Drilling cast

gmphil, Oct 11, 2:23pm
I need drill a 13.5 mill hole thru a 25mm plate .
mate rekon pilot hole 3-4 mill first
would this be correct for cast ?

skin1235, Oct 11, 2:42pm
yes, and drill very slowly, in cast it will be easy, you can use water or oil to keep the tip cool and thus get a cleaner cut

skin1235, Oct 11, 2:43pm
your pilot hole should be the width of the centre web of the larger drill

gmphil, Oct 12, 9:52am
thanks skin1235
il give it a go !

marte, Oct 13, 12:16am
Cast Iron or cast Brass does not need lubricant. Its 'self lubricating'.
Actually lubricant will make hot cast Iron hard and brittle.

But in this case it won't matter or happen much.

Cast Ali or Steel will use lubricant

whqqsh, Oct 13, 4:19am
depending on the type of cast it may grab, a negative rake on the drill could be needed (like with brass), but pilot drill will be ok

gmphil, Nov 4, 3:09pm
turn out mint ,measured web as sugested pre drilled used tat bit water . .
job done thanks .

skin1235, Nov 23, 3:16am
thanks for coming back, nice to hear success stories occasionally