RTM 351

A Company
of ThyssenKrupp
Technologies
RTM 351
Crankshaft grinder
BERCO S.p.A.

The machine and its executions
The RTM351 Crankshaft Grinder,
conceived and realized according
to highly innovatory criteria, is a
structurally balanced and highly
reliable machine, whose main
features are the utmost precision
and the top flexibility. Designed
for the internal-combustion
engine crankshaft reconditioning,
it can, on request, be tooled up
also for cylindrical grinding.
The RTM351 is available in two
executions:
“A” execution, suitable for
regrinding crankshaft with
different features and dimensions;
“D” execution, same as the “A”
execution but equipped with an
electro-hydraulic appliance which
allows also grinding of cylindrical
components such as rollers, bars,
etc.
In order to meet the manifold
work requirements, the two
1 Wheelhead plunge feed control
panel.
2 Table traverse control
handwheel.
3 Fast table traverse control
lever.
1
2
3
4
5
6
executions are available with two
different center-to-center
distances named RTM351/2400
and RTM351/3000.
The RTM351, as it comes
complete with its standard outfit,
can immediately be used for
profitable operation.
Its performances are boosted by
the addition of special devices
such as: attachment for “in
process” gauging (mechanical or
hydraulic), hydraulic wheelhead
plunge feed, hydraulic wheel
dresser, etc.
The main technical and
construction features of the
RTM351 are:
• Top geometric precision and
surface finish of the
workpiece being ground
because of the extreme
sensitivity of the table
movements and the
5 Faceplate lock knob.
6 Trip stop for automatic table
traverse reverse.
7 Hydraulic wheel dresser.
8 Electronic “in process” sizing
gauge.
stiffness of the wheelhead
assembly whose
wheelspindle is supported,
on 50% of its length, by
special babbited bearing;
• Air-float headstock and
tailstock;
• Workheads with four
movements; radial and
cross movements, 360°
rotary motion and
micrometer swing
movement, for easy and
fast centering of crankpins.
Readings on workhead to
hundredths of a mm (thou
of an inch) can be both
radial and crosswise;
• The clutch is mounted direct
onto headstock spindle,
with a view to obtaining fast
and easy balancing of the
masses in rotation.
The clutch assembly has
9 Tailstock quill lock lever.
10 Tailstock quill feed control
handwheel.
11 Wheelhead micrometer feed
control handwheel.
12 Pushbutton panel.
Fig. 1
General view of the RTM 351/3000 in the “D” execution.
Some special devices, which make grinding easier and cut the machining times, are installed on the machine.
furthermore been designed to
obtain, at the start, an
extremely smooth and gradual
engagement, this being easily
adjustable via the control lever;
• Transmission via highly
flexible and resistant
cogged belts, to ensure a
constant and even
workpiece rotation;
• Outboard counterweights
are radially adjustable and
protected by safety guards,
in compliance with accident
prevention regulations;
• Pushbutton panel with
centralized low-voltage
electric controls.
Both version can be supplied
also with stepless variable speed
workhead motor.
7
8
9
10
11
12

Standard outfit
Fig. 2
Fig. 3 Fig. 4
Fig. 2
Standard steady rests facing the
main journals.
Fig. 3
Workhead equipped with center
driving plate.
Fig. 4
Workhead equipped with
selfcentering chuck.
• Cooling system complete with
power pump, coolant tank and
3 /4” gas thread nozzle (fig. 9)
• Set of splash guards
• Grinding wheel, 915 mm (36”)
dia., 32 mm (1 3 /4”) wide,
mounted on hub
• 1 wheel balancing arbor
• 1 grinding wheel puller
• 1 grinding wheel pulling tube
• 1 oversize motor pulley, to be
used when the grinding wheel
is worn
• 2 centers with nut for
workhead
• 1 blunt center for workhead
• 1 center puller
• 2 self-centering chucks, 230
mm (9 1 /64”) dia., cpl. with
2 chuck wrenches (fig. 4)
• 2 driving plates (fig. 3)
• 2 driving dogs, 25-60 mm
(1”-2 3 /8”) capacity
• 2 driving dogs, 60-100 mm
(2 3 /8” - 4”) capacity
• 2 driving dogs, 100-150 mm
(4” - 5 15 /16”) capacity
• set of auxiliary counterweights
for workheads (fig. 6)
• 2 standard steady rests
(fig. 2)
• 1 tool kit containing: 1 center
positioning checking
attachment (fig. 6), 1
centering rod and 2 dial
indicators for ditto
• 1 square for centering rod
(fig. 8)
• DMI - attachment for taking
the crank throw (fig. 7)
• DRM - attachment for dressing
the grinding wheel face and
corners (fig. 5); the wheel
dressing diamond is available
on request
• Set of levelling pads
(13 pcs. for RTM 351/2400,
15 pcs. for RTM 351/3000)
• 1 lubrication gun and set of
service spanners
• 2 kg (4.40 lb) wheelspindle oil

