View Full Version : ebay ballscrew : Good deal or can of worms?

22-07-2010, 11:55 AM
http://cgi.ebay.co.uk/CNC-ROUTER-ballscrew-4xballscrew-leadscrew-/170517016380?cmd=ViewItem&pt=UK_BOI_Building_Materials_Supplies_Carpentry_Wo odwork_ET&hash=item27b39b2f3c

This looks very tempting, the cost of ball-nuts and machining would come to more than the asking price :)

But :(
1500mm on a 16mm ball screw, I think this is asking to much of 16mm? Assuming 1 end tied the other supported.
Even using 2 1500mm x 16mm for the Y axis the speed would be compromised by the length and diameter? I'm still getting my head around whip!
Is a standard 3Nm stepper up to the job of driving a 1500 x 16?

I'm sure if the deal is a good one they will be gone by the time the above are answered, and if they are still there... Well...

If I chopped 2 (2 for Y axis) of the 1500s to say 1000 and chopped the 3rd 1500 to say 700mm (I'm sure I can borrow a grinder), is it then so difficult to grind a little and file (hand file of course) the ends down to 10mm?

How did this end up in electronics ? My bad, sorry, was intended for general.

22-07-2010, 12:54 PM
Just as a comparison have a look at these:-


A few members have used Chai in the past (me included) and found him to be very good. Just note that you are getting all the bearing blocks as well as the ballscrews.

He will also do any length so no chopping with a grinder :)

22-07-2010, 01:15 PM
Wow, fast and to the point, thanks guys :)

Import from China, I'm always uneasy about additional charges etc but I'll look into it.

22-07-2010, 06:16 PM
16mm x 5mm, drive end fixed, remote end supported, 1500mm long. Critical speed = 933rpm (4600mm/min), load limit ~ 10kN

22-07-2010, 07:04 PM
And thank you too :)

I got as far as the calculators and charts at nookindustries.com/Engineering/Calculators.cfm but they hit me with a 'Slender Ratio' (?) error. So, it was either a morning with Wiki or a quick post here and do some work.... But boss, they're ball screws!, heh.

Always a problem buying stuff that needs a couple of quick modifications to match what you're trying to do, in this case if it costs the equivalent of 100 in money and time then I'd be better off buying new. I'll ponder :)

Thanks again guys.