Hi,

Do all half shafts and hubs have the same taper? I have a type 3 (1931 narrow) axle and a second hand hub. There feels like there might be a slightly different taper (only probably 1 degree). Is this likely, or is it just a worn hub?

When I lap the two together I get even marking on the shaft, but if I hold the hub slightly off the shaft it feels like it might have a little bit of play.

Is this likely, or am I worrying to much?

Peter, It is possible that the end of the shaft is ‘digging’ into the outer edge of the hub as you lap; I always open out the small end of the hub to the diameter of the extreme end of the shaft. Also many ‘pattern’ parts were made for 7s such as Regent in the 1920/30s so may have a slight mismatch if both parts are not from the same source.

Peter, in addition to the above, did you check for ‘high’ spots around the shaft keyway and hub before you started lapping? Failure to do this can make it impossible to get a good result with the lapping process. Also beware that too much lapping can pull the shaft too far into the hub resulting in the spur gear on the other end jamming against the inside of the diff carrier, and locking the axle. It’s a good idea to heat the hub up with a hot air paint stripper before you finally fit it. Trial fit first and check that the key is not bottoming out on the hub. I always put a blob of thick red paint on the nut and hub to show up any movement in service. I am not an enthusiast for the ‘use a scaffold pipe on your spanner brigade’ If you have a good fit normal tools should suffice.

The taper on all A7 halfshafts (including the late extended taper type) is 1:8.

Fit the outer hub to the halfshaft without the key and tighten the nut. Look at how much thread is sticking out beyond the nut. If the split pin hole is beyond the castellations, then you have probably got too much wear in the tapers of the hub and/or the halfshaft.

If OK at this point, dismantle, fit the key and re-assemble. Check the same amount of thread is visible beyond the nut. Note that Woodruff keys were always meant to be "fitted", i.e. adjusted to suit.

When doing the final assembly (as per Ian's excellent advice), if you can insert the split pin, well & good. However, don't worry if you can't. ALWAYS re-tighten the nut after the first 100 miles or so, and keep on tightening it every time you service the car. It helps if you have an open-centre wheel to stop the hub turning round, or make a bracing device out of a worn brake drum and a 3 ft length of angle iron (I think this is mentioned in the 750 Companion).

New hubs are now available, and good quality halfshafts will be soon.

David