Trying to repurpose a tread mill bed for a drum sander

[JT Loveless]

First thing I'm a real green horn about electronics. But I have a treadmill bed and the supporting electronics. It works but goes to fast on slow. Can I add a PWM controller to slow it down? It takes 3 seconds for a piece of wood to go from start to end. I would like it to take about 5 to 7 seconds to allow the drum sander to have a little more time. I have used a PWM on battery cars for my grandsons to slow them down so they won't run into my garage and hit things when they slid. I just don't know enough about this kinda thing to know if it would hurt the electronics that is feeding it.

Thanks for any advice you can give.

 

[MaxHeadRoom78]

What is the controller board part No.?
Also what or how are you controlling the speed?
Max.

 

[JT Loveless]

This is one of the controllers I was looking at on eBay:
12V 24V 48V 2000W 10-50V 40A DC Brush Motor Speed Control PWM HHO RC Controller.
I'm controlling the speed now with the original control panel from the treadmill. It has the power source and controller all in one board. I can send you a picture tomorrow of the controller that it has on it now if that helps.

Thanks,

Jeff L

 

[MaxHeadRoom78]

They only go to 50vdc?
Some such as the SCR bridge version MC-60 use a 5k pot and the PWM MC2100 uses an add on board if you want to use it for other purposes.
Both a are fairly flexible as to motors.
Some such as the above are fairly easy to use for second purpose use.
Post a pic of the orig board.
Max.

 

[shortbus=]

How big are your belt rollers, the diameter? Most drum sanders use rollers much smaller than a treadmill does. The one I'm building only has rollers around 2 inch diameter. If your using bigger ones you may have to put some king of gearing, Vbelts and pulleys, between the motor and the rollers.

What are you using for the actual bed of the sander? The part under the belt. It needs to be both hard and smooth if your going to get a flat surface on the wood. I ended up buying a wide(24") sanding belt and using a cutoff from a granite counter top.

 

[JT Loveless]

How big are your belt rollers, the diameter? Most drum sanders use rollers much smaller than a treadmill does. The one I'm building only has rollers around 2 inch diameter. If your using bigger ones you may have to put some king of gearing, Vbelts and pulleys, between the motor and the rollers.

What are you using for the actual bed of the sander? The part under the belt. It needs to be both hard and smooth if your going to get a flat surface on the wood. I ended up buying a wide(24") sanding belt and using a cutoff from a granite counter top.

I'm using the original belt and bed of the treadmill to be my conveyor to carry the wood through the sander drum. I'm using a 19" long 6" diameter steel roller with 1 " shaft that will be driven by a 2 hp motor. I'm waiting on 2 machined spacers and bearings. My problem is I want to slow down the conveyor. So it gives the sander more time to sand the piece.



so I can get the drum finished.
Here are the pics of the board and the schematic that came with it. Thanks for any help,

Jeff Loveless

 

[JT Loveless]

Max Headroom78 It won't let me post the pictures. If you email me at jloveless@ aol.com I can send them to you in an email. I have 2 pictures of the board and one of a schematic that came with the treadmill.

Thanks Jeff

 

[shortbus=]

Max Headroom78 It won't let me post the pictures.

I'm not Max, but how did you do the pictures? you have to add pictures from your computer using the "attach files" box under the reply area.

 

[shortbus=]

My problem is I want to slow down the conveyor. So it gives the sander more time to sand the piece.

Is the belt drive motor directly connected to the belt roller? If it is connected using belts and pulleys you need to change the ratio of those. If it is a direct drive from the motor you need to figure out a way to put some sort of drive belts, chains or gears in between the motor and the drive roller. Usual tread mill walking belt rollers are much too big in diameter to get a slow enough speed for a drum sander, even with a speed controller. Go online and look at any of the sander being sold and compare the diameter of your rollers to what a ready made sander has.

Maybe up load pictures of your belt system to get more help. You do know how to figure you belts surface feet or inches speed don't you? Circumference the of the drive roller X the RPM of the roller, compare yours to any of the specs of the ready made ones out there, that's how I reverse engineered mine.

 

[MaxHeadRoom78]

I just fixed one of those versions of the MC2100 for a friend.
On his, all he had for belt speed was a sensor using a small coin magnet on the belt pulley.
It requires a small PWM board to control the motor, I can sent you a source if you need one, has a stop/start P.B. feature.
BTW, I found on the one I fixed that the large 1500uf? cap on the L.V. P.S. was rated for 15vdc and had started to bulge at the top, this probably because the voltage there measured 17vdc!
Max.

 

[JT Loveless]

I'm not Max, but how did you do the pictures? you have to add pictures from your computer using the "attach files" box under the reply area.

I took the pictures with my phone and tried to upload them by attaching them but it said the file was to big. It was around 3.4mb.

 

[JT Loveless]

Is the belt drive motor directly connected to the belt roller? If it is connected using belts and pulleys you need to change the ratio of those. If it is a direct drive from the motor you need to figure out a way to put some sort of drive belts, chains or gears in between the motor and the drive roller. Usual tread mill walking belt rollers are much too big in diameter to get a slow enough speed for a drum sander, even with a speed controller. Go online and look at any of the sander being sold and compare the diameter of your rollers to what a ready made sander has.

