Converting X2 Mill To Cnc Need Advice Cutting Ball Screw

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cnctruckeic

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.I am taking the CNC challange...converting a Harbor Freight mill to CNC. Bought new ballscrews and nuts. The nuts are the flange type and I will need to cut on nut down to fit on my X axis. These are hardened so I have read about grinding them down. I have also heard about warping them and getting chips into the nut area. I have a grinder and cutoff wheel...

So folks tell me how to do this so I don't make a mess...
Thanks

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cnctruckeic said:
.I am taking the CNC challange...converting a Harbor Freight mill to CNC. Bought new ballscrews and nuts. The nuts are the flange type and I will need to cut on nut down to fit on my X axis. These are hardened so I have read about grinding them down. I have also heard about warping them and getting chips into the nut area. I have a grinder and cutoff wheel...

So folks tell me how to do this so I don't make a mess...
Thanks

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Click to expand...


Two thoughts. You can judiciously wrap them with tape to keep the grit out. Not my first choice. Or you can disassemble, do your grinding/machining, then thoroughly clean them before assembly. The nuts and screws aren't that difficult to assemble it's just tedious work getting the balls into the nuts.

Tom S.
 
I would imagine that the flanges are not terribly hard, also the nuts often are screwed into the flanges and may be removed and machined alone, I have never found one to be very hard. As seen here http://www.thomsonlinear.com/downloads/screws/Thomson_BSA_Lead_and_Ball_Screws_cten.pdf and here http://www.mcmaster.com/#ball-nuts/=14eqr2g

They are sometimes locked together after assembly by a set screw on the threads, they are sold seperatley nut + flange. Replacing the nut does not require replacing the flange. The nuts are supplied with a plastic tube that retains the balls until being pushed out when assembled onto the screw, if you have purchased an inexpensive (kit) then all bets are off.

Good luck
 
I have a couple ball nuts out in my shop and a file just skates over the flange. I wanted remove the flange on those, but I'm going to plan ''B''

From the McMaster web page: ''Ball Nuts—All are steel...... Rockwell hardness is C58-C64.''
 
JimDawson said:
I have a couple ball nuts out in my shop and a file just skates over the flange. I wanted remove the flange on those, but I'm going to plan ''B''

From the McMaster web page: ''Ball Nuts—All are steel...... Rockwell hardness is C58-C64.''
Click to expand...

I understand that, the separate flanges are not however.

As a side note turning material at RC 64 is handily done with hard turning ceramic inserts, I often reduce the shanks of HSS end mills and taps this way.

I would not want to mill such a material although is is done. http://www.hardmillingsolutions.com/
 
This is the ballscrew and nut I bought... yes they are chinese...but they feel really good...
So the ballnut was on the screw when I bought it. That said, I have never repacked the ballnut any links on how to do this?
What would you use to cut these with?

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I also have been down this road. You may want to look at http://www.hobby-machinist.com/threads/an-enhanced-x2.46702/

The nut is one piece, so there's no taking the flange off. It is hard enough to resist hobby level tooling. Grinding works surprisingly well. The #60 HF wheel did remarkably well. Have plenty of water available so you don't burn your fingers. I did one with the nut on the screw. I would not do that again. They are not that hard to put back together. There a videos you can watch. Work on it over a pan so any errant balls end up there and not in the carpet or under some heavy appliance.

Have a plan and expect that something will not work. I recommend mounting the X nut outside the saddle, rather than grinding or milling the inside of the saddle.

petcnc - Nice work threading with the cut off wheel. I prefer not to grind on my lather, but it is a simpler setup than my separate axle.

Larry
 
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