Terry Plata Posted August 25 Share Posted August 25 Challenge: The oscillator housing and gears are worn and nonfunctional. By moving the gears closer together by about .020" they again mesh and bring the oscillator back to life. The first step was to bore the drive gear shaft oversize. Step 2 is make a new brass bushing to match the new bore. Step 3 is offset the bushing in a four jaw chuck by .020". The screwdriver slot was cut to allow rotation of the bushing upon installation to fine tune rear clearance if necessary. Final photo shows the assembly complete with gears in mesh. A bit unconventional but is works! Terry Plata 3 1 Quote Link to comment Share on other sites More sharing options...
Chris Jacobsen Posted August 25 Share Posted August 25 Good idea! Another method may be adding somw friction to the driven gear to reduce backlash. Another less feasable method was in vintage car radios, they split the large gear in half and put a spring between the two to eliminate lash. Food for thought but this is probably the most practical short of getting a custom gearset. Quote Link to comment Share on other sites More sharing options...
Terry Plata Posted August 25 Author Share Posted August 25 Chris, that radio dial gear idea is a good one. Would not have worked in my situation because the gears did not really touch at all. I have attached a better photo of the new bushing to see the offset. Worn gears or not, they will not move if they don't mesh.. Quote Link to comment Share on other sites More sharing options...
Chris Jacobsen Posted August 25 Share Posted August 25 2 hours ago, Terry Plata said: Chris, that radio dial gear idea is a good one. Would not have worked in my situation because the gears did not really touch at all. I have attached a better photo of the new bushing to see the offset. Worn gears or not, they will not move if they don't mesh.. Nice! Good machine work there. The gears must have been pretty munched then. I would think it a possibility that there may be Chinese gears available if you measured the diameters and kept to the same tooth specs. Gears are always tough unless the application is common. I have a set of broken Fiat car transmission gears that will never be available outside of custom machining, only way I got the trans working again was to buy a used one from Italy.... Quote Link to comment Share on other sites More sharing options...
Terry Plata Posted August 25 Author Share Posted August 25 If the Fiat tyranny goes out again consider changing to a more common domestic trans. 1 Quote Link to comment Share on other sites More sharing options...
Chris Jacobsen Posted August 25 Share Posted August 25 7 minutes ago, Terry Plata said: If the Fiat tyranny goes out again consider changing to a more common domestic trans. Wish I could, the dimensions do not lend to any sort of easy swap though and the car is bone stock except higher compression and better carb so I would prefer not to cut it up. Quote Link to comment Share on other sites More sharing options...
David A Cherry Posted August 27 Share Posted August 27 (edited) Great idea, did you use superglue to hold it into position? You could knurl it lightly on the lathe for a pressfit, and then open it back up slightly with some emery cloth or possibly a reamer.. anyway, I like the idea.. in the past, I have done similars by rotating the front and rear bearings 90° to compensate for the ware in one direction.. Edited August 27 by David A Cherry Quote Link to comment Share on other sites More sharing options...
Paul Michael Posted August 27 Share Posted August 27 On 8/25/2023 at 3:45 PM, Chris Jacobsen said: Nice! Good machine work there. The gears must have been pretty munched then. I would think it a possibility that there may be Chinese gears available if you measured the diameters and kept to the same tooth specs. Gears are always tough unless the application is common. I have a set of broken Fiat car transmission gears that will never be available outside of custom machining, only way I got the trans working again was to buy a used one from Italy.... What year FIAT? I've got a couple . . . ! (-; Quote Link to comment Share on other sites More sharing options...
Terry Plata Posted August 28 Author Share Posted August 28 Thanks David, I turned the OD first to a light press fit. Then moved jaws 2 and 4 over .020" using a dial indicator in the tool post. Then rough drilled and bored to diameter. I was prepared to light knurl the OD but it slipped in nicely. The bore in the oscillator body is a blind hole so the new bushing has a 1/4-28 thread in the bottom for a jack screw should I need to extract. Super careful on press fits in old brittle pot metal parts. Quote Link to comment Share on other sites More sharing options...
Chris Jacobsen Posted September 22 Share Posted September 22 On 8/27/2023 at 11:20 AM, Paul Michael said: What year FIAT? I've got a couple . . . ! (-; 64 1500 spyder 4speed, that was just before they were blessed with the much more robust 5speed... I have 2 trans with a first gear tooth snapped off the cluster gear. I now have 2 spare trannys so hopefully lasts my lifetime? Always hope. Quote Link to comment Share on other sites More sharing options...
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