Lathe RPM for Roughing or Finishing

[tashammer]

I found this on Emule under the title "Woodworking - Lathe-RPM Chart.pdf". What you see is what there is, no names, no attributions so i am unable to give a source.
Are the figures right and is it a usable chart?


Lathe RPM for Roughing or Finishing

I found this chart on another website. It is just a suggestion.You may want to turn at a different speed. The formulas are below.
<table> <tbody> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> Turning Diameter (inches)
</td> <td style="border: 1px outset rgb(0, 0, 0);"> Roughing RPM
</td> <td style="border: 1px outset rgb(0, 0, 0);"> Finishing RPM
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> 2
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 1500
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 3000
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> 4
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 800]
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 1600
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> 6
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 500
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 1000
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> 8
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 400
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 800
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> 10
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 300
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 600
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> 12
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 250
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 500
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> 14
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 225
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 450
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> 16
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 200
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 400</td></tr></tbody></table>
The roughing surface speed is 160 inches/second.
The finishing surface speed is 320 inches/second.



The formulas are: Roughing RPM = 160/(PI*Diameter)*60
Finishing RPM = 320/(PI*Diameter)*60

[Skew ChiDAMN!!]

It more or less falls in in line with other charts I've seen. The speeds seem reasonable and I'd say are quite usable... but "right" is a matter of personal opinion. eg. I've had a chart up on the walls of my shed for several years now, that has the following on it:

Faceplate:
<table> <tbody> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> Stock Size
</td> <td style="border: 1px outset rgb(0, 0, 0);"> RPM for >2" thick
</td> <td style="border: 1px outset rgb(0, 0, 0);"> RPM for <2" thick
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> <8"
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 1000
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 750
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> 8"-12"
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 750
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 750
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> >12"
</td> <td style="border: 1px outset rgb(0, 0, 0);"> slowest avail
</td> <td style="border: 1px outset rgb(0, 0, 0);"> slowest avail
</td> </tr> </tbody></table>

Spindles:
<table> <tbody> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> Stock Size
</td> <td style="border: 1px outset rgb(0, 0, 0);"> RPM for <24" length
</td> <td style="border: 1px outset rgb(0, 0, 0);"> RPM for >24" length
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> <2½"
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 2000
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 1500
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> 2½"-4"
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 1500
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 1000
</td> </tr> <tr> <td style="border: 1px outset rgb(0, 0, 0);"> >4"
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 1000
</td> <td style="border: 1px outset rgb(0, 0, 0);"> 750
</td> </tr> </tbody></table>

As you can see it's a bit hard to make a direct comparison with yours. :shrug:

Apart from a couple of times when I first posted it to the wall, I've totally ignored it! :-:D I've found that the type of wood and the type of cut dictates the speed more than the dimensions.

I'm more of the school of thought: "crank it up until it vibrates, then back off a notch or two." There are obvious exceptions (obvious at the time, that is... punky wood, etc) but any "rule" can only be general, eh?

[Gil Jones]

Thanks Tas, but I rather do agree with Skew on the "speed up 'till it shakes, and slow down a bit".

[ss_11000]

Thanks Tas, but I rather do agree with Skew on the "speed up 'till it shakes, and slow down a bit".
thats what i do to...

anyway, tas's table seems pretty good:)

cheers