Using washing machine motors

[BMac]

I hope this is in the right place.

I am thinking of making a disc sander, a belt-type sander/honer and a buffing machine using washing machine motors. I don't need variable speed so wiring will be straightforward and I know I need enclosed, fan-cooled motors for safety so that bits aren't falling inside them. The rigs will be built to be secure I will get a friend to check electrics for me but am I walking into danger by overlooking something elementary that I am unaware of?

Thanks, Brendan

 

[Geno]

For your own sake try not to walk in to it!!

I take it you have considered required speeds etc and how it suits for the job at whatever diameter your disc sander will be.

 

[BMac]

Hi Geno,

Yeah, I've investigated speeds and most washing machine motors give 1450-1750 rpm but I've discovered that can be governed using a control panel from a washing machine. I don't know how it's done but the guy I am dealing with repairs machines so I'll leave that up to him if need be. However, those speeds are fine for my job and I can vary disc diameters as required.

"For your own sake try not to walk in to it!!"

You are closer than you imagine. The reason for building a dedicated sander is because I was sanding the edges of some boards with a belt sander. I held them in a vice but, when I had finished, I noticed a little bit I had missed so lifted the board and ran the belt sander over the bit in question. Its a good idea not to have your hand in front of the sander when it runs on. Have you any idea how quickly a belt sander with a 60 grit belt removes knuckle flesh? So, I don't need that experience again.

Also, I know there's the saving money element which is always satisfying but I think it's more satisfying being able to say 'I done that!'

 

[wizer]

BMac. How odd, I was just looking at motors on eBay (via Chisels link elsewhere). I've been contemplating making a sanding machine for some time. The low end commercial ones just seem to be poor quality. Never even considered using a motor from a Washing Machine. Aren't they overpowered? I know that the 2 washing machines I have owned over the years where powerful enough to make the unit jump around if they weren't sited properly. I would imagine the motor would need a very secure fixing at very least.

Interested to see the build tho, please document it. I'm certainly going to make one some day. Probably a drum sander as these are astronomical to buy.

 

[Geno]

Good man Brendan!!

Nothing like losing some knuckles to make it look like you were busy!!

I'm sure I'm like everyone else here and have had more than enough close calls with the wrong machines!

As for the sander, I'm sure there is some variable speed control that your mate is incorporating, just make sure it doesn't incorporate the intermittent reverse cycle!!

AS Wizer said, hope to see the pics on the build! I'm off to find me a few washing machines!!

Mind the knuckles!

 

[BMac]

Wizer,

If you do a search for 'homemade drum sander' lots of stuff will appear, that's what I tried but rather than pick a link I just typed that so you can copy and paste.

Also, YouTube, http://www.youtube.com/watch?v=QLy8YnNomwk

Geno, @ reverse cycle. Wouldn't you guys just love it if I made a video and that happened!

 

[Oryxdesign]

please don't leave yours unguarded or you'll do more than skin your knuckles. Watching vids like that scare the life out of me.

 

[wizer]

Cheers Brendan. I have seen that and a few others around the web. I actually have a 1/4 HP motor in the workshop but I'm not sure if it will be powerful enough. At any rate I don't have time to devote to this project just yet. It will be a fun and useful thing tho and will save bundles.

 

[Dave S]

I think Peter Lloyd has pictures of a home made disc sander in his book 'Making Heirloom Boxes'.

I think I might have an old Shopnotes kicking around with plans for one, too. I 'll have a look when I get a chance.

Dave

 

[Digit]

Forget the WM motor Brendan, too fast by miles. Look for a tumble dryer motor.

Roy.

 

[BMac]

Thank you Dave and Roy.

I haven't got any motors yet but I had been considering using a pulley to step the speed down, this advice from Roy makes things much easier.

 

[wizer]

Do we know the ideal power rating for a motor that will comfortable drive a sanding machine? Be it in HP or KW or something else?

 

[BMac]

Wizer,

I looked on Axminster to see specs for sanders and they vary between 560W and 750W with speeds of 1400-1425rpm.

That RPM seems high because when I am using my lathe to sand I generally have the speed 700-900rpm.

 

[xy mosian]

I have used old washing machine motors to drive ad hoc lathes in the past. But they only had one speed, however they were very easy to wire up. Sadly I think a lot of newer w/m motors are not fully enclosed being only skeletal frames, and of course the multi speed/direction options add to the confusion.

 

[Digit]

If modern washing machine brush motors are connected with stator and rotor in series the speed drops to more usable levels and the speed can be controlled with a dimmer switch.
That's how we test 'em.

Roy.

 

[BMac]

Excellent, thank you for that Digit.

Brendan

 

[wizer]

brush motors are connected with stator and rotor in series

What does that mean in English?

 

[Digit]

Washing machine motors wizer have the terminals for the field winding, the non-moving part, separate from the terminals for the rotor, the spinning bit.
If the power is connected simultaneously to both fixed and moving parts that is 'shunt' connected and the motor runs at high speed.
If you connect the power to one terminal of the field winding then connected the other terminal to the rotor, the brushes, and the other brush to neutral, the power runs through one part then the next and the motor spins more slowly.
This is 'series' connection.

Roy.

 

[BMac]

Well, I've run into a bit of a problem, a fatal problem actually. I went to see my washing machine motor man today and he told me I'd be wasting my time because the modern motors aren't strong enough to give sustained use because they are designed for short bursts of activity and would give up fairly quickly if run for long periods. He also told me that the torque generated by the pressure of the piece on the sanding disc would also serve to destroy the motors. At one time this would have been a viable project but not now. Oh well.

Edit 13.30pm. I've just had a thought. I wonder, in this litigious age, if he just didn't want to have anything to do with my project?

(BTW, this is a different guy from the friend who is advising me)

Brendan

 

[wizer]

Surely you're not going to be running a drum sander or disc sander for longer than the average washing cycle? If you need to take that much off your doing something wrong on the previous process.