[dwhempy]

Hello all:

Total newbie here. There is so much info here that my searches have led to frustration trying to find answers .. so please indulge me a few simple (I think) questions.

I have the Grizzly 0704 mill and the plan is to convert it to CNC ultimately. It seems to me that Hoss' method is the direction I want to go. So that said, I just acquired the mill and I want to take it apart for its initial cleanup (bought it from a fellow that changed his mind for a substantial discount). That leads me to consider installing the necessary ball screw upgrades at this time. So here are my questions:

1) After ballscrew installation/upgrade will I be able to configure the mill for use manually? The plan would be to do some milling to get familiar. Perhaps even to mill the parts from Hoss' plans and later complete the CNC conversion.

2) I'd still like to be able to do simple manual milling ... is this possible after the CNC conversion?

I expect this to be a lengthy project but would like to do it as efficiently as possible (i.e. reduce disassembly steps).

Thanks in advance. Dan

P.S. I originally posted this in another thread ... shouldn't have hijacked it. Apologies to Hoss.

[109jb]

If you plan to do manual milling to "practice", then leave the acme screws in there until you actually do the CNC conversion. Ballscrews can be back-driven leading to axis creep under manual use if you forget to lock the unused axis on the table during a cut. An acme screw has enough drag that it can't be back-driven.

[rcheli]

I agree with 109jb's suggestion. And to add to that many people want to ease into CNC and "keep the handles on". I used my mill for a few years and adjusted my feeds and speeds by the "feel" of making the cut. That was a little hard to let go of. But after I dropped the idea of keeping the handles, completed my modification and started using CNC I was glad the handles were gone. You can still do manually machining, meaning making cuts without drawing anything or working with G Code. You just do it buy using a pendant. The pendant allows you select an axis and then turn a jog wheel to move it. This is the one I'm using vistaCNC but there are quite a few out there. I often have the pendant in my hand with a finger on the E-Stop just in case it looks like the machine is going to do something I didn't expect. Usually this is because of some stupid move on my part like forgetting to touch-off after a tool change or forgetting to load the program for the next operation.

Good Luck
John

[Jim Dawson]

I'm going to have to disagree with the guys above. My mill is CNC but still has the handles. I can run as full manual, 2 axis CNC with manual quill, or 3 or 4 axis CNC. When running full manual, I just lay my hand on the axis handwheel that I'm not turning. That's enough to keep it from back driving the ball screws, it really doesn't try to do that anyway. I really like the option of running manual for some stuff and use the 2 axis with manual quill for a lot of jobs. It's really nice to have 0 backlash from the ball screws when manual milling, allows you to make climb cuts without any problems.

[dwhempy]

Thanks all for the answers. Great food for thought on both sides. I read somewhere that the new screws and the existing "wheels" are no longer calibrated either making for true "manual" milling challenges.

My thinking was #1) to only have to tear it apart once adn #2 to take advantage of having the better screws sooner rather than later. Maybe I should adjust that thinking to doing the cosmolene cleanup sans disassembly and live with it not being perfect until I'm ready to do the upgrade and seeing if I can machine Boss's parts with it as is. That should be some good practice!

I'd also welcome any thoughts on some good online training material (but that can probably be found elsewhere in the forums.

Dan

[rcheli]

I read somewhere that the new screws and the existing "wheels" are no longer calibrated either making for true "manual" milling challenges.

That would be true unless the lead of the two screws happened to be the same. I never used the dial markings on the handles that much since I installed a DRO on the mill right after I bought the mill. At the time it was the best thing I even did to the mill. Then CNC came along and it pushed it to second place. I still use the DRO when manual machining just because I am used to it and it is directly reading the table position so backlash isn't a consideration in manual mode.

[hackish]

My thinking was #1) to only have to tear it apart once adn #2 to take advantage of having the better screws sooner rather than later. Maybe I should adjust that thinking to doing the cosmolene cleanup sans disassembly and live with it not being perfect until I'm ready to do the upgrade and seeing if I can machine Boss's parts with it as is. That should be some good practice!

If you're doing a DIY CnC conversion, get used to tearing it apart and putting it back together. Otherwise, just buy a kit from ArizonaVideo.

You can certainly do something that has the handles still on it - just clamp the floating X axis end with washers and 1/4" of felt padding (used for chair bottoms). This gives enough friction that the axis won't self-drive. For the Y axis, you'll have to figure something else out since the floating end is inside the machine - I assume your motor has a through-shaft so you can do something similar on the protruding motor shaft. I'll echo what others have said, it's a waste of time. Get a pendant so you can jog the machine manually if you want.