View Full Version : What speed does a drum sander need to run at?

ozwinner

8th May 2004, 08:03 AM

Hello Gentlemens

I have got my drum sander up and running, well almost.

I have got a 1400RPM motor with a 50mm pulley on it.

That goes to a 4 step pulley, which ranges from 50mm to 100mm.

But it all seems too slow, what is the optimum speed I should run this thing at.

And how do I calculate this? The drum is just over 200mm.

The drum is made of timber also, so I dont know if this will limit speed?

Cheers, Al

bitingmidge

8th May 2004, 08:45 AM

Al,

Instinctively I was going to answer "that depends on how fast the thing that's chasing it is travelling" but then I remembered those sorts of answers are better on another thread. :D

The Performax 16-32 has a direct drive 1420rpm and a 125 diameter drum, which by my sums gives a sandpaper speed of 558 metres per minute.

(Maths is not my strong point so it would be good if someone could check!)

Your machine on a direct drive (50 dia to 50) dia using the same maths should be running the paper at 880 metres per minute.

Therefore to reduce the speed to match the Performax, you need a 100 pulley on the motor and a 65 on the drum. (I think!)

Of course all these calculations are out the window if one takes into account the speed of feed, which on the performax is variable down to zero (the fastest speed is about the rate of feed of an el cheapo thicknesser). Maybe if the drum is slow, you just feed slower....but that would need a LOT of patience!

My impression of the Performax is that it isn't spinning all that quickly as well, probably because we are used to seeing bench grinders whizz around at 3500 rpm? Maybe the weight of the drum is loading up the motor, but I wouldn't have thought it would make all that much difference once it is spinning? Have you a means of measuring the revs?

Hope some of the above is of use.

Cheers,

P

Al Burdon

8th May 2004, 09:06 AM

The formula for rpm is machine speed X diameter of pully driving / diameter of pully being driven. So for your set up the speed will be 1400 rpm or less.

My set up has a 5" driver with a 3" follower rpm =1400

therefore 1400 X 5 /3 = 2300 approx

If you search the spec sheets for sanders you will see that 1400 rpm plus is the used speed you then need to look at drum diameter I have a 4" diameter drum so go to this link

http://kadina.yp-connect.net/~tcents/metal/data/s_speed.html

and I get approx 2400 feet per min.

Take this information you obtain and compare to specs of other units and try to fit in there boundries and you should be right.

Now my set up works very well at 2300 rpm and 2400 fpm surface speed

and what rate of feed do I use. The infinitely variable handraulic system.

bitingmidge

8th May 2004, 11:44 AM

I get approx 2400 feet per min.

Looks like my maths is OK then!!

P

echnidna

11th May 2004, 09:43 PM

Generally speaking the higher the speed the faster it works and a greater depth of cut is possible. But a slower drum gives a far finer finish.

Performax is underpowered and under speed if you compare it to industrial furniture sanders. Performax obviously reduced the drum speed so they could get away with a smaller motor.

Another small drum sander to compare against is a floor sander. My old one used to spin somewhere about 4-5000 rpm with a 6" diameter drum 12" wide. But it needed a 3hp motor to drive it. (The motor is in my sawbench now)

snow

12th May 2004, 09:38 PM

Al,

My mate and I made a drum sander (see link). We discussed the speed issue at length and after some research on the WEB came up with a range between 1900/2100prm. After using it for a while I don't know how important the drum speed is. I think the issue is more the paper you use. We have tried a variety of paper but think that 80grit E weight is best.

My opinion only

Snow

http://www.woodworkforums.ubeaut.com.au/showthread.php?t=8228