833-TV CNC conversion from Dr D-Flo project

magu said:
They also take the thrust loading from the ball screws and can be a source of float in the system. Any misumi, nsk, etc uses angular contact and or a combination of bearings to support thrust and reduce backlash.
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I should clarify: there are a pair of bearings in the zaxis ballscrew plate at the top of the zaxis
FlyingAMortgage said:
The bearings are just for holding the ball screw in the adapter plates. They don't need to be anything special like angular contact. Won't be an issue. They're fine as is.

I had the mill torn all the way down, the acme screws out and the ball screws ready to install but ran into a snag. Whoever is machining the castings in Taiwan has changed (for the better) the way they are producing the Z "table" and milling the screw nut attachment surface on the other side of the casting relative to the axis, so the heavy metal kit wouldn't work as shipped. The oil lines are all protected inside the casting now though which in my opinion is a better process. I tried installing the Z-axis screw as shipped for most of a day, but it just won't fit. I finally realized that I just needed to reverse the double ballscrew nut on the ballscrew to make it work. I 3D printed an arbor after researching the process (don't want to lose all those little ball bearings!) and got it flipped around... only to break one of the oil lines right at the fitting from all the stress of rearranging them and of course they're metric and not even our local Grainger's had them. MSC did and they arrived yesterday, so I'll be repairing the broken oil line (if I can!) this weekend and putting the mill back together.

On a much sadder note, Mrs. Nelson replied to an email question with the news that Bruce had passed right before Christmas this year.
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So a couple of issues I have run into (so far) and how I worked around them:

The Heavy Metal kit is designed for the Z-axis ballscrew to connect to a replacement adapter plate that screws into the screw nutblock of the casting of the z axis saddle which had apparently been previously machined on the "top" side of the nutblock at the factory. Well, that factory process is changed, at least in my mill as shipped, and the acme screw nut was flipped on mine and the bottom of the nutblock casting was machined instead of the top. Frankly, it looks like a better design. I spent a few hours trying to make everything work as shipped but that wasn't going to happen.

I researched online to figure out how to flip a ballscrew nut around and came to the conclusion that I would need the shipping arbor that the nut was shipped with... originally... but was not included, so I 3d printed a hollow tube arbor 18mm in diameter and longer than the ballscrew double nut, screwed the nut off the ballscrew and onto the arbor while carefully holding the arbor against the end of the ballscrew and was able to flip it around and screw it back on. Now I was able to mount the ballscrew to the adapter plate on the other side of the nutblock.

All the fiddling I did with the lubrication lines either weakened or work hardened the 4mm tube (it appears to be aluminum) and I broke several of the tubes right at the compression bushing. Needless to say, no one local was stocking 4mm compression sleeves or 4mm tubing either for that matter. MSC had what I needed. I have since found a different source ( bushings: https://cnc-specialty-store.com/grease-lubrication/tubing-fittings/lube-usa-fitting-m8x1-106252 4mm compression sleeves https://cnc-specialty-store.com/grease-lubrication/tubing-fittings/lube-usa-fitting-4mm-106254 ) and am ordering some spares to have around. As you can see from the link, the compression bushings are M8 threaded. I was able to re-use those, just needed the 4mm compression sleeves and fixed tubing. Luckily I ended up needing shorter tubing because it had to be moved so I was able to use that as well. I did not have a tubing cutter but a dremel cut-off wheel worked and I cleaned the ends up afterwards with a file and blew everything out with compressed air in case there was some tiny swarf in the lines.

In hopes that this helps someone else, here are some pictures of what I finally ended up with that could actually fit back onto the z-axis without grinding any of the castings. I had to relocate the lubrication manifold as well. Bruce's instructions say "it will just barely fit" and they are not kidding at all. You really need the gib out (obviously) and I found that taking up as much of the dovetail as possible on one side while slightly angling the other side was necessary. The lubrication needs to be as far towards the top as it is possible to mount it and the lines need to run in the "up and down" direction as I've shown in the pictures to allow them to clear... or you could get out your grinder :)

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Good to know... I'm just going to go ahead and buy some tubing and fittings now so I have them.
 
magu said:
Good to know... I'm just going to go ahead and buy some tubing and fittings now so I have them.
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Funny thing: I didn't find that online company that carried them until yesterday afternoon. Spent a while looking. :)
 
Brief update: somehow I managed to not notice that the timing belt and timing pulleys were missing from the kit. I SHOULD have inventoried the whole thing to start with after receiving it, but I let my optimism get the better of my wisdom this time. Don't be as foolish as I was, inventory immediately upon receipt even if you're not going to be using something for a while.

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FlyingAMortgage said:
Brief update: somehow I managed to not notice that the timing belt and timing pulleys were missing from the kit. I SHOULD have inventoried the whole thing to start with after receiving it, but I let my optimism get the better of my wisdom this time. Don't be as foolish as I was, inventory immediately upon receipt even if you're not going to be using something for a while.

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Have you bought new ones yet? I'm using a diff stepper than bruce recommended so I have to change my pulleys out anyway. I'm not sure of the cost for new pulleys but if you want to split the cost for my replacements ill send you the ones that came with my kit.
 
joeblow65 said:
Have you bought new ones yet? I'm using a diff stepper than bruce recommended so I have to change my pulleys out anyway. I'm not sure of the cost for new pulleys but if you want to split the cost for my replacements ill send you the ones that came with my kit.
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I have new ones on the way already, but thanks!
FWIW I found the ones that Bruce was using for my kit thanks to some folks on Dr. D-Flow's website forum.
Part Numbers: A 6A 4-14DF05016, A 6A 4-18DF05020 & A 6R 4-033050 on https://shop.sdp-si.com/catalog/
 
Christianstark said:
Look forward to a comprehensive build thread with lots of pictures, including NUC installs, and electronics deep dive ;) (hint, hint)

Will enjoy watching!
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Since you (and several others) asked, and after I posted the bench test video even more asked, I made a video on the Linux CNC install (including the probe_basic gui) for the NUC I used.
 
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