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Drilling metal - speed charts vs reality
- Thread starter zze86
- Start date
Too slow better than too fast.
For anything larger than 1/4 we go on slow side.
Mill has VFD so no idea what actual rpm is, go by "look" of it.
If you have selectable rpm you hove exact rpms so you can learn what works best on your machine.
Faster rpm does cut faster but so does wear.
Slower rpm cuts slower but wear also slows.
There is a sweet spot where the wear greatly slows and cutting is optimum.
This matters in production, for hobby use start slower and work up.
It will be somewhat obvious when you bass the sweet spot.
Lesser powered equipment and larger drill bits often will let you know as they stall.
We have many times, in back gear punched 1/2 holes in steel in one shot and being in back gear plenty of torque to cut.
Drill gets tiny bit warm as heat is in chip and not drill.
Sent from my SM-G781V using Tapatalk
For anything larger than 1/4 we go on slow side.
Mill has VFD so no idea what actual rpm is, go by "look" of it.
If you have selectable rpm you hove exact rpms so you can learn what works best on your machine.
Faster rpm does cut faster but so does wear.
Slower rpm cuts slower but wear also slows.
There is a sweet spot where the wear greatly slows and cutting is optimum.
This matters in production, for hobby use start slower and work up.
It will be somewhat obvious when you bass the sweet spot.
Lesser powered equipment and larger drill bits often will let you know as they stall.
We have many times, in back gear punched 1/2 holes in steel in one shot and being in back gear plenty of torque to cut.
Drill gets tiny bit warm as heat is in chip and not drill.
Sent from my SM-G781V using Tapatalk
I recently changed the motor on my drill press to 3 phase + VFD so I can dial in whatever speed is ideal and dial it while drilling. When using larger drill bits 1/2 to 1” it seems like there is a real sweet spot where the drill just eats through steel like butter. I find it’s almost amazing to watch. That speed is typically a lot slower than my chart. before going VFD I cringed at drilling large holes in steel, now it’s almost fun.