Thread: Motor size

The max speed would probably be the only difference between the smaller and larger motors, from what I've read the length of the motor also comes into play with shorter motors running faster than longer motors, as to how much I couldn't say.

Although looking at the youtube video (I'm assuming this is the machine?)
BIJOU CREEK's Stock Duplication Auto mode - YouTube

It runs that slow that you wouldn't need to worry about the speed of the stepper motors.



{EDIT}
I was going to suggest a geared DC motor but having a look again its 6RPM on the rotary axis, unless you can find a high reduction dc motor.

Hi Ch4iS.
Thanks for the reply but my concern is will it slow down when it comes to a deeper cut with a smaller motor. What size would you recomend for this job? Yes you had the right video.
I think the machine would be easy to make and if I did it properly then I could CNC it later.(IF I learn to progran the thing) For now the slow speed should be easy to achive with the stepper motor rather than a motor and reduction box.
Kim

Hi BigStick

The 387 inch pound motors that I first put on my machine were strong enough that they could have pulled my car along without too much problem.

The thing that will make the difference with the depth of cut is the strength of the spindle (router). Go for the biggest spindle that you can reasonably afford and the depth of cut will take care of itself.

Thanks Bob.
387 It is then.
Kim

Ch4is has these motors on special right now.

It's a hard one to say which size would be suitable, but I reckon a 387 as bob suggested would do the job, if you have any dramas you could always gear it down with some belts and pulleys.


I did some searching of the chinese sites and found these high reduction geared DC motors, although small motors they might be worth considering, the higher reduction motors have similar torque ratings of the nema 34 motors I sell.

gear dc motor - GoodLuckBuy.com


{EDIT}
Also avaliable is Oatley in VIC?

Oatley Electronics

Some beefier geared motors but you'd probably need a speed controller to run the motors as slow as you need them.

Hi guys.
Ch4is can you give me some detail on where to buy these and some drivers or whatever I need to get going.
I tried all the places around here (Maitland) and nobody can help.
Do you post?
Kim

Yea you won't have any luck for stepper motors in most retail outlets, hobby shops and jaycar might have tiny motors but nothing which is usable in a cnc environment.

You can buy from myself or homanndesigns we can both ship Australia Wide (Have to give him a mention since he's a forum sponsor )

AusXmods
Homann Designs


If you buy from me you'll need (My suggestions for a 387 single axis)
Stepper Motor - Nema 24 387 oz-in
Driver - Gecko G251 (Or a G540 for a 4 axis setup, no breakout board needed with the G540)
Breakout Board - CNC4PC C10 Breakout Board
Power Supply - 48V 7.3A PSU
+ Wiring & Misc


It'll cost a large chunk of change to purchase and will be more complex to setup and run that's why I'd suggest looking to geared dc motors.

It's OK Chris, Kim has far too much money anyway so he needs to get rid of some of it as other wise the weight of his wallet will drag him down and he'll drown in a sea of moolah.

Thanks Guys.
I have one very low geard motor and didnt consider it but it might be the way to go for this job.
I will dig it out and see if it will do the job. Then I will only need one more and that might be the way to go.
Kim

Just thought of another source of gear motors if the one you have doesn't work out.

Windscreen wiper motors, low rpm's and high torque, should be able to source them for $10-20 from wreckers or ebay.

Originally Posted by Ch4iS

Just thought of another source of gear motors if the one you have doesn't work out.

Windscreen wiper motors, low rpm's and high torque, should be able to source them for $10-20 from wreckers or ebay.

Do they have gears inside the housing?

Originally Posted by jlabs1988

Do they have gears inside the housing?

Looks to be a worm gear setup.

When I was searching there was also suggestion of a PWM controller to run them at lower RPM's for a spit.

Hi Guys.
I know where there is a electric golf buggy and they have a windscreen type motor and a chain drive.
Looks like I will be geting out of this CHEEEEEPER than I expected
Kim