will they fit? Luckily the 2 cones on the drive sprocket side, are straightforward. But the brake cone isn’t, as the photo shows:
SO HOW DO I CHANGE THIS……..INTO THIS
This cone takes the reaction of the brake (hence it’s often called the brake cone) so I need an adaptor to fit onto the flats on the reverse side of the new cone – see sketch.
Fortunately, I have a friend with a lathe and many years ago I was trained as a toolmaker (46 years ago to be exact), so it can’t be that difficult can it?
I also need a small adapter ring to fit the dust shield to the new cone as the diameter is smaller, so I figure it’s best to start by making a plastic adaptor on the lathe.. and it works out OK.
TURNED ADAPTOR ADAPTOR IN PLACE
Now onto the steel part. The only material I could “acquire” was EN8 which is a medium carbon steel with good tensile strength; good for this application but a little hard for an amateur like me to machine. In the end I used a TCT tool (tungsten carbide tip) and it cuts OK but needs a little polishing to improve the surface finish.
Those of you familiar with lathe work will wonder how I added the slot – WITHOUT A MILLING MACHINE?
Well, I had to get inventive. I made another adaptor to clamp the turned part in the fixed tool holder, put an 8mm slot drill into the chuck and then used the cross slide to traverse the part over the spinning slot drill. Basically, I adapted the lathe to work like a milling machine. I’m sure it’s been done before but not by me, so I was quite chuffed that it worked …and I still have ten fingers (or is it eight fingers and two thumbs?)
The finished part looks like this,
NB: You may think the original cone looks OK but I polished the seat in a drill as I was thinking of using it. However,
- It is soft as the case hardening has worn through and
- I noticed the final drive chain from the the engine had been rubbing on the wheel and I think it’s because the seat on the cone has worn back. As the cone wears the engine moves inwards with it.
So I’m hoping the new cone will solve that problem and work reliably, as I don’t want it to fail when I’m doing Lejog; do I?
Update 11 February 2017
I’ve filed the flats on the adaptor; it took a while even though I removed the bulk of metal with a hacksaw but the outcome is fine.
Good to know I haven’t lost the metal filing skills from when I was a first year apprentice in 1970. I remember spending what seemed like days, filing the same piece of metal, to get it flat and square enough to pass my “phase test” but the techniques obviously stuck.
The finished assembly looks like this:
As the RH photos shows, the dust shield lines up well with the mating fixed part in the Hub.
New cones fitted with new bearings, spindle and grease – job done!