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Update on SB13 rebuild: Help needed.

Raydel

Plastic
Joined
May 5, 2019
The rebuild process is coming along nicely (photos to follow shortly).
Components are being refurbished as they are removed from the lathe as
table working space is limited, even though my car has been relegated
to the driveway and the SB13 has taken over the spot in the garage.
Progress is slow, but I'm very pleased with results so far.
However, I need help with one process. The lathe has had a few heavy
coats of paint applied, each seemingly with a floor mop. :scratchchin:
All the paint is being removed, right down to bare metal.
I've never completely disassembled QCGB tumblers before and am
unsure how to take apart the knurled knobs on the tumblers. The paint
was so thick you couldn't see the knurling. Last night I discovered
that the center hole on the face of the knurled knob is actually a
7/64" hex hole for an Allen wrench, but I can't for the life of me seem
to get it to turn. I tried moderate heat hoping that the knob would
expand enough to allow the wrench to turn, but so far, nothing's moving.
Would appreciate any tips/hints to get these knobs apart so that the
globs of paint can be removed from underneath. The knurling on this
one is perfect, hope the other one is just as nice.

Appreciate any advice you can give.

Ray
P.S. Got my new CF screw from Naru, thanks Stephen, superb job.
 
There is no Allen...AFAIK.

Pretty sure it's like most SBs, that hole in the end off the knob is simply a center drilled hole from manufacturing.

what holds the knob on is a straight pin that comes through the side, they are very hard to see/find as SB finished them after installing the pin.

usually if you clean the hole real good you can look in the hole and see the pin, that will give you an idea of where the ends are if you draw an imaginary line...if you do a search here from posts by FTF Engineering he had some good pics of the assembly...not sure if the pics are still there or if the $&&@ search function will find it.

That said it can be a real PITA so if you can clean it without disassembly I would do so unless there is a problem.

If you do take them apart mark the orientation of all parts cause they will only go back together one way.

if it looks like a hex perhaps a former owner tried to hammer one in there and if that's the case I would be even more hesitant to disassemble them if they are functioning as it would be a potential nightmare to remove the pins if they got deformed.


Check this thread- pic in post 12

1948 9A Gearbox Overhaul, Part 1, Removal and Disassembly
 
Hi 10K:

I was just about to post to my own msg and say "Never Mind, I found out they're pinned from viewing the SB drawings", when I saw your reply.
Thank goodness I didn't make that second post, your reply was extremely valuable, way beyond my initial question. Thank you sir!
I'm going to carefully take the tumblers apart. As I eluded to earlier, the previous painters were in no way related to Michaelangelo. :D
A few progress photos to follow soon.

Ray
 
Of course, I didn't, but do appreciate the value of your guidance.
I'm not the type to force tools, but sometimes you wish you never tried something. :angry:
It's definitely a hex hole in the tumbler. I went to maximum torque short of rounding the
Allen wrench, then backed off.:)

Ray
 
I've resisted the urge to take these apart, they usually can be cleaned up without. Also, my only repainted machine was degreased, sanded, bondo'ed, primed, sanded, rebondo'ed, reprimed, sanded, painted. Much easier than complete stripping and trying to level out the surfaces to look as nice as it was when new.
 
Hi 10K:

I was just about to post to my own msg and say "Never Mind, I found out they're pinned from viewing the SB drawings", when I saw your reply.
Thank goodness I didn't make that second post, your reply was extremely valuable, way beyond my initial question. Thank you sir!
I'm going to carefully take the tumblers apart. As I eluded to earlier, the previous painters were in no way related to Michaelangelo. :D
A few progress photos to follow soon.

Ray

Hi 10K:

Had a change of heart after closely examining the knurled knobs looking for those pins.
The pin in one of the knobs is very faintly visible, in the other tumbler, no matter how hard I try,
it's blended in so perfectly that I just can't see any trace of it. So I set my mind then on cleaning
the paint out as best I can. I'm using a brass wire wheel to remove paint on small cast iron parts.
I cut a couple pieces of wood the exact length of the maximum plunger opening and jammed it between the plunger and
the casting to force the knob to it's maximum outward travel. This made it easy to wire wheel the full
area of the casting normally covered by the knob. The unit now works like new (it ain't broke so I won't
try to fix it):-) It's now ready for painting.
Thanks again for the info.
QCGB tumbler_Res.jpg
 








 
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