pinions and spring wrappings

[Parazine]

I find that the Chummy has a ride like the proverbial ox-cart on dry springs, especially if it hasn't been used for a while. A quick spray over with WD40 fixes the problem in the late winter, when I get the car ready and seems to last for the rest of the year, even though the liquid itself seems to evaporate after a few days.

[john williams]

I am amazed at the interest my question has generated.
 As an apprentice in the garage in the late 1950s, one of my jobs on certain cars; was to jack up the car, support the chassis on axle stands then lower the jack. We then used a bolster chisel to open the spring leaves and a hacksaw blade to spread grease between the leaves .
Then attending the local Technical College, we were told that the friction between the spring leaves produced a natural "damping action".

[JohnD]

Friction between the leaves as they flex has a damping effect. I have always assumed that binding springs with cord was done to increase the damping effect.
Daimler springs were a beautiful pieces of engineering. There is a spacer between each leaf at the fixing point to keep the leaves apart. At the end of each leaf thear is a phosphor bronze 'top hat' section spacer. The 'brim' of the hat is the same thicknes as the spacer at the fixing point. The crown of the hat goes through a hole in the leaf above. It means there is no steel to steel contact between the leaves and each leaf acts independently. Thats what you got for paying £1,500 for a chassis with no bodywork in 1934. That would have bought you several houses!

 I noticed the other day that Tony Betts has an Original Ulster front spring forsale with zinc strips between the leafs to prevent wear - i would have thought tho that zinc would have rubbed through fairly quick ? 

Link to image i cannt seem to post it:

http://www.7ca.co.uk/134235.jpg

[Duncan Grimmond]

Several years ago an Austin 7eer came to me for some zinc, one square piece for one job that escapes my memory and several strips for inserting into his springs. I questioned the latter use but he was certain and as I couldn't argue with his view he went away with them. I don't know if he did fit the strips but he hasn't been back for more.
Off-cuts of 0.7mm sheet zinc available free for postage costs if anyone wants some to experiment with it... cutting to your strip dimensions is extra!

[Chris Garner]

The front spring on our Ulster has the zinc inter-leafing. I believe these to be original ( 1931 ) and there appears to be no / little wear.

[austin]

As do the rears on the sets of original springs we have.

[Tony Griffiths]

Over many years springs will take a 'set' and lose their original camber and need replacing or re-tempering. Will the oiled, greased and bound springs last longer than a set left untouched? If not, might there be no point in messing with them? Are the zinc inter-leaves found only in Ulster springs - and what's our best guess as to their function? Reducing wear? Modifying the damping characteristics of the inter-leaf friction? Improving the ability of the spring to flex? Or something else?

[Ruairidh Dunford]

Zinc interleaves were used on front and rear sports springs (normally stamped 9C, from memory) to reduce corrosion, friction and noise.

A set came with the AB Chummy and are now fitted to one of Steve H’s cars.

[Duncan Grimmond]

Zinc certainly has a "lubricating" quality (strips laid on a concrete floor make sliding heavy machinery surprisingly easy) but it also is very reactive and I would expect a degree of electrolytic action in contact with steel. This would be likely to damage the zinc rather than the steel...

[Ruairidh Dunford]

The leaves are sacrificial and can be replaced, the more expensive, and harder to make, steel lasts longer and remains functional.

Having said that, many of the interleaves I have seen appear to be original and still intact.