SFM RPM Chart

[whydontu]

So I've been pucking around with an Arduino-based calculator to calculate SFM / RPM for different material for my lathe and mill. I have a version that works for the mill, and in the process of putting together one for the lathe.

Here's the mill version. Two dials, one sets material, one selects cutter diameter.



Tonight, assembling the lathe version, while sticking jumper wires into a proto board, I managed to fry some pixels on the LCD display I'm using. No big deal, the display is worth $8. Then I started thinking, this is dumb. The math is pretty simple, I can do simple math in my head, and I have some very nice engraving machines. A 3"x5" chunk of 16ga aluminum and an Excel spreadsheet makes a RPM SFM chart that won't ever burn out, short when hit with cutting fluid, and if it gets scratched to poop I can just make a new one.

Excel chart:



I'll post a photo of a completed plate once I have one done.

 

[jorogi]

Fabulous, sign me up.

 

[Dabbler]

This is the best!

 

[Susquatch]

That's REALLY COOL! That's the kind of thing I would just print and tape to the wall beside my machine!

Currently, I use a wall chart with graphed curves on it from little locomotive (or something like that). I like your idea better!

I'd love it if you shared the spreadsheets themselves with the rest of us when you are done!

In a similar vein, I've been thinking about writing an RPN module for HP Calculators to do this kind of thing. I have several HP Emulators that run on my Android phone that can run such a program. The HP41C platform would add alpha characters to the input process.

The other idea I've had for a little while now is a speeds N feeds system for carbide inserts based on the manufacturers recommendations. I would imagine that this would probably be a lookup system of some kind with the oem recommendations for the inserts I already own but be flexible enough to add more as I acquire them. The program would then output the required speeds N feeds for my lathe and/or mill.

Cool idea @whydontu!