CTC i3 fix for loose lower 8mm rods

Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4322064.

This is a fix for an issue with a cheap CTC i3 off eBay, which has a flimsy laser cut plywood chassis. The bed is free to move by about +/-5mm laterally, due to the Y axis only being attached by 4x 8mm tubes, and the two holes in the chassis which accept the tubes are 10mm diameter (i.e. far too big for the tubes).

To fix this, I designed this replacement part which has an 8mm bore, which makes the whole assembly a lot more stable.

Height is 20mm, width 35mm, two 3mm diameter holes on 27mm centres, and central bore is 8mm.