Creating a splined stepper shaft

After doing some fiddling with my current extruder I noticed that the motor frequently missed steps due to it not having enough torque to drive the filament.  It seemed that the motor drive gear wasn't going to cut it.  The gear I was using was 14mm in diameter.  The stepper shaft itself is 6.35mm.  I had a spare motor from the photocopier that was the same model as the one I was currently using so I headed into the shop to see what I could do.  I ended up locating a knurling tool that gave the end result of something extremely similar, if not better than a splined shaft.  First I had to disassemble the motor so I could get the shaft in the lathe chuck.  It's highly magnetic so keeping it away from metal scrap is a good idea.  Then I turned down the shaft on the lathe to about 5mm to get rid of the flat side that was cut into it originally.  Finally, I used the knurling tool to give it some teeth.  The tool made some very sharp edges that work great for biting into the filament.  I really can't imaging this thing slipping on the 3mm ABS.  Here is a shot of the end result.