DoN. Nichols wrote:
This would only be possible by cutting a 7/64 hex key very short and
tightening the screws 1/8 turn at a time and then only for tools
directly opposite each other - you cannot fit two holders on at
right angles.
You can if they are short enough -- or have 45 degree beveled ends.
These *aren't* :-)
There is no reasonable need for two on opposite sides of the
post.
Seppuku?
OK, I did not realize that could be a problem. The Taig toolpost
that came with the machine has only two set screws. I note that the
LMS toolholders have four.
The more setscrews you have, the more rigid the clamping for a
longer tool. If you only can use two, use one near the cutting end
and the next one in, so the spacing is minimized.
Perhaps this sort of arrangement might work:
http://littlemachineshop.com/product...y=100520820 4
Hmm ... if you've got a place to mount it. As shown, it would
remove the middle screw from play as a clamping screw.
After your comment it would make more sense to make this arrangement on the
distal set-screw rather than the middle one.
http://littlemachineshop.com/product...ory=-419988835
O.K. Those are piston style, which certainly could not handle
two tool holders at once. The lever turns a cam inside the body, and
the clamping position for the lever is 90 degrees different for the
two stations. (The wedge style moves two wedges down at the same
rate, so two holders of *precisely* the same size in the dovetail
would clamp at the same point of lever travel -- but the odds of such
precision in dovetail width are pretty slim. :-)
http://littlemachineshop.com/product...y=100520820 4
The holder for the parting tools has no rake -- this one simply
clamps through the bar along the top being held down by the four cap
screws. This means that you will have to grind a little rake at the
end of the parting tool's top. And after a certain number of
re-sharpenings, you will have to grind off the end and make a new
rake.
It seems less hassle than having to grind a whole new parting tool from 1/4"
stock.
http://littlemachineshop.com/product...dID=-316770619
As a matter of fact I wondered about the rake angles for parting
tools. They also sell (as do others) parting tools ground from a
1/4" bit. I could find no info about their geometry.
The tool itself probably has no rake, but some toolholders can
provide an adjustable rake. One style, which I originally found on
jeweler's style lathes, has a segment of a circle at the bottom of the
slot, and a rocking steel wedge which fits the curve. You adjust the
angle (and the height of the tip) by loosening one clamp screw and
tightening the other, to change the tilt of the rocking steel wedge.
Of course, the bottom of a lantern style toolpost has a similar
rocking piece, but only one clamping screw.
I have seen a home made one like that.
Yes. You *can* make a rake by grinding the top, but your tool
lasts through more resharpenings if you have the rake built into the
holder.
It just occured to me that it might be simplest just to make a separate
toolpost just for the parting tool along the line of the original Taig
toolpost just with a shallower groove inclined at 8-10 degrees and half an
inch wide to allow the use of commercial parting blades *if* one parted at a
single distance only. Is the groove on the toolholder that holds the
T-shaped parting tool shaped in any special way or can one just get away
with a rectangular profile?
In the case of the holders which you pointed out, this would
require the parting tool holder to be taller. Perhaps aim for about 8
to ten degrees rake.
I like the choice of thicknesses offered in the actual parting
tools.
Which is why I am interested in the commercial ones rather than having to
cobble something that small and thin using a bench grinder.
Today I bought $15 digital calipers and after an hour of
experimenting I think I found a way to convert them to measure the
carriage travel.
The main thing is to preserve the part covered with the fabric
in the beam. The jaws can be milled off without problems (ideally
with the head removed at the time. :-)
I took them apart and put back together again. The main hassle I see is to
find attachment points on the Taig. I hate drilling and tapping any of the
tools if I do not have to. Fortunately the Taig has a surfeit of T-slots.
P.S. That 3" milling vise looks cute. A clone of the Kurt Anglock
style, but smaller and more affordable. Now if I could just
find a 2" of the same design for the Emco C5 mill (adaptation of
the mill column for the Compact-5 lathe, but with a heftier X-Y
table below it.
??? Which one? LMS?
--
Michael Koblic
Campbell River, BC