Reddit mentions of E-Z LOK Drive Tool - Optional - Use with 329-4, 329-401, 329-428, 303-4, 303-428, 319-4, 319-428, 335-4, 450-6, 550-1420, 650-6, 400-4, 400-428, 400-M6

Earlier I made a practice station for a set of 6 locks, but it was uncomfortable to hold in my lap while I watch TV. So I made a couple of these small holders in an hour or so. There is a brass insert for the screw, so these will last forever, and the screws will turn easily.
I would recommend making these before you try to duplicate the big rig.

I used the E-Z Lok 1/4-20 brass inserts. You can use thumb screws or knurled screws (as shown in the picture). Thumb screws are available at nearly any hardware store.
The special tool I used to screw in the brass insert is shown here, but some people may want a driver bit.

I rounded off the edges using a router table, but a sander can be used. The slot can be cut with a table saw or a small dovetail or gent's saw.

I didn't apply a finish yet, as I wanted to use them for a while. I can do that later. I used oak for these holders.

The parts can be purchased here. here. here or here and the T-handle wrench I used is available here.

Some tips:

• Drill some small pilot holes and make sure they line up because the holes from the side and top have to intersect.
  
• The large hole may cause tear-out, so you might want to drill from both sides. (That's why a small pilot hole is useful).
  
• Make sure you drill the proper size hole for the brass insert. I have 3/8" marked on the bag to remind me.
  
• When you, ah, insert the insert. make sure the slots for the screwdriver face out, so you can remove the insert in case it gets messed up.
  
• I find the T-handle wrench is easy to control and to make sure you hold the tool at the right angle. If it's tilted, the insert may not go in easily.
  
• Be prepared and have extra inserts, in case you mess up.
  
• If you use a hard wood like cherry (like my practice station), you may have to use one of the brass inserts to start the thread, then back it off (with a screwdriver) and replace it will the final one.
  
• Be safe and protect your fingers. Drilling the large hole into the block will cause the wood to grab and spin with the bit. I held it in a small vice. I also used a professional hold-down when I used the router table. Those pieces of wood are too small to be hand-held.
  
  Let me know if you have any questions.