CNC Spindle Control - can someone dumb it down for me?

[blades]

Now that we're moved (again) and partially settled, I hope to continue work on my 7x10 conversion once again. Next step is spindle control, and I'm utterly unable to comprehend what I need and how to hook it up. I can't seem to piece together enough information to make it make sense.

Here's what I've got:
- 7x with it's original speed controller. Will buy a different controller if necessary.
- G540 controller
- CNC4PC spindle encoder (encoder wheel is installed)
- Currently running trial version of Mach

Here's my wish-list:
- Would like to maintain full manual control. If necessary, I would buy another controller board and put some type of plug on the motor so it can be plugged into either controller.
- Would like to have threading capability. Have not ruled out purchasing Mach, but would rather use the free version, which apparently does not support threading.

Here's my questions:
- What else do I need, and how do I hook it up?
- If I set it up to work under Mach, will it require substantial changes to work under a different program, such as TurboCNC?

Thank you for any help, and remember, keep it dumb!
Hopefully this thread will help me and others who follow.

[Fastest1]

First buy the Mach 3. The G540 has an outut that ouputs a 0-10 vdc control signal. The pot on your spindle now just varies the voltage (0-10v most likely), you will run the output of the G540 to the same connections as your speed pot is connected to now. First you would have to verify your voltages on the pot. Measure the output of thepot as you rotate the knob. Does it vary between 0 & 10v?

[blades]

LOL, wow, that sounds a little TOO easy!
I will check into this, thank you for the info!

Question: other than the obvious advantage of the great interface that Mach has, is there any compelling reasons to part with $175, as opposed to $60 for TurboCNC?
Granted, $175 is a bargain price for a good CAM program, but as a hobiest, I'm not sure that threading capability can justify the cost for me.

[blades]

I checked it, and measured just under 18v across the outer terminals, and of course 0-18 from the center tap. I suppose that would mean that I would only have about 55% top speed using it as-is with the G540, assuming it's a linear pot?

[Fastest1]

I believe there is more than 1 way to use the output.

[ninefinger]

Question: other than the obvious advantage of the great interface that Mach has, is there any compelling reasons to part with $175, as opposed to $60 for TurboCNC?
Granted, $175 is a bargain price for a good CAM program, but as a hobiest, I'm not sure that threading capability can justify the cost for me.

Have you considered trying EMC2? Completely free. I'm using it for milling and I'll use it for my future lathe conversion.

If you are running a dedicated PC for your lathe try it out - the LiveCD can be run ( a bit slowly) without making a change to your system and will let you know if it will work with your PC LinuxCNC.org - Installing EMC2. Operating system and machine controller in one package.

I was (and still am) a complete newbie to Linux and I got it to work for me

Mike

[blades]

Yes Mike, it's a dedicated PC, and I will definitely take a look at it. I'm running Ubuntu on my laptop now, although I'm by NO means a Linux geek.

[blades]

Update: I need to replace my DVM. I just checked the voltage of a 12v regulated power supply, and it showed like 20v. I will check across the pot terminals when I get another meter (soon!).

[blades]

Found a great thread in the Gecko section of the forums (duh, I should have looked there first) that explains what Fastest1 already said. Posting a link here for future reference for others.

Is it possible? (G540 spindle control)

[sansbury]

I converted my 7x, keeping the original X and Z axis screws. If I really want to crank the handles, it takes about 5 minutes to swap out the motor mounts. I used the jfettig machines drawings for the motor mounts.

[blades]

I converted my 7x, keeping the original X and Z axis screws. If I really want to crank the handles, it takes about 5 minutes to swap out the motor mounts. I used the jfettig machines drawings for the motor mounts.

Unrelated topic, but that's cool. I did my conversion so I have motors and crank handles, with no changeout necessary. I kept the original X axis screw, but used a 3/8-10 LH acme thread on the Z axis.

You got a build thread on your conversion?
Here's mine: 7 x 10 project started

[sansbury]

No, unfortunately not. It was (is) kind of an on and off project. At first I was going to do ball screws, the whole 9 yards, then I realized that was going to cost a few hundred bucks and I decided to try out a more basic approach with the bits I had in my scrap pile, which include the stock screws and a few 125oz motors hooked up to a HobbyCNC board. The result had less than stunning performance but was good enough to make me want to keep trying.

To stay on topic, I had played with the idea of using the third axis (the motors and HCNC driver came off a dead micro-router project) to turn the speed potentiometer, just because I had it and it wasn't doing me any good sitting on the bench. Before I ever tried that, I decided to upgrade to larger motors which meant new drivers so it never left the drawing board, but I'm 99% sure it would have worked, though the G-code programming might have looked a little quirky