Fitting ball screws to Chester 16V

[Tom_Nelson]

I've just done a CNC conversion to my Chester 16V mill. I'm using an Arduino Uno with GRBL as a controller, and I'm really happy with how its all working. (photo attached)
My next step will be to replace the stock acme leadscrews and brass nuts with ballscrews. I'm looking at using SFU1204 ballscrews on the X & Y axes, but on examining the current setup, I can't see how I can find the space under the table to fit ball nuts where the current brass nuts are mounted.
I'm guessing I can't be the first person wanting to do this, so hopefully somebody can give me some advice on how to go about fitting ballscrews to this mill.

[m_c]

I'd suggest going and finding some X2 mill conversion threads, as the 16V looks reasonably similar dimension wise, so I'd imagine space limitations will be similar.
The big thread I'd suggest is Hoss's conversion one over on cnczone.com, but the SX2 is quite a popular mill to convert so there is plenty info around.

[Tom_Nelson]

I'd suggest going and finding some X2 mill conversion threads, as the 16V looks reasonably similar dimension wise, so I'd imagine space limitations will be similar.
The big thread I'd suggest is Hoss's conversion one over on cnczone.com, but the SX2 is quite a popular mill to convert so there is plenty info around.

Thanks for the lead - I've spent some time going through some of those threads, and I can see that in general it involves some machining out of the x-y plate where the leadscrew nuts are mounted. Given that I don't have access to another mill to do any such machining, I think I'll try a stop-gap solution by making delrin nuts to use with the existing leadscrews and see how much that improves the backlash and how long they last before they start to wear. I found this thread on another forum which looks quite interesting and I have a couple of delrin blocks available, so it's worth a try. http://bbs.homeshopmachinist.net/threads/43645-Making-Acetal-leadscrew-nuts-the-easy-way

I'll post my results once I've tried making new nuts.

[komatias]

Tom,

you may not have access to a mill but other on here will. It is very possible that you only live a few miles from another member that may be able to help with your project.

Since you have mounted the motors, the battle is 1/4 of the way done. Start by making the drawings of where you plan to put the mounts for the screws etc.

With a battle plan, just ask if there is anyone able to help you. You will seriously regret faffing about with half measures.

Regards

[Tom_Nelson]

Thanks for the advice,
I've ordered some chinese ballscrews on ebay and when they get here I'll figure a way to get them fitted. Closer to the time I'll cast around on this group for somebody near me with a mill. I tried looking for dimensioned drawings of the 1204 ball nuts but found 2 different sets of dimensions, so I guess it'll be better to have them in hand and measure up before going any further.

In the meantime I'm going to go ahead anyway and try making some delrin acme nuts, just to see how it works (I just enjoy trying new things). Whether they work or not won't really bother me since I've now committed to ball screws anyway.

[JAZZCNC]

Be careful when machining away the bed or base for clearence as it can release stress's and twist the bed/frame. Make sure you have plenty of meat left and not taking too much away.!

[BASMOTRONIC]

I had the same problem with my RF40 mill - I ended up modifying the ball screw housing with an angle grinder so that it would fit in the available space. The angle grinder was needed because the ball screw housing is hardened and I couldn't machine it with my mill.

With a modified ballscrew and a bit of machining on the mill bed - I managed to make it work !

[fifa]

Good day

12x4 low profile nuts shall be ok, (outer dia 24 mm). Clean the bed with acetone, and fix the nut with epoxy cast in.

Strong enough.

regards

[JAZZCNC]

Good day

12x4 low profile nuts shall be ok, (outer dia 24 mm). Clean the bed with acetone, and fix the nut with epoxy cast in.

Strong enough.

regards

Another one who doesn't look at the dates.!!!