[radiorich]

Hello Howard ,
Anyway I am glad you got the issue narrowed down and hope you get the part you need !

Sincerely richard

[morzh]

If I were too design that (I mean I woulbe told to use ball gear or be fired), I would machine a ball with a small pin at the end, drill a hole in the shaft (concave) and glued the pin in the hole. That would be unbreakable. Better yet, just drill two holes, in the shaft and in the ball, and use separate pin.

[rfeenstra]

Yes, it is a mystery.  The Scott drive is definitely larger, making it easier to machine out of one piece. Philco's is so small that I presume they felt they needed a hardened assembly, hence the ball bearing.  I machined the one for the Scott but I doubt I could do the one for the Philco!  I have a couple of these 38-116 (or maybe they are 37-116's) chassis.  I hate to break them up by robbing parts.  Perhaps you need a complete chassis!? 


Morzh - I would have just machined it out of one piece and then hardened it!

[RodB]

Rob, any light as to how the whole assy is kept together?

[HowardWoodard]

Hi Ron.  That pin holds the coarse shaft in place.  If the coarse shaft can't move, then it's three ball bearings prevent the vernier shaft from coming out.  So I guess you could say it holds the whole assembly in place.

[HowardWoodard]

I may end up buying a whole chassis + shipping just to get the shaft -- no pun intended. -- because at the end of the day, the cost is peanuts vs what it would mean to my family. Personally, I like to keep things in use as long as possible and then out of the landfill as long as possible, so I assume I could turn the chassis into a parts donor after using the tuning shaft.

It cost my brother $148 to ship the 37-9 to me here in the Seattle area. What would you want for your chassis?

Something to consider for sure.

[rfeenstra]

The outer housing has a hole in the side where a pin fits loosely (removable with a strong magnet, or in this case striking the unit on the side so that inertia would pull the pin out.)  This pin rides in the groove you see on the brass part with the gear on the end.  The fine tuning shaft is held in by the 3 ball bearings that ride on the ball bearing on the end of the fine tuning shaft.  That's why that little ball has to be strongly secured to the end of the shaft (how they did that is where our mystery is!).  To assemble this thing, you need to push the fine shaft in to compress the spring so that the 3 balls can be inserted all the way to the narrowest part of the groove.  This allows the brass shaft to be inserted into the outer housing.  Once the 3 balls are inside the outer housing, you can release the pressure on the fine tuning shaft and the 3 balls will expand outward and ride on the small ball on the end of the fine tuning shaft. Then you need to get the groove lined up with the hole and insert the pin.  The pin will hold the brass shaft in place.  The pin could fall out since it fits loosely.  It is held in place by another assembly that turns on this outer housing.  A fairly complex assembly as you can see by looking at the diagram that Morzh posted!

Since I had this unit apart, I cleaned it all up, re-lubed it, and assembled it with masking tape around the outer housing to hold the pin in. I should reinstall it in the radio chassis before I forget how the whole thing goes together!!

[rfeenstra]

This is not the place to buy or sell!  PM me.