Fig. 5 Fig. 6
Fig. 7 Fig. 8
Fig. 9
Fig. 5
DRM - Radius dresser: for dressing
the grinding wheel face and
corners, with the possibility to
adjust the radius of the crankshaft
journal fillet.
Fig. 6
Center position checking
attachment resting onto workhead
gauge blocks; the auxiliary
counterweights are mounted onto
the faceplate.
Fig. 7
DMI - attachment for taking the
crank throw.
Fig. 8
Centering rod mounted onto the
check square.
Fig. 9
Coolant tank with power pump.
Fig. 10
AEM - electronic “in process” sizing
gauge, complete with PSM 127
attachment; the measuring head is
to be located into the dial indicator
seat, as shown in the illustration.
Fig. 11
DRMY - hydraulic wheel dresser.
Fig. 12
PSM 127 - continuous
measurement attachment.

Extra outfit
• Grinding wheels, 915 mm
(37”) dia. x 350 mm
(12”) hole, 20 mm ( 51 /64”),
25 mm (1”), 40 mm
(1 37 /64”), 50 mm (1 9 /16”),
and 63 mm (2 1 /2”) wide,
part Nos. U812140170,
U812140180,
U812140200,
U806140070
and U811140030
• coolant nozzle, 1 /2” gas part
No A01.26703
• DRFM - attachment for
dressing and chamfering
the grinding wheel face and
dressing and tapering the
grinding wheel sides
(less diamond);
part No. A00A22750
(fig. 16)
• DRMY - hydraulic wheel
dresser (less diamond)
draw. No. V10A22006
(V10A22007 Imperial)
(fig. 11)
• DRP - center grinding
attachment; part
No. A00A22775 (fig. 15)
• DAMY - hydraulically -
operated wheelhead plunge
feed device (suitable for
“A” and “D” execution:
refer to fig. 1, item 6) draw.
No. VA9A22014
(VA9A22015 Imperial)
• LU/S - narrow steady rest;
draw. No. A00A22650
• LUS/DC - narrow steady
rest with builtin centering
fixture, less dial indicator
(use the one supplied with
the machine); draw.
No. A00A22675 (fig. 14)
• AEM - electronic “in
process” sizing gauge;
draw No. V26A17002
(V26A17003 Imperial)
(fig. 10)
• PSM 127 - continuous
measuring attachment;
draw. No A00.64800A
(fig. 12)
• DCST/CT - unit for checking
tailstock cross traverse
Fig. 10
(less indicator); draw
No. V11A17002
• COS M/50 - magnetic coolant
clarifier with tank in
replacement of the standard
coolant tank;
part No. V08022016 (fig. 17)
• Gravity filtering clarifier with
tank, in replacement of the
standard coolant tank;
part No. V08A14002
• AES 500 - static balancer,
part No. A00.61200C
(refer to loose leaflet)
• SFN/2B - portable belt type
superfinisher, part
No. A00.81580 (fig. 13)
• 2.5 K wheel dressing diamond,
part No. C465908000
• Collapsible table way covers,
for RTM 351/2400 execution
part No. V05A22006 (pair
assembled on the machine);
for RTM 351/3000 part
No. V05A22008
• LU - Special steady rest
135 ÷ 255 mm (5 5 /16” - 10 3 /64”)
capacity; draw. No. A00A22950
• Wheelhead and table digital
reading position control
device; part. No. V11A22002.
Fig. 11
Fig. 12

The machine and its components
Fig. 13
Fig. 14 Fig. 15
Fig. 16
Fig. 17
Fig. 13
SFN/2B - portable belt type
superfinisher.
Fig. 14
LUS/DC - narrow steady rest with
built-in centering fixture.
Fig. 15
DRP - centering grinding
attachment. The flexible drive shaft
is connected direct to the
headstock.
Fig. 16
DRFM - attachment for dressing
and chamfering the grinding wheel
face and tapering the grinding
wheel sides.
Fig. 17
Cooling system with magnetic
coolant clarifier and tank.

