Some time ago I made a GHT graver to use to deburr holes and edges while still being in the lathe. The HSS tool holder was designed to fit an ordinary file handle, and it works very nicely.
Later when I paged through the MEW Digital Archive I found two articles concerning hand turning in both metal and wood. Interesting! This meant I could make my own handles and such as required and when I needed them. Brilliant! .... But ... I needed some sort of support for the gravers/wood bits and the original C3 variety did not appeal to me as the whole of the top slide including toolpost would still be there and be in the way so to say.
Some sketching, thinking and rummaging around in the scrap/will-be-useful-some-day box produced what I needed.
- A piece of 100 mm thick steel plate barely large enough to make a 50 mm disc.
- Some smaller round and rectangular off-cuts to make a standard and a lock to fit the
- A spare wood turning lathe tool support I found cheap.
Here they are as bits before assembly.

The plate has a center 8 mm recess to fit the center peg in the C3 saddle.
The standard is made from two pieces glued together with Loctite.
A single cotter and a brass lock nut secures the support to the standard.
The standard is now glued using epoxi glue to the plate and secured just in case with a small screw from the front.
Together they make up a very compact seating which is locked using the normal top slide facilities and is of course rotatable as is the top slide. The assembly seen from the side.

Now in with the cotter and add the support, attachment complete!
A view from the user side

... and from the rear.

If it is tilted we can see the positioning hole and the fastening holes fitting the cross-slide.
In place on the lathe it replaces the top slide completely and makes very good room for turning.

It can be swung to face the spindle as well ...

... and this is the first handle for the upcoming metal turning tools.

The metal turning support is still to be made, so I will be back with these as the bits get ready.
BR
/Peter