Reusing Swedish Hanks -- annealing

[moegev]

As you know, one often winds up shattering old bronze hardware when you work on it. This is certainly the case with Swedish hanks. If you try to remove or work with them, the little crimpy arm sometimes breaks off.

I am fixing up my sails for now, while I gain experience and save up money for new sails.

While I will replace seized, unserviceable hanks, I wish to reuse the old hanks that did not shatter upon removal. At $10usd plus shipping I cannot affordability to replace all the hanks on my 3 jibs.

Has anyone tried heating the hanks to anneal them? They're not steel so that should soften the metal. My only concern is screwing up the spring inside.

Thank you in advance for your thoughts

[Alan Mighty]

Originally Posted by moegev

Has anyone tried heating the hanks to anneal them? They're not steel so that should soften the metal. My only concern is screwing up the spring inside.

I've not done the job - Led Myne has No. 2 bronze hanks and I have to date been successful in replacing some hanks and so on.

Annealing bronze requires heating to around 248 degrees C and then quenching. You do not want to over-heat and you must quench.

The traditional way of doing it would be to place the hank in a small tub with something (e.g. sand) to hold it vertical, and with water part-filling the tub. Then you play a torch flame on the arm until it is the correct temperature. And then knock the hank so all of it submerges into the water (and quenches).

That would keep the most of the hank, including the piston spring, cool.

The traditional way of getting the minimum correct temperature was to do the job in the dark and only heat until the bronze just glows. Heating until the bronze is cherry red is a mistake.

I don't think anyone uses the heat-in-the-dark trick anymore. I reckon a better way would be to use an IR thermometer and aim to bring the temperate of the arm that clenches the sail to 248 deg C (I suggest finding a reference book that gives the exact preferred temp).

An alternative and more expensive way is to buy a bottle of temperature indication lacquer, such as Tempilaq (https://markal.com/products/tempilaq...ting-liquids-1). Your torch flame will destroy the temperature indicating lacquer, so you paint lower down the arm than where you will play the flame.

[Alan Mighty]

Originally Posted by moegev

This is certainly the case with Swedish hanks.

I've always called them "Sweden" hanks, believing Sweden to have been a brand name, not the nationality of the bronze sail hank with the arm to clench the sail.


Do you have a history for calling them "Swedish hanks"?


My limited knowledge is that a Finn, Johan Michael Into (1865-1958), invented or perfected bronze piston sail hanks in the US in 1902. Mr Into had migrated to the US in about 1888. He held master mariner papers from both the US and the UK govts.

And Mr Into earned extra money skippering racing yachts for the rich and famous. Story goes that he was frustrated by the equipment (wooden hanks or metal clips of various kinds) and came up with the piston hank. His original hanks did not have the arm to clench the sailcloth. Instead the hanks had two holes through which thread was sewn to hold the sail.

Mr Into anglicised his name (Johan to John) in the US. He patented his "Sail-hank". The Delaware Marine Supply Manufacturing Co. made and sold Into's sail-hanks as "Into Sail Hooks".

J. M. Into shared the rights to the patent with two other racing skippers, Charles Barr (1864-1911) and Leonard Miller (d. 1955). Barr captained three America's Cup winners (Columbia, twice; and Reliance), both equipped with Into Sail Hooks.

My limited understanding was that the bronze clenching arm came later. But I don't know who came up with the idea. And I'm not clear about the origin of what I think of as the "Sweden" brand name.

I've attached, at least for a short time, a copy of J. M. Into's patent for his sail hank. Information about Mr Into is jolly hard to look for on the internet in English, because of the English preposition "into".

[Alan Mighty]

Bainbridge International, the UK-based wholesaler that puts sail hanks stamped SWEDEN into the hands of marine supply stores/chandleries and sailmakers around the world, reckons those sail hanks are "forged brass", or perhaps "Swedish forged brass". And the springs are "stainless steel", but the grade of stainless steel is left unsaid.

See: Bainbridge International > Swedish Brass Piston Hanks – Forged Brass

I'm still of a mind to anneal them in the fashion I described, using a torch to bring the clenching arm to 248 degrees C (playing the torch flame along the entire clenching arm with the aim of bringing all of that arm to 248C) and then quenching by knocking the hank so it falls into water.

I did however dig around and find my copy of Tim McCreight's Complete Metalsmith.

Tim distinguishes between bronze and brass: water quenching bronze, but air quenching brass.

I've always preferred water quenching all copper-based metals (in contrast to ferrous metals) on the understanding that the rapid quenching is needed to get the right crystal size for malleability etc. Tim is of course far more expert than I, so perhaps you ought listen to him.

My edition of Tim McCreight's Complete Metalsmith dates from 1982. That's before inexpensive IR thermometers (and the current suite of thermal indicating lacquers). So not surprisingly Tim uses the tried and true indicators of a dimly lit room and looking at the colour.

Attached is a quick clip from my copy of McCreight's Complete Metalsmith, 1982. I can only afford to leave it on the forum for a day or seven. See McCreight on Annealing.jpg, about 260 KB.

[Jim Cate]

Well, I've not been quite so fastidious as Alan suggests, but I have successfully annealed such hanks for re-use. My un approved technique was to soot the bending area of the arm with a candle flame or acetylene flame. Then heat with a torch with the hank lying on a flame proof surface (I have to admit that I used an asbestos tile for years for such things) until the soot burns off. Then let cool slowly. I also used this method to anneal copper crush washer and such like. I was not 100% successful, but most of the hanks survived re-installation and worked as designed.

A while back we got into a typical CF "discussion" about the proper way to anneal copper, and it turns out that either quenching OR slow cooling works. I don't know if this extends to copper alloys like brass or bronze, but in fact it did work most of the time on "bronze" hanks (whatever they are really made of).

So, good luck with your hanks, and let us know if you are successful!

Jim

[moegev]

Thank you very much all. I will try the sooty approach first, then the other darkness and sand method if that fails.

Thank you for the information.

[tkeithlu]

There is another property of brass/bronze that could help you. Yes, if you hit your old hanks a mighty blow with your hammer, you will shatter them. But, if you tap them lightly, and have the patience, they will gradually reshape.

We used to do this with brass and bronze fire hose connectors that had been run over and were "egged." You sit with the connector in your hand and tap away at the narrow end until it is round and takes the threads again.