Technical data
RTM 351/2400 RTM 351/3000
Working capacity
Max. diameter ground with full-size wheel mm 260 1015 /64” 260 915 /64”
Max. swing over table mm 700 271 /2” 700 271 /2”
Min. diameter admitted in steady rests mm 60 223 /64” 60 223 /64”
Max. diameter admitted in steady rests mm 180 7” 180 7”
Max. eccentricity of workheads (throw) mm 170 611 /16” 170 611 /16”
Max. weight admitted between centers kg 800 1760 lb 800 1760 lb
Geometric features
Height of centers over table mm 350 13 3 /4” 350 13 3 /4”
Max. distance between centers mm 2400 94 31 /64” 3000 118 7 /64”
Max. distance between chucks mm 2360 93” 2960 116 1 /2”
Self-centering chuck diameter mm 230 9” 230 9”
Max. grinding wheel diameter mm 915 36” 915 36”
Min. grinding wheel width mm 20 25 /32” 20 25 /32”
Standard grinding wheel width mm 32 1 1 /4” 32 1 1 /4”
Max. grinding wheel width mm 63 2 1 /2” 63 2 1 /2”
Wheelhead
Travel, fast mm 170 6 11 /16” 170 6 11 /16”
Travel, fine mm 230 9” 230 9”
Feed per turn of handwheel mm 1 0,40” 1 0,40”
Headstock
Workpiece rotationspeed (6) r.p.m. 12 21 24 33 42 66 12 21 24 33 42 66
*Workpiece rotation speed (stepless) r.p.m. 9-50 9-50
Table
Micrometer feed per turn of the handwheel mm 5,6 0,22” 3,6 0,14”
Fast traverse speed, per minute mm 3600 141 47 /64” 3600 141 47 /64”
Slow traverse speed, steplessly adjustable
(only for D execution), per minute mm 45-250 1 25 /32 - 10” 45-250 1 25 /32 - 10”
(for “DR” execution) mm 85-650 3 11 /32 - 25 1 /2”
Motor rating
Wheelhead kW 5,5 (7,5 HP) 5,5 (7,5 HP)
Headstock kW 0,8-0,45 (1-0,06 HP) 0,8-0,45 (1-0,06 HP)
*Headstock kW 3,8-0,6 (4,6-0,8 HP) 3,8-0,6 (4,6-0,8 HP)
Fast table traverse kW 0,55 (0,75 HP) 0,55 (0,75 HP)
Slow table traverse (only for D execution) kW 0,6 (0,85 HP) 0,6 (0,85 HP)
Hydraulic system kW 0,55 (0,75 HP) 0,55 (0,75 HP)
Cooling system kW 0,15 (0,2 HP) 0,15 (0,2 HP)
Dimensions and masses
Lenght A mm 7428 292 7 /16” 9514 374 9 /16”
Width B mm 2245 88 1 /32” 2245 88 1 /32”
Height C mm 2040 80 1 /32” 2040 80 1 /32”
Approx. weight, unpacked kg 5600 12345 lb 6040 13315 lb
Approx. weight, ocean packed kg 6700 14770 lb 7500 16534 lb
Measurements, weights and executions can be changed without previous notice. Motor rating is referred to 50 Hz frequency.
*Data valid for machines with stepless variable speed workhead motor.

BERCO S.p.A.
Via 1° Maggio, 237
44034 Copparo (Ferrara) Italy
Phone (+39) 0532 864111
Fax (+39) 0532 864259
www.berco.com
machinetools@berco.com
ISO 9001 Cert. n. 0029/4
ISO 14001 Cert. n. 0009A/2
All manufacturers’s names, numbers, symbols and descriptions are used for reference purposes only. All parts listed are of Berco original
production.The specifications and processes described in this brochure are subject to change without notice
Published by Berco Communications Dept.
00711.WM105GB00A

A Company
of ThyssenKrupp
RTM 270
Crankshaft grinder
BERCO S.p.A.

