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May 08, 2015 12:33 am
May 08, 2015 12:33 am
Subject: Re: Brake overhaul - levers
Interesting topic!
My experience on my 1933 16/80 is that the original Lagonda machining was first class - must have been a tough place to be an apprentice. Holes are where they should be and individual parts are made to high standards of accuracy and practice. I don't know about the new company's standards...
The oddly-spaced holes may have been to direct more of the braking effort to the front, but I'm not familiar with the LG45 brake layout so that's just a guess.
I'm a mechanical engineer, not a metallurgist, but my two cents' worth is:
With old castings and forgings, it's hard to be sure what the composition of the metal really is. This does mean that your weld repair should be done by someone who really knows their stuff. Cast steel should be every bit as good as its wrought counterpart for tensile strength and ductility (except that it won't have its yield strength raised by cold working). The same steel, but forged, will have somewhat better strength in the direction of metal flow, but forging was probably chosen more for cost reasons than for better properties.
As I said in an earlier posting, if I have to repair a worn hole, I will do it with brazing in a thin steel sleeve. The temperature for brazing is well below anything that will cause trouble for the lever metal, whatever it is, and the braze strength approaches that of steel. To me it's the least risky option.
Having said that, there are many ways to solve the same problem!
Alec
Interesting topic!
My experience on my 1933 16/80 is that the original Lagonda machining was first class - must have been a tough place to be an apprentice. Holes are where they should be and individual parts are made to high standards of accuracy and practice. I don't know about the new company's standards...
The oddly-spaced holes may have been to direct more of the braking effort to the front, but I'm not familiar with the LG45 brake layout so that's just a guess.
I'm a mechanical engineer, not a metallurgist, but my two cents' worth is:
With old castings and forgings, it's hard to be sure what the composition of the metal really is. This does mean that your weld repair should be done by someone who really knows their stuff. Cast steel should be every bit as good as its wrought counterpart for tensile strength and ductility (except that it won't have its yield strength raised by cold working). The same steel, but forged, will have somewhat better strength in the direction of metal flow, but forging was probably chosen more for cost reasons than for better properties.
As I said in an earlier posting, if I have to repair a worn hole, I will do it with brazing in a thin steel sleeve. The temperature for brazing is well below anything that will cause trouble for the lever metal, whatever it is, and the braze strength approaches that of steel. To me it's the least risky option.
Having said that, there are many ways to solve the same problem!
Alec