G0678 CNC Conversion Thread

[DICKEYBIRD]

Wow, very nice job Dave! Anybody can go out & buy a good chess set; it takes a real man to make the machines to make his own!

[Dave_C]

Wow, very nice job Dave! Anybody can go out & buy a good chess set; it takes a real man to make the machines to make his own!

Uh, how many people do you know go out and spend $10,000 to buy and convert a mill to CNC just so he can make chess pieces? And then turn around and convert the Mach 3 lathe to Acorn. (Which I'm glad to say was worth all the trouble)

I guess it's no different than why people climb Mt. Everest! (Because they can)

Dave C.

[martyscncgarage]

Dave, the chess set was very nicely done. Thanks for posting the picture.
So, when are you going to g to add a 4th axis to that mill?

[Dave_C]

So, when are you going to g to add a 4th axis to that mill?

I have an 8" RT that I could put a servo on real easy but it is so heavy I can hardly lift it. So I drew one up that uses a 5-C collet! It would be much lighter and it would make round stock handling real easy. Seeing how you can pass the stock through the 5-C collet and you can't on the 8" RT.

The 8" RT would still need a chuck or something to hold parts (I have a 3 jaw on a plate that fits the RT but it is not very accurate as far as run out is concerned.)

The draw back to the 5-C setup is that I end up with a 5 to 1 ratio between the servo and the 4th axis. (16 teeth on the servo and 80 on the 5-C collet spindle) I guess with a 6400 step clearpath servo that might not be an issue. ?? (6400 X 5 turns is 32.000/360 is 88.8888 steps per degree)

I'm trying to decided if I would really use it enough to make it worth the cost to build it. (Not that it ever kept me from doing something, LOL)

Grizzly makes a 5-C collet indexer for less then $70.00 that I can buy just for the shaft. It has on OD of 1.750" and is about 7" long. Just right to make a 4th axis!

Anyone have any thoughts or ideas on designs?

Dave C.

[martyscncgarage]

If you could only find a Yuasa/Haas 5c indexer. They have a threaded nose for a small Chuck.

s-l300.jpg (13.25 KiB) Viewed 2466 times

[MecTechMike]

Folks,

I recognize this thread may be dormant, but the recommendation to hook the shield to the DB9 connector can create a ground loop that may explain the problems with operation. I struggled with my VFD to keep ground noise from tripping my GFCI outlet. A 3 phase motor driven by a VFD can conduct a sizable amount of noise into the mill itself, which needs to be conducted back to the VFD through the motor's ground. In my case, the encoder itself is grounded to the cable shield. If you bring that back to the Acorn independently, then you have a potential ground loop between the mill, the VFD and the Acorn. My solution was to isolate the ground from the Acorn. This assures a single point ground return back through the VFD.

Hope this helps,
Mike

[Dave_C]

but the recommendation to hook the shield to the DB9 connector can create a ground loop that may explain the problems with operation. I st

In this case the shield is not connected at the Encoder so the reason to connect it to the shell is to create a single ended shield over the twisted pairs.


Dave C.