Step 1: Parts Is Parts
Here's what I used to cook up my gas blender. Your mileage may vary.
1 ea. Gas engine
1 ea. blender
4 ea. 10-24 locknuts
4 ea. 10-24 x 3/4" bolts
8 ea. size 10 washers
6 in of 1" diameter EMT electrical conduit
1 ea. 4mm x 20mm metric screw
1 ea. 1 foot x 3/16" square bar stock
screwdriver with various bits (torx, philips, flathead)
channel lock pliers
dremel with cutting disks
friend with welder
Step 2: Preping the Engine.
Step 3: Preping the Blender
Unscrew the base and open 'er up.
Unscrew the toothed 'gear'.
The motor on my blender was screwed to the top half of the base with four screws hidden under little plugs that I had to drill out.
Step 4: Chopping the Base
Then I used a new blade on my hack saw and cut along the line.
I cleaned up the base with some sandpaper and it looks straight enough.
Step 5: The SHAFT
The output shaft on my motor actually is designed to hold a square cross-sectioned flexible shaft for the trimmer head. I found a piece of steel at the hardware store that fit perfectly.
Next I had to find a screw to fit in the 'gear' that turns the blender blades. I found mine to be a metric screw I had lying around. I got a friend to weld the two together.
I considered grinding down the square shaft to a cylinder at one end and threading it by running it through a die, but I didn't even have a tap and die kit.
I left the shaft long so that I can trim it to fit.
Step 6: Fabricating the Mounting Flange
The engine has a compression fitting that will take a 1 inch-ish diameter tube around the output shaft. I didn't have any titanium tubing long enough, and my carbon fiber supply just ran out so I used electrical conduit.
I used a Dremel to cut four slits in the end of the tube about an inch and a half long, then I bent them outwards with pliers. I hammered them flat and lined it up with the blender base mounting holes. These holes originally held the electric motor in place so they are very sturdy.
The compression mount was a little bit loose, so I wrapped the end in aluminum tape to thicken it up.
Step 7: Final Assembly
I fired it up, and it works fine. I recommend safety glasses.
Now I need to mount the throttle and the kill switch and it will be done.