AJS & Matchless Owners Club

Having read the Committee minutes I see that the new crankshafts are still not ready after what is now a lot of years

Why in the 21st Century were they made in cast iron....? When other options were available and not made in the UK by a reliable firm such as NJB of Coventry

Why were they then hardened, then softened to rectify a fault in the machining and then hardened again....which in my opinion is a case of "Bad Engineering Practice"

Déjà vu?

http://www.jampot.com/forum/viewtopic.p ... crankshaft

They are made from ADI cast iron by Zanardi in Italy whose credentials are impeccable. They delivered the blanks exactly on time and to spec and to price.
Same material as used in some TVR cars for their cranks, and also for some critical suspension and other parts on a lot of hairy cars. Why cast, not machined from billet or other methods . . . that has been done to death in the past - and the reasons and serious advantages are completely valid. See previous posts, also articles in the Jampot over the years.

They were to be machined in Austria by a company physically close to the engineer who designed them, Markus Gräf. Some were, and the results were very good. But that firm let us all down badly on timing after finding out how hard the material is to machine. Which is why many of them have been de-treated for machining and will have to be redone, which certainly wasn't part of the plan - but doesn't affect their integrity. It's just inefficient, no argument about that.

Even removing a bit of material for the purposes of dynamic balancing is a tough 'ask' in tooling terms because they are very hard indeed.

The prototype I have been running since 2013 with billet rods attached has been superb and feels unburstable.

It was a complete pain (and wholly unexpected) that the machining shop would have let us down, but the quality of the materials, the reasons for the choice of materials, and the resulting straight-fit product are exemplary - and extremely competitive in price terms. Machining from solid or other options investigated would have cost far more for small batch production. Compare costs of these with new cranks available for other marques, with far simpler 2 bearing bottom ends . . .

I, and the other people who originally suggested the plan to the Club to get some 650 cranks made, are obviously very embarrassed about the delays,and the choice of machine-shop was with 20:20 hindsight a poor one despite their eager blandishments, but I don't think the quality of the design or choice of materials, or indeed of Zanardi, is a fair subject for criticism, because they are first-rate.
I await my second dynamo crank patiently!

For anyone interested who doesn't know the history of the crankshafts, it was discussed at great length in this thread, http://www.jampot.com/forum/viewtopic.php?f=11&t=9124 where you will find the same questions and answers received.

In a nutshell, three club members in three different countries wanted a new crankshaft so they got their heads together put a lot of time into how and where they could achieve this. Knowing that the cost would be prohibitive for just three, they asked the committee at that time if the club members would support this, which they did.

I commend any member who is prepared to put considerable effort into making something happen that is also beneficial to other club members. I hope the experience of those concerned hasn't put off others from doing the same where they are able.

"Which is why many of them have been de-treated for machining and will have to be redone, which certainly wasn't part of the plan - but doesn't affect their integrity. It's just inefficient, no argument about that".

Yes it does affect their integrity.....It is Bad Engineering Practise....

IMHO not so much bad practice, but slightly poor planning / production engineering and a lack of communication by the machining sub-contractors. If they had been up to scratch, they would have briefed the designers that the material should have been machined before hardening.

Its bad practice to harden a material, then soften it , then re harden.....especially with cast iron.....It causes structural weakness in the metal

Both sides have had their say on this again, so I suggest that the subject should voluntarily be put to bed now. Anyone who has bought a crank and has concerns about it can get in touch via the committee.