Photograph 23, showing the operation, may cause some confusion but having so much
to remove I chose to experiment a little. First, I plunged the boring tool in a little,
probably 0.5mm, and winding it out to almost 50mm. After repeating it a few times
I decided that opening up the hole as one would normally do using a boring tool was
the best method. However, when there is a substantial amount of metal to remove it
never does any harm to experiment, typically with differing speeds and feed rates.
The next stage is to finalise the steady's shape. Mount it onto the worktable and
position at an angle such that the tangent to both the small and large radii is at
right angles to the front edge of the worktable, Photograph 24, followed by machining
to the line using a small end mill, Photograph 25. Whilst on the worktable use the
same method for removing the waste (25mm dimension) and the top angle. Note the packing
under the steady to allow the cutter to pass fully through.
The next stage is to drill and tap the holes for securing the steadies arms, but
not having any easy reference edge I would suggest the following. Make a drill bush
as per Sk. 1 and use this with the smaller diameter in the recess and the larger
diameter level with the inner radius of the frame and, using a toolmakers clamp,
clamp it in this position. The clamp can then be held in the drilling vice and the
tapping size hole for the fixing screw drilled, Photograph 26. The frame has to be
positioned so that the drill just misses the end of the vice jaws. The advantage
of the method is accuracy. For me, with the arms being a close fit in the recess
and the slot made with a 5mm end mill, I was relying on the fact that the screw would
be a little under size. It was very gratifying when all five arms fitted without
any need for adjustment. With all the parts now completed, lightly chamfer all the
edges and corners, if nothing else making them more pleasing to handle, and finally
I consider that using the rotary table is the better method being quicker to make
the large holes and to position the channels for the arms. Boring the large hole
on the lathe did though achieve a better finish. Even so, the method I used for the
travelling steady is perfectly acceptable for the workshop without a rotary table
and can easily be adapted for both steadies.
Elsewhere on the site I explain how these very useful items are used.