NOTE: I just moved this from the Projects, Designs, and Technical Stuff category where I had originally, and incorrectly, posted it...As has happened with many of the older Instek instruments from the mid-late 90s (spectrum analyzers, oscilloscopes and other) that shared the same cabinet configuration, the plastic handle on my GSP_810 failed when it became brittle and the locating pins on the hubs sheared, and the hubs themselves cracked and fell apart.
However t'other day it occurred to me that I could use FreeCAD to design new hubs in such a manner that a length of aluminum flat stock could be fastened to a couple of the same to make a new handle. I got the design finished yesterday and 3D printed a prototype for final fitting last night. After a few tweaks of the design I have produced two hubs (see below for a couple "screen grabs" from FreeCAD:
(inner side showing the central post and 12 locating pins)

(outer side showing the slot for mounting the handle to fabricated of ¾ x ⅛ aluminum flat stock to be fastened with small sheet metal screws)

I plan to reinforce the long span of the flat stock handle by laminating a couple of ¾ x ⅜ oak "pads" to it.
I will update this post when it is done.
If anyone wants either the FreeCAD design or .stl model files give me a yell and i will post links to same.
Here is a screen shot of a pair of the hubs, with supports, and ready for slicing created using the
Chitubox 3D model manipulation and "slicing" application:

I use an Elegoo Mars (upgraded to a Mars Pro) printer, and a 50/50 mix of Weistek
Tenacious resin (clear) and their
Standard resin (gray) to obtain the desired detail and mechanical characteristics. The
Tenacious has an elongation-at-break of 50% or better, the
Standard EoB is 11-20%. Both are are the best I have found and reasonably priced too.
Here's a photo of the two hubs printed, fully cured, and cleaned up (I am going to paint them in ivory to match the cabinet):

Still in progress, I got slowed down by some health issues--gall bladder had to come out...
Update 01/12/2022:
Got it done! here's some photos:
head on:
right side hub:
left side from top:
left end of oak handle:
Right side hub:
front view with handle folded back:

I think it came out pretty good all things considered--time to get it listed on eBay...