Motorcycle clutch basket refurb

[olderdan]

I had a clutch basket that had become notched but was otherwise ok, tooth and bearing track wear was minimal so I decided to try and reclaim it and keep as a spare (nothing to loose).
The width of the slots is not critical as long as they are smooth so I planed out the wear in the lathe.
I used the topslide as a hand operated ram which has worked well in the past for keyways etc and with a suitable tool in a boring bar and indexed it turned out well.
This was actually done on a faceplate but I forgot to take photos at the time so I mocked it up again in the chuck as an after thought.
This is maybe not best approach for easily replaceable parts but this was done as an exercise for when there is no option, and anyway I can never throw anything away.
I have made many things in the past but never thought to record them until joining HMT.





Regards
Olderdan

[tonyfoale]

Dan,

Nice one, but widening the slots creates more backlash which can lead to a roughness, particularly in traffic when you are varying the throttle opening. This will also accelerate wear, but I guess that doesn't matter if the alternative is junking the basket.
You are a man after my own heart, I never throw anything away either.
Regarding keyways, and similar jobs like the clutch basket, you might find it useful to use a pneumatic cylinder for the tool driving instead of the hand lever. It is easy to work out how to mount the cylinder and you could use a manual valve to oscillate it back and forth or you could automate it with a set stroke with a couple of microswitches and a solenoid valve. Alternatively you could use the pneumatic equivalent of microswithes and make the whole thing air powered with no electrical bits. I use the microswitch system on my mill for slotting, usually making aluminium clutch baskets. The microswitches are mounted on a slide so it is a piece of cake to set the extremes of stroke.
I picked up a 4" cylinder at a flea market, at 100psi that gives 1257# force which is overkill for anything that I need to do.

[Frank S]

With a cylinder that is larger than you need you can always use a pressure regulator in line to fine tune the force you want. Much better than having one too small and having to bump your compressor to a higher pressure

[tonyfoale]

I found some pix of the BMW drum brake activation.


You can see the outer cable connected to the left side lever and the inner cable connected as usual to the inner cable


Here you can see the BMW solution, which I had forgotten, to the problem that I mentioned of slightly different leverage of the cam on each shoe. Basically they offset one of the cams from the usual position. to ensure that the cam contact point on each shoe was the same.
There is some other cleverness in there also. With this cable on each lever system all the springs do is pull the shoes closer relative to each other so one shoe may be pulled away from the drum while the other is left rubbing. The solution adopted was to have one spring stronger than the other and have an adjustable shoe stop. So the stronger spring would pull one shoe onto the stop so it couldn't withdraw any more and then the other shoe would be pulled back until stopped by the cable adjustment in normal fashion. In my opinion all DLS brakes should be done that way.

There is some free software on my web site about drum brakes which you might find of interest, it is freeware.

[DIYer]

Thanks olderdan! We've added your Clutch Basket Refurbishing to our Motorcycle category,
as well as to your builder page: olderdan's Homemade Tools. Your receipt:

Clutch Basket Refurbishing by olderdan

tags: motorcycle, clutch

[PJs]

Nice Save Olderdan! Twill work in a pinch for a restored street bike. Love that QCTP tool post you made, its a beauty and brilliant? Thanks for sharing with us! ~PJ

[olderdan]

A device similar to your suggestion was made some years ago designed by a very clever chap who joined our firm from BSA, this was made for form grinding helical gears on a standard surface grinder.
It worked on the principle of a stationary drum with a spiral groove containing an air cylinder and the traverse was controlled by air valves the grinder bed remained stationary.
He even worked out toe and heel compensation for a set wheel diameter to get the correct form,(tolerances were tenths), and did all this on a Hewlet Parkard calculator (no computers in the shop then).
He was a really lovely guy to work with and was much respected, sadly so longer with us.
For myself, I only have occasional use for something like this so I will stay with muscle power, I hope we will see a posting of your set up in the future.

[tonyfoale]

I just came across a couple of pix of a manual stand alone slotter. I have no other details but the pix are detailed enough for anyone who would want to build something like it.



Click the pix for full size versions.

[steamingbill]

I have been wondering about building a slotting/line scribing gadget mounted on my lathe. Any advantages of a stand alone over a lathe mounted ?

[tonyfoale]

I have been wondering about building a slotting/line scribing gadget mounted on my lathe. Any advantages of a stand alone over a lathe mounted ?

My order of preference would be like this:

1. Dedicated factory made machine tool for slotting.
2. Factory made slotting head attachment for a milling machine.
3. DIY made slotting head attachment for a milling machine. (This my method.)
4. DIY made slotting fixture for a lathe.
5. DIY made standalone device as in my post above.

For single pass cutting like scribing markings on a dial it would be hard to beat a lathe with indexing. There are several versions of the technique in past posts on this forum.