-
Scam Alert. Members are reminded to NOT send money to buy anything. Don't buy things remote and have it shipped - go get it yourself, pay in person, and take your equipment with you. Scammers have burned people on this forum. Urgency, secrecy, excuses, selling for friend, newish members, FUD, are RED FLAGS. A video conference call is not adequate assurance. Face to face interactions are required. Please report suspicions to the forum admins. Stay Safe - anyone can get scammed.
SFM RPM Chart
- Thread starter whydontu
- Start date
lucsimoneau
Well-Known Member
Hey guys - just to throw in my perspective on this age old subject of cutting speeds.
I try to make things simple for my brain and this is my think process:
Baseline value:
HSS for Mild Steel : 90 SFM --> RPM calculated from 4 x SFM / D
I tend to compare material to Mild Steel, so like non-ferrous materials (aluminum or brass) will have higher speeds (multiply by 4) and harder materials (Tool steels or stainless) will have slower speeds (divided by 4)
This gives the simple table:
When factoring in the machining process, I tend to consider the following:
- Drill: 1/2 x SFM
- Ream: 1/3 x SFM
- Tap: 1/4 x SFM
Otherwise, I have the application FSWizard on my iPhone.
Happy Holidays!
I try to make things simple for my brain and this is my think process:
Baseline value:
HSS for Mild Steel : 90 SFM --> RPM calculated from 4 x SFM / D
I tend to compare material to Mild Steel, so like non-ferrous materials (aluminum or brass) will have higher speeds (multiply by 4) and harder materials (Tool steels or stainless) will have slower speeds (divided by 4)
This gives the simple table:
When factoring in the machining process, I tend to consider the following:
- Drill: 1/2 x SFM
- Ream: 1/3 x SFM
- Tap: 1/4 x SFM
Otherwise, I have the application FSWizard on my iPhone.
Happy Holidays!
Tomc938
Ultra Member
Now I know what I’m getting for Christmas!
Thanks so much for all the time, thought and work that you put into this. Going on my wall for sure.
Your chart is well done, simple, fast and easy. Nice. I plan to make a similar chart and stick it on the drill press, lathe and mill.
I now use an over simplified version that is on my mill. Or i use the Little Machine Shop app on my phone. The app is great but not nearly as fast as a close at hand chart will be.
BTY - i used the app and your numbers are very similar (+/- 1 or 2%)
littlemachineshop.com
I now use an over simplified version that is on my mill. Or i use the Little Machine Shop app on my phone. The app is great but not nearly as fast as a close at hand chart will be.
BTY - i used the app and your numbers are very similar (+/- 1 or 2%)
Cutting Speeds
This page gives cutting speeds for turning, milling, and drilling of several different materials. It includes a calculator to figure the spindle speed required.
While I was at it, did a chart for my RF30 mill. I have a 2hp 220/3 motor and VFD, with the VFD programmed for a range of 30 to 90 Hz operating frequency to the motor. I may increase the range as I get more familiar with the machine, for now I feel it’s a reasonable spread that won’t tax the motor capabilities.
Much easier to read than the gimpy little label that was stuck on the side of the belt cover.
I need to go find a more machinery-oriented picture frame.
Much easier to read than the gimpy little label that was stuck on the side of the belt cover.
I need to go find a more machinery-oriented picture frame.
