Treadmill motor adaptation for Bridgeport type mill.

My name is Robert Brown AKA, machiningfool. I hope I am in the right place. A few minutes ago I went to the garage and collected some ideas on how to adapt the treadmill motor to the mill and to my surprise this project will be simple and straight forward. I like to use the KISS principle, keep it simple stupid, stupid being me. After removing the cooling shroud and removing the plastic fan, oh boy there was a 3/4 inch shaft just waiting for a pulley. I am approaching this project with an attitude, that I don't want to get too invasive, so I am going to keep the present 3 phase motor in place along with the variable speed belt system and power the whole mechanism with the treadmill motor. What this does is that I will have complete control of the high and low transmission of the mill and have two ways of controlling speed. One with the built in variable speed belt system and with the variable speed control of the treadmill motor. One advantage of using a treadmill motor is that there is no wiring involved, only placing the controlling electronics where you want them. The only wiring that will be required with this install is a reversing switch. I don't know if this type of adaptation has ever been done, I haven't checked the CNC forum, but I think that this will be a very cheap alternative to the, mill motor go bad situation. Total cost will be, treadmill 55 dollars, two pulleys, one belt. The reversing switch is already on the mill, so will need some short wires. I will attempt to upload some pictures as I watched the video on how to do it. I always like either, way to goes, or raw criticism, they are both appreciated. Robert Brown. Here are some pics., I hope.Attachment 4061Attachment 4062Attachment 4063Attachment 4064

Thanks machiningfool! I've added your Treadmill Motor Adaptation to our Electronics category, as well as to your builder page: machiningfool's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/treadmill-motor-adaptation"><img src="http://www.homemadetools.net/uploads/124509/treadmill-motor-adaptation.jpeg" /></a></div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/treadmill-motor-adaptation">Treadmill Motor Adaptation</a> <span> by <a href="/builder/machiningfool">machiningfool</a></span> </div> <div class="tags">tags: <a href="http://www.homemadetools.net/tag/mill">mill</a>, <a href="http://www.homemadetools.net/tag/motor">motor</a>, <a href="http://www.homemadetools.net/tag/electronics">electronics</a>, <a href="http://www.homemadetools.net/tag/switch">switch</a>, <a href="http://www.homemadetools.net/tag/controller">controller</a></div> </div> </div> </div>

OK, so am I to understand when I post info. on this project in the homemade tool section, it will also be posted automatically in the electronics section? Robert Brown AKA machiningfool

Yes, exactly. Tools you post here get automatically indexed in the encyclopedia, credited to you, and added to your own builder page: machiningfool's homemade tools. Also, threads that win an award such as Tool of the Week or Best Documented Build get moved into the Must Read section.

OK, today I identified the components and removed them from the treadmill, took some closeups so that I know where the wiring connects. I bought two pulleys, cost about 90 at Miller bearings, they had me pick them up at the Martin gears warehouse and while I was there the boss asked me what I was doing and I told him and then I asked since the motor shafts did not have key ways he suggested that he have his machinist put another machine screw 90 degrees from the original in both pulleys for more stability and I was happy about that. He didn't even charge me, I thought that was very nice of him. Included in the following pics. are the components. I am running about a two to one ratio. I will explain later. I am going to have to cut out the original mounting bracket to use to mount the treadmill motor tomorrow. The shafts on the motors were real odd sizes, so tomorrow I will have to bore them out to fit the shafts, might have to pull out my 4 jaw chuck for accuracy. The real challenge is how to affix the motor mount on the original motor, but I will figure that out, I already have some ideas. In posting this project, I hope it is okay to post in bits and pieces along the way of the project so that I don't miss any information. Here are the pics. Also if you have any question, please feel free to ask. Robert Brown AKA machiningfoolAttachment 4065[/ATTACH]Attachment 4066Attachment 4067Attachment 4068Attachment 4069

Boy, I am impressed, you guys are really on top of it, this is a first class forum. Robert Brown AKA machiningfool

Cheers, Bob! Your kind words are very much appreciated. :beer:

Ken

I believe that I read from your other post that you have used treadmill motors a couple different time on other tools in the past. Are you using the control board and power supply from the treadmill for speed control?

I loved seeing DC treadmill motors adapted to get old machines running again. are you at all worried about the differences in where the power is in the different rpm bands? does the treadmill pwm/controller make up for the differences?

