X3 Z-axis conversion

[bigvinney]

I am planning on converting the Sieg X3 to cnc but I have a question. The primary use of this machine is 2.5D milling, not full 3D milling.

My question is, how bad of an idea would it be to mount the Z-axis stepper where the original Z-axis dial is located. I am sure some backlash will be developed but how bad do you think it would be?

The dial is mounted to a shaft that uses a gear to turn the Z-Axis leadscrew.

[CarveJunky]

bigvinney,

I am in the process of converting mine right now. I thought the head was heavy enought to keep backlash manageable, but I wanted to do contouring and thought the cutter may bounce itself and introduce chatter. My mill didn't have the dampening cylinder. I took the whole assembly out and made new bearing blocks. I didn't want to machine the cast pieces. I am mounting the stepper on top of the column and using the hole from the handle bearing block for wiring and oil lines. I made a stand and will eventually have an enclosure so I can use cooling. Anyway, this is the way I am doing it, I didn't want to get it finished and then find out I should have done it.

Carvejunky

[bigvinney]

Thats what I was thinking to, so I will probably make something like the one from www.cncfusion.com and mount the stepper in the lower backside of the column.

[CarveJunky]

Bigvinney,

I had not seen that before... very nice. I did mine quite a bit different than how he does that. I wanted to get as much X and Y movement as I possibly could so I mounted my ballscre nuts differntly and actually spaced the stepper mounts and end bearing mounts further apart. I was kind of hesitant to write because I did mine so different from what I have seen. I am going to use mine for roduction so I have double ballnuts on all the axis and really stretched the X & Y. Glad to help tho...

Carvejunky

[bigvinney]

DO you have any pictures? I would like to see how you set it up.

[CarveJunky]

I don't have it all assembled yet, but I will send pics, or post them as soon as I am done.

Carvejunky

[lucipher]

The drive from the z axis handle is via the bevel gears which are not (as supplied ) adjustable so the backlash would be significant. I've just mounted my motor on top of the column after drilling a hole in the top with a hole saw. I still have backlash of about 0.1 mm which I'm investigating. A possible cause is play in the vertical gib strips, I think this is aggravated by the hydraulic piston which acts in the same direction as the weight of the head ( pushing the the head forward and down). A counterbalance system with pulleys which would support the head weight would be better but I haven't got round to that yet.