Milling T-slots in cast tool plate

[LeeWay]

Anyone have much experience cutting T-slots in cast tooling plate. Mic-6 I think it is. I know I start with an end mill and finish up with the slot cutter. I can figure out the straight slots easy enough as the troughs on the ends, but never used a t-slot cutter and would like some input as to feeds. Do I cut some and back out some, then go at it again? Like pecking at it? Perhaps the constant direct feed approach would be best? If my spindle is turning clockwise, which end do I cut from? Sorry about these meager questions, but I think knowing or finding the answers to these may save me some money on wasted tool plate.
Thanks.

[RICHARD ZASTROW]

Lee, Continous feed but blow, blast or flush out the chips to avoid recutting them. We use micro-drop biodegradeable vegetable oil (very lean ratio, 1/2 cup in 8 hrs.) with high volume/pressure air to keep slot clear. Cut straight slot slightly deeper (per spec. for size of "T" slot)with end mill prior to "T" of slot. Even works for on-site milling of "T" slots in press platens with portable milling machine.

These were steel platens, if that makes any difference.

[rigo430]

I've done this a bit and at first it can be a little hit and miss but I use a 5/16 (HSS 8 tooth) t-slot cutter to make t-slots in a MIC-6 plate. I first use a 1/4 endmill to cut down to the finish depth that my t-slots are going to be at. Then use the 5/16 t-slot cutter in one pass climb milling on one side of the channel then do the other side in 1 pass climb milling going the other direction. My spindle speed is 3488rpm and my feed rate is 10.4649ipm with this i get a fairly decent finish if you go slower or take lighter cuts you can get a better finish. Although most of your speeds and feeds will vary with your tool size i recommend about a .0005" load per tooth if you're taking a big cut per pass. I also use flood coolant to help keep the chips clean. I hope some of this was useful for you.

[LeeWay]

Thanks Guys. This was helpful. I will post some results in a few days when I get to that part. Wish me luck.

[SACEM]

Are you sure that recomended feed was so slow 0.0005" per cutting edge seems quite low to me.