RTM 270/B - 1300 - 1600 - 2000
1 Lever and knob for
adjustment of the belts.
2 Headstock spindle rotation
control lever, 3-position: start,
neutral, braking.
3 Faceplate lock pin control
knob.
4 Table traverse handwheel.
5 Lever for fast traversing the
table in either direction,
equipped with
electromechanical safety
device against unintentional
maneuvers.
6 One-shot pump for table feed
gearing lubrication.
1
2
3
4
5
6
7
8
7 Wheelhead micrometer feed
control unit, for plunge grinding.
8 Pedal control to actuate
faceplate lock pins.
9 Hydraulic wheel dresser:
opening and shutoff of coolant
as well as automatic return of
the diamond slide are
automatic.
10 Levers for shifting and
locking the tailstock quill.
11 Signal light fixture for
journal lineup.
12 Hydralic steady rest with
mechanical lock, in working
position.
13 Wheelhead traverse control
lever, 2-positions: fast return,
slow and fast approach.
14 Wheelhead infeed control
handwheel.
15 Centralized, low-tension
electric controls box, with main
switch which can be blocked
via a padlock.
16 Hydraulic pedal control for
actuating tailstock quill
retraction.
Fig. 1
General view of the machine in the “B” execution, the most complete because of specific devices and automatics.
Figg. 2,3
Diagrams showing, respectively,
top roundness and surface finish
degree obtainable with the RTM
270.
Fig. 2 Fig. 3
9
10
11
12
13
14
15
16

Fig. 4
Workhead where the fo u r
m ovements stand out in full re l i e f .
Fig. 5
Workhead equipped with 180 mm
( 7 3 /3 2”) dia. selfcentering chuck.
Fig. 6
Workhead equipped with driving
collar and center with ring nut.
Fig. 4 Fig. 5 Fig. 6
The Berco RTM 270 is a
crankshaft grinder which has
been designed to meet the
manifold requirements of those
people who must handle both
unit and production regrinding
of small and medium runs of
crankshafts.
If view of this, the RTM 270
has been realized in three
different executions, each one
having trhee different distances
between centers.
Execution “A”
It is the simplest execution and
can thus be regarded to as the
basic execution.
No automatics are provided for
in the standard outfit of this
machine, the machine being
suitable only for regrinding of
crankshafts with different
dimensions and specifications.
Execution “B”
It is the most complete
execution, being featured by
specific devices and
automatics which allow
profitable and timesaving
regrinding of small and
medium runs of crankshafts.
Execution “D”
Essentially similar to the “A”
execution, it is furthermore
equipped with a unit for
actuating table traverse and
reverse thus allowing cylindrical
grinding.
The customer will thus be able
to choose, out of these
executions, the one which
better suits his specific
requirements and add the
several optionals available in
the extra outfit.
Other techincal and costruction
features of the RTM 270 are
set forth hereunder:
• Self-locking counterweights,
radially adjustable and
protected by safety guards in
compliance with the accident
prevention regulations.
• Drive via high-resistance,
high-flexible cogged belts, to
assure an even and surgingfree
rotation of workpiece.
• Clutch located direct on the
main spindle, to obtain fast
and precise balancing of mass
in rotation.
• Air-float headstock and
tailstock.
• Tailstock quill with 50 mm
(1 31 /32”) travel, to make loading
and unloading of the
crankshafts easier and faster.
• Workheads with four
movements:
- radial movement
- cross movement
- 360° rotary motion, with fast
indexing for 2, 3, 4, 5 and 6
cylinder engine crankshafts
- micrometer swing movement.
All versions can be supplied
also with stepless variable
speed workhead motor.

Other executions of the machine
RTM 270/A - 1300 - 1600 - 2000
In this execution, the machine is equipped with:
• 2-pole motor for headstock spindle ro t a t i o n
• h yd raulic system for slow and fast wheelhead
t rave rs e
• 4 - w ay cross slide swing heads
• unit for fast trave rsing the table in either
d i re ct i o n
Fig. 7
G e n e ral view of the machine in the “A” exe c u t i o n .

RTM 270/D - 1300 - 1600 - 2000
Similar, as far as standard outfit is concerned, to
the “A” execution, this machine differs for
having the possibility to regrind both crankshaft
and cylindrical shafts.
The table, in fact, besides fast traverse, is
featured by work traverse, with automatic and
manual reversal of the feed direction.
Travel of the tables is adjustable via trip limit
stops and the traverse speed is steplessly
adjustable via the potentiometer mounted in the
electric controls box.
Fig. 8
G e n e ral view of the machine in the “D” execution.

