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 machiningfool
Last edited by machiningfool; Jul 29, 2015 at 03:03 PM.
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 machiningfool
Last edited by machiningfool; Jul 30, 2015 at 07:06 PM.
jere (Jul 30, 2015), Paul Jones (Jul 31, 2015)
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
Last edited by machiningfool; Jul 31, 2015 at 07:09 AM.
No, I don't think so, the 3 phase motor is dead. Thanks, I like questions. Robert Brown-machiningfool
Last edited by machiningfool; Jul 31, 2015 at 07:11 AM.
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
Last edited by machiningfool; Jul 30, 2015 at 07:02 PM.
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
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