Maybe up load pictures of your belt system to get more help. You do know how to figure you belts surface feet or inches speed don't you? Circumference the of the drive roller X the RPM of the roller, compare yours to any of the specs of the ready made ones out there, that's how I reverse engineered mine.

Thanks for the info. I haven't run the calculations yet. I can't change the pulleys because the one on the roller is made into it. The motor is about an inch so it's as small as they get. I used a controller on a battery car. That's what give me the idea of putting it in the slowest speed and adding another controller between it and the motor to slow it down to where I wanted it. But will that screw up the controller feeding mine?

I just fixed one of those versions of the MC2100 for a friend.
On his, all he had for belt speed was a sensor using a small coin magnet on the belt pulley.
It requires a small PWM board to control the motor, I can sent you a source if you need one, has a stop/start P.B. feature.
BTW, I found on the one I fixed that the large 1500uf? cap on the L.V. P.S. was rated for 15vdc and had started to bulge at the top, this probably because the voltage there measured 17vdc!
Max.

When I measured the voltage set to low speed on mine it was 22 volts. That will probably burn that one up wouldn't it? It does have sensor on it but I'm not sure if there is a magnet. I will check and see.

 

[shortbus=]

I can't change the pulleys because the one on the roller is made into it.

But you can use a "jack shaft" type solution. That allows you to double gear down the speed. Using two speed controllers in a row doesn't seem to me like it would work. Slowing down the motor past a certain RPM isn't a good idea either, if the motor has a cooling fan built into it. Once you get to a certain point the fan won't keep the motor cool. In case your not familiar with the term "jack shaft" -

Jackshaft - Wikipedia

en.wikipedia.org

Again just my way of doing things like this, the way I was taught back when horses were still powering things(a joke). You need to figure what SFPM(surface feet per minute) or inches per minute is needed. Then you calculate the gearing to get that from your motor RPM and roller diameter. Then with a variable speed motor you would try to get that SFPM with the motor running in the mid-range of the controller. Doing that will allow the ability to speed up when needed or slow down when needed. That is how the ready made ones are built/designed, to give the most flexibility of use.

 

[gophert]

I took the pictures with my phone and tried to upload them by attaching them but it said the file was to big. It was around 3.4mb.

Open the photo on your phone and do a screen capture of that image. Post the screen capture. It will be much smaller image file size.

 

[JT Loveless]

But you can use a "jack shaft" type solution. That allows you to double gear down the speed. Using two speed controllers in a row doesn't seem to me like it would work. Slowing down the motor past a certain RPM isn't a good idea either, if the motor has a cooling fan built into it. Once you get to a certain point the fan won't keep the motor cool. In case your not familiar with the term "jack shaft" -

Jackshaft - Wikipedia

en.wikipedia.org

Again just my way of doing things like this, the way I was taught back when horses were still powering things(a joke). You need to figure what SFPM(surface feet per minute) or inches per minute is needed. Then you calculate the gearing to get that from your motor RPM and roller diameter. Then with a variable speed motor you would try to get that SFPM with the motor running in the mid-range of the controller. Doing that will allow the ability to speed up when needed or slow down when needed. That is how the ready made ones are built/designed, to give the most flexibility of use.

I hadn't thought about a jack shaft setup. I have made those before. I wi have to change things around but it's possible. I will look at it tomorrow and see what I can come up with. I was hoping to use the bed as is but if I can't do it with electronics then it will have to be mechanical.

Thanks I will let you know what I come up with.

 

[Pommie]

Can I just clarify something, are you repurposing the tread mill as a sander or as a conveyor?
I think the conversation has got confused - or at least I have.

Mike.

 

[MaxHeadRoom78]

When I measured the voltage set to low speed on mine it was 22 volts. That will probably burn that one up wouldn't it? It does have sensor on it but I'm not sure if there is a magnet. I will check and see.

The voltage I was referring to was the Power supply which originates from that off board power transformer.
It is 16v -17v then regulated down to 5v for the micro etc.
There is often a button magnet on the belt pulley, others have a opto sensor on the motor itself.
The 22v is what you would read on the motor at low rpm.
Max.

 

[shortbus=]

Can I just clarify something, are you repurposing the tread mill as a sander or as a conveyor?
I think the conversation has got confused - or at least I have.

Mike.

It's a conveyor really he's talking about. A drum sander has a drum with sandpaper on it, and a conveyor system to feed the work through it.

 

[shortbus=]

I was hoping to use the bed as is but if I can't do it with electronics then it will have to be mechanical.

This is the type motor most feed belts use, and is similar to the one I have, https://www.bodine-electric.com/pro...rs/42a-cg-series-parallel-shaft-dc-gearmotor/
You don't really need to use a big motor for the belt/conveyor drive, I'm assuming your going with the treadmill motor? If so that's way more power than needed. If you look at the specks on the factory built sanders they only have ~1/8 HP motors, and they are gear motors. It's the gearing that slows them down and gives them enough power to work like they should.

 

[JT Loveless]

Can I just clarify something, are you repurposing the tread mill as a sander or as a conveyor?
I think the conversation has got confused - or at least I have.

Mike.

I'm using the bed as a conveyor to carry the wood under the sander. That is why I was wanting to slow down the travel speed of the belt. I'm building a frame with a 6" steel drum with bearings and a 2 hp motor to drive the drum. The bearings and the bushings came today for that part. I will be installing 4 threaded rods for height adjustment also. I hope this clears it up.

Thanks
Jeff L.