G0704 CNC Conversion (yes, another thread on this :) )

If nothing has changed, the table has an arch down the middle that was used to accommodate the original screw and nut. My Roton blocks fit without modification to the nut or table, but they don't have a flange.

I purchased a model of a BF20 back in 2014 which I have heavily modified to match my real G0704. I think it was $20. The model was nearly identical to my machine, but I definitely got bit a few times where I had a mounting hole slightly off position compared to the model. Taught me to check.

Looking online I now see a lot more free model options available. For example here is one: http://a360.co/2GrT4W0

All these machines are similar but not identical. Be careful what dimensions you assume to be correct.
 
Thank you for that file! Coo!!

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Still waiting for my son to release the computer so that I can play with that model you shared. I have three computers in the office at home: a work computer, a very old mini Mac (the one I am using now), and a super powerful/mega computer I built for image and video rendering (daughter is into character animation). Very capable and fast... but my son has taken over this one for school-at-home and VR games... I will wait until tomorrow morning to look at the model on that one, the mini-Mac is painfully slooooooow....

But it looks like I should be fine with the cut made to the saddle. So I am good to go. Next is getting time to disassemble the machine and start installing the adapters. Soon to reach the point of no return...

Stay safe and stay healthy!!
 
Well... finally started to install the kit from David.... and made a mess...

I noticed I had installed the assembly backwards...

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I had practiced taking out and installing the ball nuts... I have a laser pointer that was damaged and it was the perfect diameter for sliding the ball nuts. Of course it all went to he** when I went to install it on the G0704

I must have let a ball get out of place and the ball nut will screw one way, but not on the opposite direction (goes a little bit and stops).

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Watching Daves video, I figured out what I did wrong... one of the balls must have gotten into that space where there is supposed to be no balls... He mentions this at time mark 2:32


Sent Dave an email to see if there is a way to get out of this mess or if I will have to cut the threaded rod and order a new setup for that axis... Good grief...
 
I did take the time to inspect everything as I was taking it all apart.

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Removed the back plate to check the condition of the plastic gears. All looked good...

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I should have stopped at this point and gone to bed... but noooooooo, I had to press on and make mistakes for not checking the photos and whatnot... I kick myself... anyway, that is all for tonight.

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Great job! I have a CNC mill need to get retrofitted. Analog to Digital. I’m thinking also Mach 3 and would like to keep the servo motors.
 
Richcan22 said:
Great job! I have a CNC mill need to get retrofitted. Analog to Digital. I’m thinking also Mach 3 and would like to keep the servo motors.
Click to expand...

Thank you, but you must have missed my second to last post hahahahahha.... Great job screwing up (no pun intended) the ball nut screw setup? lol
 
I could not stay still waiting for news on how to fix my mistake... so I went ahead and installed the next one...

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Question I had, since watching a few videos I see differences... in my case the Z-Axis Gib screw does not go in all the way... this is how it was when I removed it... so I installed it the same way. The Gib will not go in any more than that.

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wachuko said:
I could not stay still waiting for news on how to fix my mistake... so I went ahead and installed the next one...

View attachment 372113

View attachment 372114



Question I had, since watching a few videos I see differences... in my case the Z-Axis Gib screw does not go in all the way... this is how it was when I removed it... so I installed it the same way. The Gib will not go in any more than that.

View attachment 372116
Click to expand...
That's actually good. Means you have a lot of adjustment left in the gib. Screwing it down increases the tightness. On my G0704, it hangs out at least that much below the slide and isn't tight enough. Need to scrape in a new gib.


I highly recommend purchasing some Hi-Spot blue and checking the gib/slide fitup. It is probably worse than you think. Some of that can be corrected with gentle bending (if the gib is bowed) or locally scraping/lapping off high spots.
 
It is out!!!! Thank you Dave for the multiple suggestions given! I started with the less destructive one and it worked!

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Going back and forth 20,000 times... good thing that I am married since I will not be able to use my hands in about a month... I have no grip! LOL

I had a towel with vaseline under the ball nut as I turn back and forth... so vaseline was getting into the ball nut as the screw was coming out... so all the balls (except those you see in the bowl) stayed inside the ball nut stuck to the vaseline.

DISCLAIMER: No balls were harm during this exercise.
 
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