Milling Steam Ports

[Aestus57]

Hi there,

I have "acquired" a Cast Iron Cylinder casting which I'm using to make a horizontal Mill engine, its 3/4" bore X 1 3/8" stroke.

I've bored it out and have now come to the stage of cutting out the steam ports for the slide valve.
Whats the best way of doing this?

Do I drill a series of holes then link them up with a slot cutter, or go staight in with the slot cutter without drilling... or drill a hole at each end and mill out in between?

I have seen situations where people have made a gang milling cutter, but don't think thats for me with my level of exprience just yet.

The ports are 3/32 wide inlet and 3/16 wide exhaust X 3/8 long.

Thanks in advance!

Regards
Peter

[lordedmond]

just leave them as a series of holes you will break the milling cutter trying to make a slot of that size

start with a small drill to check the alinement

It will make very little difference


Stuart