[cncadmin]

I started my Mill to CNC converstion. Here is a pic of the parts

[CNCnUtZ]

Why not go with direct drive, and turn you some flexable disk couplings ?

[cncadmin]

Because of the motor being in the way.

[cncadmin]

Is that how you did it?

[CNCnUtZ]

Yeah, I mounted them on roughly 2-1/2"x 0.50" Al standoffs, to accomodate the couplings, directly to the saddle and table.
The z axis, I mounted off to the right of the column utilizing the same standoffs.

I could have used some old motor mounts that came with some NSK ballscrew assemblies, but opted not to becuase they were too long, and I didnt want to cut them(might find a use for them in the future)

I was just wondering why you decided to go with what looks like(cant really tell from the pic) to be a 4:3 ratio on 20 TPI leadscrews that come with the MIcromark mill?

Seems it would be pretty slow using steppers, and you would get very low rapids with it(alot of torque though)

If you run your motors at a higher voltage than specified, youll not lose much torque anyway.

IMO a stepper system really has no need for a gear reduction.......this is best used for a servo system where you have >1000 RPM motors.

Just my opinion though.
And Im ,by no means, a pro at this stuff.............just an addicted hobbiest!

[cncadmin]

I'm really want the torque, and I plan on using 10 tpi ballscrews. The pulley's are used to allow me to mount them off to the side of the bed. I was doing to go the direct route, but I did'nt want the NEMA 34 steppers in the way of the bed. I got the Idea from a website that converted the same machine as mine.

[cncadmin]

Well I got my ball nuts and ball screw and will start maching them. I will post pics as I convert my machine to CNC. Stay tuned.

[WOODKNACK]

wHAT DOES SOMETHING LIKE THIS COST TO DO, RUFFLY? I have a homier mini mill and might do this in the future....

[cncadmin]

The ball and screws cost me 100.00.

[lstool]

Hey I recognize some of those parts. Werent they made at a place called L.S. Tool ?

[cncadmin]

Yes they were .

[cncadmin]

Well I start to lathe my ballscrews and learned a thing or to about positive and negitive rake angles. I have to buy some cutter's to make my life easier. So once I get the right cutters I will see how well my 7x10 lathe cuts. Stay tuned!

[WOODKNACK]

Still like your 7x12? I stilll havent got one yet. I have access to a 9inch south bend lathe. But want something here at my home. Was looking at that or a 9x20. I like the idea the 7x12 are more easy to move around..

[cncadmin]

I'd like to get the converstion the littlemachines has to make it a 14" lathe.

[cncadmin]

My little lathe will not cut hardened steel, I will have to get machined on a bigger lathe. So i'm waiting to do that.

[cncadmin]

Next week, I'm going to try to complete the machining to the screws and I have to make a addon to hold the thrust bearings. I will post pics of the rest of the converstion.

[ToyMaker]

Paul wrote:

My little lathe will not cut hardened steel,

Time to look at mounting your Dremel on the tool post.
Start at http:/mini-lathe.com/ for info

robotic regards,

Tom

[cncadmin]

I have a question, do you guy thing I should use a belt drive to drive my screws or direct drive?

The steppers I'm using have about 250 in oz of torque. I was going to belt drive it to get more torque out of the system. I plan on cutting steel and alum.

[cncadmin]

Here is why I question myself-

http://www.cnczone.com/links.php?s=&...link&linkid=54

It would make my life easier to do it this way. HELP!

[Zephrant]

My plan is to belt drive, with a 2:1 ratio. But that is because I am going rack/pinion, and I need to gear down the servo a little. The smallest pinion is 1.7" per revolution (0.00425").

After further research, it looks like the feature that I thought added accuracy actually divided it out. The G340 has a step multiplier, but that means it sends the equivalent of 2/5/10 pulses to the servo for each input step.

I need the opposite, more resolution, not less. I guess I could find encoders with more counts.



I know the Shop-bots do a 3.5:1 gear down on their steppers.

Zeph