I needed a little more headroom

for my Shopbot Buddy, since I was carving 3" thick stock, and kept triggering errors when it went to its safe height. It was actually a fairly simple matter to replace the original 3 foot long 3" high top piece of extrusion supporting the bridge with another that's one size bigger (4.5" high). I got this from Alufab: https://www.alufabinc.com/product/1-...ing-extrusion/ .

I was initially worried about stressing the cables coming out of the control box, but was pleasantly surprised to see that the box was supported with brackets that were designed to accommodate a higher position (see photo attached). It was easy to raise the box up into the new position (supporting it underneath while I did that) and re-secure it to the bracket, which gave me enough slack for the cabling.

I loosened the T-slot screws on the top and sides that held the bridge onto the top extrusion, then, supporting the bridge with wooden cribbage, I was able to jack it up an inch and a half, slide the new higher extrusion into place using the same T-nuts and bolts, and tighten everything down again. It seems just about as rigid as it was before, and the inch and a half of added height is a real boon.

Andrew Werby
computersculpture.com

Great job Andrew. Welcome to the SBF.

You may find this thread interesting to compare notes.

Pay close attention that the new extrusion doesn't introduce some movement when the tool is cutting parallel with the gantry I-beam. The factory one is bolted to the steel support/roller plate, which prevents movement.

Some AL plates that tie the original and new extrusions together will prevent movement. 8020.net sells these for $4.65/ea....or since you have a CNC, you can route your own ;)

-B

Thanks, Brady. The guy in that thread was a bit more ambitious than me, and added an entire new section of extrusion for a 3" boost. I just substituted a 4.5" extrusion for the top 3" one, boosting it up 1.5", so everything is still bolted together pretty much the same way it was originally. It seems fairly solid, but if I notice any wobbling, I'll put in some stabilizer plates like you suggest.

Andrew Werby
computersculpture.com