I like that take pictures. When My wood handle splits I will have to do something else.
OK, finally had some time to start on a "Bondo" knob. But first...
I called the local Cat dealer to satisfy my curiosity on the valve price. $734.82, based on the part number in the
Surplus Center description. That makes the valve from SC quite a bargain IMHO.
So, on to a handle to hold the switch. I have a Massey with the Dyna QPS transmission. What does that have to do with hydraulics, you ask? Nothing, except to complicate my knob fabrication. I like the way the Dyna QPS shift knob fits my hand, and how easy it is to use the buttons on top to shift. So I thought it might be a good template to copy for the joystick knob. Here is what the shift knob looks like:

This is my joystick lever, with the stock knob removed. It just pushes on, no threads, no setscrew. So it just pulls right off, leaving a smooth shaft.

Notice also, it angles back and inward toward the driver. That is fine for the round knob that comes on it, but for a knob like the shifter I am trying to copy, not so good. For that knob (really "grip" seems a better term for that shape) it should be sitting straight upright. At least it seems that way to me. I am pointing all this out so when you see my grip skeleton you will understand why it is angled on its 3/8" pipe base. Actually, this wire form was only a trial skeleton to just get ideas on how to bend up some 1/4" rod for the final form. But it turned out to be more sturdy than I anticipated, so I went ahead and welded it to the pipe. At first it only had two "legs" and would flex some in relation to the pipe, so I added two more and that stiffened it up a lot. The pipe is a 3/8" X 4" nipple. To get it to fit the joystick lever I ran a 1/2" drill bit through it to clean up the rough inside.

Next I used fiberglass reinforced auto body filler to cover the skeleton. You could use regular bondo, but I felt like the fiberglass would give it extra strength. I am not sure if it is necessary or not, but I figure it can't hurt. I also think the fiberglass will keep it from cracking. Regular bondo will crack with age if it is very thick, hopefully this reinforced stuff will hold up better. I used Bondo brand reinforced for this project, but another brand is Tiger Hair. It took about two applications for it to start to take shape. Sorry, I didn't get any pics of the formative stages. I will say I had most of the knob at the top filled in, then cut it out with a Dremmel to make room for a little cardboard "box" I made to create a cavity for the switch. The next pics are after I covered it with the box in place.


After filing it to shape I drilled a hole from the bottom of the switch recess down to the pipe at the base. Here you can see the hole at the bottom of the recess.
Then I put a piece of clear tubing through the hole and fastened it to the pipe. The cable ties are just temporary. This will be a conduit for the wires. Then I "buried" the conduit with bondo, filed and sanded to the (almost) final shape you see in the last pics.



Next I will make an oval shaped aluminum plate to fit on the flat top of the knob for mounting the rocker switch. More pics when I get that done.
jp