Hello All,


First time poster short time reader.

So this whole cnc thing is all new to me. I have been reading and studying as much as possible. As I have narrowed down my first project. I feel I should first give you the story why I am here in the first place.


The robot

It started last September. I got the crazy idea that I would like to build a robotic arm like we had in shop as a kid. This project would be fun for me and my kids to play with and learn. While looking online and researching the robot build, I ended up on a cnc router page and then cnczone.

The router

the router is interesting to me. You see at the shop I work at we have 10' x 5' cnc router, so the plan changed, to a router. After much more research, a few Ebay parts and some debating, I realized that the bearing kits and slides available online were some what restricting to my limited budget and wood is out of the question.

The Mini Mill

This has brought me to the mini mill. I am sold on the Harbor Freight Central Machinery Model 47158. Though small it has the potential to machine the expensive bearing blocks for the router I would eventualy still like to build. I have 3 small nema 23 steppers, Minebea co. Type 23km-k series. I got these on Ebay for about $50 with S and H. These motors were a custom build for Kodak. Therefore the specific specs were not available to me. I emailed them on the specs and I recieved no reply. I figure they can't give out the specs because of some restrictions with Kodak. This led me to buy both a unipolar driver kit and a bipolar kit. The unipolar board with 3 drivers was a cheap buy, $26 on Ebay. The card was an old design so I decided to rebuild it. The IC's are Allegro 5804 unipolar stepper drivers. With some research I narrowed down a design for a new controler card. In the meantime, I also purchased a SteppmasterNC model SOP-2b 4 axis controler. It came a few days ago and the 5804's have gone to the back of the bench. Now this was a hare rasing event, nowing vagley that the motors were around 107 oz, somewere between 1.5 - 3 amp and no clue if bipolar or unipolar . I fearlessly pluged one motor into the SOP-2b and fliped the power switch. The initial test went good, the motor locked and no sparks flew. If it had, the $300 driver investment would have gone up in smoke, but it didn't. So I loaded Mach 2. After about 2 hours of poking around Mach 2, I finally realized that I couldn't find the manual jog controls becouse my screen resolution was set for 600x800. After reseting the resolution, I found it and yes the motor moved!!!!

So here I am Driver, motors, cam and cad softwares and ready to invest in the mill. I know the motors will be a little weak, I am already looking for new ones, Got any ideas?

This leads me to the original question,

HOW IN THE WORLD DO YOU CONTROL THE SPINDLE SPEED?!!!

I know from the PDF on the mill that the spindle motor is DC. I am thinking of just a relay to let Mach 2 turn the spindle on and off, then controling the speed (high and low) manualy. Though this seams a bit cave man to me. I have found a few speed controlers on ebay but, budget in mind, know that it will be much cheaper to assemble a variable speed spindle control. Any Ideas???

I do not, as of yet, have the specs on the spindle motor. I can assume that it is 12v-24v and 2 to 7 amp. The PDF on Harbor Freight dosn't get that specific.

Thanks for listening to my adventure so far and any feed back and advice will and is greatly appreciated.


Thanks,

Chris