widos 4600 User manual

WIDOS Einsteinstr. 5 Phone [phone]
Wilhelm Dommer Söhne D-71254 Ditzingen Fax [phone]
GmbH E-mail: [email protected] Webside: www.widos.de
Working Instructions
Translation
Heating Element Butt Welding Machine
WIDOS 4600
Keep for further use!

Idendification of Product
30.08.19 Working Instructions WIDOS 4600 Page 2 of 32
Model: Heating element butt welding machine
Type: WIDOS 4600
Serial number / year of construction: see type plate
Customer Entries
Inventory-no.:
Place of working:
Order of Spare Parts and After Sales Service:
Address of Manufacturer WIDOS
Wilhelm Dommer Söhne GmbH
Einsteinstr. 5
D-71254 Ditzingen
Phone: [phone]
Telefax: [phone]
[email protected]
http://www.widos.de

Introduction
30.08.19 Working Instructions WIDOS 4600 Page 3 of 32
Purpose of the Document
These working instructions give you information about all important questions which refer to the
construction and the safe working of your machine.
Just as we are you are obliged to engage in these working instructions, as well.
Not only to run your machine economically but also to avoid damages and injuries.
Should questions arise, contact our advisers in the factory or in our subsidiary companies.
We will help you with pleasure.
According to our interest to make our products and working instructions continuously better, we kindly
ask you to inform us about problems and defects which occur during operation.
Thank you.
Structure of the Working Instructions
This manual is arranged in chapters, which refer to the different operating phases of the machine.
Due to this structure, the searched information can be easily found.
WIDOS 30.08.2019
W. Dommer Söhne GmbH
Einsteinstraße 5
D-71254 Ditzingen
All rights reserved
Reprinting only allowed with permission of the corporation.
Any changes prior to technical innovations.

Contents
30.08.19 Working Instructions WIDOS 4600 Page 4 of 32
1.DESCRIPTION OF THE PRODUCT .................................................................................................. 6
1.1.Usage and Purpose-oriented Use ...................................................................................................... 6
1.2.Machine Overview............................................................................................................................... 6
1.3.Safety Measures.................................................................................................................................. 7
1.4.Conformity ............................................................................................................................................ 7
1.5.Designation of the Product ................................................................................................................. 7
1.5.1Technical Data ...................................................................................................................................................7
1.6.Equipment and Accessories: .............................................................................................................. 9
2.SAFETY RULES .............................................................................................................................. 10
2.1.Explanation of the Symbols and Indications ................................................................................... 10
2.2.Obligations of the Owner .................................................................................................................. 11
2.3.Obligations of the Worker ................................................................................................................. 11
2.4.Measures of Organisation ................................................................................................................ 11
2.5.Information about Safety Precautions ............................................................................................. 11
2.6.Instructions for the Staff...................................................................................................................11
2.7.Dangers while Handling the Machine .............................................................................................. 12
2.8.Maintenance and Inspection, Repair ............................................................................................... 12
2.9.Dangers Caused by Electric Energy ................................................................................................. 12
2.10.Dangers Caused by the Hydraulics .................................................................................................. 13
2.11.Special Dangers ................................................................................................................................ 13
2.11.1Danger of Catching Clothes by the Planer ..................................................................................................13
2.11.2Danger of being burnt by Heating Element, Reception Box and Welding Area ...................................13
2.11.3Danger of Stumbling over Hydraulic and Electric Wires..........................................................................14
2.11.4Danger of Squeezing by Clamping Devices and Guideways ...................................................................14
2.12.Structural Modifications on the Machine........................................................................................14
2.13.Cleaning the Machine ....................................................................................................................... 14
2.14.Warranty and Liability ....................................................................................................................... 14
3.FUNCTIONAL DESCRIPTION ........................................................................................................ 15
4.OPERATING AND INDICATING ELEMENTS ................................................................................ 16
4.1.Elements on the Hydraulic Aggregate ............................................................................................. 16
4.1.1Hydraulic aggregat with pressure gauge analog ......................................................................................17
4.2.Elements on the side of the aggregate ............................................................................................ 17
4.3.Separating device for heating element ............................................................................................ 17
4.4.Elements at heating element and planer ......................................................................................... 18
5.STARTING AND OPERATING ....................................................................................................... 19
5.1.Starting ............................................................................................................................................... 19

Contents
30.08.19 Working Instructions WIDOS 4600 Page 5 of 32
5.1.1Replacing the Reduction Inserts...................................................................................................................20
5.1.2Using Small and Large Reduction Inserts ...................................................................................................20
5.2.Welding Process................................................................................................................................ 21
6.WELDING LOG AND TABLES ....................................................................................................... 23
7.MAINTENANCE AND REPAIR ...................................................................................................... 25
7.1.Clamping Elements ............................................................................................................................ 25
7.2.Planer ................................................................................................................................................. 25
7.3.Storage ............................................................................................................................................... 25
7.4.Used Hydraulic Oil ............................................................................................................................. 25
7.5.Checking the Hydraulic Oil-Level ..................................................................................................... 25
7.6.Venting the Hydraulic Cylinders ....................................................................................................... 26
8.TRANSPORT .................................................................................................................................. 27
9.HYDRAULIC AND ELECTRIC DIAGRAMS .................................................................................... 28
10.SPARE PARTS LIST ...................................................................................................................... 31
11.DECLARATION OF CONFORMITY ................................................................................................. 32

