[Chaps]

Angled brushes--correct. I found a video by Hoss where he tested a treadmill motor that seems to have the same problem--decreased RPM and lots of sparks from the brushes in CCW direction. I did not see a fix in the video or an alternative.

[mrcodewiz]

No, probably not. The one I picked up runs fine in either direction. I don't know what your needs are but if you don't want to look for one that has straight brushes, you could always mount it upside down on the side of the head. A mill is still pretty useful even without reverse.

[RX-Heven]

I opted for a treadmill motor. I picked this one up for about $70 I think but as Hoss' stuff points out there is some additional work to make mounts for them. There seem to be a lot of treadmill motors out there that would work.

I'm interested in your motor solution since you say this treadmill motor you have has straight brushes and will work in reverse, has good torque and rpm.

Do you have a model number or source where it came from?

[mrcodewiz]

Here is one although its a bit more than I paid. Wouldn't hurt to try making a lower offer

DC M-285375 2.80 HP Treadmill Duty 2.25 hp Cont 110 VDC - eBay (item 140505922734 end time Mar-28-11 13:24:52 PDT)

[mrcodewiz]

Looks like they used them on Reebok/Sears treadmills too

Pro Form Reebok Sears Treadmill Motor Part 286075 - eBay (item 180606809871 end time Mar-30-11 13:45:31 PDT)


I like these because they have a fan built into the shaft on the back end of the motor. It sucks air from the bottom to the top. It would be nice if it blew air from the top down. It may be possible but I haven't tried to reverse the fan blades yet.

[Maglin]

Some brushwork might be in order for a CW only motor that has straight brushes and not angled ones. Like a little chamfer on both edges. Easily done on a stone by hand. I actually just looked on craigslist for busted treadmills and found one that had the walking belt tore up. It was still almost new. Was a Pro-Form but the motor isn't the best quality but would still get the job done.

Really the only way I see to be able to reverse would be with a switch. Pretty much just need to reverse the +/- wires to the motor and it's going the other direction. The controllers are built for one direction as far as I can tell so it would have to be inline after the controller. It was what I had planned on doing. I'm sure you could find a special relay or sorts that would do the same thing and be able to change direction with Mach with a 0-10v output. I never looked into that far so I don't know of any electrical switches or relays that you could do it with for Mach control. Ops sorry wrong info I put here. You would need a special 4 pole switch but still ensure it's 50A rating and shouldn't run much over $10 for it.

[paulsv]

mrcodewiz-

What requiired you to use taller mounts- the shaft length?

Also, what are you using for a controller?

[mrcodewiz]

...

Really the only way I see to be able to reverse would be with a switch. Pretty much just need to reverse the +/- wires to the motor and it's going the other direction. The controllers are built for one direction as far as I can tell so it would have to be inline after the controller. It was what I had planned on doing. I'm sure you could find a special relay or sorts that would do the same thing and be able to change direction with Mach with a 0-10v output. I never looked into that far so I don't know of any electrical switches or relays that you could do it with for Mach control. Ops sorry wrong info I put here. You would need a special 4 pole switch but still ensure it's 50A rating and shouldn't run much over $10 for it.
...

The G0704s alread have a reversing switch in the control box. I would be curious to know what people do through Mach though. I am using one of Keling's C11 boards which has the 0-10v control. I would like to know how to make it reversible.

mrcodewiz-

What requiired you to use taller mounts- the shaft length?

Also, what are you using for a controller?

Yes, the shaft is pretty long and I didn't want to cut it down. I am using the KBMM-125 but mostly out of frustration. I went through 2 motors and while I was waiting on the 3rd I just wanted to eliminate all of the electrical demons in these things so i bought a new controller and the treadmill motor. You could probably get by with the stock controller if you swapped out the HP resistor. The KBMM is just nice because it has inline fuse holders for both AC and DC.

You will also need to get in there and do a little rewiring because the way it is from the factory, the AC line passes through the board that controls the RPM readout and when you put a motor on that draws more amps it will start to smoke that board. I split the AC line off and ran one to the RPM board and the other to the controller.

[paulsv]

What is the need for a reversing spindle? Tapping? Left hand drill bits? I've never used reverse yet on my mill.

[pete from TN]

I would not hesitate to put a DC motor on one of those mills if my machine was suffering from these motor issues. It is a simple setup and has good torque and is relatively cheap. Mine would spin in either direction too so not sure about all of the treadmill motors obviously. I got mine from the Surplus center years ago. Might check there for a decent DC motor and controller. The controllers can be a bit expensive tho.. Definitely would want reversing for tapping or just if you have a funky cutter like my homemade fly cutter that could spin either way. Tapping is the main attraction tho... peace

Pete

[TerraWombat]

I've used a revering spindle to power tap aluminum many, many times.

