I made one out of a Rear Axle Frame Rail Bumper just to see if it could be done. I already had an Insulator that was in good condition, which I used as a guide.
The most difficult part was to get angled edges straight and true...the hole, which I expected to be the most difficult part, turned out to be easy. Since heat is an issue, I first put the Bumper in the Freezer overnight. That kept it cool enough to keep the rubber from becoming sticky and had a far lower flex factor which made the straight cuts much easier.
For the hole, I used a piece of Stainless Steel Tubing which I sharpened on the inside edge and put into my drill press set at the lowest speed. Along with Mineral Oil as the lubricant, it cut straight through the Bumper.
For the straight cuts I used a thin piece of Stainless Steel that I sharpened on one edge and heated using a Heat Gun, not a flame, to control the temperature. I first built a simple Wood Miter Box and a small Jig the hold the Bumper in place and at the correct angle inside the Miter Box. After experimenting a bit with the heat, I was able to get the straight cuts I needed without burning the rubber.
Rounding the front corners I used more Stainless Tubing to cut the correct Radii and then cut the Slot to the Hole. At first, it kept flexing, so I had to freeze it again. I found that cutting each side of the Slot a little at a time, made the cut much easier to do. The first time I cut all the way through one side which caused it to flex so easily that I couldn't make the remaining cut.
The first one took a few hours because of the various tools I had to make but after that, not counting freezer time, it took about 15 minutes to make another one.
Not suggesting that anyone else go through all of this trouble, especially since it seems that there is a source for these, but I'm a tinkerer and thought I'd share how I made one.
Ray
