For some reason, and I am unable to fathom out why, the wheel nut spanners for all three of my small horsepower Rolls-Royces have become increasingly incompetent and incapable of compressing the spring-loaded, serrated locking plate sufficiently far to allow reasonably free rotation of the wheel nut when using the hammer. In consequence, it has been very, very difficult, if not impossible, to tighten up the wheel nuts on some hubs to remove all play. My MOT man is convinced I have failing wheel bearings, which I most certainly have not. Excessive use of the hammer has told me that all is not well.

Early 20/25 Locking Plate and shallow central screw.

Whether the root cause is an excess of copper/nickel and chrome plating on the wheel nuts or the result of some creeping distortion of the spanner over many years of use, I do not know. I have lubricated the screw threads which drive the spanner's compressing cup inwards, I have removed what might be an excessive depth of paint at obvious points of contact on the spanner, all to no avail. In trying to achieve maximum compression, wrongly I have even used a hammer on the tommy bar with disastrous results, either bending or even breaking it (see the one illustrated here) On my 1924, 20 hp car, the cause appears to be clear: the hub locking plate has a central screw which stands very proud and when the compressing cup is screwed inwards it rams up against it, preventing the cup travelling any further, thus disallowing a complete separation of the two sets of serrations on the locking plate and the wheel nut. In most cases for the three cars, the serrated edges of both have been so tight on bashing the spanner handle clockwise that it has become a very frustrating process attempting to get the serrations of the two lined up for full locking.

Mid-Series 20/25 Locking Plate with no central screw	Early 20hp Locking Plate with proud central screw

Placing some hard packing behind the rims of the compressing cup of the spanner did do the trick and for months I used a couple of half inch washers bent across their diameters to a right angle. If the washers are too big they catch the serrated edge of the locking plate and wheel nut and so their size is critical, hence the bending of them in the vice. However, holding the two at opposite poles or thereabouts is a pain whilst one is trying to rotate the small, fixed tommy bar or the lever and ensuring that the spanner's two spring- loaded levers do not dislocate from the grooves behind the shoulder of the wheel nut, all at the same time.

I estimated an optimal extra distance the locking plate would be required to travel in order to allow deeper separation of the two sets of serrations. 3 millimetres seemed about right. I then drew a simple design of an inner sleeve and 3 mm rim extension, no wider on diameter than the existing cup, and got a lathe expert, a friend of a friend, to make one up and to fit it into the spanner. It worked beautifully and so he made me two more. Removing a wheel nut is now so easy and eradicating all slack between wheel and hub on tightening up has been achieved completely.
Three weeks after all three spanners had been modified, it suddenly hit me that for the 1924 20hp car with its axle shaft nut screw standing proud like a chapel hat peg or its analogous anatomical relation, the problem is easily solved by removing said screw prior to operating the wheel spanner, but then there is always the risk of losing it in the event of a need to use the spare wheel (in mud at the Annual Rally, in the garage floor debris or down a rainwater drain etc.).

If you fancy making yourself one, be aware of the way in which the locking plate works. If you have removed a brake drum using all the special tools, you will know what I am talking about. At the centre of the locking plate it is the protective cap over the axle shaft nut. It is a separate component and it varies in design between the 20s and the early to late series of the 20/25s. If your adaptation of the cup is too small on its internal diameter or has no central hole at all, the spanner cannot perform whatsoever because the cup extension you have fitted will simply press against this cap, which is immoveable. Just remember that your extension must press solely on the locking plate and nothing else.

Underside view of Compression Cup showing Cup Extension.	Side view with extension to cup. Note bent tommy bar.

The friend of a friend, retired man Arthur Booth of Nottingham, has expressed a willingness to make and fit such an extension for fellow enthusiasts for £20 plus post and packaging.
Arthur's e-mail address is atb12@tiscali.co.uk and his telephone number is 0115 9654958