Drilling and tapping cast iron?

[Sid]

I have an Incra router fence on a Woodpeckers table, but I could use the space that table is taking. I also have a router mounted in an extension on my Craftsman 22124 table saw, so I'm considering drilling and tapping holes for mounting the fence on the cast iron saw table. The mounting screws are size 10-24.

I've done some some simple drilling and tapping in steel and aluminum but never in cast iron. Any problems or precautions I should know about before attempting this?

Sid

[maxparot]

Use a sharp drill bitand cutting oil. Don't put too much pressure on the bit let it do the work. Centerpunch your spot before drilling. Asside from that cast iron drills easy.

[RodKirby]

I have drilled/tapped cast iron many times - BS table, Scroll saw table, TS table.

After aluminum, cast iron has a very "grainy" feel when you use the tap.

Just be "gentle" - the cast iron is very brittle. No more than 1/2 a turn before backing out. I use paraffin wax on the tap (always). Dont forget to countersink before tapping. Also, don't overtighten the screws DAMHIKT!

[iceman61]

When drilling it's all feeds & speeds. Slow your speed down on metal as opposed to wood. The harder the metal the slower your speed. Use steady pressure when feeding the bit. I've been in a machine shop background for years & always use cutting oil. My father on the other hand likes Johnsons Paste Wax. (go figure)

When hand tapping, turn the tap about 1/2 a turn & back it up 1/4 turn. Keep the hole well lubricated. Lubrication also helps to rinse the chips away from the cutting threads & out of the hole. If you are tapping a hole that doesn't go all the way through, use a starter tap followed by a bottom tap the same size.

Good luck!

[cgallery]

Couldn't you mount the fence to a piece of wood, and clamp the piece of wood to the table when you need to use it?

[Sid]

Thanks, guys. It was easy!

I drilled and tapped 6 holes that fit the mounting plate just right. The hardest part was getting past the idea of actually drilling holes in that beautiful table top. With your tips and reassurances, all went well.

Thanks
Sid