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Author Topic: Augusta progress  (Read 18465 times)
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Mikenoangelo
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« Reply #210 on: 22 January, 2021, 09:45:57 PM »

Lots of fiddly work involved to sort out the rear shockers.

First the saddle brackets for the connecting link. Hard to hold them to mill away the old welds on the bracket but a few clamps and a length of ex Stanley Steamer front axle tube did the trick (147. The shockabsorber arm ends were machined to take a new sleeve for the rubber bush (148).The arms had been severely fettled in the past and one had much welding done so rather than just welding the sleeve in place I copied a Hartford method, making a bracket fitting around the sleeve and bolting to the arm (149).The arm has three leaves held together with rivets, avoiding which meant making the bracket a bit longer than I wished. The trick with making multiple identical parts is to sandwich them together and machine them in one go (150). Lastly the bush sleeves will be welded into the bracket - but only when lockdown lets me out to visit the welder.

Then that strange offset link. I didnít think I could bend the strip neatly to copy the design seen in Davidís pictures and spent a while  pondering how I could simplify the job, eventually coming up with this design which just involves drilled steel strips bolted together with spacers between to provide the necessary 16mm offset between top and bottom bushes while still giving clearance between the link and the lower part of the floor and frame of the body (151).

I think the  position of the shock absorber and its connection to the axle are compromised by the offset and lack of lateral float. Perhaps the existence of two designs of the link indicates a recognition of this as a problem by Lancia.

On our car at least, the previous bodged repairs to the saddle bracket suggests that there are forces which the saddle bracket does not like. Davidsís second photo shows the wear to the inside of the link which must result from side thrust. I assume there are some side forces when one wheel goes over a large bump which are taken  by flexing of the arm and in the metalastic bushes in which the link articulates. The original offset links are made from something  harder than  mild steel and probably are just as stiff as my version. I am replacing the metalastic bushes with polyurethane inserts and will make sure they have enough side float on the inner sleeve to allow a bit of movement.

Mike


* 147. Machining the saddle bracket.jpg (166.89 KB, 640x480 - viewed 184 times.)

* 148. machined ends.jpg (109.35 KB, 640x480 - viewed 186 times.)

* 149. New ends to armsjpg.jpg (108.74 KB, 640x480 - viewed 188 times.)

* 150. Mass producing.jpg (166.09 KB, 640x480 - viewed 183 times.)

* 151. Prototype of new link with original.jpg (88.57 KB, 640x480 - viewed 187 times.)
« Last Edit: 22 January, 2021, 09:56:45 PM by Mikenoangelo » Logged
Dikappa
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« Reply #211 on: 23 January, 2021, 07:47:30 AM »

I love that machine work!  Makes me feel soo clumsy....
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nevillesponge
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« Reply #212 on: 24 January, 2021, 02:56:58 PM »

Mike, thatís impressive! I hadnít given thought to the wear being based on stresses. Iíd just assumed (perhaps naively) that it was because of having no bushing left due to degrading and general movement whilst driving. Your suggestion makes perfect sense, so Iíll need to keep a close eye on my brackets once Iím out on the road again.
David
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Mikenoangelo
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« Reply #213 on: 01 February, 2021, 09:32:17 PM »

Today while making connecting plates for the rear shock absorber links I had a flash of inspiration on how to hold the links to machine the rounded ends and smooth the sides.

Very simple in the end. Using the 300mm  rotary table with the stack of plates lined up with the centre of rotation of the table I found that a combination of two (sacrificial) blocks of aluminium bolted down to the table and then clamped together with a large ďGĒ clamp made an excellent vice to hold the stack of plates. Face down to round the ends and sideways on to skim the width, with short lengths of 6mm and 10mm rod in the holes to keep the plates lined up. I had drilled the plates in a stack so that measuring and marking was only needed once.

So I learned something new which makes the rotary table much more versatile.

Mike


* 152. shocker links.jpg (93.51 KB, 640x480 - viewed 103 times.)

* 153. Rounding the ends.jpg (147.1 KB, 640x480 - viewed 104 times.)

