Assemble linear-actuator using off-the-shelf parts for < $600?

[offtherack]

Hi all,
I'm trying to assemble a simple linear motion system with a budget of about $600 (not including motor/controller). I'm wondering if it is possible to do this using off-the-shelf parts and hopefully without having to machine anything (drilling mounting holes is probably OK). This is for a (for fun) personal pet project not related to CNC, so please recommend other forums if appropriate.

Details: I'd like to build a system to move a platform weighing 30 pounds over a distance of 6 feet horizontally. The platform is about 3 feet by 1 foot, and I'd like it to move at a maximum speed of 3 feet / second. This is a project in an office environment for fun, so doesn't need to be very precise (say 1/4-inch precision in the motion) and the operating environment is a benign office environment. My tenative design was to mount two cheap linear rails about two feet apart on some stiff substrate (plastic or maybe aluminum extrusion), mount a belt-drive between the two rails and affix limit switches near the ends of one of the rails.

I was wondering if anyone knew if there's somewhere I can buy off-the-shelf parts to assemble this. I looked at McMaster-Carr, but couldn't figure out what parts I'd need - for example to attach the drive pulleys. I also poked around at 8020, but their linear motion support is limited.

As you can probably tell, I'm not a mech-e (I'm a software engineer), so any pointers to info would be greatly appreciated.
Thanks,
Josh

[pzzamakr1980]

Look at the wood router build ups forum. They would have a bunch of designs that you could use for your design.

[jseiler]

Try this one:

http://www.cncrouterparts.com/

You can buy 80/20 linear extrusion from ebay from manufacter's surplus (great guys to work with, btw). Since your weight requirements are rather low, you probably could ride this on aluminum plate. 80/20 used to machine things to spec (drill mounting holes for plate for cncrouterparts trucks to ride on). With acme screw from someone cheap (use-enco for instance) and dumpstercnc.com nuts and coupler's, you should be under your $600 budget.

l8r,
John

[ahren]

Josh,
You could definitely use my carriages for this application -- I also sell motor mounts and bearing mounts to make the assembly easy. I usually recommend using dumpstercnc's antibacklash nuts, but for ease of assembly you might consider something like these:

http://cgi.ebay.com/Low-Profile-Delr...QQcmdZViewItem

Best regards,

Ahren
www.cncrouterparts.com