loctite or silver solder

I am building a stuart D10 They no longer supply a one piece forged crankshaft and you have to build one up from 1/4 drill rod, and 1/8 x 3/8 flat stock for the webs.They suggest two alternatives for this. Either use loctite and small metal pins at the joints, or silver solder the whole thing together.

I have some experience with the silver solder but am far from being an expert.Would the high heat tend to warp the shaft? Is the loctite and pins a suitable alternative?

Any advice as to which way to go and possible procedures would be greatly appreciated. There are two journals on the shaft.

Thanks, John.

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Loctite 638 is more than man enough for the job. But if you have the ability to silver solder there is no reason why you should not do that either.

The advantage with loctite is that one does not have an unholy mess to clean up if your technique is not 100% with silver soldering.

Either way keep the main shaft in one piece until the joint is done and cut or mill out the center bit as a final stage as this will avoid any misalignment.

Nick

+ 1 for loctite .

Just about finished the stuart score engine and used loctite on it and was easy to do .

I still pinned the crank webs to the crankshaft but didn't bother with the big ends , loctite by itself would be more than strong enough but i liked the added security of pins .

Just make sure everything is super clean before you put the loctite on , nice brite steel so a qiuck polish with some scotch brite and then i used acetone to clean everything up.

I have heard of people using liquid paper to mask areas that they don't want silver solder to flow to but i have never tried it so can't say it does,or doesn't work.

On larger engiens I tend to solder but something like the 10 will be OK with loctite of the sort of number Nick mentions. To save a mad panic I would suggest doing it in two stages, first the pin into the two webs leaving the main shaft loose, then when that has set do the other two web to shaft joints.

To answer your concern, silver soldering shouldn't warp the shaft but you need to be very neat and use the minimum of solder to get a bright ring around the joint. Feed each joint from the side AWAY from where the journals will be to help avoid contamination.

It can be done as it was one of the first silver soldering jobs I did.

Neil

The risk of things going wrong, and of not being mendable, are much greater with silver solder. You will also find it difficult to avoid the heat affecting the bearing surfaces as masking is rarely 100% effective. So Loctite seems better to me.

Cheers, Tim

Buy some extra material and try both! Treat it as a way of gaining skills.

As for masking I find Tipex typing correct fluid works very well and I am a messy silver solderer.

JA

When I rebuilt a Stuart Turner S9, I had to make a new crankshaft, but instead of fabricating it, I made it from solid. I had some steel, I think it was 5/8" x 2", I hope it is still working well for the bloke who stole it a couple of years ago, or who ever he sold it to.

Ian S C

The Beng's steam engine and flame eater kits specifically mention NOT to silver solder due to problems with distortion. They advise soft soldering only for the crank shafts. I thought it would be okay to silver solder but I will have to try it some time to see what really does happen !

30 years ago when I built Martin Evan's "Dart" I Loctited and pinned the crankshaft. I am sure that the 1/8" roll pins were sufficient on their own but the Loctite gave added security in the 1" dia. shaft.

Thanks for all of the great advice, I really appreciate it, John.

Some years ago I made a crankshaft with a half inch shaft held together with Loctite. I then managed to damage one end in some way; can't remember what now. Never mind, it comes apart if you heat it, doesn't it? I gripped the damaged end in the vide and applied the heat. A little later, with the web material a nice shade of blue, and the application of a twelve inch adjustable spanner, with a great deal of squealing, I managed to twist the web from the damaged shaft. I have used Loctite, without pins, for crankshafts ever since.

That should read "vise", sorry.

My smallest motor has a built up crankshaft using shaft lock adhesive(it wasn't Loctite), the shaft and crank pin are 3 mm, the crank webs are 2 mm, it seems to be holding up ok.

Ian S C

Did you drill the crank plates while they were clamped together ?

Edited By Brian John on 13/09/2016 11:24:58

If it is of any help: I followed Jason's and Neil's advice and loctited and pinned the crankshaft of a 10V. It has proved to be fine.

**LINK**

Ron