[Starleper1]

That's really the only reason for a reversing spindle.... Tapping. Other than a left hand drill but how often does anyone use that?

[RX-Heven]

The KBMM is just nice because it has inline fuse holders for both AC and DC.

Well I bought that motor and am in the process of ordering a KBMM-125 and a heat sink. Which of these resistors will I need? I'm pretty sure it is either one of the last two, just not sure which one would be better. The treadmill motor I bought is listed as:
2.8 HP @ 130VDC
2.25 HP Cont. Duty @ 110VDC
HORSEPOWER RESISTORS

You will also need to get in there and do a little rewiring because the way it is from the factory, the AC line passes through the board that controls the RPM readout and when you put a motor on that draws more amps it will start to smoke that board. I split the AC line off and ran one to the RPM board and the other to the controller.

How do you split the AC line off?
Will I need different fuses or anything else to get this combo up and running properly?

Hope you don't mind me riding your coattails and (most likely to continue) picking your brain on the matter... I'm an ignoramous in regards to electrical speak.

What is the need for a reversing spindle? Tapping?

After tapping by hand for years and years, and now having gotten used to doing it on the mill, there is NO going back.

[mrcodewiz]

Well I bought that motor and am in the process of ordering a KBMM-125 and a heat sink. Which of these resistors will I need? I'm pretty sure it is either one of the last two, just not sure which one would be better. The treadmill motor I bought is listed as:
2.8 HP @ 130VDC
2.25 HP Cont. Duty @ 110VDC
HORSEPOWER RESISTORS

How do you split the AC line off?
Will I need different fuses or anything else to get this combo up and running properly?

Hope you don't mind me riding your coattails and (most likely to continue) picking your brain on the matter... I'm an ignoramous in regards to electrical speak.

After tapping by hand for years and years, and now having gotten used to doing it on the mill, there is NO going back.

You need the last one (1.5 HP). While you are at it, you might as well order a 3/4 horse one so when you get your replacement grizzly motor you can have that as a backup should you ever need it. You will also need the KB-9861 heatsink (see my album referenced below to see what it looks like). For fuses, you will use 25A ceramics for both AC and DC for that motor.

I wrote up a quick PDF that explains where I ran all of the wires and attached it to this post. It lists each of the main components' (AC in, speed controller, reverse switch, power switch, and main board) connections and where they connect to. I also put up some pictures in this album:

KBMM pictures by mrcodewiz - Photobucket

I am not an electrician either. I just sort of traced the wires back to determine how to isolate the rpm board from the ac that feeds to the controller. Most other connections I left alone because the functionality of the board depended on it. There may be other better ways to do it but it seems to be working for me. And look how much prettier this KB piece is than the board that came with the mill.

[Maglin]

If tapping is the only reason for reverse you can do without it. Their is reversing tapping heads that don't require reverse. They are a bit more expensive than the compression/tension tapping heads but not by a large margin. I know Tormach sells one on their site but I'm not to sure if it's as versatile as their compression/tension heads.

[RX-Heven]

You need the last one (1.5 HP)....
I wrote up a quick PDF that explains where I ran all of the wires....
I also put up some pictures....

:banana:

[Johann ohnesorg]

Hy there,
Whatever you do with the KB electronics motor contoller, add a heat sink plus heat sink compound glued to the back. It has two bolt lugs for exactly that and force cool the motor driver heat sink.
Over here in Germany, many people get rid of the DC motor and switch to three phase phase plus a VFD. More torque, wide RPM range. After that mod, it´s an even better machine.
One could also think about the Sieg X3 motor plus the X3 driver board and adapt it, there are little to no complains about that drive. Even better, because the X3 drive is a brushless DC motor and Grizzly has it in stock for the X3 because they also sell that one. I think Keling electronics also sells it here on CNCzone.

Cheers,
Johann

[mrcodewiz]

Hmm...I did not add any thermal paste between the controller and heat sink. Maybe I will go back and do that.

[TerraWombat]

Yea, the thermal conductivity of air is pretty poor

[Johann ohnesorg]

Take a look between the SCR and the mount, too. If it´s a chinese drive it may come dry. KB has heatsink compound there. If you find something like a plastic washer leave it where it is, it´s silicon rubber, both an insulator and a conductor of heat.