Joined: Aug 2017 Posts: 2,748 Threads: 31
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Location: Auckland, NZ
A colleague building up a very derelict RP found the rear stud flanges perilously close to the brake cam etc. The problem possibly relates to a recent enquiry. I notice the clearance on early cars is only about 1/16 inch and 1/8 on original semi girling.
I have not seen the car but it occurred to me that the cause may be a conversion of an earlier axle. Is clearance problematic with this work? How can a converted axle be easily identified?
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I was wondering whether this was an indication of whether the halfshafts had been over-lapped. Would also like to know the variables (and what practical measures to do about it!), as Bob.
Joined: Aug 2017 Posts: 848 Threads: 22
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Location: Near Cambridge, UK
Car type: 1928 tourer (mag type), short chassis Gould Ulster
Over lapping of halfshafts does nothing to the hub location; it just pulls the pinion into the inside of the differential, resulting in metallic particles in the diff oil.
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The axles which had Girling/semi Girling brakes from the factory had threaded bosses at the axle end for the 4 off 5/16" backplate mounting bolts. An adapted axle will need to use a nut and bolt setup. If there is very little clearance between the wheel stud and the brake cams, it is possible that someone has just used a hacksaw to cut away the original backplate and not machined axle ends to form the spigot that the Girling backplates locate onto.
Machining the spigot is a simple job on a lathe, but as the hole in the axle end has not been concentric to the bearing surface in either of the cases I have machined, I would be wary of just sticking a bull nose live centre in the hole and getting to work. Either use a fixed steady on a bearing surface, or use a fixed steady and then skim the end of the hole true before using a tailstock centre.
Joined: Aug 2017 Posts: 2,748 Threads: 31
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Location: Auckland, NZ
Thanks Stuart
I had forgotten, esp as other later makes owned all had nuts. Was too lazy to clear a path under my stored car to inspect.
Use of steadies can resolve many centring problems. I guess many amateurs do not have or never use. Decades ago I converted several housings with good threads to car stands reasoning that unlikely to ever need early ones again. Did not consider possible adaptation.
(And for those not addicted the challenge of how to set up for accurate work is much of the allure of lathe work)
