Turning speed Question?

[Mark Stewart]

I know that some where otu there is a formula for figuring turning speed. How do you guys figure your speeds? I am interested in your opinions.

Thanks Mark

 

[Rob]

If it's real out of round, I start slow and once round, speed up to a confortable speed. I usually never go over 1000 rpm's.

 

[Mark Stewart]

So Rob how about with sanding?

 

[NCTurner]

The slower the better for sanding...heat is your enemy! As far as turning speed, usually determined by the pucker factor, but you shouldn't to turn at more than 1000-1500 as Rod said, and usually slower for larger pieces. Remember the larger the piece the faster the outside is spinning.

 

[reprosser]

Assuming you are asking about turning bowls and such (spindle work is usually done at faster speeds)

My lathe won't run below about 600 rpm, so that is where I usually stay. I sometime turn up the speed to overcome vibrations or to remove waste wood quicker. My sanding is always done at the lowest speed.

 

[Mark Stewart]

Sounds like we have the same lathe . 1st speed is 600, 10th is to scarry to mention.

 

[Mike Davis]

From a machinist point of view it is simply a matter of determining the surface feet per minute of the object being cut (or the cutter, which ever is turning).

I don't have my Machinist's Handbook with me so I'm working from memory. Getting worse every year. :rotflm:

So I think wood is recommended to be cut at around 1500 surface feet per minute. Softwood slower and hardwood faster.

A simplified version of the formula is RPM = (4xSFM) / Diameter in inches

So, let's say you are turning a 10 inch bowl at 1500 SFM.

Then 4x1500= 6000 / 10 = 600 rpm or to simplify further you could divide 6000 by the diameter in inches to get RPM.

2" = 3000
3" = 2000
4" = 1500
5" = 1200
6" = 1000
8" = 750
10" = 600
12" = 500
14" = 420
16" = 375
18" = 330

 

[Mark Stewart]

You know I was a machinist(CNC only) and I never had to do any of this calculation. The machine did it for me.:rotflm:I caint find the keyboard of the floppy drive on this darn lathe. No auto pilot either.

 

[PChristy]

Speaking of sanding - have any of you guys ever done any wet sanding on your green turnings - I seen it done on a video and I tried it awhile back up to 400 grit and it worked pretty good

 

[Mark Stewart]

no but I must investigate. Do you hav a link to this wet sanding vid?

 

[PChristy]

no but I must investigate. Do you hav a link to this wet sanding vid?

Sorry Mark it is on the video that I won at the Klingspor gathering awhile back

 

[PChristy]

You get wet/dry sandpaper and a wet paper towel and keep the wood wet while sanding - it doesn't cause any heat - try it see what you think