Specific devices and automatics
Each execution of the RTM 270
is fe a t u red by its own specific
d e v i ces and automatics; others
a re available on request as
s c h e m a t i cally shown at right.
S t a n d a rd outfit
E x t ra outfit
Not provided fo r
Executions
A
B D
devices and automatics
H yd ralic wheel dre s s e r
P/No. A00A17750
Wheel dresser
H yd raulic pedal control for actuating tailstock quill
re t ra ct i o n
H yd raulic pedal control for actuating the wo r k h e a d
locking pins
H yd ralic steady re s t
D PA/L signal light fixture for journal lineup
Wheel dresser for hyd raulic steady re s t
Plunge feed device for grinding fillets and diameter
of cra n k s h a ft journals - P/No. A00A17725
Unit for actuating the automatic table trave rs e
and re ve rs e

Fig. 9
Rear view of tailstock showing the
tailstock quill actuating cylinder
and the actuator which controls the
workhead fa ceplate locking pin.
Fig. 10
H yd raulic wheel dre s s e r.
Fig. 11
Wheel dre s s e r.
Fig. 9 Fig. 10
Wheel dresser
A B D
Unit for dressing the face and
the edges of the grinding
wheel, with the possibility to
adjust radius of the crankshaft
journal fillet. The dressing
diamond is supplied only on
request.
Hydraulic wheel dresser
A B D
It is installed on the top of
wheelhead and allows fast
dressing of the grinding wheel
face with uniform movement,
even if the crankshaft is
mounted in the machine.
The diamond slide speed is
adjustable at will and
movement can be reversed
automatically.
A handwheel with indexed ring
allows the adjustment of the
diamond cutting depth as well
as the compensation for
reduction in grinding wheel
diameter after each dressing.
A ratchet lever allows obtaining
the micrometer work jogging of
the diamond holder, with
constant increments.
Unless clearly required when
placing the order, no diamond
will equip the wheel dresser.
H yd raulic pedal control fo r
a ctuating tailstock quill
re t ra ct i o n
The device actuates, thro u g h
the hyd raulic cylinder in fig. 9
the tailstock quill re t ra ct i o n .
The pedal control (16 fig. 1)
l e aves the operator free hands
thus facilitating the cra n k s h a ft
setup.
A built-in contriva n ce pre ve n t s
the tailstock quill from re t ra ct i o n
when the grinding wheel is in
working position.
H yd raulic pedal control fo r
a ctuating the wo r k h e a d
locking pins
A B D A B D
This device allows, through the
h yd raulic swinging act u a t o rs
s h own in fig. 9, the locking pins
to enter their seats in the
workheads in the positions
which we re preset for ce n t e r i n g
c ra n k s h a ft journals.
It actuates the locking pins of
both headstock and tailstock at
the same time through the
pedal (8 fig. 1) located in the
l ower part of machine bed, thus
speeding up ce n t e r i n g .
Fig. 11

Specific devices and automatics
A B C
S t a n d a rd outfit
E x t ra outfit
Not provided fo r
Fig. 12
Fig. 13 Fig. 14
H yd raulic steady re s t
A B D
It is small-sized steady rest and
can pra ct i cally be used with all
c ra n k s h a ft types.
It is fitted with a device, linked to
the upper shoe, for checking
centering of cra n k s h a ft journals.
A p p roach to and return from the
wo r k p i e ce are hyd raulic and
c o n t rolled manually, by
a ctuating a leve r.
S a fety microswitches pre ve n t
fast automatic trave rse of the
table when the hyd raulic steady
rest is in working position.
Wheel dresser for hyd ra u l i c
steady re s t
A B D
Shape and dimensions of this
grinding wheel fa ce and ra d i u s
d resser have specifically been
designed for use on the “B”
execution of the machine.
It is mounted on the table,
opposite the hyd raulic steady
rest, leaving the cra n k s h a ft in
the machine. The dre s s i n g
diamond is supplied only on
re q u e s t .
D PA/L signal light fixture fo r
journal lineup
A B D
It is mounted on the top of the
h yd raulic steady rest and is
f i tted with a stylus that, once
c o r re ct journal wheel lineup is
obtained, switches on a signal
l i g h t .

