Ball screws

[Pete92]

Hello,

As some may have seen in my previous post, I am planning to convert my mill to CNC control.

My latest question is weather or not I need to convert to ball screws. There is quite a lot of play in the current screws and nuts, how will this effect the accuracy of cut?

What ball screws do you use and how to you fit them to the machine? Does it require specialist griding?

Cheers,

Pete

 

[Herbiev]

If you have a lot of backlash in your current drive I would check out ebay for anti backlash ballscrews for the size you require. I.E. if the stepper motor rotates 55 degrees and you have 20 degrees backlash then I feel there could be problems. Having said that I must admit I am in the process of learning cnc conversion so members who have been there could probably shed more light on the subject.

 

[gadabout]

Yes, you need to convert , its not just the backlash but also the force required to move the acme screws, friction etc and the ability to climb mill with ballscrews, in my opinion no cnc should be without them, using acme screws and cnc is a waste of time and effort , once you fit them you will see the benefits

Mark

 

[stevehuckss396]

I use the ball screws from McMaster Carr. Get there ball nuts also. Then dump all the balls out of the nut and buy good quality 1/8 inch balls and reload. They are cheap but for 8 bucks worth of good balls I have less than .001 backlash and accuracy is respectable.

 

[blighty]

like the others have said. balls and nuts are a must. yes you could use what you have, but you will be very disappointed with the results.

its the smae with a lot of thing's.... all the parts add up to one thing, if one part is a bit "that will do" then the rest of it will count for nothing.

i got my ball screws and nuts from here.... http://www.worldofcnc.com/ballscrews-c-406.html

if you let them know what the sizes are for the fixed and floating end, he will machine them for you.

 

[aarggh]

On ebay linearmotionbearings and econvenience will both machine the fixed and floating ends to whatever you want at a good price. LMB does it routinely for the Grizzly crowd and Hoss's followers on the zone, but the way they are packed is a disgrace in my opinion. I've found Leo from econvenience to be far better in wanting the customer to be happy. The packing from Leo has been superb on my orders.

cheers, Ian

 

[Wizard69]

This is all true, ball nuts are for the most part a requirement.

Yes, you need to convert , its not just the backlash but also the force required to move the acme screws, friction etc and the ability to climb mill with ballscrews, in my opinion no cnc should be without them, using acme screws and cnc is a waste of time and effort , once you fit them you will see the benefits

Mark

 

[Pete92]

Cheers for the advice. I have emailed some places to get prices.