Thought I would share this in case anyone else is thinking about fitting DRO to their Tom Senior E type mill. I hope it helps.

Special double ended tool with 5mm drill and one end and removable 6mm tap at the other. Avoids horrible mistakes and keeps drilling and tapping vertical.

Just enough room to get the centre and rear holes completed.

Fitting homemade reader head brackets which started out as ¼” x 2¼ alloy angle, machines to squareness. The holes M6 holes in the Y slide were marked up on the surface plate and drilled on the bench drill.

Reader head cover fitted and designed to stop oil from the X slideways getting near the reader head.

The X axis slide reader head fitted. The X axis travel stops need to be removed from the front of the slide but it can all go back as it was originally if needed.

Keeping the readout cables tidy and out of the swarf.

And at the back too, no dragging the cables through swarf and eventually all 3 axis cables hang on a wall mounted hook.

A new design of quill stop plate was designed in CAD with a left side extension to support the Z axis reader head and manufactured by high pressure water cutting.

The DRO kit was for 2 axis but I purchased a 3 axis console and the magnetic strip that was left over from the Y axis was bonded to the pre-milled parallel recess in the machine head. There it is, 3 axis DRO and painted in Tom Senior semi-gloss green so it does not look too out of place. DRO has really transformed the mill! No tedious calcs to account for the .005” feed screw backlash and totally precise parts to within 3-4 tenths of a thou with trying too hard.