C-Spanner for Colchester Student

I would like to swap chucks and I don't have a C-spanner.
It should be around 5.5" or 140mm diameter and would be grateful for any pointers where I could get one.

"Mike Perkins" wrote in message
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When I had an LO fitting Colchester I got a C spanner flame cut at a local place, then case hardened the pointy bit.
AWEM

On 22/05/2012 08:26, Andrew Mawson wrote:
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I'm starting to realise how scarce these beasts are!! Even adjustable C-spanners only seem to go up to 120mm diameter.
In the end I used some very large stilsons which worked rather nicely and have managed to swap the chucks over.
I though case-hardening was exactly that, being more or less a suface effect with very little penetration, and would have little effect on strength?
Many thanks for the idea. What thickness steel did you use?