Fig. 15 Fig. 16
Plunge feed device fo r
grinding fillets and diameter
of the journals
A B D
This hyd ra u l i ca l l y- o p e ra t e d
d e v i ce allows to obtain the
wheelhead work feed, with
p reset speed and travel, fo r
grinding the fillets and diameter
of cra n k s h a ft journals (fig. 13).
Oleomechanical table
traverse and reverse unit
A B D
This unit, which gives the
machine the features of a
cylindrical grinder, is most
profitably used in engine
rebuilding shops in as much as
it is often necessary to grind
parts other than crankshafts
such as bars, rods, etc.
It consists essentially of:
- a d.c. motor with electronic
speed adjustment for the
automatic work feed of the
table (traverse speed is
adjustable from 5 to 300
mm/min -2”+11 13 /16” per
minute)
- an oleomechanical unit for
reversing table traverse,
either manual or automatic
via limit stops sliding onto a
scale secured to the table.
Fig. 12
H yd raulic steady rest and DPA / L
signal light fixture mounted on its
t o p .
Fig. 13
Wheelhead work feed device
c o n t rols panel.
a) Feed speed adjustment knob (fo r
grinding the cra n k s h a ft journals)
with fast approach lever;
b) Wheelhead travel adjustment
k n o b ;
c) Knob for engaging and
disengaging the wheelhead
automatic fe e d .
Fig. 14
Wheel dresser for hyd rauulic steady
re s t .
Fig. 15
C y l i n d r i cal grinding on the Berc o
RTM 270, “D” exe c u t i o n .
Fig. 16
E l e ct ronic conve rter for the
automatic table work fe e d .

Fig. 17
Standard outfit
Fig. 19
Fig. 18
• safety guard s
• cooling system, complete with
p ower pump and tank on the
back of machine, with
s t a n d a rd 1 /2” gas thread nozzle
(fig. 19)
• set of splash guard s
• 1 grinding wheel, 710 mm
(28”) dia. 25 mm (1”) thick,
mounted on whelelhub
• 1 dummy shaft wheel
b a l a n c i n g
• 1 wheelhub puller
• 1 ove rsize motor pulley, fo r
worm wheel
• 1 truncated center fo r
wo r k h e a d
• 2 ce n t e rs with ring nuts fo r
workheads
• 1 center puller
• 2 180 mm (7 3 /3 2”) dia. selfcentering
chucks, with chuck
s p a n n e r
• 2 driving dogs, 20 ÷ 60 mm
( 3 1 /6 4” - 2 3 /8”) ca p a c i t y
• 2 driving dogs 60 ÷ 115 mm
( 2 3 /8” - 4 1 2 /3 2”) ca p a c i t y
• 2 driving collars
• 2 normal steady rests (fig. 17)
• 2 auxiliary conterweights
(fig. 18)
• 1 tool kit complete (fig. 22),
w i t h :
- 1 center position checking
a tt a c h m e n t ,
- 1 centering rod,
- 2 dial gauges for ditt o
• 1 square for centering rod
(fig. 21)
• 1 feeler gauge for the
centering rod (fig. 23)
• DMI - attachment for taking
c rank throw (fig. 20)
• 7 adjustable wedges fo r
machine levelling
• 1 grease gun
• set of serv i ce spanners
• kg 2 oil for wheelhead
l u b r i f i ca t i o n .

Fig. 20 Fig. 21
Fig. 22
Fig. 17
Normal steady rests onto the table.
Fig. 18
Workhead position checking
a ttachment. The cra n k s h a ft is held
b e t ween chucks. A u x i l i a ry
c o u n t e rweights fitted to wo r k h e a d
fa ce p l a t e .
Fig. 19
Coolant tank and power pump.
Fig. 20
“DMI” attachment for taking cra n k
t h row .
Fig. 21
Centering rod mounted on square ,
for centering cra n k s h a ft journals.
The cra n k s h a ft is held betwe e n
ce n t e rs .
Fig. 22
Tool kit with attachment, ce n t e r i n g
rod and indica t o rs .
Fig. 23
Centering rod mounted via a
s u r fa ce gauge on the DMI
a ttachment, for truing the ce n t e rs .
Fig. 23
All items in the standard outfit
a re common to the diffe re n t
executions of the machine.

