delusional wrote:
Whatās a nubbin? Itās not much.
Itās a little cylinder of plastic, shown on the left here:
Picture credit to JasonWW
The nubbin fits into the center ring of the larger piece of rubber, and they both go into the FW3Aās switch mechanism.
The Switch of an FW3A will not work without the nubbin.
When you twist off the tailcap of an FW3A, the switch mechanism falls apart.
They were saying something about glueing the switch, but it didnāt happen, might happen in the future, who knows?
In the meantime, the nubbin is very easy to lose. I opened my tailcap once with no problem, but on the second time I lost my nubbin.
I didnāt even know there was ānubbin to lose.ā So I wasnāt really watching for it. Now I need a new nubbin.
_
It took me about three minutes to make a new nubbin.
I took out one security bit, marked CR-V4, from a set.
You can see itās got an outer rim and a cup in the middle. This is designed for āsecurityā screws.
_
Next I hammered the bit through a plastic drink bottle cap. See the left hole? This did not work because my nubbin got stuck inside the cup of the bit. I damaged the nubbin prying it out.
On the second attempt I stopped a little short, leaving a bit of plastic remaining around the outer ring, and the nubbin was still attached to the cap. I cut the nubbin from the cap with a knife.
See the nubbin on the right, still attached?
_
And finally, you can see my new nubbin, in itās new home, ready to reinstall in my FW3A.
It seems to work really well. ā¦. at least itās been holding up very well for a few hours.
You also see the drill bit on top, and on the left, the nubbin that got damaged.
I had a half dozen more bad puns ready to go, but decided itās better if I donāt.
If others would like to join in, thereās nubbin stopping you.
ā¦
@ delusional ā¦ If you want to resize your pics Iāll delete this.
Thatās the main symptom of a switch tube contact issue. I havenāt seen it happen on my production sample, but I know the issue well from seeing it on earlier prototypes.
Loosen the tail a bit, loosen the head, then tighten the tail as much as you can, then tighten the head. The issue should go away.
If the issue returns, loosen the head, tighten the tail again as much as you can, then tighten the head. Try to keep the tail as tight as possible. And always tighten it tail-first.
The circle on top of a lego brick is 4.8 mm across.
The FW3A nub is 2.0 mm across.
If youāve ever had coarse-grain sugar, like ārawā or turbinado brown sugar, the FW3A nub is about the size of one grain of sugar. Maybe a relatively large grain, but still. Itās basically the size of a single cake sprinkle.
Seems like a piece of a plastic welding rod would be suitable here. Harbor Freighr used to sell this pack but couldnāt find it on their website any mor. Is it possible for that store to go downhill?
I am thinking about this nubbin issue, (piston) while I do not have a light yet after only reviewing images and M4D M4X ās video, would it be easier or more practical to bond a suitable object to the dome of the switch?
More thinking and experimentation would be required. the dome probably deflects or deforms which would cause a distortion and break the bond. I donāt know I donāt one have to futz with.
The switch to me appears to be metallic in fact it looks a dome of a membrane switch.
To replace the nubbin itself Amazon offers these items Plugs
I can image cutting one of the smaller ones 1/16 inch diameter to size these plugs are tapered so the size could be improvised. Then use some RTV to bond it in place.
I am just thinking out load here so I really donāt know if this would work.
This nubbin issue is really bothering me I donāt know if I will buy a light because of it. It is IMO a manufacturing flaw the design is clear I think it was executed improperly.
Also a suggestion for the adhesive - Pliobond. Itās a very tacky contact cement that resists solvents. Iāve been using it when repairing old cameras, gluing everything from light seals to rubber bumpers to the old peeling leatherette on the bodies. If itās improperly placed, once the carrier solvent evaporates it peels away with no residue.
Silicone comes unstuck to easily. Goop much more tenacious bond and remains flexible. Maybe this whole thing is a non issue if the switch is never taken apart. Has anyoneās come un-nubbined otherwise?
If the switch isnāt disassembled I donāt think there is room for that to happen?
It would be nice to know the materials being used so one could use an appropriate adhesive.
If mine gives me issues I might try Bisonās Plastic Adhesive since itās what I have.
But I donāt have high hopes for it working since Iāve a suspicion that the big part might be PP which the Bison isnāt suitable for.
In case someone wonders, that Bison adhesive is just a mix of PVC and solvents so it sort of āmeltsā the parts together.
Unfortunately I donāt have a very good soldering station so canāt really test the softening or melting point of the plastic accurately.