Gear rack

[windsor@muskoka.com]

I have a unistrut style shopbot , and am thinking about lengthening it by changing the X rails . I've found a local source for the unistrut , but need to find a source for the gear rack . It apears to be glued on . ----Any ideas on where to find the gear rack , and any other suggestions would be welcomed . Thanks Mike

[tlempicke]

Yes try
http://www.mcmaster.com/
They have what you are looking for at a reasonable price.

[rgbrown@itexas.net]

Mike,

A couple of things. The rack IS glued on with 3M VHB tape. The rack is a "standard" rack available from many sources. I found a local source (Martin Gear) that had a factory 40 miles from me. It ahs been a few years but I THINK it was a 3/8" wide "20 pitch" gear. You will need to make sure the tracks "mesh" properly "end to end". I cut "half-lap" joints, placed a small section of "rack" face to face and drilled and pinned the two pieces of adjoining rack together.

A piece of piano wire between two handles will slice through the VHB tape holding the old gear track to the rail. It can then be cleaned and prepped to go on the "new" rail.

Ron Brown

[tlempicke]

We had to splice two pieces of rack together also. The two together were longer than what we needed so we cut off the end and then used that as a spacer to hold the two pieces that we needed in registration while we welded them.
To say it another way - put the two pieces you want to splice end to end. Turn the scrap piece upside down so the teeth mesh across the gap and weld or drill or otherwise fasten.

[gerald_d]

A gap is allowed between the racks - the adhesive will hold them in the correct place. Welds or dowels are not essential.


298

[bill.young]

Mike,

When putting rack on the strut tools, ShopBot also put some JB Weld adhesive in the gap where the two pieces meet, to help keep them in line.

Being careful to keep it out of the teeth of course!

Bill