Yes, I use the same controller from the treadmill with the same motor so I am assured of a match. I have powered my SouthBend lathe and it sure turns it into a Cadillac of a lathe. In back gear it is amazing how slow and powerful it is. I have powered my 12 inch band saw and am able to slow the blade down for metal cutting. I also made a large sander out of a treadmill and someone asked what do I sand with it, and I said anything I want. I turned a Ryobi mitre saw into a metal cold cut saw by reducing the rpm from 5000 to 900. I have made 40 cuts of 3/16ths thick steel, 10 inches long with a carbide 10 inch wood blade. The trick is the slow rpm. Also there are no sparks. As far as rpm, it is adjusted for the job that I am doing and that is done with the pulley ratio. I also look for a treadmill that has either a knob type speed control or the slide type rather than the push-button type, I feel that I have more control.

As far as power and rpm is concerned, the dc motor has torque at low rpm and since it is adjustable rpm has never been a problem. Some 2.5 hp treadmill motors turn at 7000 rpm, so in that case proper adjustment of pulley sizes would be warranted unless there is some reason to desire 7000 rpm and in that case a 1:1 ratio pulley setup would be used.

Mounting the treadmill motor the way I am doing it has its challenges, because there is no where to secure the mount. I came up with this universal procedure whereby the mount will be secured by stainless T nut straps wrapped around the existing motor and then securing the treadmill motor mount as I will show you in the pictures below. The advantage of this type of install is that it will work for any mill. I had an advantage with this Lagun motor is that the electrical box is cast into the motor casting, so I am using that for stability. Today I bored out the pulleys for the motors and fabricated the mount. I cut out the original mount from the treadmill and sized it to the mill motor and will secure it with T nut straps, I think it will be sturdy enough. The original motor turned at 1825 rpm and I believe this treadmill motor turns at 4800, so I am using a two to one reduction, so I think that will do it, after all, I will have variable speed from the treadmill controller and also the variable speed belt drive on the mill. The Lagun mill was 3 hp and this treadmill motor is 2.25, plenty of power for the way I run my mill. I am not a hotrodder when it comes to milling. By using the original mount from the treadmill, the adjustment design is retained. I am using a 5/8 inch belt and pulleys. The T nut straps were a little difficult to find around Tampa, but I found two around 9 1/2 inch diameter, but they are a little too big, so tomorrow I will fill the gap with some wood planted around the motor to take up the slack. Here are some pics. Robert Brown AKA machiningfoolAttachment 4070Attachment 4071Attachment 4072Attachment 4073

Well, this project went as if I knew what I was doing, unlike some of my other projects. This is the fourth day into the project. The straps worked out well and by using the original mount that came off of the treadmill, it made the adaptation simple. Now all I have to do is reinstall the mill motor into the mill and locate the positions of the controls, so here are some pictures of the treadmill motor installed complete with belt. This installation will work with any Bridgeport type mill. Total cost, pulleys-90.00, belt-10.50, treadmill-60.00, straps-18.00. Two hundred is a lot better than 800.00 to 1200.00, and if this motor goes bad, it's only 150.00. Robert Brown AKA machiningfoolAttachment 4086Attachment 4087Attachment 4088

I like it a lot, nice work! I like your table too a very versitle design.

If you have problems finding T bolt clamps in the future, worm drive clamps (from plumbing supply stores) can be cheaper and daisy chained together if you can't find one that is long enough. There is also strapping used to suspend pipes, it has holes punched in it through out for adjustment. Both options are stronger than one would expect, and pretty inexpensive.

This might be a dumb question, but will the your old AC motor generate voltage by being driven by the DC motor? Or does it only work that way with DC motors?

The only viable clamps for this install is a T nut clamp because they have to be cinched down very tightly, regular radiator clamps would not work they would strip out. As it turned out, the clamps were exactly the correct length. I thought at first they were too long, but they were correct. Also what table were you referring to? Thank you for your interest. Robert Brown AKA machiningfool

No, I don't think so, the 3 phase motor is dead. Thanks, I like questions. Robert Brown-machiningfool

I made a previous statement in a post that, "This install can be adapted to any Bridgeport type mills", well that assumes that on the top of the mill motor there is a stub of a shaft to mount a pulley. On this Lagun, there was. It was for a plastic fan. I think most motors have a fan, so when that is removed there would be a short shaft for a pulley. This is my first attempt at this install, so I don't know about other mills. I forgot to suggest that this type of use for a treadmill motor on a mill would be even easier on the type of mill that is a V belt driven quick change type and not variable speed since the pulleys are already there, just switch the motor. Of course, a new mount would have to be constructed. That would turn a belt driven type mill into a real machine. Robert Brown AKA machiningfool

I always looked at old treadmills as sources for motors and a few other parts. But using the matching controllers is indeed very clever. Thanks for the idea!

