facing the back of the lathe) of the position sensor.

 

I started with a ½" x ¾" x 1 ¼" aluminum block.  One of the corners needs to be rounded off to let the block fit against the base of the Sherline under the tail stock.  Then I drilled two #11 holes (body drill for 10-32 screw) in the center and one end of the block as shown in the photo.  The spacing is not all that important since I used the block as a template later on.  I drilled a 3rd hole (#21) and tapped it 10-32.

 

The second piece is a plate used to tie the position sensor to the lathe carriage.

 

 

 

The two bottom holes are spaced based on the holes on the sensor.  The top hole was located drilled after mounting the sensor.

The next thing to do is to drill and tap holes in the base of the Sherline.  The Sherline base is thin cast iron - easy to drill and tap but the result is not all that strong - strong enough for this purpose.

I first drilled & tapped the right hand hole.  I used the sensor track to locate the hole - the left edge of the mounting bracket should be lined up with the left edge of the Sherline head block.  The hole should be high enough to let the mounting bracket clear the base by 1/8" or so. I then bolted the other end of the track to the tapped hole in the aluminum block using the white plastic washer that came with the DRO unit as a spacer.  I then bolted the other end of the track to the Sherline base using the hole I had drilled & tapped - also using a white plastic washer.  I then used the holes in the aluminum block to locate where to drill ad tap the two holes on the left.

The next step was to take the track off the base, drill and tap the two mounting holes for the aluminum block on the left side of the base. 

Next, bolt the plate described above to the position sensor and bolt the track onto the Sherline base using the 3 tapped holes. Then move the sensor to line up the tab on the top of the plate with the tapped hole in the Sherline saddle and mark the location of the hole that is needed in the tab. Then remove the track & drill the hole.  Remount the track and bolt the plate to the saddle - this part is now done.  The only thing left to do is to mount the readout.

Note that I keep my Sherline lathe on a plywood base with 3/8" feet so that I can store it on a shelf and bring it out when I need to use it.  This was helpful because I was able to run the wire from the sensor to the display under the plywood and bundle up the extra as well.

 

 

The final piece I made was a bracket to hold the display.  I used a 1/8" thick 1.3" x 1.25" brass rectangle.  Drilled ¼" for the display mount and #5 for the Sherline belt cover bolt.  With two notches to clear the  bumps on the belt cover bracket.

I used the knurled bolt from the DRO unit and another of the white plastic washers to bolt the display to the bracket.  Here is what the final assembly of the display looks like.