rung fu clone RF-45 ZX45 cnc conversion

[TomS]

Hello Tom
this is not the same seller but it is the same board
Ebay item number
261213650116
also the Uc100 is shipped with a gender changer now
Steve

Thanks. Placing an order today.

Tom S

 

[Roadstercycle]

Hi Steve, just wondering if your anti backlash ball nuts you got are really no backlash. I seem to have about .010 play in my x-axis. Just wondering if you noticed the same and just use anti backlash in Mach 3 to compensate?

 

[dracozny]

Hi Steve, just wondering if your anti backlash ball nuts you got are really no backlash. I seem to have about .010 play in my x-axis. Just wondering if you noticed the same and just use anti backlash in Mach 3 to compensate?

I had a crap ton of play in the ones linearmotionbearing2008 aka Chai sent me. Do not trust the spacers out right. I bet you can get almost a quarter turn more in them if you pull the pins.

 

[jumps4]

hi Jack
I have no idea what your setup looks like but if you have the thrust bearing from china that comes with the ball-screw, then I would look there.
disassemble the bearing and make sure the outer races are facing thin side out away from each other and then put a thin spacer between the outer races of the bearings. the inner races cannot touch each other or the bearing will not have any preload when you adjust the Locknut on the ball-screw.
but to answer your original question, the screws I have still have .0014 backlash on X & Y and it is in the ballnut.
Steve

 

[Roadstercycle]

Thanks Steve, I did do what you said on an earlier post about the bearings. They where in backwards and I did pit a spacer in between to separate the outer races. I will go through that again before a order double ball nuts or 2 more standard ones to make a double nut setup. On my other machine I used Mcmaster carr ball nuts and screws, doubled up the nuts and get about .0005. They are tight but accurate. Back to the drawing board.

 

[Roadstercycle]

Steve, I checked it out again and went another .012 shim so now I'm at .024 shim between the races. I really did not see any difference. How wide of shims did you use as a comparison?

 

[jumps4]

I would remove the motor, lock the table and turn the screw back and forth to locate the play.
if you cannot find play in the ballnut or bearings, then if your gibs are too tight you will see what looks like big backlash
when you check it with an indicator, but what is actually torque in the screw building up before it can break loose the gib to allow motion.
Steve
there are two videos about what is going on with ballscrew torque and gib adjustment I did a while back here
http://www.hobby-machinist.com/thre...part-the-way-i-do-it.19633/page-5#post-187038

 

[Roadstercycle]

Thanks Steve, It's the ball nut. Ordered 2 more nuts to double up to fix this. Anti backlash in a single nut I think is a sales gimmick. Single nuts with no backlash are very expensive compared to the Chinese stuff as we've both discovered.

 

[dracozny]

Glad to see the doublenut resolved your issues.

 

[Roadstercycle]

Yes, it worked great, thanks.