WIDOS Einsteinstr. 5 Phone [phone]
Wilhelm Dommer Söhne D-71254 Ditzingen Fax [phone]
GmbH E-mail: [email protected] Webside: www.widos.de
30.08.19 Working Instructions WIDOS 4600 Page 6 of 32
1. Description of the Product
This chapter gives important basic information about the product and its prescribed use.
All technical details of the machine are put together as a general arrangement.
1.1. Usage and Purpose-oriented Use
The WIDOS 4600 has been designed for heating element butt welding of pipes and fittings with a
diameter range of Ø = 75 - 250 mm.
It is a machine for construction sites and particularly designed for the usage on-site, as well as in the
workshop.
For this reason, the frame is kept small so that it can be used even under difficult conditions
(e.g.building ditches).
All use going beyond is not purpose-oriented.
The manufacturer is not responsible for damages caused by misuse.
The risk is held only by the user.
Also part of the purpose-oriented use is
respecting all the indications of the working instructions and
performing the inspection and maintenance works.
1.2. Machine Overview
1 Planer
2Reception box
3Heating element
4Basic machine with clamping tools
5Hydraulic aggregate
1
5
3
2
4

Description of Product Chapter 1
30.08.19 Working Instructions WIDOS 4600 Page 7 of 32
1.3. Safety Measures
In case of wrong use, wrong operation or wrong maintenance the machine itself or products standing
nearby can be damaged or destroyed.
Persons being in the endangered area may be injured.
Therefore these working instructions have to be thouroughly read and the corresponding safety
regulations must be necessarily adhered to.
1.4. Conformity
The machine corresponds in its construction to the valid recommendations of the European Community
as well as to the European standard specifications.
The development, manufacturing and mounting of the machine were made very carefully.
1.5. Designation of the Product
The product is designated by two type labels which are attached at the aggregate and at the basic
machine.
They contain the type, the serial number and the year of construction of the machine.
1.5.1 Technical Data
1.5.1.1 WIDOS 4600 General Data
Material: PP, PE 80, PVDF, PE 100
Pipe diameter range: outside-= 75 - 250 mm
Transport box (lxwxh):
Weight:
Cases with compartments for reduction
inserts:
4 compartments:
7 compartments:
9 compartments:
appr. 950 x 850 x 570 mm
appr. 40 kg
appr. 680 x 410 x 310 weight: appr. 10 kg
appr. 1160 x 410 x 310 weight: appr. 16 kg
appr. 1470 x 410 x 310 weight: appr. 21 kg
Packing box (lxwxh):
Weight:
appr. 1230 x 980 x 670 mm
appr. 67 kg
Weight (without boxes): appr. 93 kg
Fuse: 16 A
Wire cross section: 1.5 mm²
Emissions - The sound intensity level while using the planer is
appr. 86 dB (A).
- When using the named pipe materials and when
welding below 260° C no toxicant damp arises.

Description of Product Chapter 1
30.08.19 Working Instructions WIDOS 4600 Page 8 of 32
Ambient conditions in the welding area: - Take care for cleanness (no dust at the welding
area)
- Do not weld below 5° C, if necessary preheat
- Avoid humidity, if necessary put up a tent
- Avoid strong sun rays influence
- Protect from wind, shut the pipe ends
1.5.1.2 Planer
Motor: Monophase-alternating current motor
Power: 1150 Watt
Voltage: 230 V (10 %)
Nominal current: 4.5 A
Frequency: 50 Hz (10 %)
Speed n1 of motor: 760 rpm
Speed n2 of planer: 60 - 100 rpm
Attached elements: On/off-switch with fixing device
Connecting cable and plug with earthing contact
Weight: appr. 14 kg
1.5.1.3 Heating Element
Power: 1500 Watt
Voltage: 230 V (10 %)
Current: 6.5 A (10 %)
Frequency: 50 Hz
Outside-: 320 mm
Surface: Nonstick coated
Elements: Electronic temperature control
Control lamps, on/off-switch
Connecting cable and plug with earthing contact
Weight: appr. 6 kg

