"Jim Wilkins" wrote in message
...
On Feb 14, 11:35 pm, "Michael Koblic" wrote:
"Jim Wilkins" wrote in message
...
I attach a pivot post to the table of the mill, ...
Those would be the GT18 steering sectors?
That piece fit on the lathe after sawing it roughly to size. I clamped
the square blank flat on the bandsaw table with tee bolts to cut off
the corners. Then I set the saw upright and followed a scribed circle
as far as the wide blade allows, then opened up the kerf with a chisel
to make clearance the next cut.
I should be able to the very same tomorrow (once I found where the knocking
noise is coming out of the Craftex). BTW, when you got your band saw, did
you change the oil in the gearbox right away or did you trust the Chinese
and left it for a year or so?
If the disk can be clamped firmly to the mill table, ...
I have to digest this...
The upright pivot post is held in the vise, the disk rests on 1-2-3
blocks which raise it above the jaw tops. Tee slot clamp bolts clamp
the disk onto the 1-2-3 blocks, leaving a small space in between to
mill tangents to the OD. It's slower than sawing because of all the
reclamping but doesn't risk cutting in too far by accident, and leaves
only a little metal for the lathe to remove.
Got it.
For even larger circles I set them up on a shaft and round them with
an angle grinder, ...Think of an old foot-pedal grindstone frame. You
could spin the disk with a sanding drum in a drill.
I think you mentioned this to me before. In fact I believe it was the
inspiration for this marvel of technology:
http://www.flickr.com/photos/2768312...7607743618739/
Michael Koblic,
The ladder-shaped frame of my sawmill is the model. Both wheels needed
truing and the front one considerable flattening. I used the
crosspieces at the inner ends of the wheels for tool rests, ie to hold
the grinder steady.
You could make a similar frame out of wood by laminating 2x4's with
the ends alternating to form glued finger joints. I'd make two side-by-
side rectangular bays, the second providing a tool rest for faceplate
turning.
The faceplate could be a large pulley faced with plywood. The bearings
on the motorcycle wheels were tight enough to use one as a lathe
faceplate, though the protruding axle interferes. If you did that you
could drive the tire by friction or remove it and run a vee belt on
the rim. I used the sprocket only because I needed to transmit several
horsepower, it required a separate countershaft.
I think an X-Y table would be stiff enough for a tool rest. I acquired
one plus the headstock from a scrapped SB lathe and a brake lathe
tailstock to build a large wheel lathe, but haven't needed to set it
up yet.
Another one to digest :-)
I was thinking that if I return to red neck technology I would probably make
the ring spin horizontally this time. But anything will be considered. The
important thing is to spin the work piece quite slowly otherwise the grinder
works quite inefficiently, at least on the face. The RedNeck lathe v5.01
went at less than 100 rpm and could have gone slower.
I found that an X-Y *vise* was capable of holding lathe tools quite firmly
and take large cuts. Here it is with a boring bar holder I made:
http://www.flickr.com/photos/2768312...7614869315843/
I have to add that the wobble was all in the chuck: The spindle had a runout
of only about a 0.001" :-)
--
Michael Koblic,
Campbell River, BC