A while back there was a discussion regarding a reproduction timer that was less than stellar coming out of the box. Someone asked for a photo of my fixture for cleaning up the runways - see attached.
Is there any significant chipping with that setup Steve? I remember Uncle Stan talking about using a counter-rotating Dremel setup. Now that he has more toys in the shop he may have come up with a different approach.
Thanks for the photos.
Garnet
No there isn't Garnet. I take real light cuts progressively. This was an original Tiger I cleaned up for a fellow T'er.
Nicely done!
Garnet
I am not quite sure how you center it vertically, Steve. It looks like you have some wiggle room in how you set the timer in the jig.
I suppose one could use a dial indicator as you turn the chuck to see if there is run out on the races, but since the timer might be a used piece, the races won't be true. Just thinking it through.
Steve, I think I have an old New Day timer that I am currently using. A few years ago I looked at the timer inside and noted the plastic separating the contacts had worn. Can you refinish this type of timer? Any idea how thick the brass contact patches are? If the surface was smooth I'd try a carbon brush to reduce wear.
Richard: The timer case is centered in the jig as it is machined out much like an original timing cover plate and using a dial indicator - I'll take a photo of the side that the case clamps into and try to post it tomorrow.
Cecil: I have not tried to face off a New Day but I suppose I could try one - I have some here - just have to set the boring bar cutter up a bit different. Not sure how deep the contact segments are - might experiment on one.
I believe it was Stan Howe that posted a pic of a simple jig to clean up the timer, maybe he will chime in. Cecil I use my drill press with a mandrel and cut of wheel to dress up the new day, I would stick with the original type brush though, KB
KISS... its a 1000 rpm timer. Dont over engineer this stuff. I chucked mine into a 4 jaw chuck and indicated off the rim that fits the front engine case. Just like a timer alignment tool.
Where the chuck engaged the case is pretty rigid due to the fiber ring and contacts so there was no distortion. This old timer had the roller making contact only on the forward half of the contact ring and was worn into it at least 1/8" all the way around. The roller itself was a gonner and got destroyed removing it from the camshaft stub. I used a simple tool holder (no boring bar) with a carbide tipped tool and cut away. It probably took 3 passes to finish.
The contacts are actually a pretty good grade of steel as the chips turned dark. For the experts here, you can check it with an ohm meter when finished. Mine read infinity. A stock used roller finished the job off and even with the larger ID the spring was still tight and no roller float or bounce. troop
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Trooper, I do mine the same way except with a 3 jaw chuck.
Taking light cuts doesn't require tightening the jaws tight enough to distort anything and using the outside cutting tool for boring insures there is zero spring in the "boring bar".......
I see, so you indicate on the inside edge of the cover between the edge and the race. I saw where you placed the cover in a recessed area but figured you'd fine tune the alignment so your cut would be true to the centerline of the case.
I like it better than using a chuck because it eliminates the possibility of distortion by tightening the jaws and it places the case perfectly vertical.
The cut needs to be true to the outer diameter of the case. I get my fixture set up then check it with a dial indicator, adjusting until there is no runout on the OD of the fixture or timer case.