Small nicks in ball screw

[guru_florida]

I have a nick in the contact points of two ball screws. Probably caused by a mechanical lockup of the machine these came from.

The ballnut travels smoothly and freely during the entire range except one location on the screw, thus my deduction on being due to a nick/dent. The ball nut still travels over the area without locking, but it vibrates badly. Inspecting that location, sure enough, there is a single nick in the edge (contact point) of the screw.

Is it possible to repair this somehow. I assume its impossible for a hobbiest as it would have to be reground and larger balls used?

I already cleaned and polished the screw...I feel like the other parts are smooth but the nicks still vibrate the nut.

The screw is an NK C3T, 0.55" diameter, 18" long ground (not rolled). The nut is an external return, single return, single nut.

Anyone know the approx. price of some of the ballscrew repair services?

Thanks,
Colin

[guru_florida]

oops. That was NSK ballscrew, not NK.

[guru_florida]

Really? No one knows how ball screws are repaired?

[RICHARD ZASTROW]

If repairable, we have them reground and re-balled as you mentioned.

Dick Z

[guru_florida]

Thanks Dick Z, I can always count on you for a good answer. I figured there isnt really anything else that can be done. The nick is very tiny (need a magnifying glass to really seem them) so regrounding shouldnt be a problem. I think the price will be the factor.

[PrecisionSpindl]

First, you should check with the manufacturer of the machine for pricing and delivery. There is no rhyme or reason how manufacturers charge. Some will have low costing, others high, some will have stock on the shelf, others will have no stock.
You could try the ball screw manufacturer.

When you get answers to the above, then you will know whether to entertain a quote from a ball screw repair facility. Our repair cost will probably be around $800, 3-4 day delivery. It will have to be at the repair facility to determine whether the nick is repairable.

For shipping details, contact us:

Precision Spindle & Accessories Inc.

www.precisionspindleinc.com tel. 519 671 3911
haviland@precisionspindleinc.com fax. 519 652 5994

[guru_florida]

Thanks Precision, I bought these two ballscrews on ebay. Such is the risk you take for using such a thing. I was wondering what the cost of repair would be. I expected it to be around what you say but no one would give a ballpark figure without me shipping them off. It is for a DIY project at home so I can go with another pair that arent dinged up. The ones I have arent worth much.

Thanks for the ballpark figure on the repair, you were the only one that seemed willing to provide one.

[handlewanker]

Just my 2 cents worth, couldn't you just program your CNC, whatever, to slow down when the ball screw "ding" is reached?

That is, if the balls are all in good nick and not also "dinged" by the screw "ding", otherwise you're going to get a few more "dings" along the way.

The "ding" will eventually hammer itself into a pothole of enormous proportions, same as a pot hole in the road surface gets bigger by the number of cars that hit it.

One thing'd for sure, if the original owner of the screw/nut assembly didn't consider the repair cost effective or feasible, you have your answer, neither will you.
Ian.

[BallScreWE]

We'll charge you $375. Yes that's without seeing the actual screw, but by trusting your description of it. This includes, regrinding & reballing with appropriate sized balls (we stock balls in 10 millionths increments). Turn around 2-3 days.

Dave Winter
www.winterengineering.com.