[B_Smith]

I'm hoping to achieve at least a precision of 0.05mm (0.002").

It's for small parts on a heavy construction desktop mill. 303ss, 4140, mild, and brass.

I'd like quality parts.

TIA
Brit

[ardenum2]

$500 per rail, $200 per carriage and about $3000 for a ballscrew

you can take your chances with chinese c3 stuff in which case:

$100 per rail, $50 per carriage and about $600 for a ballscrew

which way do you want to go?

[B_Smith]

Not Chinese.

[ardenum2]

Not Chinese.

where do you live then?

[joeavaerage]

Hi,
I have bought second hand linear motion parts, often new old stock and from the top tier manufacturers like NSK and THK for a fraction of the new price from:

https://www.ebay.com/str/industrialp....m47492.l74602

To achieve the accuracy you want you'll require ground ballscrews, either C5, or even better C3. C7 rolled screws will just not be good enough. Downside is that genuine ground screws are
expensive....and that's why I buy second hand.

My new mill (about 2 years old now) is using second hand 32mm diameter 5mm pitch BNFN double nut C5 screw by THK. They were sold as second hand, but when I got them I'd have sworn
they had\never been installed. They still had the manufacturers original test certificate and numbers matching. They are great. I got three, with six FK25's including shipping to New Zealand for $1000USD.
If I had bought new I would expect to pay OVER $1000 per screw WITHOUT the FK25's. Talk about a bargain!

I got from the same company three sets (6 rails, 12 cars) new old stock 20mm HSR series rails and bearing cars made by THK. They cost me $750USD including freight to New Zealand, another bargain.

I could not have afforded to build my machine without these cheap parts.

As Ardenum has pointed out there are Chinese suppliers claiming to have C5 and C3 ballscrews but at one tenth the cost of THK, NSK, Bosc Rexroth etc. Quite frankly I think they are BS.
Its very tempting to believe that they can sell you stuff 'that good for that cheap', but there are just to many holes in their advertising, and no serial number matching test certs. There are lots of
things that I will buy from China but fake ballscrews....not on your bloody life!

Craig