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Motorcycle frame material types

Gents,

Does anybody have a description of the type of metals used for frame tubing and frame castings as used on 30ties era motorcycles.
Specifically Norton would be nice but I assumme they all used similar types.
BSI spec numbers or other international spec numbers would be most useful.

Does anyone have experience with using TIG and 308L or 316L on the casting/tube and intermediate kopper/brass weld material?

Cheers,

Rob

email (option): wd16h@telfort.nl

Re: Motorcycle frame material types

Aloha,

I did some TIG-welding on the cast iron where you mount the rear wheel. Sorry can’t remember the name of the part, but the forky thingy that the rear axel sits in with big nuts and so on. It was badly bent and needed fixing.

I think we used 12.64. Worked out well, but with some “sissling and popping” if you know what I mean.
This was entirely on the cast iron alone, not on the frame tubes or the joint between the two. Rather a concern was not to heat the whole thing to where solder in the joints would start melting (which at one time happened on my Bonneville).

Don’t know if this answers your question?

Best regards,

Simon

Re: Motorcycle frame material types

The tubes are mild steel and the lugs malleable iron castings...I'm not a welding expert so would seek the right information reference welding the lug material...The tubes can be tig welded without any issues...Ian

email (option): ian@wright52.plus.com

Re: Motorcycle frame material types

Hello Simon, Ian,

Thank you for the answers.

My problem is a crack in the casting which might have propagated into the tubing.
I need to open it up to see where it goes.

That means there is an interface with copper.
I am just not sure you can TIG weld the combination.
I have never done TIG welding on a frame, only on sheet metal where there is no copper "contamination".

What filler material would be correct on such combination? Simon mentions 12.64 but are there others?
Any other things to look out for? Preheating the frame or such.

Cheers,

Rob

email (option): wd16h@telfort.nl

Re: Motorcycle frame material types

I generally would say it is unlikely that both the cast iron and the frame tube has cracked simultaneously. But then again I have not seen your bike.

Main thing to look for when doing these type of major welding jobs on a frame I would say is to put the frame in a jig. 😀

Best regards,

Simon

Re: Motorcycle frame material types

I take many small items to a local fabricating company to get them welded...As I said I'm no welding expert but the chap nearly always does the job while I wait and usually Tig welds most things...What I do know from observation is that it's not going to end well if there is ANY contamination from residual braze or similar...The metal to be welded must effectively be clean, no paint, rust, braze, solder etc.....Ian

email (option): ian@wright52.plus.com

Re: Motorcycle frame material types

Rob, which frame lug is it that is damaged and how bad is the crack? As discussed on here before the material for the frame lugs is not simple cast iron, this would be to brittle for this application. Malleable iron is used, a type of iron that is cast and then heat treated to anneal it so there is a degree of flexibility in the material after treatment. Strike a cast iron lug with a hammer and it will crack or shatter. malleable iron will bend and only crack after repeated blows, more like steel. Malleable iron can be repaired by bronze welding, so can steel frame tubing so this may be a possible method of repair but it needs to be done by somebody experienced in this type of work, especially if it is a safety critical repair,ie. not just cosmetic. DO NOT try mig or tig with a steel or iron filler rod on a frame joint that was brazed during manufacture, it could cause serious embrittelment of the joint

Re: Motorcycle frame material types

Hello Gents,

Thank you for all the imput so far.
As usual in these cases, there appear to be differences of opinion on what can and what cannot be done.
In the end I decided not to do it myself.
I think it may be useful for the "public" to learn how my frame has been repaired.


Today, an ex ships machinist with 30 years of welding experience on all sorts of materials and combinations with TIG, MIG and MMA equipment, TIG welded the frame using 316L Cress filler material.

I first removed material around the crack in the casting which then showed that the casting was cracked because the original frame brazing done during fabrication in 1937 had not been filled properly at all. The visual end was brazed all aound the tube but inside the casting there was a non filled void which can explain why the crack developed. It went through the hole for the original positioning nail.

The welding was done by first heating the frame part with a flame and then sort of spot welding the crack in order not to put to much heat in it.
Directly after each weld he hammered around and on the weld with a small bench hammer to disperse internal stresses.
Apart from some fizzling of the "burning" zinc in the original brass there were no big problems. I did remove as much of the brass as I could before this operation and there was no brass where it was supposed to be.
It all looks quite ok for me. Only need to clean it up a bit.
He has used this technique on many frames over the past 30 years and never had or heard of problems. He has made a number of complete featherbed frame's over the years as well so I trust he has done a reliable repair.

"The proof of the pudding is in the eating" so I will see what happens.

Cheers,

Rob


email (option): wd16h@telfort.nl

Re: Motorcycle frame material types

Practical experience goes a very long way in situations such as this....Glad to hear you got it sorted Rob...Ian

email (option): ian@wright52.plus.com

Re: Motorcycle frame material types

Hi Ian,

I am also very relieved.
I did struggle with it as I am not the most experienced TIG welder and all the different possibilities and warnings did make me less certain.

Based on an earlier remark on the forum that we do not "air" our final solutions on the forum I thought it to be useful to add this experience.

The guy started his working life as ships mechanic and saw most of the world making repairs on different ships. Then came family which made him shore based. Since then he did all sorts of mechanical jobs, many of them including welding.
He also made garden gates in his own smithy as well as many restorations of historic metal work for houses.
TIG welding of pure copper to cress appears to one of his many self developed skills.
He now mostly manufactures specialty parts for several machinery companies, all in his own workshop.
He is one of those guys that lives and breathes metalwork in all its aspects and applications.

Another plus side, he also rides Nortons:slightly_smiling_face:

Stay safe,

Cheers,

Rob

email (option): wd16h@telfort.nl

Re: Motorcycle frame material types

Well done Rob! and the welder!, can you ask him if he can do my frame as well? the early Big 4 one, that has a crack in the same spot as yours, saddle downtube, and to the rear of the saddle lug, where the 2 rear tubes join the casting, and then there's the Enfield frame, but that can wait.

Cheers,

Lex

email (option): welbike@welb**e.net

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