* 154. Skimming the sides.jpg (155.8 KB, 640x480 - viewed 103 times.)
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Jaydub
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« Reply #214 on: 02 February, 2021, 08:04:30 PM »

 
 Nice Job Mike, but only simple, as you put it, if the have the machinery and knowledge to use said machinery!
 Clever stuff as usual from you.
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1600 HF. S2.
Mikenoangelo
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Posts: 286


« Reply #215 on: 16 February, 2021, 08:17:40 PM »

Slow progress on the rear shock absorbers. It turned out that both were well worn, the wooden friction discs being so thin that the protective rims on the blade like arms were nipped together and the arms themselves squeezed out of parallel. One shock absorber was extremely tight until freed off by cleaning the discs.  

The Augusta friction shock absorber relies on a very strong coil spring to clamp the arms and friction discs, the degree of clamping being determined by a nut on the bolt holding it all together, the nut is locked by a split pin and therefore not readily adjustable. I struggled to find a means of setting the friction to an acceptable level because the springs on both shockers are so strong that the slightest compression of the spring virtually jams the movement of the arm. Clearly something is wrong, perhaps a previous bodge, as one of the clamping bolts, which should have a peg/notch arrangement to restrain the head of the bolt, had been swapped for an ordinary hex bolt and although one shocker had a spacer on  the outer end of the boss on the body of the shocker which acts as the bearing around which the arm swings, the other did not.

I found when taking them apart or re-assembling them, a plate bolted across the chassis side of the cast base will hold the spring compressed so other bits can be removed or fitted. In place on the car of course the base is bolted to the frame so the spring is controlled and the arms can be detached if needed.

Looking through a box of Andre Hartford bits, it struck me that I could dispense with the Lancia coil spring and use readily available Hartford parts, along with a new centre bolt, a Hartford star shaped dished spring and a few other bits to convert the Lancia design to something of a Hartford which would be a much better option.

Pictures 155 to 157 show the original and replacement parts. A new bolt with peg to stop the bolt turning, a tubular spacer to replace the spring, a slimmer spacer (recessed to take a clamping nut to hold the bolt to the base) , the original Lancia dished washer, the Hartford star spring, the tension adjusting nut (with indicator needle) and finally a locknut. The recessed spacer is needed as it acts as the bearing for the outer disc and arm, the centre boss on its own being a bit too short. Note the tension adjusting nut has to be 28mm AF to fit the Hartford indicator arrow and also needs a short spigot on the inner side to adapt the 14mm bore of arrow and spring to the 12mm of the Lancia size bolt. The locating peg hole was drilled 4mm and the peg made from a short length of 4mm drill shank loctited in place.

The original wooden friction discs were under 4mm thick but after a bit of measuring I found that replacing them with 5mm material would work, although needing 0.5mm or 1mm packing between ends of the short arms where they are bolted to the base. With this the arms and discs are parallel and the protective rims on the arms are just slightly separated. Photo 158 and 159. I suspect the originals were about 4.5mm thick but that was not available.

The available wooden discs for Hartford shockers are of a different size to the Augusta version but I found a supplier who can laser cut 5mm oak to suit and these fitted perfectly. I have a spare set if anyone needs them. They need to be soaked in oil before fitting and the metal faces of the arms greased.

The shockers can now be adjusted simply and they feel to operate very smoothly with only moderate ďstictionĒ. Now all I need is a visit to the welder before it can all go back together.

We know Lancia was an individualist but I do wonder whether the unusual design of the Augusta friction shocker had something to do with getting around patents?


Mike



* 155. Original bolt, spring and dished plate.jpg (135.4 KB, 640x480 - viewed 42 times.)

* 156. New bolt, spacers, Hartford spring and nuts.jpg (166.58 KB, 640x480 - viewed 41 times.)

* 157. New parts together.jpg (136.89 KB, 640x480 - viewed 42 times.)

* 158. Old and new discs.jpg (150.42 KB, 640x480 - viewed 39 times.)

* 159. Discs parallel when assembled.jpg (167.09 KB, 640x480 - viewed 41 times.)
« Last Edit: 16 February, 2021, 08:32:02 PM by Mikenoangelo » Logged
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