Hey Woodswalker,
If you do a conversion be sure to post pictures and descriptions. One small warning. The amount of time I thought I would need to do this job has been off by several orders of magnitude. Be prepared so that won't get you down.
Good luck.
Sofa-bed continued:
Here is the Inner Slider. It has four mounting holes but two are so close together I'll just consider it as having three mounting points. I want to increase that to five.

Just like with the Base Plate, there is a "stop" that dictates the size of a screw that can be used with the Inner Slider. The largest screw that the unmodified slide will allow is a #6. I want to increase that at least to a #10 screw.
For comparison here are (from L to R) #6 (0.13"), #8 (0.16") , #10 (0.19") machine screws and a 1/4" (0.25") bolt.

The stop is located on the Middle Slider.
Here you can see the stop and how it won't clear the head of a #10 screw on the Inner Slider.


To modify the slide, drill out the rivet holding the stop in place just like I did with the Base Plate.

Warning: After you remove the stop from the Middle Slider, the next time you move the Inner Slider this is what's going to happen.

The ball-bearing slider is going to pop out from between the Middle and Inner Slider. That is after all what the "stop" was meant to stop from happening. Even being as careful as I could, one of the ball bearing took off and was last seen heading for a new life under the washing machine.
To fix this situation take a #6 screw and with a hacksaw, shorten it to about .3".
MISTAKE: In this picture I'm not doing this correctly. If you are going to saw off part of a machine screw or bolt always thread on a nut so it's between the head and where you're making your cut. Then after you're done cutting, unscrew the nut all the way off. The nut moving through the just cut threads will sometimes help in knocking off burrs and correcting misalignment in the threads.

Sometimes a little filing is needed to correct thread ends.

Take some needlenose pliers and insert the shortened #6 screw into the stop hole.

Screw on and tighten down a nut. I should have put some locktite on the screw. I'll have to go back and fix that.

Use the hacksaw to remove any protruding threads.


The new stop still restrains the ball-bearing slider but allows a #10 screw head to pass by it.


Use the magnet to catch the filings and drill two more holes in the Inner Slider.

That gives me the five mounting points.

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