Intro: Universal Metric T-handle
This design was born out of a need to save space in my tool bag. I already had allen/hex wrench sets, but no T-handles. Instead of buying more tools I decided to design a handle that would work with my existing wrenches. This handle is designed to fit metric wrenches but it will work with most imperial sizes as well.
Step 1: Design
I used Autodesk's 3D CAD do make my drawings. This was a bit of an iterative process because I wanted to print in ABS. This material is very strong but tends to shrink a bit as it cools, so it took a few test prints to get the hole sizing just right.
The use of autocad is covered in many other instructables so I'll just summarize the drawing process.
The first step was the layout. I drew this to work with the largest seven wrenches in the set. The arrangement of the holes ensures there is plenty of material around the wrench to absorb rotational force.
The second step was to run a couple test prints to get the hole sizing right.
The third step was to convert the final drawing to a STL file format that the CAM program can accept.
Step 2: CAM and Printer Setup
Now it is time to print.
I am printing with a PrinterBot Simple Metal with the heated bed upgrade. I've added springs under the print bed to enable manual bed leveling, and mounted a new power supply to the printer for portability.
The PrinterBot uses Cura as the slicer. This is a very capable open source program. The settings I'm using are shown in the pictures. I recommend printing this as dense as possible.
Step 3: Printing
This step is pretty much just waiting for the printer to finish. I have found that printing ABS on a raft with the fan off reduces warping.
Step 4: Finishing
I wanted to make this tool easy to clean so I decided to dip the finished print in acetone. This will "melt" the outer layers together and form a glossy smooth surface. This takes a little practice to get right. I recommend trying this on a piece of scrap to get your timing down. The part will dry and harden quickly.
Step 5: End Product
That's about it. My print took around five hours to complete. If you would like to make one of these yourself, I have posted the STL file on Thingiverse. If you enjoyed this instructable, please vote for me.