Monday, 4 October 2010

The man that can..

One of the essentials of pre 65 trialling is knowing someone who knows whats what what works and what doesn't. I 'm fortunate to have one on my doorstep, the other is knowing a 'man who can 'so that when your muse tells you to head off in one direction you have someone to hand who can make stuff ( well is essential, quickly is good, cheaply is fantastic!)
Access to a decent lathe and knowing how to use it, an industrial pillar drill and a stock -pile of various metals in sheet, rod and tube are all strong qualifications so step forward my father.
Normally happily making model steam engines ( stationary, rail and marine) or sailing or running them, he can usually be persuaded to produce some fantastic pieces of bespoke metalwork such as bushes, spacers and tube etc. all to your specific requirements. Over the years we have found that rather than working to drawings and measurements it is much more accurate to build to fit. Especially so on sthings like swinging arm bushes where the present dimensions may be far from what they were originally. and where two formally identical round holes are no longerround nor identical.

So to the depths of the Lake District I travelled armed with a box of aluminium sheet and rod plus the bike as it stood so that we could 'make to fit' . Hopefully at the end of the day iIwould have pre load spacers for the forks, spacers for the rear spindle, an original pre 65 rear brake plate that fitted the Sherco 17mm spindle and various other spacers.

In the space of a couple of hours we had the rear spacers turned on the lathe and drilled out for the 17mm spindle and they fitted first time! We made up mock ups with 22mm copper tube to get the right lengths so that the wheel was centred and the chain ran true then replicated them in alloy. The off side was simple as it is single piece and on the chain side we cut two pieces so that they and the brake back plate made up the required distance and bingo..
The brake back plate soon became the owner of a 17.5mm hole.

i have earlier said that the forks ran great and they do but they do 'sometimes' have a tendency to drop a quarter of an inch upon putting weight on them. I believe that this was because i was using an old valve type spring in each one as a preload spacer. Springs being what they are I suspect that they moved a little and became unseated so we made up a couple of 'top hats from alloy to do the job instead and popped them in.. As near as dammit the same sag and suspension movement so we'll try them ( movement of the old valve springs was approx 5mm over their 35mm length so we opted for 32.5mm long spacers as a mid point)

I think i also mentioned earlier that some of the brackets were 5 - 10 mm too wide so we made some tube to use as spacers rather than packing the gaps with washers.. I ended up with 8,10mm and 3/8 of an inch i/d tubes with an o/d of 15mm.

a nice days pottering and a decent lunch thrown in!

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