Robin S. wrote:
On Jul 30, 10:55 pm, joel wrote:

all combinations of
fast/slow feed rate, fast/slow RPM, large/small cut seem to make no
difference.


None of those words are numbers. Machining at this level is a numbers
game for the most part. A "heavy" cut is different for different
people.

We'll assume you're using an actual boring insert and boring bar.

What feed and speed combinations have you actually been using (numbers
please!)? Did you look up the recommended feeds and speeds for the
tool you're using? That info should be available in the same catalogue
from which you selected the boring tool, and it does make a difference
so make sure!

Your boring tool sits no more than 3-1/8" out from the tool post....
RIGHT? Overhang is *really* important when you're boring.

With brass, you can always go slower. If I was having problems, I'd
probably run at 400 or less RPM to start. Feed rate is *heavily*
dependant on the insert so look it up! The cut should not be squeeling
ideally. Work to get rid of that or you'll see it in the surface
finish.

Good luck. Learning is difficult but worthwhile.

Regards,

Robin

I do a lot of boring on all sorts of holes, pulleys bushes and the like.
I use just one tool its a brazed on carbide onto the steel 3/4in high
by 1/2n wide steel.
BUT the carbide isnt pointed, its got a 1/8th in radius that
doesthecutting. with a 1/4in flat back from the radius.
This supports the tool against the work as you feed in the cut.
Usual angles on top face and rake.
Never cuts grooves or ridges.
I can take a heavy cut on ali or a finishing cut on steel/cast ciron.
Its a fault in my view of the cutting tip shape your using.
Ive a pointed carbide insert on a coromant boring tool and that doesnt
work either!!
I do harpen my carbide tips with a diamond wheel tho lubed with kerosene.
Do try that type of cutting tool shape, I dont think you can buy it my
shape, you have grind it yourself.
For brass you dont need carbide.
Use 01 hardened or any tool steel will do.
Yes I use a Le Blond royal from 1942. Ive mentioned it before it was a
lease lend from you all . Much used , lovedand appreciated.
Ted Dorset UK.
..