Here is a winter project I recently completed. I've been using a single Ram-ball mount on a plate for my GPS for directions and to monitor my speed. Well, seems I need to have an even better warning system (ahem), so I figured I better add my radar detector too! So, I went to my trusty computer and set about designing a mounting plate to hold two Ram mounting balls. The goal was to have a place to mount my Garmin Nuvi-style GPS unit and my Valentine 1 radar detector. I started with the plate design and stand-offs. The stand-offs are designed to mimic the factory stepped shoulder bolts. Here are the designs:
The plate is 1/4" aluminum; use whatever you can find at a scrapyard that is cheap. The dashed lines that cross in the corners are where you drill the 1/4" holes. I used a jigsaw with metal cutting blades to carve out the basic shape. The dimensions are a bit funky but they work. I probably should have put them in metric, but I was using a dimensional steel rule and an old English unit caliper when I took all the measurements. If you click on the image you should be directed to my Smug-Mug page. Save the image to your computer and then you can print the image in actual size and you can use it as a marking and drilling template.
These I turned out of 3/4" diameter aluminum rod.
The bolt is a 6 mm x 1.0 button stainless button cap screw, 40 mm long. The washers are stainless #12 washers. These work well with 6 mm and 1/4" bolts/screws as a #12 hole size is almost exactly 0.25" in diameter (standard 1/4" washers are sloppy).
You will see that I used a 3" diameter hole saw and a 2.25" hole saw to take some material out of the plate. I also rounded things off with a file and and a sanding wheel.
The 1" Ram ball mounts have 1/4-20 threads. I used 1/4" button head stainless cap screws, 3/4" long, again with #12 stainless washers.
The assembly looks like this on the bench:
I also needed a power supply for the Garmin. I tried to order a regulated 5 V supply, but the guy went out of business and stole my $20! Oh well, if that is all I ever lose in life, I'm doing pretty good. Needing to finish the project, I decided to take apart the Garmin power adapter and rework it for my needs. These things are glued together, but if you take out the fuse and begin prying apart with screwdrivers, you can get the glued joints to pop apart. You get something that looks like this:
To modify the power supply we need to unsolder two leads and add some wires:
Sorry about the lack of focus on a couple of these shots; my camera has found its way to the garage floor once too many times; I went out and bought a new camera after these shots.
I already had a Nuvi mount from Ram but I did need to make a mount for the V1. I added some industrial strength (strong and moisture resistant sticky stuff) to the V1 and to a 2"x2" Ram flat plate mount. This has worked very well.
Here is a view of the parts all mounted up (sans windscreen):
I used a Valentine power cord and adapter you can purchase on their website. I ran all the wires in through holes that exist below the windscreen mounting hardware, then snaked the wires along the left side of the bike following other factory wiring harnesses. I have a circuit expansion board under the seat and plugged the two leads into that using a 2 amp fuse. Last picture shows the toys operating:
Probably the hardest thing to make are the little stand-offs. You can likely substitute small sections of pvc pipe or other material to make them. The small diameter shoulder is nice, but I don't think it is mandatory.
I wish I had more time for the writeup, I hope this is clear enough. If not, please pm me or post questions and I will try to answer them.