With the housing done I
decided to tackle what was coming to be the most
problematic part of the whole project. When I'm
writing this I still don't know if it will work or not.
I decided that I wanted
the spindle shaft hardened and ground, at least the
lower part with the taper and after discussing it with a
local company they supplied me with a piece of SS2511
Unfortunatly I didn't snap
any photos while machining the shaft but here's two I
took fresh off the lathe:
The main diameter of the
shaft is 30mm and it is 240mm long. There's a M32X1.5
thread that will be used to lock the bearings in place.
This photo shows the setup
I did to machine the slots and mounting holes for the
drivedogs. First I made a collet kind-if-thing that fits
the 30mm OD of the shaft. Then I used two Vee-blocks in
the vice to clamp it.
Using a 10mm endmill I
then machined the slots.
And here's the finished
shaft before sending it out for hardening and grinding.
You can see the "collet" I mentioned just above the
threaded part of the shaft.
So now comes the problem.
The company that does the hardening and grinding for me
told me to leave 0.4mm on the surfaces I wanted them to
grind - and I did. But since I shouldn't harden OR grind
the upper part of the shaft I machined that to it's
final dimension. (30mm). This didn't turn out well
because the shaft got oval from the heat of the
hardening and now there wasn not enough material to
machine it back to being round. I should ofcorse have
realised this was going to happen but I didn't and
I was now facing making a new shaft - something I did
NOT look forward to. But then someone at a online forum
suggested to have the shaft plated to build up enough
material so it once again could be machined round and to
the right dimension and I got hold of a nice guy that
promised to help me with it.
And here it is. You can
see the newly applied metal at the top. I was kind of
expecting to see a nice shiny surface but this is what
it looked like. I chucked it up in the lathe and took a
light cut. The material was quite hard and left a nice
surface. I then brought the shaft back to the grinding
shop for a second time. As of today (2007-09-22) I
haven't got it back. We'll see how it works out.
I got the spindleshaft
back from the grindingshop. They did a good job:
The shaft looks very nice.
The surface on the taper is a little rougher than on the
outside but still very nice. The dimensions are exactly
as I expected - no more, no less. I'm happy.