Thank you for your statement, I also use the metal out of the stand and have made a stand for a fiberglass roll and a stand for a small outboard motor. Robert Brown- machiningfool

Well I spent all day trying to install the mill motor in the casing with no success. I have done it before, but that was along time ago. I finally watched a video on how to do it and forgot that there is a way to compress the variable speed pulley spring, so I bought some bolts and tomorrow I will begin again. There is little room between the case and pulley to stretch the belt on, so by spreading the pulley apart, It will be easier. Funny, I have done it before without compressing the spring, but I was younger and I had help. Robert Brown-machiningfool

Aha, I figured it out. I have been beating my head against the wall. The way it is done is this, first compress the spring on the lower half of the pulley, then remove the C ring and then the bottom half of the pulley slides off of the shaft, then I take that half of the pulley and set it in the casing under the variable speed belt. Once that is done, the motor, with the top half of the pulley, is lowered into the case. The shaft goes through the lower pulley and then through an inspection hole in the bottom of the case. The C ring is then replaced through the inspection hole, then the two bolts compressing the spring are removed and the installation is complete. I didn't discover this until I compressed the spring with the two bolts and discovered that I could then remove the C ring and the bottom half of the pulley would slide off of the shaft. This is a no sweat install compared to trying to force the belt on without taking the two halves of the pulley apart, whew! I knew there had to be an easier way to do it. Robert Brown-machiningfool

The above post correctly describes the sequence of the install, but I will say, I have been working all day installing the motor, it is not easy, even the prescribed way. First one of the keyways came out when I was lowering the motor and I didn't know it, so when I tried to reinstall the C ring it wouldn't go because the collar was in a bind. I saw something lying on the floor and yes, it was one of the keys, but when I reinstalled it there was no longer a bind and from there on it was fairly easy after having to by a 33.00 set of expansion ring pliers. It is now installed correctly. It would be quite a bit easier with two people, a luxury I don't have. Here are some pictures portraying the install. As it turns out, designing the treadmill motor adaptation was easier then the install of the stock motor on the mill. Thanks for all of the interest, the rest of the adaptation will be coming here shortly. Robert Brown - machiningfoolAttachment 4095Attachment 4096Attachment 4097Attachment 4098Attachment 4099Attachment 4100Attachment 4101

Very interesting. I looked through your u2oob vids and am impressed with you KISS applications. I've been long intrigued by the idea of treadmill motors for small lathe and mill applications. It NEVER would have dawned on me to use the old motor as an adapter like what you are doing on your mill.

I have several questions about the treadmill motors.

Are there better brands or are they like so many things these days where the components are all made by one source and the different treadmill manufacturers all buy the same stuff?

I spent 10yrs as a millwright/mechanic in fruit and vegetable packing making and installing equipment. We used DC motors a lot and they were way more heavy duty looking than the treadmill motors I've seen. So pardon me if I'm a little skeptical. But the stuff we installed also was 5 or 10x's more expensive so I wouldn't be wanting to pay that much unless I could find a deal which I've not been able to find. But there are literally tons of treadmills on Craigslist for cheap and sometimes even free!

So as it seems you've made several conversions I'd like to ask do they stand up? I've seen it said they are way over rated. I can't wait to see how that little motor does on you Lagun.

While I can see it's pretty easy to keep the same controller they don't care about making the electronics tidy and compact. Have you ever messed with buying another controller? I ask because usually the free treadmills have a problem and I suspect it's the controller.

I have had no problems with the conversions that I have made, not one failure, but realize my operation is not a commercial one. When I buy a treadmill of course I run it, if it doesn't make any funny noises, I buy it. I have never had to buy a controller, if ever one fails I suppose I would just go buy another treadmill. They are so cheap, so I don't see buying anything outside of the treadmill package. Now on this installation, since I think possibly that this mill installation will make the treadmill motor work harder than in the treadmill, I am going to put an ammeter on it to see how the motor is doing. This motor is rated continuously at 12 amps and anything above that requires a fan, so while running it, it doesn't go above 12 amps, I should be OK. As far as brands are concerned, once you get them out of the treadmill, they all look pretty much the same to me, I don't worry about it, because If anything fails, and it hasn't, I will just go buy another. There are some differences in the rated RPM and hp. Some can run at 7000 and some at 4800. HP from 1.5 to 3. I am doing this install for under 2 hundred as compared to 1000 to 1500 for either a re wound motor or a new one, so I am willing to take the chance, we shall see, I should have this thing running tomorrow, hopefully. Robert Brown-machiningfool.

