is that the crank from Andover ??

https://andover-norton.co.uk/en/shop-details/15997
nice piece of cake..............!!

Yeah but its not stock....

With their recent tie up, I imagine this is the crank that Hemming was previously marketing?

So who in the UK went to the expense of making the gear to forge it? As for the price.....plus vat.....
Decades ago NVT had a few std crank forgings test machined by Laystall Engineering of Wolverhampton with a view to producing them as spares (MINUS the stress raiser they had previously left inside the drive side half so they break more easily) but Mr Negus told me that the cost was so great non were to be manufactured He also told me that he had the drawings changed to ENSURE the stress raiser was a thing of the past and that with the inside of the drive side crank CORRECTLY machined to drawing the extra bit taken from inside the crank still allowed them to be balanced correctly. Wonder what happened to the pile of crank half forgings?? I ASSUME they were forged??

J. M. Leadbeater said:

So who in the UK went to the expense of making the gear to forge it? I ASSUME they were forged??

Click to expand...

Nothing in the link indicating they are forged; most likely billet steel. For our Nortons, once you move to a billet steel, the material durability is so much better than the factory original that forging would be a bit excessive.


Looks very similar to what I have been getting from a manufacturer here in the States.

When you make a billet crank in the states, do you use barstock or simply cut a piece out of a bloom ? I've been involved in making large gun barrels out of what was essentially 4130 steel. If you ever do a sulphur print on the end of a bar, you invariably find a line of sulphur inclusion right in the centre of the bar. In making a crank, I don't know how you would avoid it. We tried using a local product by purchasing with certificate and found the sulphur and phosphorus levels were too high. Typically the desirable levels for both of those elements should be down around 0.005 per cent Our answer was to use a carbon arc furnace with selected scrap, however you guys might have vacuum degassed steel ?

Can't say for sure today, but a few years back the most common material for custom billet cranks here in the US was 4340 VAR (vacuum arc remelt) steel. The initial melt is a vacuum induction melt, and then it's remelted in a vaccum arc furnace. It's definitely clean enough for crankshafts, with very low sulfur and other contaminants levels.

Ken

I doubt we can buy that quality steel in Oz. Our defence manufacturing has pretty much gone, and that would be the only area where there might have been demand which would justify the steel suppliers stocking it. Ever buying high silicon aluminium seems to be a problem these days, and we have not had the Hiduminium RR alloys after the 40s. However I have found a supplier of titanium rod.
As I said I am amazed that Ken has got such a quality response to his efforts with the cylinder heads. I know he is still looking for another foundry to make them and is having difficulty finding suitable contenders.

Fast Eddie said:

With their recent tie up, I imagine this is the crank that Hemming was previously marketing?

Click to expand...

Indeed it is. This was confirmed to me by Simon Amos.
It should be noted that the crankshaft was developed for racing, featuring a low moment of inertia. This may result in an outright dangerous road ride, especially in the wet.
There is no mentioning of possible unsuitability at the Andover site.

Regards,

Knut Sonsteby

Why? - surely no more dangerous than riding a suitably equipped race bike on a wet track, know the bike and ride to the conditions track or road, I would have thought.