Drill spindle for steel
 

Hello,

Does anyone use or can recommend a spindle for drilling steel? I was thinking around 5hp @3000rpm would be enough.

A setup like the following would be ideal.

http://www.youtube.com/watch?v=0Ek_Fy5onCg

Thanks
Dave

Very interesting video. They said that their spindle was 3.8kW, which translates to just under 3hp. Did you catch the fact that the cutter was cooled by spraying mist THROUGH the cutter?

...and the exterior "sensing" frame was also used as a hold down and stripper bar.

A LOT going on in that small area of the machine.

If your just drilling you could use Milwaukee 4253-1.
http://www.milwaukeetool.com/power-tools/corded/4253-1

Here's some food for thought.
http://mechmate.com/forums/showthread.php?t=3334

The relevant post is #8.

I've found the problem to be generating enough down pressure to drill effectively. It's pretty slow. A lead screw z-axis might fare better. Center drilling and then finishing up on a drill press works pretty good.

3.8kW is 5HP , and drilling that large holes would require a massive weight gantry

I just finished one CNC drilling machine which uses 22 and 25mm drills for drilling square steel tubes 1.5mm thick. Force for a drill that large required 2:1 reduction on a 10mm lead ballscrew and NEMA34 9801 motor.

Damilo is correct. 3.8 kW is 5hp. I must have used the wrong search terms when I found an equation that used something like 1.25kw per hp. A Google search this morning showed that 735 to 750 watts is normally used to equal 1hp, so 3,800 watts divided by 750 is 5hp.

Cutting steel
 

Unlike wood plastic or foam cutting steel is usually done at a lower speed. It is harder to form a chip. It takes less speed but greater pressure. If you cut it to fast you just heat up your tool and the piece. Once the heat raises it takes the temper from your tool. At that point it is a lost cause. I tried to find the Ben Krasnow video on cutting steel. I have seen a couple of videos of cnc cutting steel. I hope you have patience. I don't think the Mechmate is a good tool for this task. It will do it but the machine is made for softer materials. I invested in a Tormach when I want to do metals. Best of luck to you.