Extra outfit
The items listed in the extra
outfit can be used with any of
the three executions of the
machine.
Fig. 24 Fig. 25 Fig. 26
Fig. 27
• grinding wheels, 710 mm
(28”) dia. 203 mm (8”) hole,
t h i k n e s s e s :
20 mm 5 1 /6 4” code U 8 1 2 1 4 0 0 4 0
32 mm 1 1 /4” code U 8 1 2 1 4 0 0 6 0
40 mm 1 9 /1 6” code U 8 0 6 1 4 0 0 3 0
50 mm 2 ” code U 8 1 1 1 4 0 0 0 0
63 mm 2 3 1 /6 4” code U 8 1 1 1 4 0 0 1 0
• 1 /4” gas thread nozzle
( for wheel thickness more than
20 mm - 5 1 /6 4” )
code A 0 1 . 2 6 7 0 3
• 3 /4” gas thread nozzle
(for wheel thickness more
than 25 mm - 1”)
code A 0 1 . 2 6 7 0 4
• DRFM attachment for dre s s i n g
and chamfering wheel fa ce
and for dressing and tapering
wheels sides (fig. 27), less
d i a m o n d
code A 0 0 A 1 7 8 0 0
• DRP center grinding
attachment (fig. 24)
code A 0 0 A 1 7 8 2 5
• LU/DC normal steady rest with
built-in centering fixture
(fig. 26), less dial gauge
code A 0 0 A 1 7 7 0 0
• LU/S narrow steady rest fo r
n a r row journals
code A 0 0 A 1 7 6 5 0
• LU/S/DC narrow steady re s t
with built-in centering fixture ,
less dial gauge
code A 0 0 A 1 7 6 7 5
• s e l f - centering chuck 180 mm
( 7 3 /3 2”) dia. complete with
t h ree sets of three jaws, max.
external capacity 245 mm
(9 4 1 /6 4” )
code A 0 0 A 1 7 2 1 7
• pair of collapsible way cove rs ,
in re p l a cement of the standard
c ove rs
code V 0 5 A 1 7 0 0 2
• magnetic coolant clarifier with
tank in replacement of the
standard tank (fig. 25), for
cooling system
code V08A17010
• g ravity filtering clarifier with
tank, in re p l a cement of the
s t a n d a rd coolant tank
code V 0 8 A 1 4 0 0 2
• diamond for the wheel
d re s s e rs
code C 4 6 5 9 0 4 0 1 0
• SFN2/B portable belt type
s u p e r f i n i s h e r. Please re fer to
the loose leaflet (fig. 31)
• AES 500 static balance r
(please re fer to the loose
l e a f l e t )
• AEM elect ronic sizing unit
(fig. 30)
• PSM 127 continuous
m e a s u rement attachment
(fig. 28)
• unit for checking tailstock
c ross trave rse (fig. 29)
code V 1 1 A 1 7 0 0 2
• pair of knobs with indexe d
bushing, for shifting the
workheads ra d i a l l y
code V 0 4 A 1 7 0 0 2

Fig. 28
Fig. 24
Grinding a center with the DRP
attachment.
Fig. 25
Cooling system with magnetic
coolant clarifier and tank.
Fig. 26
Steady rest with built-in centering
fixture.
Fig. 27
DRFM attachment for dressing and
chamfering wheel face and for
dressing and tapering wheel sides.
Fig. 28
PSM 127 continuous measurement
attachment.
Fig. 29
Unit for direct check of the
tailstock cross traverse; the dial
gauge is the one in the standard
outfit.
Fig. 30
AEM electronic sizing and control
unit. To be used in conjunction
with Berco PSM 127.
Fig. 31
SFN/2B portable belt type
superfinisher.
Fig. 29
Fig. 30
Fig. 31

