OzVMX Forum
Clubroom => Tech Talk => Topic started by: pmc57 on July 24, 2010, 10:22:31 pm
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I was tired of the flogged our kick start lever flopping around on the RM so I thought I'd give it a bit of a resleeve to give it some more life.
First I had to make a special jig / fixture to hold the lever in the four jaw chuck before I could bore it out.
(http://i917.photobucket.com/albums/ad20/pmc57/SAM_0616.jpg)
Once set up in the four jaw it was into the hard work.
(http://i917.photobucket.com/albums/ad20/pmc57/SAM_0615.jpg)
Once the lever was bored out it was on to make the sleeve. The sleeve was made from high tensile steel with an interference fit (shrink fit) to the bore of the lever. The ID of the sleeve was given about 0.002" clearence on the pin.
(http://i917.photobucket.com/albums/ad20/pmc57/SAM_0618.jpg)
(http://i917.photobucket.com/albums/ad20/pmc57/SAM_0620.jpg)
Nearly as good as a new one, but a closer clearence fit on the pin would have made it ideal, 0.001" perhaps.
Many thanks to Oldfart for letting me use his lathe.
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Very clever making that Jig. great work.
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gee great job love your work.just walked in after a great aussie win over the spring blocks
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This is Ji's older brother folks....dont be fooled by the hairy arms.... ;D ;D ;D ;D...must have been a bit scary with that lever spining around, I reckon you should have made the bush half the thickness so you dont weaken the lever. Are you coming to Conondale next weekend Pete?
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Not a bad job and a good result. I would have held the kick start on the tool post and reamer in the chuck though.
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I'll be there Davey, just not riding, saving myself and the pocket for my skiing holiday the week after.
I gave the thickness some thought, there's still plenty of strength in the lever, the steel they use in those levers is also high tensile, I went about 2.5mm wall thickness of the sleeve which still left on average about minimum 4mm of wall thickness on the lever.
It was a little delicate with the lever flying around, that was the only problem, I was restricted to about 250rpm. I could have spent more time and added a counter-weight, if I were to do more I might go there.
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That is a well though out jig. Good idea.
Where is Ji by the way? I hope he hasn't deserted us. I love his tutorials (seriously).
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nice job ive got a few to do myself but i think ill just bore them in a drill press and use the lathe to make the bushes ;)
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At last. A "how to" that I can actually use and is practicle. Thank you..... :)
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Not a bad job and a good result. I would have held the kick start on the tool post and reamer in the chuck though.
Indeed. Stewart - do you have a vertical slide?
Luke
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Lozza's suggestion of holding the lever in the tool post and having a reamer in the chuck is another alternative, however we can only work with the tools we have available at the time and as Luke said a vertical slide attachment would make it easier to set-up. This method does also require additional tooling like micometer adjustable boring bar that can be mounted in the chuck, you wouldn't find many home workshops have these, a reamer is only designed to remove 0.5mm of material max. and can't be used to take out 2.5mm/side (5mm on dia).
TT5 Matt's method of using a drill in the drill press will work, but I would like to finish it off with a reamer to obtain a suitable surface finish, hole quality (roundness) and size tolerance so the sleeve fits as well as possible. Choose a nominal bore size you want to achieve then buy a HSS reamer (ie 19mm diameter) to suit, drill out to 18.5mm and ream to finish.
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Luke , No ......Should I buy one.
It was a please watching a master at work .....also note the gap was removed ;)
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so what did you do to the male end of lever, i would assume it was equally worn.
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Luke , No ......Should I buy one.
It was a please watching a master at work .....also note the gap was removed ;)
NOTED!!!
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so what did you do to the male end of lever, i would assume it was equally worn.
get a new knuckle or if there the same as a bitchy burner with a leckie start which only gets use when the battery is stuffed it will be like new and use your recondition top half,old yams are good for that as the splines 250 up are the same so plenty of choices on epay and go for $15 up,some even are the right shape/length
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Would it worked just as well if you welded up with nicole bronze and then machined a new hole? rather than a sleve.
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Lozza's suggestion of holding the lever in the tool post and having a reamer in the chuck is another alternative, however we can only work with the tools we have available at the time and as Luke said a vertical slide attachment would make it easier to set-up. This method does also require additional tooling like micometer adjustable boring bar that can be mounted in the chuck, you wouldn't find many home workshops have these, a reamer is only designed to remove 0.5mm of material max. and can't be used to take out 2.5mm/side (5mm on dia).
TT5 Matt's method of using a drill in the drill press will work, but I would like to finish it off with a reamer to obtain a suitable surface finish, hole quality (roundness) and size tolerance so the sleeve fits as well as possible. Choose a nominal bore size you want to achieve then buy a HSS reamer (ie 19mm diameter) to suit, drill out to 18.5mm and ream to finish.
The boring head would be unnecessary, you can use plain cutting tools in the chuck. The hole centre was not critical dimension just the hole and bush have to be concentric.A 'D bit' would have been perfect for this application.
Yes correct drilling then reaming to final size in the go, tool post jigs are far more rigid.
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Hoony
In this case the male end was in good condition so I didn't need to do anything to it.
If it were worn there's a couple of options, if only slightly worn you could put in in the four jaw and take a light cut to clean it up to make it round and parallel and make your sleeve to suit, or if badly worn and deformed you can weld it up and re-machine it, circlip groove and all. I've done this before and it worked well.
This is when you have to ask yourself is it worth the time and effort if new items are available for < $150.
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In my 42 odd years of working in engineering related jobs I have discovered about 400 ways to skin a cat. :)
Depending on the cat and how keen he is to be skinned. :)
You have used one of those ways with an excellent result. ;)
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Spot on Mike52, there's oddles of ways to do this job, the trick is knowing the various options and working out which can achieve the result you need with the equipment you have.