> that can be moved by tightening a bolt. Here's your chance to avoid the
> stupid mistake I made - buy a good one or you'll end up with this:
>
> http://www.triumphspitfire.nl/brokensplitter.jpg
>
> That thing came from Machinemart in the U.K. and cost little, but was
> scrap after splitting two stubborn ball joints on my Spitfire, while I had
> another two to go. The one I have now cost about $36, but I'm sure it will
> last the rest of my life.
>
This kind of follows on from what I was saying about camshafts earlier
today. From the looks of the fracture, it seems that this was a gray iron
casting. Castings are not bad, as long as the correct material is used.
For this kind of application, malleable iron would have been a better
choice, or a forging would be the best. Gray iron has a relatively low
tensile strength (20,000 psi to 60,000 psi) and fails with little distortion
before fracture occurs, which is what this appeared to do. Malleable iron
has greater tensile strenght and will deform before breaking.
I assume that Machinemart is the UK equivalent of our Harbor Freight, which
is an importer of cheap tools and machinery from China and other Pacific Rim
countries. They are OK, as long as you realise that what appears, on the
surface, to be a good tool, may not be so good under the skin. As in much
of life, you get what you pay for.
Michael Marr
Naperville, IL
1960 TR3A
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