Front axle sheared through. A fatal design flaw??

[mole42]

The inner taper mates first with about 0.1mm play in the outer taper. I.e. you can wobble the axle from side to side when inserted into the link. Surely this cannot be correct? Other have said to lap the axle in, but this is a lot of lapping! It does appear that there is a problem with the specification of one of the parts. This amount of play is sufficient, in my view, to allow the flexing in the axle that caused the breakage in the first place. It could also affect the handling. Does anyone have any connections with the companies that make these parts so that we can follow this up?

This is pretty much the same as my experience with Witor axles and my old vertical links. I thought the link might be worn even though there was no evidence of movement on the stub axle so I went ahead and lapped the parts together. You said in post 37 that "they all come from the same supplier" so maybe the machine shop has the CNC setup slightly wrong?

Richard

[dasadrew]

Got my Witor stub axles today - pretty good and quick service!

Am a bit surprised that the steel seems to have inclusions in it (see pic). Not so worried about this, but they are said to be out of high grade EN24T steel, which is also used for aicraft propellor shafts and landing gear. I must admit I've not seen that sort of inclusion (or corrosion?) on the aircraft components which I've seen.

Drew

DSC01569.JPG

[wilf]

I also received my new stub axles, plus the new uprights that I had also ordered from Chris Witor.

First job was to check the taper fits - below is the result of blueing them - quite happy with that, could not be better really, no need for any lapping in. Fit was the same no matter which upright I fitted each axle into.

IMG_4699r.jpg .

[MikeParker]

I also received my new stub axles, plus the new uprights that I had also ordered from Chris Witor.

First job was to check the taper fits - below is the result of blueing them - quite happy with that, could not be better really, no need for any lapping in. Fit was the same no matter which upright I fitted each axle into.

The Chris Witor vertical link looks a bit different to the one from Rimmers, so may be machined differently.

So, are you saying if you put the axle into the vertical link (upright?) that you cannot rock the shaft from side to side? The problem with the blue compound is that it will still wipe evenly from female to male providing both tapers are of constant angle. In my case both the link and axle are newly machined and are of constant angle, but slightly different angle to each other. The link has a steeper taper than the axle, hence it can rock from side to side.

[mole42]

I also received my new stub axles, plus the new uprights that I had also ordered from Chris Witor.

First job was to check the taper fits - below is the result of blueing them - quite happy with that, could not be better really, no need for any lapping in. Fit was the same no matter which upright I fitted each axle into.

.

I'd have been more than happy with that as delivered - mine were like that after 4 hours of hand lapping.....

The next check is to see what camber you get with the new vertical links and adjust the shims accordingly. I had to put 0.014" on the offside and 0.022" on the nearside with the original links. I guess the original shims had been lost along the way!

Richard

[wilf]

MikeParker

I checked the fit - when very loosely fitted you can discern some side to side rock, but as soon as you put the slightest effort into pushing the shaft home into the taper that disappeared.I can't see it being any problem at all, the witness marks ( showing up in the blackening on the spider) look even on both mating areas.

mole42 - won't know for a while as this will be a winter project, but thanks for the reminder that I will need to check/set up the camber, next job will be to find/make a camber gauge!

[DJT]

Torque setting for stub axle to vertical link is 50-65 lb/ft. I think by the time it's done up that tight there won't be any movement remaining.

[mole42]

, next job will be to find/make a camber gauge!

There’s quite a usable one available for the iPhone…

[wilf]

Of course - I forgot that, thanks.