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Can you add a speed controller to stationary belt and disc sanders?

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Forum topic by SawTooth1953 posted 05-01-2016 08:35 PM 1069 views 0 times favorited 14 replies Add to Favorites Watch
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SawTooth1953

308 posts in 2772 days


05-01-2016 08:35 PM

Topic tags/keywords: sanding burns speed control belt sander disc sander question sander motor speed

I use my large disc sander and stationary belt sander to “sand to the line” after rough cutting a pattern. Too often I get burn marks. I know about taking light passes, and using a light touch, and using a coarser grit first if I have a lot to reduce, make quick passes, etc. I am also aware some woods are very prone to overheating/scorching…but who wants to avoid beautiful woods just because they aren’t easy to work with?

All those tips are good but they still don’t ensure a clean outcome. All the tips are aimed at trying to get the job done with sandpaper that is moving too darned fast. I conclude that I’d like to slow down the disk sander and belt sander because I’m sick and tired of getting burns in spite of all my efforts. I cannot be the only one.

So my question is: Will I ruin my tool or ruin an add-on speed controller if I try that route? (The speed reducer is the type made for routers.)

I don’t know the type of motors in my tools. What I’m using is the Ridgid oscillating belt sander and the other is a large disc sander from Grizzly. At times I use a basic combo disc/belt sander and sometimes a HF 1” belt sander.


Does anybody have experience adding speed control to these types of benchtop tools? If not a router-type speed controller, than what type?

BTW, I don’t recall seeing this advice before: One thing I noticed on the large disc sander is the sandpaper is flying by fastest at the outside, and slower nearer the center. Of course I’m staying on the left side so the disc direction is downward, but the point is that when sanding smaller things nearer to the center, it is a lot less likely to burn. Now I wish I could find a ‘sweet spot’ on a belt sander. :)

-- Spence in Skokie, IL


14 replies so far

View conifur's profile

conifur

955 posts in 617 days


#1 posted 05-01-2016 09:00 PM

I know you cant use that on induction motors, I would bet your Grizzly is an induction motor. As far as your Rigid I doubt that is an induction motor. I have one of those types of speed controls, just got the instructions out. First page, first item
WARNING
it is compatible with any universal AC/DC brush type motor 15 amps or less.
NOT for use with the following types, brushless, induction, shaded pole, and soft/slow start motors.

-- Knowledge and experience equals Wisdom, Michael Frankowski

View Jim Finn's profile

Jim Finn

2413 posts in 2388 days


#2 posted 05-01-2016 11:17 PM

Yes, what conifer said!

I have two 6”x48” x9” belt/disc sanders from harbor freight. They have induction motors so cannot be slowed with a speed controller but they are belted motors so are slowed a bit but not enough for the disc sander on it. I do not even use the disc sander on them because of the “too fast” problem you speak of. I use the belt sander only and can do anything the disc can do but without burning the wood. These sanders are the most used equipment in my shop.

-- "You may have your PHD but I have my GED and my DD 214"

View Fred Hargis's profile

Fred Hargis

3945 posts in 1959 days


#3 posted 05-02-2016 11:24 AM

There’s not much you can do to slow those down. Certain single phase and most 3 phase motors can be controlled with a VFD, but not the ones you have. I bought the Grizzly sander with a 1725 RPM motor for that reason.

-- Our village hasn't lost it's idiot, he was elected to congress.

View bigblockyeti's profile

bigblockyeti

3668 posts in 1186 days


#4 posted 05-02-2016 12:04 PM

They both use an induction motor, you could control the speed with a VFD which can be more difficult to wire than a machine using a three phase motor, but not always.

View oak500's profile

oak500

1 post in 982 days


#5 posted 05-03-2016 09:21 PM

You could try changing the belt pulley size to change the rpm.

View MrUnix's profile

MrUnix

4234 posts in 1665 days


#6 posted 05-03-2016 09:27 PM

They both use an induction motor, you could control the speed with a VFD which can be more difficult to wire than a machine using a three phase motor, but not always.
- bigblockyeti

Please explain how you use a VFD with a typical single phase induction motor… I’m intrigued!

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

View SawTooth1953's profile

SawTooth1953

308 posts in 2772 days


#7 posted 05-04-2016 05:48 AM

Is it just me, or is it crazy that companies sell sanders that give us fits by running too fast to sand without scorching the wood?


You could try changing the belt pulley size to change the rpm.

- oak500

oak500, none of my sanding machines have belts or pulleys… If they did, I’d do what you suggested.

-- Spence in Skokie, IL

View SawTooth1953's profile

SawTooth1953

308 posts in 2772 days


#8 posted 05-04-2016 06:07 AM



There s not much you can do to slow those down. Certain single phase and most 3 phase motors can be controlled with a VFD, but not the ones you have. I bought the Grizzly sander with a 1725 RPM motor for that reason.

- Fred Hargis

The Grizzly sander with a 1725 rmp motor is the one I have that burns wood all the time…especially if I’m sanding nearest the left edge of the disc where the sandpaper is whizzing by the fastest.

Grizzly says about that sander (model G7297)- it spins at 1725RPM and Motor: 1 HP, 110V, single-phase, 10A, TEFC

I don’t know enough about motors to know if that is one that is excluded from use with the speed control
(excluded ones were stated above as: brushless, induction, shaded pole, and soft/slow start motors.) I looked up TEFC: “A TEFC enclosure on a motor means “Totally Enclosed, Fan Cooled”. This motor is probably the most commonly used motor in ordinary industrial environments.”

To me, that doesn’t describe the characteristics of the motor in a way that helps me answer my original question about adding a speed control. To those in the know, does “single-phase” provide the answer in some obscure way. (Obscure to me, that is!)

-- Spence in Skokie, IL

View MrUnix's profile

MrUnix

4234 posts in 1665 days


#9 posted 05-04-2016 07:33 AM

It’s not happening with the motor you have.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

View Fred Hargis's profile

Fred Hargis

3945 posts in 1959 days


#10 posted 05-04-2016 10:57 AM



It s not happening with the motor you have.

Cheers,
Brad

- MrUnix

What he said^^^^^^. Since that’s direct dive there’s nothing you can do with sheaves, either. Best to search for other options. You didn’t mention what grit you were running, it may be that changing to a different (probably more coarse) grit may help. Otherwise it’s off for looking for a different sander.

-- Our village hasn't lost it's idiot, he was elected to congress.

View MrRon's profile

MrRon

3926 posts in 2709 days


#11 posted 05-04-2016 03:06 PM

Universal motors have brushes and therefore can be used with a router type speed controller. No brushes, no speed control.

View splintergroup's profile

splintergroup

829 posts in 688 days


#12 posted 05-04-2016 03:57 PM

There are ways, but they get rather expensive. Remember that the surface speed of a disk gets faster as you move towards the outer edge. Sanding closer to the center may be enough to help you out?

View conifur's profile

conifur

955 posts in 617 days


#13 posted 05-04-2016 04:47 PM



Universal motors have brushes and therefore can be used with a router type speed controller. No brushes, no speed control.

- MrRon
</blockquote
That motor is an induction motor, so it cant be used with a router style/rheostat speed controller.

-- Knowledge and experience equals Wisdom, Michael Frankowski

View SawTooth1953's profile

SawTooth1953

308 posts in 2772 days


#14 posted 05-05-2016 04:14 AM

Thank you all for your input.

Splintergroup, yes I did find that sanding small pieces closer to the center did avoid burns.

-- Spence in Skokie, IL

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