[leoliver]

Friday night, I was running a 1" titanium plate , on a old K.T. vertical data-mill. Program drills 2 - entry holes for a 1" wave-cut.
The night before, a 1" "heretical" insert drill , was destroyed attempting to drill both holes at 150 RPM, F.4 and .20 peck.
Someone said try a 1" spade drill at 500 rpm, F1.0 and .20 peck. I thought the RPM was too fast, but trusted the person and the drill burned up on the 2nd hole.
I want to try another 1" spade drill tomorrow. But at a slower rpm (maybe 200 rpm) , and possibly a different feed and peck.
I do think the rpm was the primary cause of tool failure.
Can someone please give me a correct RPM( not in sfm please) , and a feed rate and peck depth. For a 1" spade drill( single carbide insert, 45 degrees) drilling thru 1" thick aircraft titanium.
Thanks.

[tbev]

I've done 0.75in diameter blind holes, 4in deep and I preferred using a pilot hole. I'm on a Tormach that has a really low h power so I couldn't turn a big cutter that slow so I'm sorry I can't be more help but I thought I'd throw that out there, a smaller pilot gone might go a long way. When I mill the came size hole I just mentioned I use a 4f carbide end mill at around 1700- 2,400RPM. Slow with a good sized bite. Good luck, sorry I'm not more help.

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