If you try this it's strictly at your own risk! But, I've modified two without any problems.
Remove the front locking ring (red-ring) by unscrewing it.
Remove the large rear adjusting ring by unscrewing it off the rear of the lens.
Mark the front moveable lens housing and the rear lens housing so you can re-assemble them in the same position. This is important!!!
Here's the first tricky part. Remove the two brass guides that ride in the two slots. The screws are glued in and can be very hard to break loose. These should already be marked with one or two center punch marks. If not, mark them in some way so they go back together in the same position and on the same side as you originally found them. This is also important!!!
The two halves of the lens will now simply slide apart. The glass won't fall out, unless they have been previously damaged.
Here is the real tricky part. Remove about 1/2" from the front of the silver half (the rear lens) and about 3/8" from the rear of the black half (the front lens). Chase the threads that you messed up during cutting.
The slots on both sides of the rear lens must be lengthened toward the rear of the lens. You may also have to file the rear ends off of the brass slot guides.
Clean all the chips out of the two halves. You may also have to clean the inside lens surfaces.
That's all there is to it! I would recommend you use a lathe or milling machine to do the cuts, but since I didn't have one I used a band saw with a metal cutting blade. No reason a hacksaw wouldn't work if your real careful. I used a file to lengthen the slots.
The modification works reasonably well for a lens thatís considered a paperweight by todayís standards. Your probably outside the design range of the optics for focus, so donít expect 12 feet to be as good as say 100 feet.
Here is the lens taken apart. The two rings are the pieces that were cut off.