New tooling ad with several videos just hit my mailbox which
should be of interest, even if beyond the reach of home
Shows how your CNC lathe with spindle indexing and live
tooling can cut splines and gears improving 1 and done
Also how new high pressure [1,000 psi] coolant can improve
productivity and finish.
Some other interesting products/applications
On Wednesday, May 20, 2015 at 12:21:43 PM UTC-7, F. George McDuffee wrote:
In your example you won't have concentricity issues because it's a one and
done with all variables being controlled in one op. That's the way to go if
In my case, we make some gears using pinion wire running it on a lathe. We
buy the wire which is drawn through a die.
The supplier threads one end of a bar as shown in this photo and then pull
Here are a couple gears I make and a different sized pinion wire:
The issue with buying pinion wire is concentricity. The OD is rarely concen
tric with the pitch and minor. Concentricity issues cause major backlash is
sues in assemblies that don't have backlash compensation Using a round 5C c
ollet doesn't work, you start off by not being concentric.
In our case I had Hardinge make us some collets that chuck on the pitch dia
meter, shown here;
This way all the critical dimensions are concentric with the ID and OD turn
The next major issue was how to deburr the parts. Using ThinBit tools to ma
chine the OD dimensions and they are great tools better than any other but
under microscope there still left microscopic burrs on the teeth which is n
ot allowed by the customer.
To remove the burrs and polish up the parts, after a lot of searching I fou
nd a "Magnetic Finisher" that does a wonderful job. The machine shop size i
s about $27,000.00. Since we are making small & micro miniature parts for t
his product line I found a Magnetic Finisher that is used for polishing rin
gs and cost less than $500.00.
Similar to this one;
Sounds like it's beating the parts up but it's not. Will add more informati
on on this deburring and polishing machine later.
Sandvik makes milling gear cutters with inserts. It's one of their
specialties. They're trying to replace gear hobbing with gear milling
in a lot of applications. They even have agreements with Gleason to
co-develop gear milling.
One of their really interesting projects is their uP-Gear system for
"milling" spiral-bevel gears on a five-axis milling machine. At that
point, you have to scratch your head over whether it's really milling,
or if it's actually gearless generating.
Very cool stuff. Not much there for hobbyists -- the prices will make
your ears flap.
What is the potential to use *ONE* of these inserts in
either a "fly cutter" in a mill or insert holder in a
shaper? I have made several gears but my limiting factors
are the high costs of the store bought numbered cutters and
the difficulty of hand grinding a "line out" HSS tool bit.
Either square lathe tool bits or small end mills ground to
the numbered involute profile both inch and metric module
could be a viable hobbiest/repair tool concept. Anybody
care to make a guesstimate of what it would cost to cnc
grind number an involute profile [or the circular arc
equivilant http://tinyurl.com/lhcb9mz ] with clearance on a
1/4 to 1/2 square HSS bit and/or appropriate size HSS end
Also does anyone have a trick to set the c/l of the tool on
the c/l of the gear blank in either a mill with fly cutter
On Sat, 23 May 2015 09:01:45 -0500, F. George McDuffee
That's an interesting question. I'd take a good close-up look at how
they support and clamp those cutters, and then see what you could work
up as a single-point cutter holder.
You can start here. There are some pretty good photos.
> I have made several gears but my limiting factors
===================Thanks for the link.
For the smaller size gears I am interested in, the "edge"
cutting inserts used in the CoroMill 171 look to be the
choice. Should be relatively easy to modify a 2MT 1"
adapter http://tinyurl.com/lka5pys to take one insert.
Inserts are double ended.
Quick google and MSC check didn't find price/availibity
info. Got a source/site?
When I turn the locating stub arbor that snugly fits into the gear
blank I leave a centering point or plug on the end. A point is good
when I can find and mark the cutter centerline, otherwise a plug the
same width as the cutter tip helps with visual alignment.
I've been buying involute gear cutters on ebay , average price is about
$25 for singles , around $150 for a set of 8 .
I use the cutter to make a light cut on the end of the arbor , then rotate
arbor and machine it flat , then make one pass with the gear cutter on CL .
I then use that cut to center the cutter for later sessions . I recently
figured out that not all of my cutters are the exact same thickness ...
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