On Sep 28, 8:02*pm, Larry Jaques
wrote:
On Tue, 28 Sep 2010 14:30:16 -0700 (PDT), GarageWoodworks

wrote:
I'm still struggling with my X,Y tables for my H-mortiser. *I've tried
full extension drawer guides and they had way too much vertical
slop. * I also looked at under-mount slides today at Woodcraft and
they too had too much slop.

How were they mounted? *Were the X guides in the closed position when
the table was up against the Z gantry? *Were the Y guides just a
couple inches open when the table was centered? *Most joints won't be
but 2 inches in either direction, so you should have the ball bearing
glide stiffness working -for- you. *Weight of the table and part
should keep them pretty much together, too. *(Support that stray end
of a long table leg, bed sideboard, or whatever, though.)

I am thinking about using 4 steel rods (2 per axis) and using guide
bushings. *Four bushings total inserted into two separate equal
lengths of wood. *The wood would support the table (two per axis).
If I lube the crap out of the steel rod do you think this would work?
Hope this makes sense.

If you use old-technology, go with sintered bronze bushings and grease
or oil them, not the rods.

If you use linear motion bearings, you won't have slop and they'll
have seals around them. *They're not cheap, though.

CNC routers usually use 5/8", but for the shorter tables, you could
probably get by with 7/16 or 1/2".

--
You can't wait for inspiration. You have to go after it with a club.
* * * * * * * * * * * * * * * * * * * * * * * * * * * --Jack London

I found a local company that sells sintered plain bearings at $4.50 a
pop. Very reasonable IMHO.

http://www.applied.com/apps/commerce...&mp=FB-1013-16

The rod is $13.50 for 18". i just need to think of a design that uses
the least number of plain bearings. 4/axis might be pushing it.?.