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I need information on the mounting of the rear panels to the cabinet on a orthophonic credenza. What I have is deteriorated back panels with no hardware. I think there is 4 mounting points based solely holes and mounting hardware on the cabinet. It looks like 1 wood screw in the middle of the lap joint in the middle of the 2 back panels. 3 holes that are ¼" x 20 thread brackets. back set in the cabinet floor. Must be a spacer involved. I have the new back panels made and veneered. Just want to restore the machine as close as I can.

There's a little (1"? 2" at most?) metal bar that holds them together with two screws. I'm sure someone has a spare somewhere. I'll take a picture of mine when I get home - it's off at the moment because I forgot to put it on and can't be bothered to spin it around just for that.

I'm not aware of any little metal bars as Gunnar mentions. The single screw hole you see at the seam is where an oval head wood screw goes, to tie the right & left halves together. To my knowledge, there are no spacers between the panels and brackets at the bottom. Just snug up the 3 screws to pull the panels tight against the bottom edge of the cabinet. (prevents vibration & rattling, I presume)

Here are the proper screws. They have the same, wide pan head that motor and motor board mounting screws use as well. Note the use of an unusual washer/spacer under the head of each screw. I have no idea what their purpose is, but I've seen them used on every Credenza I've had anything to do with. I do not believe they are the spacers you expected to see under the panels. I also have a photo of the wood screw that ties the 2 panels togther. All the photos were taken with little lighting and less space. Hopefully, they're still informative.

I remember that the bottom back panel screws on the Credenza I used to own were screwed into a metal L-shaped bracket like this one I spotted on a completed eBay auction --
(From: https://www.ebay.com/itm/125494351848?c ... 7675.l2557 )

OrthoFan

Thanks, Gunner, Jerry and OrthoFan. Jerry the pics helped now I know what I am looking for. The screw type is called a "slotted truss head" So far I have only been able to find them in stainless steel which I can not gun blue if they were steel or blacken if they were brass. I do have the center wood screw and washer. OrthoFan my cabinet has the "L" brackets which are threaded ¼" x 20. Still looking I think I will try Fastenal next.

Herderz wrote: Sat Oct 22, 2022 3:33 pm Thanks, Gunner, Jerry and OrthoFan. Jerry the pics helped now I know what I am looking for. The screw type is called a "slotted truss head" So far I have only been able to find them in stainless steel which I can not gun blue if they were steel or blacken if they were brass. I do have the center wood screw and washer. OrthoFan my cabinet has the "L" brackets which are threaded ¼" x 20. Still looking I think I will try Fastenal next.

Don’t waste your time looking at fastenal, go straight to the place that has almost always had everything you need:

https://www.mcmaster.com/90271A542/

Many other options for lengths if you look around. I think these are zinc plated, but you can always remove that with some acid if you don’t like the zinc.

I'd be surprised if these threads are really ¼-20 and not ¼-24. For such short thread engagement, it may not even matter really.

Thanks, anchorman. I found what I needed at Grainer. McMaster-Carr would of been my next pick.
Jerry you are probably right, that 24 pitch thread is apparent in the machines that I have worked on. When 24 per inch hits ¼ in. it is not common anymore today. ¼" is now 20 pitch coarse and 28 pitch fine. Just a note, It is ¼" x 20 now. I ran a tap through all 3 brackets. It will probably be ok. Going coarser thread uses a larger tapping drill, plus you don't need that much pull strength using such a thin bracket.

Victor used ¼-24 threading most commonly, I can’t think of any ¼-20 fasteners in the product line.
Once again, one measurement is worth a thousand expert opinions. The Starrett thread gauge verifies the 24 thread pitch. Every one of you should own a gauge.

The slight pitch difference between 20 and 24 TPI in the thin metal L-bracket should make little difference. If it were me though I would have put out a call for some original back panel bolts. They are quite common.

Regarding the thick grooved spacer. It certainly allows the screws to be installed and removed by hand but I’ve not seen a reference in Victor documentation that verifies this observation.

Mark