Technical data
Working ca p a c i t y
Max. diameter ground with full-size wheel m m 150 5 2 9 /3 2”
Max. swing over table m m 540 2 1 1 /4”
Min. diameter admitted in steady re s t s m m 30 1 1 1 /6 4”
Max. diametera dmitted in steady re s t s m m 140 5 3 3 /6 4”
Max. eccentricity of workheads (throw ) m m 1 2 0 4 2 3 /3 2”
Max. mass admitted between ce n t e rs kg 3 0 0 661 lb
Geometric fe a t u re s
Height of center over table mm 270 1 0 5 /8”
Max. distance between ce n t e rs (2 exe c u t i o n s ) m m 1300 - 1600 - 1950 51” - 63” - 76 2 5 /3 2”
Max. distance between chucks (2 exe c u t i o n s ) m m 1270 - 1569 - 1919 50” - 61 2 5 /3 2” - 75 9 /1 6”
S e l f - centering chuck diameter m m 180 7 3 /3 2”
Max. grinding wheel diameter m m 710 2 8 ”
Min. grinding wheel thickness m m 20 2 5 /3 2”
S t a n d a rd grinding wheel thickness m m 25 1 ”
Max. grinding wheel thickness m m 63 2 3 1 /6 4”
W h e e l h e a d
Travel, fa s t m m 1 8 0 7 5 /6 4”
Travel, fine m m 1 6 5 6 3 1 /6 4”
Max. travel for plunge grinding m m 1 , 5 . 0 6 0 ”
Feed per turn of the handwheel m m 1 . 0 4 0 ”
H e a d s t o c k
Wo r k p i e ce rotation speed (6) r. p . m . 16 - 22 - 30 - 40 - 52 - 70
* Wo r k p i e ce rotation speed (stepless va r i a b l e ) r. p . m . 12 ÷ 6 0
Ta b l e
M i c rometer feed per turn of the handwheel m m 5 , 8 4 . 2 3 ”
Fast trave rse speed, per minute m / m i n 6 236” in/min
S l ow trave rse speed, steplessly adjustable (only for D execution), per minute m / m i n 0,05 - 0,35 2 - 13 9 /1 6” in/min
Motor ra t i n g
W h e e l h e a d k W 4 (5,50 CV)
H e a d s t o c k k W 0,45 ÷ 0,24 (0,6 ÷ 0,32 CV)
* Headstock k W 0,24 ÷ 1,45 (0,32 ÷ 2 CV)
Fast table trave rs e k W 0,55 (0,75 CV)
S l ow table trave rse (only for D exe c u t i o n ) k W 0,62 (0,84 CV)
H yd raulic sys t e m k W 0,55 (0,75 CV)
Cooling sys t e m k W 0,15 (0,20 CV)
Dimensions and masses
Lenght A (see fig. 32) m m 4500 - 5500 - 6219 177” - 216 1 7 /3 2” - 244 2 7 /3 2”
Width B (see fig. 32) m m 1 7 6 0 6 9 1 /8”
Height C (see fig. 32) m m 1 8 3 7 7 2 2 1 /6 4”
A p p rox. mass, unpacked (exec. 1300) k g 3 2 5 0 7 1 5 0 l b
A p p rox. mass, ocean packed (exec. 1300) k g 3 8 2 0 8 4 0 4 l b
A p p rox. mass, unpacked (exec. 1600) k g 3 4 0 0 7 4 9 6 l b
A p p rox. mass, ocean packed (exec. 1600) k g 4 1 0 0 9 0 3 9 l b
A p p rox. mass, unpacked (exec. 1950) k g 3 4 5 0 7 6 0 6 l b
A p p rox. mass, oce a n p a c ked (exec. 1950) k g 4 1 5 0 9 1 4 0 l b
M e a s u rements, masses and executions can be changed without previous notice. Motor rating is re ffe red to 50 Hz fre q u e n c y.
*Data valid for machines with stepless variable speed workhead motor.
Fig. 32

R T M 3 5 1
R T M 5 7 5
Others crankshaft grinders of the RTM series
Besides the RTM 270 Berco is
manufacturing other crankshaft
grinder models; their main
specifications are set forth
hereunder:
RTM 351
Center height over table
350 mm (13 3 /4” ) .
Max. swing over table 700 mm
( 2 7 9 /1 6” ) .
Max. distance between ce n t e rs
2400-3000 mm
( 9 4 3 1 /6 4” - 118 7 /6 4” ) .
Max. mass admitted betwe e n
ce n t e rs 800 kg (1760 lb).
RTM 425A
Center height over table
425 mm (16 3 /4” ) .
Max. swing over table 850 mm
( 3 3 1 /2” ) .
Max. distance between ce n t e rs
4020 mm (158 1 /6 4” ) .
Max. mass admitted betwe e n
ce n t e rs 1200 kg (2645 lb).
RTM 575
Center height over table
575 mm (22 5 /8” ) .
Max. swing over table
1150 mm (45 9 /3 2” ) .
Max. distance between ce n t e rs
4020 mm (158 1 /6 4” ) .
Max. mass admitted betwe e n
ce n t e rs 1200 kg (2645 lb).
RTM 700
Center height over table
700 mm (27 9 /1 6” ) .
Max. swing over tablea
1400 mm (55 1 /8” ) .
Max. distance between ce n t e rs
5700-6900 and 8000 mm
( 2 2 4 1 3 /3 2” - 271 2 1 /3 2” e 315”).
Max. mass admitted betwe e n
ce n t e rs 6000 kg (13200 lb).

BERCO S.p.A.
Via 1° Maggio, 237
44034 Copparo (Ferrara) Italy
Phone (+39) 0532 864111
Fax (+39) 0532 864259
www.berco.com
machinetools@berco.com
ISO 9001 Cert. n. 0029/5
ISO 14001 Cert. n. 0009A/3
00910.WM101GB00A
Published by Berco Communications Dept.