Today, I mounted the treadmill motor on the mill and started to organize the controls here are some pictures, thanks to all for your interest in my project. Robert Brown-machiningfoolAttachment 4118Attachment 4119Attachment 4120Attachment 4121Attachment 4122

Thanks for all the info Robert. Especially the >$200, lets me know what to gauge what you have into the project.
I don't see the emoticon for eating popcorn as in I'll be watching for updates how it goes. I've got a mill drill that is a pain to change speeds on and changing over to this kind of drive would be worthwhile.

Well, I won't be eating popcorn for a while. I got it running today, but evidently I chose the wrong pulley ratio. It barely turns, so what I am going to do tomorrow is go back to the original pulley on the treadmill motor. It is about 1 1/2 inches, then go to a 12 inch on the mill motor. The belt on the treadmill is a flat belt, so probably less drag than the V belt I used, so I will also go back to a flat belt also. There is more drag caused by the variable speed pulley system on the mill than I thought. The treadmill motor is a high speed motor, probably about 5 to 7 thousand, so I am going to have to put the original pulley/flywheel back on and try to raise the RPM. Thanks for everyone's interest and I will just keep on keeping on. Robert Brown machiningfool.

If you read the previous post, I had trouble getting the treadmill motor rpm up, so I changed the ratio from 2 to 1, to 7 to 1. I cut the original treadmill pulley off of the flywheel and am using the same type of belt that goes on the treadmill, just larger, 38 inches. Since I couldn't find a 9 inch pulley with the same v arrangement of the treadmill pulley, I cut the 5/8 inch V belt and glued it around the 8 inch pulley for the original installation, and will run the micro v belt on the rubber flat surface. It worked on my lathe. I just ordered the belt, will be here tomorrow. The number of the belt is a Gates number==380J8. 38 meaning the length O.D. J, meaning a micro poly-groove V belt and the 8 meaning 8 grooves. Hopefully this arrangement will bring up the rpm on the treadmill motor. I am posting some pictures of how I am arranging the controls. I placed the controls close enough to the motor so that I don't have to cut any wires, they feed right into the top of the box. The long wires, if they will fit, will be coiled up in the box, also not having to be cut, if not I will cut them. I also took a shot of how I mounted the control box on the mill. I used the two bolt holes that was used for the inspection hole cover, worked out well. Now you might notice somewhere that it says Bridgeport, so the base is Bridgeport and the head is Lagun. I bought just the base at one time with no head because it was only 500.00 and later found the Lagun head at a machine shop that was all apart and they gave up on it, so I bought it, rebuilt it and that is what you see on the Bridgeport base. Next post will be the results of the new belt and pulley system, running correctly, I hope. Robert Brown-machiningfoolAttachment 4127Attachment 4128Attachment 4129Attachment 4130

:popcorn:[url] Well, the original 1 1/4 inch pulley on the treadmill motor did it. With a 1:7 ratio it now has enough power for the mill. I powered it up today as you will see in the video and it runs fine. Spindle speed is 2000, can go higher, but motor is running cool at that speed. That is in high speed gear also runs smooth in low speed. Here are some pictures of the pulleys, I am using the same type belt as the original treadmill only larger 38 inches. I took the 5/8ths inch v belt, cut and wrapped around the large pulley and glued it with CA. The belt runs nicely on it. I am also going to try to upload a video, we shall see. Robert Brown machining fool.Attachment 4153Attachment 4154[video=youtube;jcKwKfgV961]https://www.youtube.com/watch?v=jcKwKfgV96I

Here are some pictures of the control box buttoned up. The reverse switch works. There are some treadmill motors have their brushes at an angle for only one direction and some are at 90 degrees. The 90 degree models should be more favorable for reversing. The angled brush type might work just as well, I don't know. Mine happened to be at 90 degrees. So, except for painting the box and wrapping some motor wires, this project is finished. Robert Brown machiningfoolAttachment 4167Attachment 4168

