[gmcurrie]

Hi all,

I believe these laptop security drawers are on ball-bearing slides - 1.5mm steel construction - any good as XY stages in a DIY/hobbyist build?

[bobsch]

Several people have built machines using drawer slides. Do a search on "drawer slide" for the pros and cons.

[CarbonKevin]

Depends on what you want to cut.

I built a 28" x 24" x 10" machine using heavy-duty full extension slides. I wanted to cut foam, wood, and possibly some aluminum...foam is no problem, wood isn't too bad, but aluminum requires some seriously shallow passes and slow feed rates.

Drawer slides do have reasonable stiffness along one plane of rotation, but not enough along the other two - some seriously design work is needed to achieve this, using multiple pairs of bearings to give stiffness in multiple planes. Anoyther problem was dust and debris working their way into the slides...if you can't design a very good dust collection system, bits of junk WILL get into the rails, and the entire thing will loosen up, requiring a full teardown and rebuild, shimming each axis to take up the slop that develops.

Let me put it another way...I'm designing a new machine to replace the one I have using linear rails. I found some incredibly stiff 13" THK units for the Z axis on ebay for under $50 Can, shipped...the X bearings and rails were around $80. My Y rails were the priciest, at around $150 Canadian. All in all, I've spent just under $300 Canadian on actual linear bearings. The trick is watching eBay like a hawk.

As a comparison, on the previous machine, I wound up having to use two sets of 12" slides for the Z axis, two sets of 24" slides for the Y axis, and two sets of 28" slides for the X axis. This cost me somewhere in the vicinity of $105, but the results wasn't good enough for me.

There are stiffer slides out there that might do the job sufficiently...but look at the pricing, it should be pretty clear where your money is best spent.

http://www.leevalley.com/en/hardware...614,43616&ap=1

If you still want to do this, search my posts, I went into greater detail on linear rails in another thread. In the long run, being a cheap bastard cost me more time and money, although the experience is priceless - my second machine will be far better with this experience under my belt than had I built a full linear bearing machine from scratch before.

Cheers!

[gmcurrie]

Hey guys thanks for the replies -


I'm just starting out - experimenting with steppers ripped from old printers & so on - not up there in the Heavy-Duty league just yet.. : )

Was aware of the usage of drawer slides in DIY CNC, but then I came across the laptop drawers in a websearch & it seemed to me that as being a factory unit, there might be less alignment issues involved in an X-Y build as they will be already 'square' (as opposed to two slides that have to be then mounted, & might have alignment issues?)

Talking of which, any opinions on the like of these - ? I've checked out the part PDFs, but seemingly no mention of accuracy/tolerance -

They kindof look interesting - inexpensive, & nice to have that 4-hole mount plate on top.

Regards,