Who is the best online ball screw supplier and stepper motor selection

Hello Ladies and Gentlemen this is my first post.

Can anyone tell me who is the best supplier of ball screws and nuts. I want to buy online so I need prices and dimensions of the nut displayed.

Also how machineable are ball screws ? Are they too hard to machine on my Myford ML10 or ML7 or do I need a cylindrical grinder !!

Also I am going to have a crack at retrofitting CNC to a Chester tools Champion 16v milling machine ( link here http://www.chesteruk.net/store/champ...speed_mill.htm )

I need an idea of roughly what torque I would need for the stpeer motors on the x y and z axis ?

I think 4Nm on the x and y and 6Nm on the z because of reference to this machine which is a similar size and type. ( link here http://www.arceurotrade.co.uk/Catalo...Hobby-CNC-Mill )

Any help most appreciated

Kindest regards

Nick

Nick,

Welcome to the forum.

I'll try and answer your questions, I'm sure other will leap in with their 2p worth...

'Best' supplier is all relative... what is your criteria? price, delivery, aftersales? If you want a UK supplier with good aftersales then Gary at Zapp has a good reputation. If you want price, then ebay is your friend, there are a couple of good sellers in China.

Ballscrews are hard, but can be machined, you can break through the hardening with a toolpost grinder...

For motor sizing see the tutorial here. While sizing from what others have done is an approach, it usually means oversized motors as generally its all been guesswork, and oversizing is a waste of money and can be less effective - the static torque of the motor has little bearing on its effectiveness as speed and drive voltage have as big a part to play as well. The tutorial will give you some guidance into what your options might be. Ultimately 'it all depends' is often the answer...

Not claiming them as the best but eBay seller linearmotionbearings2008 has a wide range of ballscrews, nuts, couplers and supported rails at very competitive rates. He will also provide end machining to your specification for only a few $$ (or £s).
There's a least one thread regarding this seller over at cnczone.com.

Yes they can be machined but you will need some form of collet chuck to hold them correctly. Then you will need a carbide tool to cut them with not that difficult as long as you take it easy.
I found it more difficult to make the holder for the ball nut.

Peter

Let’s not forget Motion Control Products, Marchant Dice and of course my company AXISCNC.

Quality, the ball screws coming out of MCP are a mixture of Chinese and Taiwanese products, these would also be coming from the same manufacture as the ones from MD.

Do you need traceability, MD offer full material and process traceability?

Ball screws are made in Taiwan and the lower cost ball nuts you see popping up on sites like eBay are coming out of China. The quality difference in the Chinese vs. Taiwanese is fairly significant, the Taiwanese being the better product.

Hardness,
Ground ball screws should have a greater depth of hardness through to the core of the screw, when they do the grinding process more heat is generated over a longer period of time and this heat is able to penetrate towards the core of the screw.

Rolled ball screws should be that bit more malleable, this is needed for the rolling process when producing the ball thread on the screw. The screw should then be case hardened; this would normally be done to a shallow depth and as a final machining process.

Lee

Didn't realise you were back on eBay Lee, thoughts you'd given that up for a while...

Yeah i did for abit, hoping to launch again properly very soon. Im currently working on the .com and making arrangments for other things as well.

So much to do, never enough time and the time i do have, i dont manage :).

All good fun, cant wait for summer to kick in !

just read your feedback :) there's always one isn't there... 9 purchases on eBay and he's given negative comment to 3 vendors... all of whom have excellent track records...

Is there any mileage (excuse the pun) in buying from the states. I know the dollar isn't as good as it used to be. Do you find that savings can be made or better quality can be had? Customs is normally the killer these days on importing. Interested to hear your views on this.

Another happy customer from linearmotionbearings2008
Dave