Thread: power feed on mill/drill

Can you please tell me what is the problem with the windscreen wiper motor's worm drive, Mike?
I was thinking of using one on my mill-drill.
Maybe bigger ones are available? from trucks?

Jordan

hi JordanThe worm drive appears to be designed to function in one direction , it tends to chatter if you reverse the direction of travel. It also doesnt have a very fast max. travel speed . Maybe the truck wiper motor would perform better . The motor I used is a small thing from a Falcon . Mike

PS one idea worth considering is those 12V starter motors the model aircraft guys use to start their engines, you hold the motor against the propeller spinner . link

12 Volt 12V DC RC Plane Boat Nitro Engine Starter Motor - Brand New in Box | eBay


http://www.ebay.com.au/itm/12v-START...item2eb8c1e2aa

Thanks MIke.
The wiper motor has a built in gearbox to slow down the output shaft, that the r/c starter doesn't have, so it's not immediately attractive.
Good point about the reversing - not something a wiper motor never needs to do.

Jordan

Hi Mike,
Would it be possible to add something like the tumbler reverse on a lathe so the motor turns the same way all the time?
Also there is a forum member that runs his 12Vdc motor at 24VDC for fast jog(if memory serves which often it doesn't)

I don't think either of those motors would be designed with long life(in hours) or long duty cycles in mind.

Cordless drill might be the go if you add more gearing. If it doesn't work you still have a cordless drill

On another note. Is PWM the best way to go on powerfeed? Wont any change in "gib drag"* or the cutter load result in larger speed changes than some other method of control? Granted I have little idea what I am talking about, just thinking aloud.

Stuart

*that's my term for a mill like mine with ways that are loose in the middle and tight at the ends.

Mike, Stepper motors are the go. My son has built them onto his mill and lathe. All from motors removed from other products along with the control cards. May need a bit of electronics knowledge though.
Regards,
John

Hi John

If I was going to use a stepper motor, I might as well go all the way and go CNC . But It is worth investigating , thanks

Stuart . I think a Ride on mower or quad bike 12V starter motor would last for a long time , these are aperm. magnet type motor I would think ? In a mill power feed situation, the load on those type of motor would be rather small compared to turning over a internal combustion engine .

12v STARTER MOTOR 110cc Chinese Quad, Pit dirt bike Buggy 50cc - 125cc Thumpstar | eBay


The drawback is, you have to make a reduction gear , and some type of clutch to disengage it eg for manual hand wheel feeding . Not sure about PWM and your comments - but some PWM controllers have a reverse function so that is a handy way to reverse . I haven't noticed any change in speed with load when using the wiper motor , the PWM does a good job in that regard. Mike

I made a power feed for mt HM-45 a couple of years ago. I used a 24VDC inline gearmotor. I made dog clutch to engage/disengage the drive, used a speed control and a big arsed 24VDC power supply to drive it. Work well. I started a post on here as I built it. I can try and find it if you like.
I considered, steppers, high voltage DC's and settled on the 24V route.
You will need a motor thats has a max speed of about 250 rpm ( for high speed traverse ) with normal speed range of 0 to 200 rpm. Can't remember what sort of power or torque is needed. If you find the specs of a comercial power feed, that will give you clues.
Steve

Originally Posted by Sterob

I made a power feed for mt HM-45 a couple of years ago. I used a 24VDC inline gearmotor. I made dog clutch to engage/disengage the drive, used a speed control and a big arsed 24VDC power supply to drive it. Work well. I started a post on here as I built it. I can try and find it if you like.
I considered, steppers, high voltage DC's and settled on the 24V route.
You will need a motor thats has a max speed of about 250 rpm ( for high speed traverse ) with normal speed range of 0 to 200 rpm. Can't remember what sort of power or torque is needed. If you find the specs of a comercial power feed, that will give you clues.
Steve

That is useful info. Would a friction clutch be OK ? The Harrison lathe uses a spring loaded friction clutch with bronze faces . For the power fed on the mill, you could make up a spring loaded cam device that engages the clutch .

Originally Posted by morrisman

That is useful info. Would a friction clutch be OK ? The Harrison lathe uses a spring loaded friction clutch with bronze faces . For the power fed on the mill, you could make up a spring loaded cam device that engages the clutch .

I don't know if a friction arrangement would work or not...might be worth a try. It needs a fair bit of torque to drive the table. I didn't consider that. I just made a castellated drive to fit the table.

I was thinking about a 12v geared motor from Jaycar. 12V DC Reversible Gearhead Motors - 160RPM - Jaycar Electronics

At $40 the biggest cost would be a power supply. Needs up to 14 Amp. The torque is rated at 55kg at 55RPM. I am not sure what this figure means to be honest. I have not followed this up yet because I am busy getting the mill setup. This would be a lot more simple than a stepper motor to set up and I am not sure that there would be any advantage to a stepper motor unless CNC operation was being considered.

I spend enough time setting stuff up without adding to the complexity unless it provides a definite benefit. I would only have a power feed on the X axis to provide a consistent feed rate, and because I love standing back watching the lathe on power feed.

Dean

Check out these blokes for motors too:

http://secure.oatleyelectronics.com/...41dea7b2c22915

It's been a while since I took a wiper motor apart but I think the chatter comes from the way the worm is set up. In a rotary table or such like the worm is on eccentrics so that backlash can be eliminated. This is all from a vague memory but I think that wiper worm drives are pre-loaded in the drive direction with a spring. It means they don't need the eccentrics but the trade off is that they are one way. If you were prepared to muck around a bit and maybe even make up a new housing you may find you are able to mount the worm in such a way that the spring can be replaced by a rigid element, meaning that it could drive both ways without chatter.

A thought.

Michael

Originally Posted by Oldneweng

I was thinking about a 12v geared motor from Jaycar. 12V DC Reversible Gearhead Motors - 160RPM - Jaycar Electronics
Dean

Nope, too small and too slow. Look at the dimensions. Something from Oakley's would be closer. Something 24V, ~400W and a max speed of 250 rpm, or a little higher would be ideal (IMHO )
A 12V motor will draw too much current and make finding a power supply harder.

Originally Posted by Sterob

Nope, too small and too slow. Look at the dimensions. Something from Oakley's would be closer. Something 24V, ~400W and a max speed of 250 rpm, or a little higher would be ideal (IMHO )
A 12V motor will draw too much current and make finding a power supply harder.

Ok. Thanks for that info. I have no idea at this stage so will accept your comments as a voice of experience.

Dean