G0704 Conversion X-Axis Seems too Tight

[Braf1895]

I recently made some first chips with my converted G0704, and learned a lot on the first few go runs (like double checking step down/overs before hitting the GO button). I noticed that the X-Axis is way harder to turn by hand than the other axes. Z-Axis is smooth as butter, no problems. Y-Axis is a bit tight, but can be turned freely. The X-Axis is super tight. To the point that I lose steps every once and a while. I think I have it narrowed down to the table ends are too high, and causing it to bind/bow the screw. Is this something anyone else has run into in the past? Is the only/best solution to just make new table ends?

 

[graham-xrf]

There are many so ways things can get "a bit tight". Chips contamination in sensitive places for a start!
When you say "converted", does that mean the lead-screws were replaced with ball-screws?

Regardless all that, it's a machine. You can look for and find the source of the X-axis binding up. Probably the first step is to eliminate anything to do with the drive parts by temporarily de-coupling them from the table, and checking to see if it slides on the ways OK. If the alignment of the ball-screw with the table ways gets even slightly out, it will bind up somewhere.

This forum is full of CNC conversion experts. I am sure they can help you.
I intend to do the same conversion to my mill, which is pretty much identical to yours, but badged with a different brand. Thus, I have not been at this long enough to have gathered experience, but I do know that the table has be set up to slide on the ways smoothly and accurately before even it gets driven by leadscrews.

 

[Braf1895]

Probably should have mentioned that I am indeed using ballscrews. 1605 if I recall for X and Y, and 2005 (can't recall) for Z. I'll take a shot at tinkering with it tomorrow. Too hot in the garage with all the cars cooling down from the day.

 

[Braf1895]

Figured out what my problem was. The moment I took off the table end on the opposite side of the stepper side, the X-Axis became far easier to turn. Works like a charm now. I'll have to make a new end plate if I want to keep it on there. Also, note to self, always use thread locker for screws in a machine.

 

[macardoso]

Braf,

Welcome to the forum, it is a great place to be!

I'm also a G0704 conversion guy. Did mine back in 2013 and use it a ton. Always tinkering with something. Sounds like the alignment of the screw to the ways was a bit off (end plate not quite right). Easy enough fix. Also be aware that the ways on all of these import machines can have error. They can be bowed, twisted, tapered, etc. Not much you can do other than adjust the gibs to allow movement even in the tightest spots at the expense of slop in the loose areas. The machine can be scraped by hand to correct these geometric errors, but it is really not worth it.

 

[Braf1895]

Braf,

Welcome to the forum, it is a great place to be!

I'm also a G0704 conversion guy. Did mine back in 2013 and use it a ton. Always tinkering with something. Sounds like the alignment of the screw to the ways was a bit off (end plate not quite right). Easy enough fix. Also be aware that the ways on all of these import machines can have error. They can be bowed, twisted, tapered, etc. Not much you can do other than adjust the gibs to allow movement even in the tightest spots at the expense of slop in the loose areas. The machine can be scraped by hand to correct these geometric errors, but it is really not worth it.

Thank you for the welcome! I noticed that when adjusting the gibs while it was still a manual mill. I had some issues at the extreme ends of the x Axis feeling tighter, but it was nothing like what I had after the ballscrew was added. It was so tight that I couldn't turn the screw by hand and needed a wrench.

 

[macardoso]

Thank you for the welcome! I noticed that when adjusting the gibs while it was still a manual mill. I had some issues at the extreme ends of the x Axis feeling tighter, but it was nothing like what I had after the ballscrew was added. It was so tight that I couldn't turn the screw by hand and needed a wrench.

Yeah, sounds like you definitely had a misaligned screw.