Ground ballscrew bargain... and a hexapod?!

[bikepete]

Just a heads-up on some ballscrews which are so good I can't help but share the link...

Take a look here on ebay (http://www.ebay.co.uk/itm/191840572508)...

Brand new THK precision-class ground, 32 diameter 10 mm pitch, long pre-loaded nut... 300 mm usable travel or a smidge over. The details don't seem to be in the current THK catalogue but going by the model code on the packaging, they seem to be a slightly 'custom' version of the EIK model listed in this catalogue in German (page 108):

http://hsb.org.pl/Katalogi/Kugelgewindetriebe%20301-1G.pdf

The end machining is a bit short for standard BK25 blocks but I think by removing one seal (and making other arrangements to keep crap out) it'll work...

I ordered one and when it came ordered two more. They come in the original THK boxes with an inspection certificate. Lovely smooth, tight action when turning by hand. For £71.50 inc postage each it's a steal...

I have no connection with the seller except as a happy customer. He says he has plenty of them - they were spares for a now discontinued motion platform (he has two of those too if anyone wants one - hexapod mill maybe?):

18229

[komatias]

Whats the preload class on these?

[bikepete]

Not entirely sure. The feel is of a sort of light/medium preload I'd say - tight but not notchy at all. The PDF I linked to above says (in the table on p. 108) that the preload (Vorspannung) is 1.3 kN - but I'm not sure how that is measured. P. 49 says the preload is achieved through pitch offset of the different races within the single nut.

[bikepete]

In case it helps the entire model number code is:

EIK3210S-6RRG0+535.5LC5

and the one I have in front of me has serial number KX04K05797 - that is also the only thing etched onto the ballnut itself.

Mmm, just found more in another THK catalogue (p. 15-248) (https://tech.thk.com/en/products/pdf/en_a15_174.pdf):

S is presumably 'Special'
6 is six ball circuits
RR is labyrinth seals both ends
G0 is "zero or less" axial clearance i.e preload
535.5L is threaded length
C5 is accuracy class

[komatias]

Very nice indeed! I keep having to remind myself to stop drooling over things like this for a while http://www.sherv.net/cm/emoticons/fighting/bash-head.gif . After all I am having a clearout.

[Boyan Silyavski]

so 6 of these and i will feel exactly like this guy on the video


https://www.youtube.com/watch?v=PEZCZzghGFE


/just before my wife comes home and throws me out/