Todays Project - What did you do today?

[Pete O]

With the DRO and coolant drain all done, I got back to putting a radius on the second cheek plate for the frankenmill. I've found it difficult to clamp these to my RT, the workpiece itself takes up so much of the table that there's little room left for a clamping arrangement that doesn't interfere with the cutter at either end of the arc. I came up with the solution of spigotting the workpiece to the centre bore of the table.
A muffin-tray ingot of excess from my last aluminium casting made a good size blank for the job.
   

Turned that into a bush with an 8mm bore and an OD to match the centre bore on the rotary table. Drilled and tapped an M8 hole on the underside of the workpiece and attached the spigot.
   

With the spigot taking the lateral force from the cutter, clamping is a whole lot easier and far more reliable.
   

Don't be upset that the radius is not centred on the workpiece- there's more machining to do on the cheekplates once they are mounted.

I've no doubt this is common practice- spigotting from a blind hole on the back of a workpiece- but I had not seen it before. I suspect that simple aluminium spigot will see plenty of use in the future.