Power feed motor suggestions?

[websterz]

I want to uncouple the leadscrew on my 7x12 from the gear train and run the power feed from a separate motor. I don't thread and want a variable power feed. I am not sure how much torque I will need, I just know I want something in a 12VDC gear motor that I can run on a PWM motor control. Any help would be appreciated. 

Oh yeah, the physically smaller the motor the better. 

[mklotz]

Automotive window or windshield (windscreen) wiper motor?

12V electric screwdriver?  (I use one as a crude power feed on my Unimat.)

[John Hill]

The hobby shops sell 12V DC motors and matching planetary gear reduction boxes (same format as a power screw driver).  As well as the car windscreen, etc, motors I would be looking at knackered battery drills many of which are scrapped because the battery is shot but usually the drill itself is in good order and only needs a couple of wires to your DC supply.

One clear advantage of the windscreen wiper motor is that they are already highly geared down usually via a worm and wheel.

[John Rudd]

I'm currently adding a power feed to my mini mill using a wiper motor from a Ford Fiesta/Escort....I'm using a Velleman pwm controller built form a kit to provide speed control....


I'll add some snaps later

[Weston Bye]

I just added a Nema 23 stepper motor to feed my Sherline lathe.  That, a Geckkodrive controller and a 555 variable oscillator completes the package.  Though more pricey than a DC motor and PWM, the feedrates are rock solid stable unless the load is greater than the stepping torque.  A DC motor will vary in speed with even subtle changes in load, unless operating with some sort of feedback.

The stepper feed on my lathe is part of a larger electronic threading project, but I am sure that the power feed will see more use in ordinary turning than in threading.  I love it!

[cedge]

I have an independent power feed on my C4 lathe and wouldn't want to give it up. It was the first ting I transferred from my 7x14 Micromark, when I upgraded.  I can't really make a recommendation as to what motor and controller you'll want, but I can recommend a way to mount it.

I originally mounted the gear motor directly to the end of the lead screw and found that the lead screw picked up vibration from the gear reduction. It sometimes hit a harmonic that left marks on the work piece. I happened to have a couple of timing pulleys in my junk box that had been there forever, so I began to experiment. These are similar to the cleated kind used to drive the mini lathe,

The final mount required an extension on the end of the lead screw to accept one of the pulleys. I then made up a flat with an adjustable slot and mounted the motor to this so the motor tucked behind the back of the lathe, below the ways. In effect, the whole thing wraps around the end of the machine and is out of the way of things. The belt tension is adjusted by sliding the motor and bracket. No more vibration problems since the belt isolates the motor from the screw. (Note:.... the extra shaft length was left to allow the addition of a hand wheel if desired. Quite handy at times.)

Steve