Genuine Blacks Charpy/Izod Notching Broaches
Our broaches meet most standards i.e. BS, ISO, EN, ASTM and many other International Standard notch profiles.
Due to the variety of broaches and notch configurations, broaches are ordered separately.
All broaches, which have a unique serial number, are tested to ensure that they cut the correct form before despatch and a Certificate of Conformance is issued with each broach.
Our broaches are manufactured using the latest CNC grinding techniques at our factory in Kent, giving customers the reassurance that they are purchasing a quality product.
STANDARD BROACHES
Our standard broaches are
designed for use on carbon and low alloy steels.
DRAWING |
BROACH |
NOTCH |
DEPTH |
ANGLE |
RADIUS |
BROACH |
CARBON & LOW ALLOY STEELS |
COMMENT |
CNB30-027A2 |
C |
V |
2mm |
45˚ +/- 1˚ |
0.25mm +/-0.025 |
X |
< 42 HRC |
|
CNB30-028A2 |
M |
V |
1mm |
45˚ +/- 1˚ |
0.25mm +/-0.025 |
X |
< 42 HRC |
|
CNB30-002A2 |
H |
V |
3.3mm |
45˚ +/- 1˚ |
0.25mm +/-0.025 |
X |
< 40 HRC |
For use on round specimens. |
CNB30-035A2 |
T |
V |
3.5mm |
45˚ +/- 1˚ |
0.25mm +0.020/-0.025 |
X |
< 35 HRC |
GOST 9454 (0.1/0.27mm radius). |
CNB30-004A2 |
JS |
U |
5mm |
|
1 mm +/-0.025 |
Y |
< 32 HRC |
With packer CNB30-029A4 - 2 cuts required. |
CNB30-005A2 |
N |
U |
2mm & 3mm |
|
1 mm +/-0.025 |
Y |
< 32 HRC |
When cutting 2mm depth, only 2/3rd of cutting length is used. |
CNB30-006A2 |
P |
U |
2mm |
|
1 mm +/-0.025 |
Y |
< 35 HRC |
|
HARD CUT COATED BROACHES
This is a superior broach to the standard broach and is
recommended for use on our Variable Speed Machine for tougher, harder and
stainless steel materials to extend tool life.
If used on our Hand Machine, tool life is dependant on a smooth cutting
action by the operator and the machining difficulty of the material.
DRAWING |
BROACH |
NOTCH |
DEPTH |
ANGLE |
RADIUS |
BROACH |
CARBON & LOW ALLOY STEELS |
COMMENT |
CNB30-027A2H |
C |
V |
2mm |
45˚ +/- 1˚ |
0.25mm +/-0.025 |
X |
< 52 HRC |
|
CNB30-028A2H |
M |
V |
1mm |
45˚ +/- 1˚ |
0.25mm +/-0.025 |
X |
< 52 HRC |
|
CNB30-002A2H |
H |
V |
3.3mm |
45˚ +/- 1˚ |
0.25mm +/-0.025 |
X |
< 50 HRC |
For use on round specimens. |
CNB30-035A2H |
T |
V |
3.5mm |
45˚ +/- 1˚ |
0.25mm +0.020/-0.025 |
X |
< 45 HRC |
GOST 9454 (0.1/0.27mm radius). |
CNB30-004A2H |
JS |
U |
5mm |
|
1 mm +/-0.025 |
Y |
< 42 HRC |
With packer CNB30-029A4 - 2 cuts required. |
CNB30-005A2H |
N |
U |
2mm & 3mm |
|
1 mm +/-0.025 |
Y |
< 42 HRC |
When cutting 2mm depth, only 2/3rd of cutting length is used. |
CNB30-006A2H |
P |
U |
2mm |
|
1 mm +/-0.025 |
Y |
< 45 HRC |
|
PLEASE NOTE
When notching steels with a greater hardness than in the tables above and
notching "superalloys" on our variable speed broaching machine with “hard
cut” broaches, the broach life will be dependant on the
machinability of the material
For difficult to machine materials -
if you have doubts about the suitability of our broaches to notch your
material we would ask you to check with us for confirmation that our
broaches are suitable.
Please be aware that following trials
we have found that our "hardcut" broaches will not notch, Stellite 6.
Broaches are a cutting tool and are considered a consumable item.
Broaches will wear and without care teeth can break, so warranties on our
broaches are generally excluded.
BROACHING MACHINABILITY
Many test houses ask RJW Ltd “what material
hardness can your broaches notch”?
Broaching specimens on our
machines is dependent on the process machinability. Broaching
machinability is best summarised as how easy the broach can cut the
notch in the specimen material and is not solely dependent on the
materials hardness. The cutting of the notch is dependent on the type
of machine and broach used and also the specimen material properties.
1 - The type of machine
General machine explanation:
CNB35 Hand broaching machines are suitable for broaching small
quantities of easy to moderate, machinable materials. These broaching
machines do not have a constant cutting action compared to our
motorised broaching machines and this non-constant cutting action
could influence the broach life.
CNB31 Fixed speed motorised
broaching machines are suitable for broaching large quantities of
easy to moderate, machinable materials. This machine has a constant
cutting action, which will help improve broach life. The easiest way
to explain its limitation is to compare drilling mild steel and
stainless steel with a twist drill. If the drilling machine has a set
speed for drilling mild steel and then a stainless steel material is
drilled, the drill cutting edge will rapidly fail because the drill
speed is too fast. Our fixed speed broaching machine has a cutting
speed set to broach general mild steel specimens.
CNB34
Variable speed motorised broaching machines are suitable for
broaching easy to difficult, machinable materials. This machine has a
constant cutting action and a broach speed which can be altered,
allowing it to broach a range of different materials.
2 -The
type of broach
Always apply cutting oil to the broach.
Our standard uncoated broaches are suitable for easy to moderate,
machinable specimens.
Our hard cut broaches are suitable for
easy to difficult, machinable specimens. Hard cut broaches should
increase broach life, providing an even cutting action is applied.
“V” and “U” broaches. The volume of material cut when producing U
notches is greater than V notches, so when cutting materials with
more difficult machinability properties, U notch broach life will be
less than V notch broaches.
All our broaches are made in our
factory in Kent. Our broaches are ground on a CNC grinder, made with
European sourced material and vacuum heat treated to ensure their
quality.
3 - Specimen material properties
The
machinability of the specimen material is dependent on its, chemical
composition, heat treated condition, hardness, if it is welded at the
notch section, if the material work hardens, yield and tensile
strength. The specimen’s material properties will affect the broach
life.
For example stainless steel is softer than carbon steel,
but stainless steel machinability is more difficult than carbon
steel. When broaching stainless steel compared with carbon steel, the
broach speed must be slowed. The tool life when broaching stainless
steel will be less than carbon steel, as a stainless steel specimen
is more difficult to broach than a carbon steel specimen, i.e. its
machinability is more difficult.
When machining stainless
steels & super alloys care must be taken when machining the 10 mm
square or sub-size specimen, to ensure the surfaces are not work
hardened. If the surfaces are work hardened then broach life can be
dramatically reduced.
Broach Regrind Service
We also offer a broach regrind service. Please note this
is dependant upon the condition of the broach. We only grind the land
(cutting edge) and not the form. Generally if the form is worn or more
than one tooth adjacent to another are broken then it may not be
practicable to re-sharpen the broach.