Soldering VS adhesive - better bond?

[Predreadnut]

Im thinking of using a gearbox that has output shafts smaller than my 1/8" prop shafts, so Ill have to sleeve the output shafts. The question is what would provide the best possible bond ? Im thinking that solder would break under the pressure of sudden starts and stops. Discuss.

[Kmot]

Loctite green formula.

[Olscuzbut]

If you are using a colar with an allen screw to tighten on the prop shaft, I just drilled a hole in the sleeve so that the set screw bites on the prop shaft or the gear box shaft. That way if it all has to come apart at a later date, its all free. Not sure if that answers your question or not.

[toesup]

If you are using a colar with an allen screw to tighten on the prop shaft, I just drilled a hole in the sleeve so that the set screw bites on the prop shaft or the gear box shaft.

I had to do exactly the same on one of my Springers, WW. The Gear had a bigger Dia. hole than the shaft i wanted to mate it too.
I made the 'top hat' adapter and cross drilled it so the set screw in the gear bit in to the shaft and not the adapter.

If all else fails, epoxy the adapter in to the gear and not on to the shaft... ;)

[patmat2350]

No wait, you are joining two shafts? One is 1/8", the other, what, 3mm? 3/32"? You need a coupler between them?
You aren't looking at the Tamiya battleship box are you? A horrid thing...

[Predreadnut]

No, this is an ancient stainless steal gearbox stamped with " made in occupied Japan". I bought it from former Admiral Tom O Dell and was thinking of using it on my latest project. This gear box allows you to run one motor to two shafts,counter rotating. Its actually well made and fairly quiet. The prop shafts are 1/8" , I not sure what the output shafts are, Ill check them tonight. They are considerably smaller when compared to the prop shafts. Im thinking of using a Speed 400 turning two 1 1/4" props on 6volts. Do you think the 400 can handle it? I'm using it in a small predreadnought BB, so its suppossed to be very slow.

PS I wasnt very clear, Im using Dumas couplers between the output shafts and the propshafts. Im not sure what Im using between the motor and gearbox yet. Of course, I could purchase a correct gearbox, I found a perfect one for around $34.00,but I thought on this build I would keep the cost down by using alot of stuff from the parts drawer. :)

[patmat2350]

Well, no question, soldering is better than glue... but glue may be enough!
I have silver soldered sleeves onto shafts before... easier if you can break the assy down first...and an oversize sleeve can be turned true in the lathe.

If the shaft is 3/32" (2.3mm) like many 400 motor shafts, then use brass tube as a quickie sleeve and CA or epoxy it together... it may work well enough.

Another alternative- Graupner's u-joint are available in a variety of bores. $.

Motor- does the gearbox have reduction? A smaller motor may well be enough.

[tghsmith]

my idea solder some brass tube into the dumas couplers, to match the shaft size, drill the the tube through the set screw hole, clean up the threads with a tap if needed..

[Brooks]

You many not need to solder and drill the brass tube liner. If it is soft brass, the pressure of the setscrew will clamp the liner to the propshaft. I've used this method.

K&S brass tubing is pretty hard, but you can soften it by heating to red hot and letting it air cool. Or, perhaps you could find some soft aluminum tube; not sure about electro chemical corrosion with the dissimilar metals, though. I can't say the ultimate shear failure, where the brass liner would start spinning on the shaft.

Silver solder is very strong. It requires a very clean surface for wetting and adhesion, and that can be hard to obtain inside a brass tube. If your first attempt to solder fails, discard the brass tube and try with a fresh piece. The heat of the soldering iron or torch will cause so much oxidation of the brass, that I find it's simpler to start afresh.