I thought that I would share this little tip with you, it has to do with identifying the wires on a 3-phase reversing switch. There I was staring at six wires on the 3-phase reversing switch and without a wiring diagram. I am now trying to convert this switch to reverse a treadmill motor, only 4 wires are involved, two power and two for the motor. I reasoned that if I could identify two wires that, when a continuity meter is put across them, no register would be made when I switched from neutral to forward and then to reverse. Those two would be my power wires. I found them and then put a 9-volt battery across the two wires and then hunted two other wires that registered 9 volts , either Positive or negative on the meter when the switch was turned to one side or the other. Then when I switched the switch to reverse, the meter would read the opposite of the first reading, then I knew that I had the motor wires. Surprisingly enough, it worked, I now have a DC reversing switch from an AC 3- phase switch. If you have any questions, feel free to ask. One could also make a reversing switch from a double pole, double throw switch, but I already had this switch already mounted. Robert Brown machiningfool

This thread has been moved to the Must Read subforum. Congrats (and thanks) to Bob for making such a valuable contribution!

Thanks Ken, I appreciate it. I was attempting to clean out my garage and throw away things I thought I would never use, but I am having a hard time since I always think I might use that item someday. While attempting to throw things away, I found one of those things that I previously didn't throw away, an ammeter. Today I think I will attempt to install the ammeter in order to see exactly what the draw in amps are drawn from my treadmill motor install, might be interesting. Bob. OK, continuing this thread, I installed the ammeter, but first consulted a youtube video, because it has been a long time since I installed one. When I found the ammeter in my garage, I also found the shunt that went with it. This is the kind of ammeter that requires a shunt. I am including the video that I watched and is very accurate on how to do it, better than I could explain. Also two pictures of the shunt and ammeter installed. The ammeter shows 6 amps running at full speed, way less than I thought. This treadmill motor can run at 12 amps continuously without cooling, well within the range for continuous running without a fan. I am lucky enough to have the motor in the path of my room fan. Bob.https://www.youtube.com/watch?v=7MGed7WKwAAAttachment 4181Attachment 4182

My recollection (it's been 13 years) is that the ammeter I installed in the RV also required an external shunt, one terminal of which supplied the voltmeter. If one wired it backwards, absolutely nothing worked. Don't ask how I know that! :lol:

Ken

I learned the hard way along time ago. Before I knew how to use a multimeter, I thought I would see how many amps a circuit was pulling, so I put the probes in parallel and blew the amps portion of the meter. I then learned that an ammeter is hooked in series and the voltmeter is in parallel. The guy in the video, I believe explained the ammeter circuit well. Bob.

I wanted to add to the amperage test, the 6 amps was in full throttle low speed and when I shifted to high speed, it pulled 8 amps, still well below the continuous operation level. In high speed, the spindle turned at 2000 rpm and could be increased with the variable speed belt system in the mill, if I needed it. So, there you go. Bob

Here is one more post, I think, to show what the final product looks like complete with the ammeter. The last picture is the beginning of a project, a CNC router, that I started a few years back. The building of my house got in the way, so I will begin again here shortly. I have everything for the project, except for 2 drives and rails for the table. This will be the type that the table moves and not a gantry. It is going to be 48 inches of travel, X and Y and 8 inches Z. I am using Adept type robot arms for all movements. I purchased them because everything is already installed, ball screws, rails and servos, not steppers. They are very fast in movement as they were designed for rapid movement for placing items. I am using KSI labs Centipede board and Granite drives. Bob.Attachment 4183Attachment 4184Attachment 4185

I am a little slow to remember sometimes and when I was mentioning what adaptations that I had made using treadmill motors, I forgot to tell you about an outboard motor that I had converted. It was a Chrysler 8 horse motor, took the gas motor out and installed a 2.5 hp treadmill motor, the transmission had reverse, so I didn't have to reverse the motor. It worked fine until I got to the end of the cord, about 50 ft. from the dock and then it pulled out of the receptacle. Obviously kidding, the original design was to be a hybrid, powered by a Honda generator. Would have been better designed to have the DC motor a 12 or 24 volt motor, or just buy a trolling motor. It is obvious that I have too much time on my hands. Bob.https://www.youtube.com/watch?v=WKD4kIo2Hq4Attachment 4304Attachment 4305

Hi Robert,
If you get DC motors without a speed controller you might want to have a look at 'The Aussie Shed", his is very simple, cost effective and works great.