"Ned Simmons" wrote in message
...
On Mon, 27 Mar 2017 09:00:22 -0400, "Jim Wilkins"
wrote:
"Ned Simmons" wrote in message
. ..
On Sun, 26 Mar 2017 18:29:54 -0400, "Jim Wilkins"
wrote:
"Cydrome Leader" wrote in message
news
What's the name for installing a roll pin in the direction of a
shaft,
sort of like how a square key sits? That might be the lazy next
option.
Dutchman or Scotch key.
http://www.practicalmachinist.com/vb...62/index2.html
Good luck drilling straight along the seam between different
materials.
-jsw
Around here a Dutchman is an inlaid patch, most often a repair to
a
defect in a wooden piece. I know the device under discussion as a
Dutch pin.
The problem drilling the joint between different materials can be
minimized by starting the hole with an end mill as close as
possible
to the desired size, then enlarging, if necessary, with a drill.
Still
can be pucker-inducing.
My preference is for a tapped hole and set screw instead of a pin.
Easier to disassemble, less fussy than fitting a pin, and also
retains
the mounted component in the axial direction.
--
Ned Simmons
I second that for a steel hub on a steel shaft. Otherwise tapping
along the joint bertween dissimilar materials is worse than
drilling.
If the hub is softer than the shaft I broach a keyway in it. The
necessary guide is easy to turn to whatever size the hub bore may
be.
You can set the broach cutting depth to not weaken the hub too much,
and adjust the cutting depth with shims sheared from hobby store
brass
or tin cans.
I mill a key slot in the shaft and then make a key that's a snug fit
in the shaft and perhaps a looser one in the hub if there's space
for
a setscrew. The width of the key is easier to adjust than the
slots'
because you can use a larger, stiffer endmill.
The key can be stepped without much trouble if the slots are
different
widths, for example if a 1/8" shaft slot needs extra cleanup passes.
-jsw
Though not as easy to remove, a broken tap is as secure as a
setscrew.
g
Last time I remember doing this was mounting a herringbone sprocket
http://www.silentsync.com/silentsync...yncŪ-sprockets
bored out to just below the teeth (~8" ID?) on a large hollow
machine
tool spindle. The sprocket was free machining steel, the spindle was
pre-hard 4140. Nerve wracking, but there's a couple set screws in
the
assembly, no broken taps.
--
Ned Simmons
The cast aluminum handwheel on my lathe's collet closer is attached to
the steel tube with two axial setscrews which are more in the aluminum
than in the steel. It certainly can be done by someone with more skill
than I have.
-jsw