Early Douglas fork repair

[George Kulisiewicz]

Recently I posted pictures of my 1913 Douglas in the hunt for some parts when a few people wrote in telling me the top of my steering that connects holds the front fork springs and travel linkage was backwards… come to find out so was the bottom end too… after disassembling everything I noticed the forks are loose and able to pull out of the top fork assembly (see pic) upon further inspection there is a small hole in the front of the top of the fork tubes that looks as if they may have been pinned in at one time?…as well as soldered in? Would they have used a type of solder? I would have expected a brazing but it’s definitely a solder looking color and not brass … sorry for the poor lighting in the picture… any help is greatly appreciated. Thanks George



Photo lightened to improve shadow detail - Dave, 27Dec2023

[Hutch]

Hi George,

Yes it appears they would have been originally pinned. The pins that Douglas use in their frames look a lot like nails....so much so I think they actually are nails? :-).

The forks in the picture I have attached have been repaired a long time ago and it looks like they brazed the repair with bronze which confuses the issue slightly, so it is difficult to see what they originally used for attaching the top part to the tubes. So I will investigate further (i.e. if they used a Silver Brazing Alloy or Bronze, Douglas would definitely not have used Soft Sn/Pb solder or Silver Solder for this job). The melting temperature of the material used for the join on your forks might possibly give an indication as to what it is? .

As with all steering components - Safety First - so best to get it sorted properly! I am definitely no expert on repairing forks and if I were you would investigate what you have very very carefully. When I was a teenager I was riding a pushbike when the forks broke and I crashed head first into the bitumen.....this was well before helmet wearing on pushbikes was common - let alone compulsory. Luckily it was at fairly slow speed so no real damage done to me (well not that I have noticed  ! :-) )

-Hutch

Edit:- To tidy up wording.

[George Kulisiewicz]

Thank you for taking the time to inspect your forks and take pictures as well… At this point, I believe maybe somebody tried repairing these forks at one time using something else other than the brazing method… In order to properly repair them I will be brazing them back together… If anybody knows anything different, please feel free to chime in. Thanks again for the help.

[cardan]

Yes, pinned and brazed with a free-flowing bronze, with an appropriate flux. The old-timers used to call the bronze they used "spelter" - not sure what it was but (in Australia) it came as a 1/8" (or so) square section wire and had the property of easy flowing and the ability to draw into the join between a tube and lug. But there are modern equivalents. If someone has used something else on the joint - like soft solder - you'll have to clean all that off, possibly by bead blasting. While I sometimes use silver solder for round tube in bored-out lugs, where the fit can be a couple of thou, here a bronze of some sort is called for. I use bright steel nails for pins, in freshly-drilled holes so that the nails can be knocked in with a snug fit. Flux the pins before they go in.

Leon

[Hutch]

Hi George,

I cleaned off some more rust and crud off the forks and managed to find evidence of what appears to be original bronze blazing (other than where the repair was done). The tubes appear to be a tight fit in their respective holes and also, whomever originally brazed these forks together did a neat job and there is not much of a fillet to inspect. The Brazing does have a bit more of a "silvery" look to it compared to some bronzes I have seen which is why I thought I had better look at it more closely.

I agree with Leon and all traces of the "solder" used for the repair should be removed before brazing the parts back together.

(Interesting comment about Spelter Leon, I think Spelter is an alloy of Lead (Edit) Copper and Zinc (with Lead as a possible impurity) and Bronze of course is Copper and Tin, so different material, but they appear very similar. Spelter is used as a substitute for Bronze in some applications, although more softer and not as strong. Some confusion could happen as Leon states the term "Spelter" can be used as a name for Bronze!. After reading Leon's comment I thought "Would Douglas have used spelter (the Lead Copper / Zinc version) for this joint??" Probably not, but if I get a chance I will have a look into identifying Spelter from Bronze. During WW1 there was a shortage of Copper to make Bronze so possibly Spelter was used as a substitute for some applications? )

-Hutch

Edit: Corrections to add Copper as alloying element in Spelter.

[cardan]

"Hard solder is fuses only at red heat... Spelter is a hard solder composed of copper and zinc, usually of equal parts; sometimes tin or other metal is added... The term spelter is also commonly applied to zinc." From Motor & Gas Power Pocketbook, 1913.

Looks like bronze. I'm not suggesting anyone use it, although I have a roll hanging on my wall that I sometimes use myself. For nostalgic purposes.

Leon

[Hutch]

Leon,

I had more of a look into the word Spelter and seems it can have many meanings and several "reputable" sources state different things (!) but as you suggest, the common theme is zinc. It can contain Lead as an impurity so I corrected my comment above to include Copper.

-Hutch

[cardan]

The old-timers used to call the bronze they used "spelter" - not sure what it was but (in Australia) it came as a 1/8" (or so) square section wire and had the property of easy flowing and the ability to draw into the join between a tube and lug.

Almost sorry to have mentioned this. I thought it was interesting, and it was just a statement of fact. My late friend Jack learned to braze up frames from an old-time cycle builder who had a forge in his back yard business in Preston in the 1930s when Jack was a young lad. I had many conversations with Jack about brazing, bronze (old and new), spelter, fluxes, blow lamps and the kerosene that powered them, and so on, and my spelter wire came from Jack's shed.

I'm also sorry that my 1913 definition of spelter as a hard solder made from copper and zinc and other metals doesn't agree with "reputable" sources. Facebook?

Leon

[Hutch]

I don't use facebook -never have. I put the word reputable in inverted comma's deliberately - I think one source I looked at was Wikipedia.....say no more! :-)

I think it is great that Jack passed on his knowledge to you and I also think it is very interesting. I apologize if I came across as being overly pedantic as it was not deliberate.

-Hutch

[eddie]

Bear in mind that when carrying out 'brazed' repairs to tubular components, holes that are actually in the joint could be for locating pins, or single holes in just one component are probably to provide good access for the spelter. You may also find a random hole somewhere along the tubes that provides a breather for the expanding/contracting gases within the tube - without that breather, the spelter will (with the temperature change) get blown/sucked out of the joint. If there is a breather hole, leave it until everything else has cooled, then just fill it with soft solder to keep the weather out.

  Regards,
                Eddie.