Morris Minor Owners Club

Where it is essential that a nut should remain fastened when subject to vibration, it should be (a) secured with a spring washer OR (b) secured with a locking tab OR (c) be secured with locktite or punching/hammering the threads OR (d) be a nyloc nut.

So...... How come wheel nuts are just done up tight? Why bother with locking devices on other nuts?

Discuss........

I will assume that wheel nuts are checked more frequently than other nuts. I actually tend to use spring washers on most things, just for that extra bit of self satisfaction.

Far more frictional area exists on the tapered surface of a wheel nut. By the time you take into account thread lead-in and corner chamfers on an ordinary nut there's not a lot of mating contact left!! (old Whitworth maybe not so bad as they sometimes had less/no corner chamfer on the contact side, and bigger chamfer on the outward side, thus making them theoretically non-reversible.)

John (?) Beardmore wrote a long piece on here a while ago postulating that spring washers did almost nothing, and I have to say I agree with that

Hello Andrew,

I think I would rather use them than not. I know that some are better than others, the ones with the slant cut seem to dig into the head of the bolt when you undo it. I did have a car once that had all the sump bolts wire locked (about 30 of them) that was quite a lengthy task to do (And yes I do have wire locking pliers)

Alec

It is interesting, the MZ uses almost no spring/locking washers - virtually everything that needs to stay put on an MZ does so through a process of being 'done up very tight'*.

That doesn't stop me using Nyloc or Spring washers on the minor, and tbh, I put Nyloc on the seat on the MZ, because they kept shaking themselves off

(*The clutch is on a taped shaft and all that holds it there is doing it up tight, and friction!)

Hello Kate,

tapers are a common way of securing tools in lathes\drills\milling machines etc. No screws either just insert the tool and it is gripped in the taper.

Tapers can be very difficult to split when assembled for a long time, showing what a secure method it is.

Alec

The good old Morse taper... Remember them well from my toolmaking days.

Many modern engines have no keyways on crankshafts or camshafts and rely on the nut holding the pulley in position, some engines use diamond covered washers to give more grip for a given clamp load where high "stab" loads are present because of very severe cam profiles but most normal production engines just rely on the clamp load from the nut, no nylock or spring washer in sight.

Some engines use a keyway on the crank but the slot in the pulley is twice as wide as the key, this gives the engine assembly operator a rough guide for assembly then when the timing is accuratley set it will be somewhere in the middle and held by the clamp load of the nut, on final tightening the key will actualy do nothing. PSA/Ford/Volvo DW10 engine is an example.

Modern electric nut runners which can tighten a bolt/nut to an accurate torque or a torque and angle and high quality consistent materials mean that spring washers or nylocks are not needed on modern engines, the closest is some exhaust manifold nuts which are squashed across the thread before they are fitted and some bolts which have a pre-applied thread locking compound although on a normal engine this will only be the flywheel bolts.

On a different tack, modern sealants/glues are quite capable of sticking an oilpan on an engine with no fixings, no manufacturere has dared do it yet though!

Steve

During my days studying for an engineering degree, I read that the wings on most passenger aeroplanes are glued on. The glue is so strong, it is actually stronger than a nut and bolt but, for aesthetic purposes they also rivet them. The only reason they rivet them is the general public won't accept glued wings as a safe method of attachment and would probably refuse to get on a plane that had glued on wings!!!

I always check them for traces of Araldite on the wings before boarding!

Dean wrote:During my days studying for an engineering degree, I read that the wings on most passenger aeroplanes are glued on. The glue is so strong, it is actually stronger than a nut and bolt but, for aesthetic purposes they also rivet them. The only reason they rivet them is the general public won't accept glued wings as a safe method of attachment and would probably refuse to get on a plane that had glued on wings!!!

Known as "chicken rivets"