That’s good information Rob, thanks. I don’t know which end of the wear resistance scale they would have selected or why but my thinking would be to go for the softer end to reduce the wear rate on the spring leaf and the cast housing, ie the expensive and tedious items to replace.
Shouldn’t the spring be captured whether the spring is up or down? I would have thought that they used a round bar of bronze slightly smaller than the cast diameter and then cut to fit either side of the spring with a few thou clearance for a smooth slide. The first photo shows this type of arrangement and Mike’s photo look like they are worn out badly?
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Yes, they are seriously worn. You can also see the thinning of the spring leaf set, so there could be another 3mm lost there too.
There is no running clearance tolerance specification that I can find anywhere for any vehicle with this system, so logic would step in and you would assume that when new, the running clearance would be small, probably no more than 20 or 30 thou.
This is not repeatable when the housing is worn and would require oversized trunnions. If you have the stock and machining facilities to mill them to size, you can go another hundred years.
That is the arrangement with replacement parts on my MG-TA.
Though the originals were half-rounds, and the tops were very worn.
The Morris conglomerate probably had enough volume that they could get half-round stock to size.
Jaguar or SS or their chassis supplier also didn’t do it that way. Perhaps they had a source of half-round stock.
I haven’t found a source of half-round stock, so I decided to order a 6" length of 1.5" diameter 936 bearing bronze, yield strength 21,000 psi, Rockwell hardness B26, so on the softer end of the Rockwell scale.
Thanks for all the good information, looks like I will have to re visit the road spring trunnions, I would be interested in how Rob manufactures new ones, please keep us posted Rob
Mike
I still have not heard from Worcester Classic Spares about the gaiters. I have sent them 4 emails.
I will try a phone call.
Progress has begun on making the bronze bearings.
Stock in hand.
First cut in the band saw took about 15 minutes.
Second cut also 15 minutes.
Unusual saw marks pattern, maybe due to flexibility in the band saw blade.
Two good pieces plus an extra.
Slitting into halves took 20 minutes each.
This was tricky as the saw cut didn’t want to stay straight.
But its ok, each piece is at least .1" oversize in height.
This is what we machinists call “roughed out”.
Next step, I have to set up my 1950 Atlas industrial drill press as a milling machine. This old thing is a workhorse, but since its set up for industrial production, it doesn’t have a hand crank for easily changing the table height.
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Rob
Polite Question?
Did you check the inside diameter of the trunnion housing, along the whole length as they become tapered and oval, if yes, how was it?
Regards
David
No wear detected in the trunnion housings. They were pretty well filled with grease. All the wear seems to have been on the flat surfaces of the bronze bearings. My guess is it was the lack of gaiters allowed the rusty ends of the flat spring leaves to rub on there.
I made one mistake, should have squared up the end of the rounds before slitting them into half-rounds. But as an old Polish machinist once told me, you’re not a real machinist until you can fix your mistakes before the boss finds out.
Two halves clamped together, milling the ends in an X-Y table.
Milling the flat face. This stuff does not machine like steel or aluminum which curls up; it sort of turns to powder.
My calculated height should be .590" but I stopped at a height of .600" and will trial fit them before taking off any more.
All done.
The installation method is to let the weight off the axle, put in the top one, jack up the axle, and put in the bottom one.
As the old ones had 97,000 miles on them, I don’t think I’ll need to do this again.
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Thanks for sharing that Rob, I just need to order all the work shop tools to make mine !
Do you have the final dimensions so I can look to getting some made ?
Next job on my list is front Axle out to get the axle eyes repaired, looking for a auto machine shop in Milwaukee, notes taken on the previous threads about the axle eyes
That’s a real nice fit Rob. The housing and top spring leaf are showing no appreciable wear. There’s more than a hundred years of life in this now. Do you know what the side thrust washers are made from - brass or steel? I would expect brass. They are called ‘rubbing plate’, pt no 43869, C637.
The side thrust bearings are steel
In reviewing this, I see I neglected to take a picture of the side thrust bearing and the thin shim.
Nice work Rob, never thought about using my drill as a mill, next project
The shim would need to be sized to ensure that no side pressure/force is exerted on the trunnion assembly when tightened so that it could rotate freely. A fiddly shape to cut by hand.
Yes, that undoubtedly explains why I found 3 on one side.
They had a punch press to make them.
I would trace them out using the cover plate, and since they are only .008" thick, use scissors and hole punches to cut them out.
Is Worcester Classic Spares the only place to get these rubber spring gaiters?
I’ve sent 4 emails and no response.
I tried calling but the call would not go through.
Is there anyone in the UK that could call them and see if they are still in business?
+44 (0)1905 821569
Their office hours are Monday to Friday 1PM to 5PM.
If you get through, ask them to check their email and spam folder for my messages.
As you say, they are only open 1pm to 5pm UK time, Monday to Friday, and have been closed over the Easter Holidays. The phones are not answered outside these hours and no answer machine either, but they are still trading and I spoke to them this afternoon. They have checked their emails and none have remained unanswered, so perhaps your’s Rob have dropped into the black hole of technology!!!
To confirm, their email is
info@worcesterclassicspares.com
They say they normally respond to emails within 48 hours.
Ok thanks. That’s the email address I’ve been using. I just sent email number six.
I tried calling on the phone, but all I got was a recording, “Your call cannot be completed as dialed. Check the number and dial again.”
I guess the term “dialed” applies to touch screen android phones?
That message I believe would be from the telephone/network providers, and usually indicates the number dialed is incorrect or includes a wrong or extra digit.
I think the number for Worcester Classics from the USA would be:
011 44 1905 821569
(011 being the international exit code from the USA, 44 being the UK dial code, you then drop off the initial ‘0’ and only use 1905 for the local area/city code, and finally 821569 the specific client number).
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