Simple T handle that requires no extra glue/screws/zip ties to assemble. Max size: 4mm hex key. (5/32 imperial) Stem sizes are not critical just pick one slightly larger or the same as your hex key. Hex sizes: 1.5mm 2mm 2.5mm 3mm 4mm Compatible with the 5 hex keys from the Craftbot 3d printer. 8-4-15: Updated Stems, increased thread tolerance by 0.125mm. Check out my other designs here: http://www.thingiverse.com/Kezat/designsFor the larger hex keys the bottom of the stem hole can be widened to allow the stem to seat farther down the hex key. If only one stem is printed at a time make sure it has good object cooling or print more then one at a time. Due to the design of the stem it may fall over during printing if the bed adhesion is not that great, adding a brim should solve that issue.