- Joined
- Feb 2, 2013
- Messages
- 3,629
i test sharpened drills in aluminum, but have never heard of the steel treatment...
maybe annealed steel? or 12L14????
maybe annealed steel? or 12L14????
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New Drill Break In
- Thread starter Baithog
- Start date
- Joined
- Jul 26, 2011
- Messages
- 4,142
I just drill with new drills.
I would agree with the "band saw blade break in" reply. If you look at a newly sharpened drills cutting edge under enough magnification, normally there will be striations or mini burrs caused by the grinding wheel. These will be right at the cutting edge. Drilling a soft material at slower speeds and feeds tends to wear these away as opposed to possibly breaking them when the harder material is drilled. This wearing is similar to "honing" a razor. If the "striations" are broken off, they usually take "parent" material with them which leads to premature dulling of the tools cutting edge. However,,,unless this is a high production, closely controlled situation it isn't worth the effort.
- Joined
- Feb 1, 2015
- Messages
- 9,631
Wouldn't these burrs depend upon the sharpening method which, in turn, depends upon the manufacturer? Harder steels also form less of a burr than softer steel. I could see this practice occurring when drills were made of steels like O1 and W1. I haven't looked at HSS under a microscope but my perception is that it forms very little burr.
The direction of the grind and grit of the stone will also affect the edge.
There is a small curl of metal created on an edge when sharpening, Woodworking tool users experience it. Also, anyone sharpening a knife. Years ago, when I was more fanatical about knife edges, I would use a hard Arkansas stone and a 50X microscope to put a micro bevel on the blade.
I can cut several cords of firewood with a new chain saw chain. However, resharpened chain, done with a chain saw file, cuts very well for the first few cuts but performance rapidly deteriorates to a mediocre level. Due to the nature of the sharpening, there is always a burr on the tooth. Ground teeth, using a rotary tool similar to a Dremel, create less of a burr and hold an edge longer.
Bob
- Joined
- Mar 16, 2013
- Messages
- 12
I've never done this for a drill but its a fact for bandsaw blades that all their manufacturers acknowledge. Edges need careful break in to last well, so why not a drill edge.
Personal experience of this all of us have got, which any of you can verify with a hand file. A brand new file will easily cut brass, but use one that's old or has been used on steel for much of its life, and it will skate over the surface of brass, a bit like it was hardened steel, even though brass is way softer than steel.
Using a file modifies the cutting edge like stropping a razor, removing micro-burrs etc as 'bearrr' said above and subtly changes the top rake and relief angles at the very edge.
My father used to keep 2 sets of files, one set for brass; the other for cast iron and steel. When a file wore enough to make filing brass hard work, it graduated to the steel set. He never had a mill and had to remove any metal with a file so depended on them cutting at their best. He was a master at it too, could file a surface dead flat and square to any other surface. Check out his handiwork, these knives he filed out of annealed files. He would use any file, but never made a knife out of anything other than a (Canadian) Nicholson file, which he considered superior to all others) - jv
Personal experience of this all of us have got, which any of you can verify with a hand file. A brand new file will easily cut brass, but use one that's old or has been used on steel for much of its life, and it will skate over the surface of brass, a bit like it was hardened steel, even though brass is way softer than steel.
Using a file modifies the cutting edge like stropping a razor, removing micro-burrs etc as 'bearrr' said above and subtly changes the top rake and relief angles at the very edge.
My father used to keep 2 sets of files, one set for brass; the other for cast iron and steel. When a file wore enough to make filing brass hard work, it graduated to the steel set. He never had a mill and had to remove any metal with a file so depended on them cutting at their best. He was a master at it too, could file a surface dead flat and square to any other surface. Check out his handiwork, these knives he filed out of annealed files. He would use any file, but never made a knife out of anything other than a (Canadian) Nicholson file, which he considered superior to all others) - jv
Last edited:
- Joined
- Dec 25, 2011
- Messages
- 591
Brownell's mentions it on their instruction sheet for install a barrel liner (page 2)
As
a
general
rule,
the
liner
drill,
like
all
drills,
cuts
better
after
some
use.
For
this
reason,
and
to
learn
the
feel
of
when
the
drill
is
cutting
properly,
we
recommend
that
you
drill
two
or
three
junk
barrels
before
the
first
lining
job.
This
usually
cures
the
tendency
of
the
drill
bit
to
stick
or
jam.
https://www.brownells.com/userdocs/learn/Inst-143 Barrel Liner.pdf
As
a
general
rule,
the
liner
drill,
like
all
drills,
cuts
better
after
some
use.
For
this
reason,
and
to
learn
the
feel
of
when
the
drill
is
cutting
properly,
we
recommend
that
you
drill
two
or
three
junk
barrels
before
the
first
lining
job.
This
usually
cures
the
tendency
of
the
drill
bit
to
stick
or
jam.
https://www.brownells.com/userdocs/learn/Inst-143 Barrel Liner.pdf