Thread: Buffer RPM questions

Here's a link I posted a year ago explaining the SFM.

I'll copy and paste it here for easy reference

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I actually just wanted to bring this thread back to life as I always read so many good tips and talks about the polishing and buffing.

It seems I never hear talk of the 'Surface Feet Per Minute' or SFM. If followed properly you can calculate the ideal dia of the wheel to be used for a particular material.

SFM relates to the distance in feet that the workpiece surface or cutting edge travels in one minute.

There's a simple math formula for this.

SFM = 1/4 of the wheels's diameter * arbor speed.

The ideal SFM for Stainless Steel is around 8000 sf/min. Plastics go from 1200 to 4000 sf/min.

When buffing with speeds over 5000 sf/min you get into 'molecule migration' territory. In short, molecules start to move around and this is what cause the heat generation which can become to excessive.

For example If you are using a 3600rpm polisher, by using a 10" wheel = 1/4 of 10 inches = 2.5 inches * 3600 = 9000 SFM.
A little high. It could pass but by chosing an 8" wheel it becomes (2 inches x 3600rpm) 7200 SFM. It's lower but it could work too.

Now you con easily use an 8" wheel on an 1800 RPM polisher = equals 3600 SFM. It's far from the 8000 needed for steel. Difference is it will take you much much longer to get the desired result but at a safer usage.

Off course no one says you need to follow this procedure but it can give you an easy and rough estimate as to what wheel to use.

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I have an 1100, 1850 and 3600 RPM and use them all.

Thank you to everyone that has been helping me as I try to make a decision on this.

To Max and Lynn, would you guys mind sharing what buffers you're using in the lower (1100/1800) RPM range?

1100-Caswell 3/4 hp
1800-Baldor 1/3 and 3/4 hp

Have fun,

Lynn

Originally Posted by heirkb

Thank you to everyone that has been helping me as I try to make a decision on this.

To Max and Lynn, would you guys mind sharing what buffers you're using in the lower (1100/1800) RPM range?

Originally Posted by heirkb

Thank you to everyone that has been helping me as I try to make a decision on this.

To Max and Lynn, would you guys mind sharing what buffers you're using in the lower (1100/1800) RPM range?

I'm a sucker for Baldor, mainly because these buffers truly are workhorses for me so they need to perform daily, Baldor really stand behind their motors and other products, it's US made and it's a proven brand. The 1100rpm is a made in China buffer from Caswell that works really well.

Originally Posted by Lynn

1100-Caswell 3/4 hp
1800-Baldor 1/3 and 3/4 hp

Have fun,

Lynn

Originally Posted by Maximilian

I'm a sucker for Baldor, mainly because these buffers truly are workhorses for me so they need to perform daily, Baldor really stand behind their motors and other products, it's US made and it's a proven brand. The 1100rpm is a made in China buffer from Caswell that works really well.

Does the 3/4 HP concern either of you on your buffers? I'm going to wait to hear back from Glen on why he doesn't like high HP, but was wondering what you guys think.

The higher HP will only come to your benefit once you start throwing 10" and higher wheels on those buffers.

On my 1/2HP baldor I can still use an 8" wheel comfortably but feel that if I use a bit to much pressure it slows down. Not by much and it's not really an issue but I have no problems whatsoever with a 6" wheel or smaller. Once I use an 8" wheel on the 3/4HP Baldor I can't get the damn wheel to slow down no matter how much pressure I put on the wheel. lol

4" and 6" wheels is what I use.

Besides the HP, torque would be the second most important thing to look for. A buffer will have more torque then those grinder/buffers they sell. Also many cheat with the HP they list as it's mostly the peak HP they use as a selling gimmick. Ther's always a reason why there will be a difference between a $350 buffer or a $85.00 one.

I too have been looking for a buffer and saw Brads resto vids and he uses a varialbe speed grinder seen here Delta GR450 8" Variable Speed Grinder with Tool-less Quick Change | ToolBarn.com any thoughts if its a good one, it seems to work for him. Not too bad on the price either, do you think this would be a good starting buffer?

Originally Posted by heirkb

Are buffers with more horsepower more likely to destroy your hand if it gets caught? I'm really new to any power tool/motor related things, so I apologize if this is a stupid question.

You missed the key word "Irrational" I won't wear cut proof gloves for the same reason, the thought of the wheel grabbing them, scares me way more than getting cut...

And yes the higher HP and Torque can hurt ya more, I can stop any of my wheels with just a bit to much pressure, and I am good with that...

Myself right now I am thinking of an 1100 rpm one just for plastic/acrylic polishing...

Originally Posted by gssixgun

You missed the key word "Irrational" I won't wear cut proof gloves for the same reason, the thought of the wheel grabbing them, scares me way more than getting cut...

And yes the higher HP and Torque can hurt ya more, I can stop any of my wheels with just a bit to much pressure, and I am good with that...

Myself right now I am thinking of an 1100 rpm one just for plastic/acrylic polishing...

Just as a note, I have been getting good results for plastic and acrylic with the tumbler.

Originally Posted by thewatermark

I too have been looking for a buffer and saw Brads resto vids and he uses a varialbe speed grinder seen here Delta GR450 8" Variable Speed Grinder with Tool-less Quick Change | ToolBarn.com any thoughts if its a good one, it seems to work for him. Not too bad on the price either, do you think this would be a good starting buffer?

I think that if I were to get this, I'd just pay the extra forty bucks and get the Caswell 1100 (or was it 1800? I forget now). It seems that having a buffer so that I don't have to worry about hitting the motor and whatnot would be a safer bet for me.