Expand width of PRT96? Spindle vs PC Router?

[dogfuel]

I have two questions I'd love some input on ...

Has anyone "widened" a 48x96 machine to 60x96? Longer y rails, longer rack pieces, some new wiring, longer table cross members ... anything else? Is the x carraige stiff enough to support this? My tolerances are not as tight as some (within .01) but I do not want a really sloppy machine either. Any ideas on cost?

If my PC router has the power for my purposes (cutting .75 Ply and HDPE), is there an advantage to me investing in a Colombo spindle? Do they offset the disadvantage of additional weight and resultant flex?

Thanks in advance,

Joe

[dogfuel]

My tolerance requirements ... not "my tolarences"

[davidallen]

I widened mine. I now have a 6 X 12 cutting area. the original system was 2 x 12. it had the original x rails so I used them to widen the y axis.

I had to lengthen the control line to the far side of the carriage but there was enough slack in the lines going to the z axis.

for my use, I haven't noticed and problems with flex.

[Brady Watson]

Joe,
I have a 5X16 PRT. You can widen your machine relatively easily by replacing the cross-beams with longer angle iron. You can also rebuild the X-car with either aluminum extrusions sold by 8020.com or use steel tubing to replace the utility strut.

I also run a Colombo and have to say that I am very happy with it. It is very quiet compared to a PC router. I believe it is 4X quieter in fact. You can digitally set the speed of the router within 60 RPM of your target speed. It will electronically maintain that speed using all of it's 5HP when milling materials that would normally bog down a PC. The Colombo is about 20lbs heavier than a PC router and required a 7.2:1 gearbox on the Z to reliably lift the router. I haven't had any problems with the router sagging in the middle...my spoilboard is as smooth as glass when surfaced.

Run-out on the Colombo is nil. I also will probably never have to replace the ceramic bearings in it...You do need to warm it up for 10min or so to seat the bearings properly each time you run it.

-Brady