Capillary clearance for a soldered joint

[Bill PudneyParticipant @billpudney37759]

The latest project to keep me out of trouble is to repair and (slightly) refurbish a Heko power hacksaw. They were made in Victoria (Australia) in the 60s and maybe 70s and are a small, light, very simple thing designed for use by, for instance, farmers. They use a form of scotch yoke to turn the motors rotary motion into the linear movement for the saw. Originally the scotch yoke was a weldment of steel flat bar. The one I have is fairly badly worn, to the extent that it's VERY noisy. So, I have made a new one which is bolted together using button head socket screws.

My plan is to solder the various joints to assist the screws, and try and prevent fretting. As I'm reluctant use anything I don't already have (the saw only cost $26) the planned solder is Tinmans solder which I think is 50/50 lead/tin. My very basic question is, what thickness shim should I use to get reasonable capillary action?? I have some 0.002", 0.003" and 0.005" brass shim.

Happy New Year everyone!!

cheers

Bill

Edited By Bill Pudney on 01/01/2017 03:11:40

[Bill PudneyParticipant @billpudney37759]

[Nick_GParticipant @nick_g]

Posted by Bill Pudney on 01/01/2017 03:11:15:

which I think is 50/50 lead/tin.

Bill

.

Am I reading / interpreting your post correctly.?

Are you planning on joining steel parts together with that blend.?

Nick

[HopperParticipant @hopper]

I've never worried about that. Just put the pieces together and solder away. The solder will follow the heat. Unless you have precision scraped the surfaces of the steel pieces dead flat there will be suficient gap and sufficient surface roughness to allow the solder to flow in there. Probably get a better joint if you tin each piece first then clamp them together and heat it all up, adding extra solder as needed.

Sounds like an interesting project. Got pics?

[Paul LousickParticipant @paullousick59116]

Hi Bill,

Soft solder is not very strong and only suitable for joining sheet metal. Silver solder or braze welding would be much stronger. Or welding.

Paul.

[Bill PudneyParticipant @billpudney37759]

Nick G Whats surprising about that blend?? I think its 50/50 tin lead. I bought it as a stick of tinmans solder, for mechanical joints, not electrical. Actually making tinplate fuel tanks for model aeroplanes

I was/am planning on tinning all the joints, wiping away excess, bolting all the bits together, aligning, soldering, running in a bit until there is a nice fillet, then dowelling.

I understand that soft solder is not very strong, its there in an attempt to prevent any movement and to support the screws/dowels. I still have the toolbox that I made during my apprenticeship, with some soldered and some riveted joints. I'm trying to not have to buy anything for this project, hence the no welding

The Boss will be requested to take some photos.

Thanks chaps, I reckon I'll do more or less as Hopper suggested. There certainly won't be any precision scraping!!

cheers

Bill

[HopperParticipant @hopper]

Bill, you're a man after my own heart: use what ya got in the shed. Good luck with the project.

[Ian S CParticipant @iansc]

If the bolts are well placed, I would forget the solder. As long as you use plain steel (usually black) socket head screws/bolts, these are high tensile, and don't be stingy on size.

Ian S C

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