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Re: Grizzly G0678 - 8" x 30" Variable-Speed Vertical Mill CNC Conversion

Posted: Wed Nov 22, 2017 7:06 pm
by francoCNC
martyscncgarage wrote: ā†‘Sun Nov 12, 2017 12:17 pm Franco, did you see this thread about the PM 727?
viewtopic.php?f=60&t=1105&sid=469200d86 ... 178d12c6b0
Hi. Yes I did. There is so much good information moving back and forth, it's hard for me to keep tabs on it all. :shock:

Dumb question: Is there a way to setup your forum profile to get email notifications when there is activity on a thread you've posted on?

Re: Grizzly G0678 - 8" x 30" Variable-Speed Vertical Mill CNC Conversion

Posted: Wed Nov 22, 2017 7:10 pm
by francoCNC
Hi. You sound like you have some interesting projects going on. I like the idea of the G0678 conversion, but I'd like to use the table as the Z-axis and that does present some challenges. I'm still mulling it all over. I'm also thinking about the G0722. Decisions, decisions...

Re: Grizzly G0678 - 8" x 30" Variable-Speed Vertical Mill CNC Conversion

Posted: Wed Nov 22, 2017 7:22 pm
by Dave_C
I just stopped by the Missouri Grizzly warehouse yesterday and they have been out of the G0678 Mill for a bit. They have 5 on back order already and say they have 13 on order, expected delivery about the 2nd week of December.

So maybe I will go ahead and get one so I can start on this conversion. Instead of raising and lowering the knee, I'm opting to put a ball screw on the quill, 5mm lead and maybe a 2:1 step down on the belt ratio. That way I can mount a smaller frame size motor on the Z. I've seen this approach done and I like the way it works. The draw back is the short 4" of Z but then I can lower the table as needed. This will create a bit of a challenge in building meaningful tool tables.

Just more stuff to work out.

I still have to find the ball screws and the spindle encoder (one that has a mount, not the one for the motor end)

And I need to find out if I can use Metric ball screws and still have the DRO in inches. (I think that is easy but I have not done it with Centroid) I don't want my offsets, tool lengths and such in metric. I still have an imperial thinking brain!

Dave C.

Re: Grizzly G0678 - 8" x 30" Variable-Speed Vertical Mill CNC Conversion

Posted: Mon Nov 27, 2017 2:22 pm
by Centroid_Liviu
Having Metric ball screws and displaying everything in Inches (or the reverse) is not an issue with the Centroid.

Re: Grizzly G0678 - 8" x 30" Variable-Speed Vertical Mill CNC Conversion

Posted: Mon Nov 27, 2017 8:43 pm
by francoCNC
Dave_C wrote: ā†‘Wed Nov 22, 2017 7:22 pm I just stopped by the Missouri Grizzly warehouse yesterday and they have been out of the G0678 Mill for a bit. They have 5 on back order already and say they have 13 on order, expected delivery about the 2nd week of December.

So maybe I will go ahead and get one so I can start on this conversion. Instead of raising and lowering the knee, I'm opting to put a ball screw on the quill, 5mm lead and maybe a 2:1 step down on the belt ratio. That way I can mount a smaller frame size motor on the Z. I've seen this approach done and I like the way it works. The draw back is the short 4" of Z but then I can lower the table as needed. This will create a bit of a challenge in building meaningful tool tables.

Just more stuff to work out.

I still have to find the ball screws and the spindle encoder (one that has a mount, not the one for the motor end)

And I need to find out if I can use Metric ball screws and still have the DRO in inches. (I think that is easy but I have not done it with Centroid) I don't want my offsets, tool lengths and such in metric. I still have an imperial thinking brain!

Dave C.
Hi. I always use metric ball screws on all of my projects and I always run my control in inch units. Currently, I have a mill and a lathe with metric ball screws and CNC 12 is running in inch units without any problems.

Re: Grizzly G0678 - 8" x 30" Variable-Speed Vertical Mill CNC Conversion

Posted: Mon Nov 27, 2017 9:09 pm
by Dave_C
I appreciate the feedback on the Metric ball screws. I've been reading the Centroid Manual and I think I can see how to set it all up. I did some math for the 5mm lead so I could see what I needed to enter in the table for "motor turns per inch".

Dave C.

Re: Grizzly G0678 - 8" x 30" Variable-Speed Vertical Mill CNC Conversion

Posted: Fri Dec 08, 2017 4:38 pm
by DanielCA92563
Just for my info why the G0678 over the precision Mathews - PM-940M with hardened ways?

Iā€™m with you on the small frame and travel of the bf-20s
Best,
Daniel

Re: Grizzly G0678 - 8" x 30" Variable-Speed Vertical Mill CNC Conversion

Posted: Fri Dec 08, 2017 5:12 pm
by martyscncgarage
Dave_C wrote: ā†‘Mon Nov 27, 2017 9:09 pm I appreciate the feedback on the Metric ball screws. I've been reading the Centroid Manual and I think I can see how to set it all up. I did some math for the 5mm lead so I could see what I needed to enter in the table for "motor turns per inch".

Dave C.
Dave just rereading this. You can set up metric screws in the Wizard just click on machine units, change to metric, and enter the metric pitch natively. You can flip back to Imperial (inches) when done. The software will take care of the calculations.
Marty
IMG_20171208_140901627.jpg

Re: Grizzly G0678 - 8" x 30" Variable-Speed Vertical Mill CNC Conversion

Posted: Fri Dec 08, 2017 5:13 pm
by Dave_C
For me the decision is real simple, I live within 3 miles of the Grizzly warehouse so I can pick up what ever I want after I have looked it over from top to bottom. I don't like buying something I have not seen or gone over.

The G0678 has these advantages for me. It already has a 3 phase motor, a Yaskawa drive that runs on single phase, hand scrapped ways, hardened table, reusable control panel mounted up top, RPM display that is also the controller for the drive (Grizzly hides this behind the front panel) and I can pick it up local.

Just different strokes for different folks, not better, not worse, just suits me for what I want to do.

And it fits in the space I have in my small shop while the Tormach PC1100 is too large. Besides, the fun for me is the design and build of the machine!

I'm working on the control panel today!

Dave C.