[Wildkard]

Hello all, I am in the process of planning a build based on the CRP2448 manual, but with the long axis shortened to only 24 inches and I have a few questions.

I am planning on using this mostly to do light production work cutting basic shapes out of phenolic plastic with fairly low precision needs, but would also like to be able to do some more precise work in other materials, especially aluminum for side projects.

1. The 2448 plans use 60in extrusions for the long axis of the bed, this is 12in longer than the travel distance, does this ratio hold up for a shortened bed, i.e. I would need 36in bed rails?

2. Can I use the Pro rack and pinion parts with the extended linear carriages, it looks like i could but I would hate to buy them only to find out otherwise.

[LeeWay]

I don't see why they would not work. You can study the available drawings to see what might be different. I find that the guys at CRP's (Ahren and Cory) answer questions quickly and always seem to have the right answer. No extra charge.
To figure out the right lengths for everything, you would need to mock up each axis in CAD. Pretty easy since most of the necessary drawings are already available. You would be able to see rack lengths, extrusion lengths and actual machine footprint that way.
Good luck with it and above all, have fun.

[ahren]

Hi Wildkard,

You can scale things the way you mentioned if you want to go with a custom sized machine. There is some wiggle in the length of the gear rack you use -- this does not need to be precise. You just need the length of gear rack to be somewhere between the travel you need and the overall length of the axis.

You can use the PRO rack and pinion parts with a standard machine kit, but you will need to add an additional part to the gantry to shift the larger pivot of the PRO R&P units -- otherwise they will interfere with the high z plate. We have these in stock, just shoot us a message through the website and we can work this up for you. Incidentally, we also have 36" pre-drilled steel we can sell you if you want to buy it from us.

Best regards,

Ahren
CNCRouterParts

[Wildkard]

Thanks for the replies guys, should have a message from me soon.