Motor for PM-45 Hand Crank?

[Ray C]

All,

Can someone recommend a motor to replace the manual hand-crank on a PM-45 mill? BTW: Not interested in converting to CNC -just adding this as a convenience.


Thanks

Ray

EDIT: BTW: I'm talking about the head/column crank -not the table cranks.

 

[GaryK]

All,

Can someone recommend a motor to replace the manual hand-crank on a PM-45 mill? BTW: Not interested in converting to CNC -just adding this as a convenience.


Thanks

Ray

EDIT: BTW: I'm talking about the head/column crank -not the table cranks.

Look for a gear head motor. With a direct connect that's the only way you can get the torque required not to mention the slower speed. Find something with the RPM you want and then worry about torque.
To find the torque you need, use a torque wrench to see how much is required to crank it up, and I would then double it just to be safe. I have a PM-45M on order so I might be interested in doing the same thing.

Here's a place that has some. This Looks like it can do the job. Check the torque on your machine though.

Gary

 

[sanddan]

I added a gear motor to my mill using a 1/4 hp motor at I think 170 rpm. I used timing sprockets and belt to connect the motor to the crank shaft and a DC motor control card mounted in a box to the back of the column. I also use 2 gas springs to counter balance the head. At 70 in-lbs torque it will move the head without the springs but you get better control with them. The controller has adjustable speed but for some reason mine isn't working correctly.


200 to 250 RPM would be about right using the springs and having the speed adjust. For large movements use top speed and for fine movements you could slow it down. It is way better than cranking that handle.

 

[jgedde]

What do you mean "better control" with the gas springs? Can you elaborate? I've been wondering if I should add them.

I'm currently making a new Z axis gib for my PM-45 (the fit of the original isn't great) from G2 Pearlitic Dura-Bar cast iron. My mill has always suffered from some amount of stick-slip and droop when trying to use the Z axis crank as a replacement for the knee.

What are the pertinent specs on the gas springs you used?

Thanks,
John

 

[sanddan]

John,

Without springs the motor could move the head but seemed to work harder going up than down which makes sense. With one spring the motor runs up and down similarly but going down will tend to coast somewhat. This is only an issue when trying to move the head a small distance. With 2 springs, the up and down movement is the same and the head stops as soon as the motor switch is stopped. The springs are 100 lbs each and are SPD p/n GSNI-3610-100. I made two brackets to mount the spring and installed it at the full head height so it matched the springs full stroke. The "stick-slip" you refer to, was that when going down? Mine did that until adding the second spring.

Dan

 

[bvd1940]

All,

Can someone recommend a motor to replace the manual hand-crank on a PM-45 mill? BTW: Not interested in converting to CNC -just adding this as a convenience.


Thanks

Ray

EDIT: BTW: I'm talking about the head/column crank -not the table cranks.

:thinking:
Find a battery drill or a AC drill that is cheap, make a permanent mount to fit around the stub in the column wire in a two way switch and mount in a convenient place & your good to go.:thinking:
Battery drills are a dime a dozen with no battery, power supplys are easy and cheap to make or just get one off Fleabay)

 

[outsider347]

bvd1940

Do you use the the drill motor alone, or with the planetary gear reduction?
tks

 

[bvd1940]

You could use a low geared bat. drill complete if you want, also if you wanted faster or slower you could add timing pulley or sprockets & chain.
Ifin I was doing it I would just make a bracket with a saddle and straps for the drill, a power supply & a 2 way switch.

 

[gotmax59]

I just put one on my pm45. I used a wheel chair motor on 12 volts, with a 10 amp cheap H F battery charger for a battery. I mounted the charger on the side of the stand in the back. I used timing pulleys and a belt. It works very well . I will try to get some time and post some pics. I have about 160.00 in the hole set up.

 

[gotmax59]