The most commonly used configuration found on weapons from the 1930 - 40s which had the finger rest grip was a splined tube with spanner screws, a detail of which is shown below. This kept the handles from rotating out of position. If you are installing on commercial spades with 5/8" tubes with no spline you will have to find another way to hold the handles in position. Some ideas are shown below.

For round spade grips handles no provision needs to be made to prevent rotation.

A small Allen screw can be used to prevent rotation. It only needs to penetrate the handle enough to pin it in place, perhaps 1/32" - 1/16". Grinding a point on the Allen screw will make it easier to change the toe-in without having to drill holes in the handle. With a bit of planning, the screw can be made to seat flush with the surface of the bracket. The spanner screw will then keep the Allen screw from backing out.

You want the resin handles to be snug, but not tight. The handles were cast around rods which were dimensioned from original handles, however tubes & handles can vary slightly. If the resin handles are tight you can sand the inside carefully using sandpaper wrapped around a wooden dowel or by taping sandpaper to a metal rod as shown at right and then chucking it in a drill press.

This is a relatively easy bolt to make. Keep in mind that the shank of a 1/2" carriage bolt is .45", so the hole in the handle need only be 15/32". If you know you are going to use this method, be sure to let me know so I can pour the resin around the correct .46" rod and give you a good fit with your 1/2" carriage bolts.

Use 1/2" carriage bolts long enough to provide a 4" unthreaded shank. Remove the square shoulder, shape and drill the bolt head, then drill and tap the bottom 1/4-20.

Using a second, shorter carriage bolt, turn the shank down to 1/4" and thread it.

Left: This is an easy one if you have access to a welder, but not a metal lathe. You don't have to weld the top nut if you do not have a welder, but it looks cleaner.

The caps are made from carriage bolt heads. Details on making these bolts can be found by clicking HERE.

When removing the FN30 handle, loosen the bottom screw only. The tube can only be removed through the top of the handle.

You may be able to remove the screw using two small drill bits and a screwdriver. If not, you will have to make a spanner wrench. The screw on my back plate was so tight it actually sheered the pins off my spanner wrench on the first try.

After you have removed the screw you can use a wooden dowel small enough to fit into the bottom end of the tube. Use the dowel to drive the up and out of the handle. Mine was very tight and took some patience. Be careful holding the back plate in a vise while turning the spanner screw or removing the tube. The top and bottom brackets on the FN30 back plate can be torqued out of true with the body. After removing or tightening the spanner screw check the trigger to see that it still functions smoothly. If it does not, you can gently tap the end of the handle to one side or the other with a leather mallet or small hammer and wooden block until you get smooth trigger action.

HANDLE & TUBE SPECS

The measurements shown here were taken from original GI handles and hardware.

Click on the drawing to enlarge.