Original New SpadeGrip Crankfire Installation Instructions
Additional Instructions for Spade Grip Crankfire Units:
The Spade Grip pattern units are essentially the same as the Pistol Grip type Crankfire units. So the basic instructions are the same, with some minor exceptions/additions.
1. The Spade Grip unit, installs as a complete replacement for the original Pistol Grip back plate assembly. The back plate/buffer tube component of the Spade Grip unit is a modified original 1919A4 back plate. Theoretically it should fit any 1919A4 receiver. However, it has been my experience that there are more than a few variations in the machining dimensions on various semi auto RH side plates and the overall fit that results when these semi auto plates are used to build a gun. So, if you encounter any appreciable resistance when sliding the Spade Grip unit back plate into your receiver; Stop, Look and File as required, to fit it to your gun. Also check that there is sufficient clearance between the front edge of the Crankfire Housing and the rear edge of the RH side plate. Some of the plates run longer than original. There should be enough clearance for most if not all plates, the way the unit is assembled. If not, the main housing can be moved to the rear on the buffer tube by loosening the two 1/4-28 Allen head screws that secure the main housing clamp to the buffer tube and moving the unit back. This brings us to the next difference worthy of mention.
2. The lower half of the main housing clamp is drilled and tapped in the center for #8-32 thread. There are "Two" Allen set screws installed. A short one, on top of the longer one, to lock it in place. The longer screw extends up through the wall of the buffer tube to bear in one of the four indexing slots in the buffer plug. It is there to replace the spring loaded detent that originally kept the buffer plug from backing out on it's own. If the main housing is to be moved or removed or if you want to adjust the buffer plug for tightness, the short set screw will have to be removed and the longer one backed out enough to clear it's slot in the buffer tube wall. When reassembling the main housing to the back plate/buffer tube, be sure the long set screw lines up in the slot and has clearance to pass through the buffer tube wall and reach the indexing slot in the buffer plug.
3. Like the Pistol Grip Crankfire units there is a clearance cut in the upper right portion of the main housing clamp, to allow a screwdriver to be used to turn the bolt return spring rod and lock it into the bolt, or unlock it as the case may be. On the Spade Grip unit the "reach" is a bit greater, so it may be easier to do, if you remove the dust cover, to be able to see where the end of the screwdriver is.
Note: The shape, dimensions and spacing of the grip frames used are duplicates of the M2HB frames, and the grips are M2HB surplus pieces. Any grips and grip tube/cap assemblies that fit the M2HB can be used.