Gil HASH wrote:
Hello for all
A newbie's strange question of the day :
Can we choose between HSS cutters, end mills versus cutters or end mills
with carbide inserts
what are the advantages and disadvantages of each one?
I have one 1" "little hogger" style carbide insert endmill. It cost more
than a regular 1" endmill, but it can be fitted with new cutting edges
for about 60 cents (it has 2 triangular inserts, so you get 3 sets of edges
for about $2.00 on sale.) For rapidly removing a lot of material,
planing off the top of some piece, etc. there is nothing that will beat it.
I use almost NO real HSS anymore. I use some Cobalt-HSS end mills
in the larger sizes, such as M-42 and M-57 in 3/8 to 3/4" diameter.
For 1/8 - 1/4", I have moved almost completely to solid carbide end
mills. They can be had for ~ $3.00 each in small quantity on eBay, and
the quality is very good. (There are also some plain HSS cutters from
China that are execrable! They look like they were free-hand sharpened
by an 80-year old blind man, and that is doing a disservice to the blind
and elderly! These things come in blue 2-piece plastic tubes with a
paper label, with the size rubber-stamped on the label. If you see those,
run!)
I find the M-42 and M-57 cutters last 3-5 times longer than plain HSS.
Stellite is also very good, if you run across some of them.
I also use some Mo-Max cobalt lathe cutter blanks in my fly cutter, and
it does a VERY nice job, and needs to be sharpened every few months!
The chips come off blue and smoking. I could probably run it even harder,
but I can't stand the burns from the chips.
On lathes, carbide with negative rake inserts are great on machines with
the power and rigidity to use them, but there is little negative rake
machining done on mills, I think. Pretty much all standard milling
cutters are set up for some positive rake. So, there shouldn't be any
concern
for rigidity and power when making the decision between the cutting
tool materials. On the other hand, Carbide works best at much higher
cutting surface speeds, so a higher spindle speed will be a great help
when using carbide. A 1/8" cutter in aluminum comes into its own at
30,000 RPM with carbide, for instance.
Jon
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