Make a "Shroud Holder" to simplify the Installation of a PME Style Safety
This is a shroud, held in the jig, with the holes and cuts completed. To see this process, click HERE.
First, square up a block of steel or aluminum about 2 x 3 x 3/4-inch, the dimensions aren't special. While your at it, mill a step along the long sides about 1/4 x 1/4 - inch. The rule in the above photo is resting in one of the steps.
About an inch from the long end, strike a line across the short dimension of the block, and then strike a center-line length-wise. Drill or bore a hole at the intersection a couple of thousandths bigger than the major diameter of the buttress threads on the shroud.
With your 3-inch saw (you need one to install the safety anyway) slit one the center line into the hole.
Make another slit about half way between the hole and the long side of the block. Both slits go clear through the block.
I used a 1/4-inch socket head cap screw to drive the clamp. I drilled a 1/4-inch tap hole through the short dimension of the block, half way from the edge of the hole and the edge of the block, centered on the block thickness. Looking at the photo above, the hole nearest my fingers was enlarged to pass the head of the cap screw, the hole in the middle was enlarged to pass the body of the bolt, and the remainder of the hole (big section on the right) was tapped to match the (1/4-inch) bolt. A washer was inserted to provide a bearing surface for the bolt head. I HOPE YOU READ THIS BEFORE YOU BEGIN-IF YOU FOLLOW MY INSTRUCTIONS-THE TAPPED PART OF THE HOLE ENDS UP BEING 1 and 1/2-INCHES, YOU MAY NOT HAVE A TAP CAPABLE OF DOING THIS-THINK AHEAD J .
The idea is to clamp the threads of the shroud but not distort either edge of the block. The clamp screw does its' job without flexing either reference step. Remember, the mill-work to install the safety will require holding the jig first by one edge and then the jig will be rotated 180 degress and held by the other edge.
A shroud was installed and clamped. The shroud was rotated until the spindle hole was centered over the line, not the center-line, but the other line. Then a transfer punch (1/4-inch) was passed through the spindle hole and a mark made. If this mark didn't fall on the line, rotate the shroud and try again. Now, this punch mark needs to accept a 1/4-inch alignment pin, so either drill a 1/4-inch hole and fit a pin, or drill and tap for a 1/4-inch shoulder bolt. And that's it.