Help choosing parts for DIY router

[zasadat]

My students and I are building a 4'x8' router. The bed is done and I am ready to purchase linear guides and start building the gantry. I am looking for advice. I want reasonable accuracy. The machine will be used for plywood cutting, sign-making, and foam machining for lost foam casting. What type of rail/support/bearing system should I use for the x axis? Where should I buy these parts? My school does not wish to purchase from E-bay.
Thanks, Tim

[TOTALLYRC]

Reasonable accuracy is a very subjective term.

+-.010 should be good enough for most wood routers making signs and for lost foam casting stuff. Black pipe and skate bearings like you can see on many machine would be very inexpensive if you want to go real cheap. Thompson linear rails on the other hand would be real nice, but pricey, especially if you need to buy them new.

My router has 1.5"? diameter supported round rails which are very nice, but the flex of the wooden base far excceds the accuracy of the rails and the rest of the machine.

Mike

[zasadat]

Mike,
Thanks for the reply.
I believe +/- .010" would be adequate for our needs. This machine will be for teaching, not production.
I don't have to worry about losing my hair, it is already gone.
I have seen some examples, and believe we could make our own. What are skate bearings? Are they actually bearings for skateboards or rollerskates, or is that a nickname for a specific type of bearing?
Thanks,
Tim

[TOTALLYRC]

They are actually bearings that you can buy for roller skates or skate boards.
Price is usually pretty good and are as close as most malls.

Take a look at this joe's 2006 build for idea's on how it is done.

http://www.cnczone.com/forums/showthread.php?t=40007

Mike

[zasadat]

Mike,
Thanks for the link. I will check it out.
Tim

[BobF]

The Joes2006 double pipe setup is also pretty stable, and since it is all mounted to a torsion box, relatively stable compared to some other skate beariing setups.
Post some pictures and let us enjoy your build. You will get lots of feedback.
This is another Joes2006 build. It was built by a couple of students in someone else's class. I bet your students would get a kick out of it.
http://www.cnczone.com/forums/showthread.php?t=46425

[zasadat]

Hi Bob,
This will probably be a long, slow project. The kids and I don't get much time to work on it. I downloaded files for a Joe router to help gather ideas. I contacted a distributor today to get pricing on rails and bearings. Aargh! We will be building our own system for linear motion on the x, y, and z axis.
Thanks,
Tim

[budP]

do a search for ahren he makes some really good stuff for rails also fine line automation.
budP

[BobF]

Tim
You can get pretty good service out of skate bearings and angle. I know Joe cut a lot of kits on his 2006.
On the 4x4 he used V bearings and aluminum angle. There a couple of bulds with pics in the forum.
Let us know how you decide to go with the build, I may have some left over bits from my build.