Tool:0.281 dia 0 helix TIN coated carbide drill

A need arouse to drill and tap lots of blind 1/4-20 holes in 3/4" thick hardox 45-50RC hard plate.

So if you ever need to do this use:

1) DRILL
Tap hole: >0.202" or bigger.  5/8 deep.
Drill used: Tialn coated carbide drill.
S=1418 RPM
F=2.6 IPM
NO Peck, No Coolant

2)TAP

Out Company used to have somebody else plasmacut cutting anvils for us.
This was expensive, plus heat generated by plasma caused already unstable anvils to warp like crazy making them very hard to grind flat.

So when foreman told me to machine one on CNC i immidately asked him to buy one of those nifty Hanita TiALN coated Varimill cutters.
Too bad they are too expensive. So the company bought same style of cutters made by Niagara. 0.5" end mill there is x3 cheaper than hanita's. Plus i believe cutting tools made to the same specs, out of the same materials are performing identical.

The machine we ve been using for this is really shaky and busted, so dont laugh at speeds and feeds that we came up with.

So basically, Specs Are:

• Material: Hardox pre-hardened steel Rc 45-50
• Cutter: 4 Flute, Stagger Flute TiALN coted 0.5" Micrograin Carbide End Mill, 2.5" Overall, 0.625" Flute Length, 1" overhang
• Operation: Slotting
• Speed: 1200 RPM
• Feed: 4.8 IPM
• Depth OF Cut: 0.125"
• Plunge method: 2.5 Deg Ramp/Helix, Or Plunge into 0.281Dia pilot hole at 3 IPM
• Coolant: Airblast + Oil

Lately we've been doing alot of anvils out of 3/8 or 1/2" Hardox steel (Rc 45-50)
Aside from having to machine profiles and pockets we also have to drill some mounting holes.