I just finished my DYI slate handle for my Denecke slate. We have had a lot of rain in California so I finally completed the project. I had more time than money! There are additional posts on the topic in Manufactures & Dealers, but I my case this is a DYI project.
Tools used: Drill Press, Drills, Counter Sink Bit, Hacksaw, Files, Tap and Die and a Belt Sander.
Materials used: Scrap Aluminum, 2- Flathead Screws, 2- Roundhead Screws, Sandpaper and Lay-out Fluid.
Note: I did bore 2 small holes to mount the handle to the slate, using the original Denecke hole spacing (not seen in photos).You can see the layout lines and hole spacing/placement in the bottom image.
Mark