Compound table conversion of an old Deckel mill

[John11668]

I dismantled the table and put aside the old leadscrews, which I have to say were pretty awful.
I was not really concerned , as by this time I had already decided to replace with ball screws anyway. I settled on a set like these. https://www.ebay.co.uk/itm/Ball-Scre...D09nBYWd-BzNAQ It was a risk but the british prices were so much higher and my guess was that UK suppliers were probably buying from here anyway. And even if they were not of the highest quality they would still be a massive improvement on my rough old table. I also knew it was likely that I would need to shorten them so I did not want to take risks with expensive kit. Delivery only took a couple of weeks and in the meantime I had work to do on the table castings.

This ballnut mounting plate was easily fitted to the face of the saddle





From what I could see the dovetail slides were reasonably parallel to the front and back edges of the table, albeit that the machining was typical far eastern standard, but it would do for the agricultural job I was planning . With the table inverted on my mill and clocked to the back dovetail slide, the front and back edges of the table (and the other dovetail) were all parallel within a couple of thou. My thinking was that even if they weren’t true then as long as I could tighten the gibs to take out excessive slap, then it would do for me. I was pleasantly surprised though.
I did however run a big end mill over the end faces to ensure squareness with the slides and to give decent square seat for the eventual fit of end bearings.
I went on to do similar with the cross slide and base . I left milling of the seats for bearings until I had all the kit in hand in order to formulate a plan for mountings here. I ordered the remainder of my kit, bearings fixed and floating, flex couplings , motors and drivers, along wth PSU and breakout board, from Zapp automation.
With hindsight it might have been cheaper to buy the ballscrews , bearings, couplings etc as a set .
It may depend on the sizes , and whatever deals are going at the time https://www.ebay.co.uk/itm/Antibackl...harwYhBTXLHl6g
The arrangement of the ball screws and bearings turned out to be very simple and very much in a similar style to the original screws and mounts , and I was even able to recycle the old bracket on the table end . My first attempt at mounting the x motor did not take into account the endfloat in the motor due to spring thrust washers. When first powered up with a cordless drill there was significant back and forward shift. Plan b involved a steel block mounted to the end of the table to give a seat for a fixed bearing and also to give a fixing for the motor mounting brackets.




Please remember that this was always going to an agricultural exercise, a first attempt which might then lead me on to something more sophisticated , so the design is in keeping with that . I was however quite pleased with it when I eventually got it running and wonder how it compares with the typical new Chinese budget machines.