Bolt Down Milling Plate

Some time ago I made a simple bolt down milling plate with M4 fixing points and itself bolted to the table with M6 CSK bolts. The aim being to give me a board that would allow me to mount small items and where I could drill through and waste the board over time.

bolt down milling plate fitted to Sieg mill

The milling plate here fitted to the table of the Sieg SX2.7 milling machine.

M4 threaded holes on a 20mm x 20mm grid with 9 x 5 points.

I used 4 countersunk M6 bolts to fix it to the table. Thus no heads protruding above the surface of the plate and so maximising the working area.

I used my homemade double T-nuts that have M8 and M6 tapping in the one longer nut. I made these originally for the low-profile clamp. But they are just generally used.

The 5mm thick aluminium plate was itself machined on the Sieg milling machine. This is very easy to setup using the DRO.

The first part where I made use of this plate was the smokebox door for the Burrell traction engine. The 2mm thick steel plate allowed me to bore a whole through it and then drop the door snugly into the hole. Then I could bolt this plate to the table and very accurately establish the centre of the hole using the DRO.

Burrell smokebox door

As you can see in the first image I then held the door in place with an external clamp. This is the first use of this bolt down milling plate. I will be using it again as it allows me to work to the surface and beyond. I don’t have to worry about the table surface so much.

Not sure if this is a breadboard, waste plate or bolt down milling plate? Whatever it is very flexible and hence very useful. Definitely worth making before you need it.

low profile clamps on milling machine

Low Profile Clamp

This low profile clamp idea came about as I wanted to machine a large plate that was too large for the milling vice.

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