I am looking for information on half- or quarter- round
profile cutters in small [1/4 inch Ø sizes. I currently
plan on using 1/4 inch round X 2 inch HSS blanks rather than
1/4 inch drill rod [silver steel for our UK readers], with
the thought that I can grind a circular approximation of the
involute curve and make a profile cutter like an end-mill
[slot drill]. The full depth of cut for a 1.0 M/M module
gear is only 0.085 inches with a flat tip/root space of
0.031 to 0.038 inches so this seems doable. This is part of
my ongoing effort to make a complete set of change gears
[including 63T for metric transposition] for my lathe.

I have managed to locate reasonable priced "drops" of
suitable size delrin/acetel and canvas reinforced phenolic
[bakelite/formica/micarta/tufnol]. I have also invested in
a 0.025 slotting saw and arbor to gash the gear blank and
clean most of the material out before using the profile
cutter. From what I have learned half-round/single lip
profile cutters should be OK with plastics, but what about
steel? If I do decide on steel it will most likely be 1018
as one of the listed uses is gears.

From a quick internet search it appears that bakelite and
nylon/delrin are common materials for lathe change gears.
What has the groups experience been with these gears?

Any one have experience using this type/size of profile
cutter in gear making or on steel? Any
suggestions/observations welcome.

One enhancement/complication I am considering is making
provision of eccentric relief. Anyone have experience with
this and if so how much eccentric relief is
necessary/desirable?

FWIW -- the least expensive B&S style 1.0 M/M module cutters
I have been able to locate are 33$US each + S/H and I would
also have to buy or make a 2MT arbor to fit the 16 M/M hole.
Additionally, my vertical mill is light duty, and a
end-mill/slot drill type cutter should put much less stress
on it than 2-1/2 inch diameter B&S style cutter with
considerable overhang. With a 1/4 Ø 2MT collet I gain
considerable headroom.


-- Unka George (George McDuffee)
...............................
The past is a foreign country;
they do things differently there.
L. P. Hartley (1895-1972), British author.
The Go-Between, Prologue (1953).