Once I had the material, I just had to gather the necessary tools.
Step 1: Tools and Supplies
Rotary Tool (Dremel)
Various grit sandpaper - I used 120, 220, and 320
Sheet Steel ( I used 16 gauge, but much thinner will work)
Step 2: Measuring and Cutting the Basic Shape
After some quick work with a straight shear, the rectangles come out no problem.
Step 3: Cutting Out the Viewing Window
I then traced my card again on one of the rectangles I cut out. I made sure to trace it centered left to right, but about an 1/8 " low top to bottom. This is to leave some space for the lanyard or clip to attach to.
Now you can start cutting out the traced pattern with your dremel and a cutting wheel. I just played it by eye, since I was not too concerned with exact placement, But I cut about 1/10" inside the square. The card will need a small lip of material to hold it in place.
I put it in the sandblaster one more time just to quickly remove the marker ink.
Step 4: Rounding the Corners
In order to make sure both sides had the same curves, I cut the front first to a pleasing shape, then traced this onto the back plate.
After the shear, I quickly went over these with a bench grinder just to smooth them out.
Step 5: Cutting Spacers and Spot Welding
I welded a spacer onto the left, right, and bottom of one side ( the front in my case, but it does not matter which side you choose).
Now you just need to sandwich the spacers between the two pieces of metal and spot weld again. The weld may not be quite as strong since you are going through three pieces of metal, but it should not matter on such a low stress application like this.
Step 6: Cutting Out the Clip/Lanyard Hole
The vertical cuts will be much shorter than the horizontal cuts. This means the cutting wheel may not cut deep enough (through the material) before it cuts to tall of a slot. I ended up drilling holes on the right and left side, then cut out the metal between to avoid this problem.
Step 7: Making a Smooth Finish
Step 8: Last Notes
If you would like something other than the raw metal look, or simply a little more protection, powder coating is a great option for something like this.