When I first got my surface grinder operating some time ago, various difficulties made me think I needed an absolute read-out of spindle height, so I purchased a simple single channel remote head DRO from a prominent Sydney supplier.

I soon discovered that the loose nut on the SG was, in fact, the one on the controls, so the DRO lay on the shelf.

The other day I decided to install the DRO anyway,

Not a problem, or so it seemed.
Got all the mechanical stuff sorted, then had to slide the read head off the scale to attach the spindle bracket.
As the head came off I heard a 'rattle'.

On the bench the rattle was found to be a loose M3 nut.
Inspection of the head backplate showed 6 mounting points, 4 with nuts inserted and 2 blank holes.
Testing with a M3 machine screw revealed looseness in all 4 visible nuts.
But, one nut was unaccounted.

So, dismantled the head carefully and removed the 4 nuts. No sign of the unaccounted nut.
There is a very small compression spring which holds a guide against the scale that is easily lost.
The nuts are sub-size M3, so none of my stock would fit.

The 5 available nuts were glued into the plastic backplate using JB Weld, and the head re-assembled.

All installed on the SG and it works 'Ok'.
Not great because of read-out time delay, one must very slowly do small adjustments to avoid overshooting.
No issues with read-out values.
The DRO will be a great asset for future jobs.

DRO Surface Grinder compr.JPGDRO Backplate compr.jpg

John