This is a modification to mount an NXT vertical adapter on an older Shocker SFT body. This retrofit requires two separate mods:
1. Drill a new mounting screw hole exactly 0.475" behind the vertical adapter hole (threaded 1/4-28)
2. Modify the frame and/or vertical adapter so they can both be mounted together. This is sometimes required because the NXT adapter might intrude into the frame. It depends on the specific combination of frame/adapter being used.
New Vertical Adapter Screw Hole:
This is a semi-precise hole that must be drilled 0.475" behind the stock SFT vertical adapter hole. I've heard of people that do this by hand but it would be tricky to do. I suppose the easiest way to do it by hand would involve using the NXT adapter to eyeball where the new hole should be positioned, then use a hardened punch tool to create a small spot in the bottom of the body.
The harder part about this mod is that the threaded screw hole must be drilled exactly perpendicular to the body. This would be tricky to do with a hand drill since you only have one shot. But if you get it right then you've done the most difficult step.
The way I perform this modification is by clamping the body in a milling vise (using some wood to avoid scratching the body) then I use a dial-indicator to ensure the body is perfectly level. The back of a Shocker body is taller than the front. You might not be able to see it with the naked eye, but it's definitely true. Therefore if you don't level the body then the new hole will NOT be straight.
After clamping and leveling the body, I again use a dial-indicator to precisely locate the vertical adapter hole. I then move the mill 0.475" further back and drill the new hole at this location.
Frame modification:
One of the markers modified for NXT vertical adapter also needed a Shocker NXT frame retrofitted to install on the same body. There's a problem with this scenario because the NXT frames are longer in length compared to the SFT frame, so there isn't enough room for both NXT vertical adapter and NXT frame installed on the same SFT body. One of them can be installed, but not both. The picture below shows the frame lined up on a body with NXT vertical adapter screw installed...
I shouldn't have accepted this job but I took it anyway. I was able to eventually get the parts to fit after some very careful milling, but I would never perform this modification again - it was simply too risky. Regardless, I'll show how the milling was carried out in the pictures below.
