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Stub axles on a herald


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Having broken one of my vertical links I've been ordering things and finally I think have the right parts to get it back together. However, fitting the stub axles to the vertical link is proving a bit of a challenge. The manual asy tighten up with a nyloc (various combinations of washers shown in various places) but what do you do to stop the stub just turning in the vertical link?

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Hmmm I wonder if it would be better to use a non nylock nut first to pull the stub into place and lock it then replace with the nylock. Both the taper surfaces do also need to be completely grease free so best cleaned with an alcohol...

Now you probably need to use the split pin hole at the other end of the stub to hold it to undo the nut.

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They can be a very tight fit in the housing and no amount of tightening the nyloc will pull them right in; you may just end up stripping threads. Use the old-school physics method of freezing the stub axle and heating the upright, contract one and expand the other, and be sure they're fully seated before tightening and certainly before rebuilding and using. 

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3 hours ago, Colin Lindsay said:

They can be a very tight fit in the housing and no amount of tightening the nyloc will pull them right in; you may just end up stripping threads. Use the old-school physics method of freezing the stub axle and heating the upright, contract one and expand the other, and be sure they're fully seated before tightening and certainly before rebuilding and using. 

How do you know when the stub is fully home Colin, does the parallel part have to come right up against the vertical link?

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2 hours ago, johny said:

How do you know when the stub is fully home Colin, does the parallel part have to come right up against the vertical link?

No, it's an interference fit (If that's the correct term) as the cone of the axle progressively widens into the vertical link, and when fitted there's a slight gap visible round the rear edge - see photos - so the torque tells you it's seated, but the first one I ever did back in the 1990s seemed to be seated until a good friend spotted that there was room to go still, and told me to redo it, and I promptly stripped the threads on the nut trying to torque it to the correct place by force alone. After that I always gave it a bit of assistance before tightening. I also have a 'new' one on my shelf since the 1990s that drops out if no nut is used. I wonder are there manufacturing 'tolerances' too for new axles, which may not be an absolute perfect fit and require fettling? In any case I just dislike drawing it fully home on the threads alone, me being me I'll break it.

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I tried putting a small screwdriver through the hole for the split pin to hold it to get the nut off - I snapped the screwdriver :( (luckily I was wearing specs)

I have managed to get the nut off by using a puller to hold the stub tight to the vertical link. I don't have any non nylocs of the right size to try, but it's needing quite a bit of force just to get the nut going (before reaching the nylon bit) I don't know whether it's the wrong thread or poorly made in terms of the new nut or the stub.

I'm going to try different combinations of new/old nut/stub and see if I can work out what's going on 

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How far does the stub axle fit into the upright without any tightening? The method I've always used before was that either the upright gripped the stub axle (including the time where it gripped it too tightly, too soon), and the nut turned, or else I just held the stub axle hand tight whilst turning the nut on the other end until it was able to draw the axle in. The nut shouldn't be so tight that it breaks screwdrivers before turning... that's a good indication of something wrong.  

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On 10/04/2024 at 15:32, johny said:

Thanks Colin. And yes Im sure there are discrepancies in manufacturing stubs as a taper's dimensions are quite difficult to specify let alone machine correctly...

The only way to check that would be to use "engineers" blue on the stub and by gently offering the "taper" to the axle the dicrepancy would show. Machining innacuracies especially on small batch work, would not be at all unknown. The Person who turns the stub is likely not to be the same as who bores the holes.

In the days before bearing shells, it was the accepted method of ensuring bearing`s where running on the full surface. You used a scraper to gently remove any high spots. (Been there done that, once on the bed of a 28ft Lathe, took 3 of us in turns nearly a month to get it right, between breakdowns).

Pete

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Got one in. It looks like the thread is a bit dodgy on the other one.

Wheel back on now and I can start what I was going to do over the easter break - oh wait, that's over now :(

 

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