Motor head help

[Wildmine]

Hello there!
I have three DC motors i want to use for a CNC machine, the only problem is the heads is not how i want them.
They look like this:
**broken link removed**
But i was thinking of using threaded rods to move the axis:

Do anyone have any other ideas on how i can move the axis?

 

[audioguru]

The gear on the motor is called a "pinion", not an axis. The threaded rod is called a "rack". Cars use a rack and pinion for steering.
There are tools called "pinion removers". I have never seen one.

If you quickly heat the pinion before the motor shaft gets hot then the pinion expands and will slide off the shaft.

 

[Wildmine]

Thanks, but how would i connect a rack to it then then?

 

[atferrari]

The gear on the motor is called a "pinion", not an axis. The threaded rod is called a "rack". Cars use a rack and pinion for steering.
There are tools called "pinion removers". I have never seen one.

If you quickly heat the pinion before the motor shaft gets hot then the pinion expands and will slide off the shaft.

If you ask someone to do this for you, make sure he really knows how. I got one stepper destroyed by a good willing mechanic that had no actual idea of how to do it.

BTW, are you sure that you could do some serious CNC with those mottors? Think of steppers.

A picture of what rack & pinion is in the simplest form.

 

[alec_t]

Can you find a larger gear to attach to the screwed rod and mesh with the pinion? You may well need reduction gearing anyway.

 

[JimB]

This is a mechanical problem rather than electronic.

How are you intending to use the screwed rod?
As a "rack" ?
or
as a "leadscrew" with a nut which provides the motion to the CNC machine axis?

Using it as a rack is probably a very bad idea.

Using it as a leadscrew should be ok, but with that motor you will need a reduction gearbox between the output of the motor and the leadscrew.
As already mentioned, you will probably be better off using a stepper motor to directly drive the leadscrew.

MVH

JimB

 

[audioguru]

The servos in my small radio controlled airplanes use gears then a rack and pinion.

 

[Wildmine]

I like your idea atferarri, but the only problem is that it isnt straight as you can see in my picture

 

[shortbus=]

The motor looks like a brushed DC motor. How, when using it for a CNC, are you going to control position? Steppers are normally used for DIY CNC, because they can be controlled to a small fraction of rotation.

 

[atferrari]

I like your idea atferarri, but the only problem is that it isnt straight as you can see in my picture

Of course, I am showing something mentioned by somebody else. Yours is just a threaded rod not to be used as a rack.

Fisrt, as suggested before, Google for "leadscrew", then, when you understand it, google for "backlash" and finally google for "spring-loaded nuts" / "balls screw" (think of LOT of $$$ here).

Once done you will be able to answer the basics of your own post and make a decision.

The next day, you will be googling for "steppers" and you will start to smile in relax. Old printers / plotters are nice.

Buena suerte

 

[ClydeCrashKop]

You will find too much info at https://www.cnczone.com/forums