welding steel base or just getting aluminium extrusion

**routercnc** · 10-12-2017

OK, then either:
pilot 3.3 mm for an M4 x 0.7 (coarse thread)
pilot 3.5 mm for an M4 x 0.5 (fine thread)

In general I would use coarse thread, especially into aluminium. Get a countersink to clean up the hole and get snug fit of the rail onto the plate - snail countersinks are great.

Also, thread lock (the type you can undo) the screw into the hole as the spindle vibration can undo them.

**reefy86** · 10-12-2017

thanks mate ill take a look at those

**reefy86** · 10-12-2017

Originally Posted by routercnc

OK, then either:
pilot 3.3 mm for an M4 x 0.7 (coarse thread)
pilot 3.5 mm for an M4 x 0.5 (fine thread)

In general I would use coarse thread, especially into aluminium. Get a countersink to clean up the hole and get snug fit of the rail onto the plate - snail countersinks are great.

Also, thread lock (the type you can undo) the screw into the hole as the spindle vibration can undo them.

is this what you was talking about for thread lock or is it the stuff in a bottle?
http://www.longlok.com/s.nl/it.A/id.42699/.f