Description of Product Chapter 1
30.08.19 Working Instructions WIDOS 4600 Page 9 of 32
1.5.1.4 Hydraulic Aggregate
Power: 0,3 kW
Voltage: 230 V (10 %)
Current: 2,7 A
Frequency: 50 Hz
Hydraulic oil tank: appr. 1 L
Electromotor and pump:
Speed: 1380 (rpm)
Max. working pressure of pump: appr. 120 bar
Working pressure: 100 bar
Volume velocity: 1.9 L/min
Weight : appr. 23 kg
1.5.1.5 Basic Frame
Dimensions (lxwxh): 800 x 420 x 460 mm
Reduction inserts: Dimensions can be selected
Material frame: Machinery steel
Material clamping shells: Aluminium
Weight: appr. 40 kg
cylinder: 35 mm
piston rod: 30 mm
Length of stroke of cylinder: 140 mm
Max. force: (F=P*A) 5200 N (at 100 bar)
Velocity of piston rod: 6.2 cm/s
See spare parts list for article numbers and single parts
1.6. Equipment and Accessories:
The following accessories are part of the first delivery:
1 Tool bag for 10 parts
1 Socket spanner size 27
1 Torx screw driver T10
1 each Allan key angulate, size 3 / 6 / 8
1 each Allan key with T grip size 4 / 5
optional Different sizes of reduction inserts, roller brackets for the pipes

WIDOS Einsteinstr. 5 Phone [phone]
Wilhelm Dommer Söhne D-71254 Ditzingen Fax [phone]
GmbH E-mail: [email protected] Webside: www.widos.de
30.08.19 Working Instructions WIDOS 4600 Page 10 of 32
2. Safety Rules
The base for the safe handling and the fault-free operation of this machine is the knowledge
of the basic safety indications and rules.
The safety indications of this chapter represent the general part.
Particular information is listed directly before the corresponding actions are described.
These working instructions contain the most important information to run the machine safely.
The safety information must be read by all persons working on the machine.
2.1. Explanation of the Symbols and Indications
In the working instructions, following denominations and signs are used for dangers:
This symbol means a possible danger for the life and the health of persons.
The non-respect of these indications may have heavy consequences for the health.
This symbol means a possible dangerous situation.
The non-respect of these indications may cause light injuries or damages on goods.
This symbol means a possible dangerous situation by moving parts of the machine
The disrespect of these indications may cause heavy crushings of parts of the body
resp. damages of parts of the machine.
This symbol means a possible dangerous situation due to hot surfaces.
The disrespect of these indications may conduct to heavy burns,
respectively to self-ignition or even fire.
This symbol gives important information for the proper use of the machine.
The non-respect of these indications may conduct to misfunctions and damages on
the machine or on goods in the surrounding.
Under this symbol you get user tips and particularly useful information.
It is a help for using all the functions on your machine in an optimal way and helps you
to make the work easier.
The regulations for the prevention of accidents are valid (UVV).

Safety Rules Chapter 2
30.08.19 Working Instructions WIDOS 4600 Page 11 of 32
2.2. Obligations of the Owner
The owner is obliged only to let persons work at the machine, who
know about basic safety and accident prevention rules and are instructed in the handling of the
machine, as well as who
have read and understood the safety chapter of this manual and certify this by their signature.
The safety-conscious working of the staff should be checked in regular intervals.
2.3. Obligations of the Worker
All persons who are to work at the machine are obliged before working:
to follow the basic safety and accident protection rules.
to have read and understood the safety chapter and the warnings in this manual and to confirm by
their signature that they have well understood them.
to inform themselves about the functions of the machine before using it.
2.4. Measures of Organisation
All equipment required for personal safety is to be provided by the owner.
All available safety equipment is to be inspected regularly.
2.5. Information about Safety Precautions
The working instructions have to be permanently kept at the place of use of the machine.
They are to be at the operator's disposal at any time and without much effort.
In addition to the manual, the common valid and the local accident protection rules and
regulations for the environmental protection must be available and followed.
All safety and danger indications on the machine have to be in a clear readable condition.
Every time the machine changes hands or is being rent to third persons, the working
instructions are to be sent along with and their importance is to be emphasized.
2.6. Instructions for the Staff
Only skilled and trained persons are allowed to work at the machine.
It must be clearly defined who is responsible for transport, mounting and dismounting,
starting the operation, setting and tooling, operation, maintenance and inspection,
repair and dismounting.
A person who is being trained may only work at the machine under supervision of an experienced
person.

Safety Rules Chapter 2
30.08.19 Working Instructions WIDOS 4600 Page 12 of 32
2.7. Dangers while Handling the Machine
The machine WIDOS 4600 is constructed according to the latest technical standard and the
acknowledged technical safety rules.
However, dangers for the operator or other persons standing nearby may occur.
Also material damages are possible.
The machine must only be used:
according to the purpose-oriented usage
in safety technical impeccable status
Disturbances, which may affect the safety of the machine must be cleared immediately.
2.8. Maintenance and Inspection, Repair
All maintenance and repair works have to be basically performed with the machine in
off position.
During this the machine has to be secured against unauthorized switching on.
Prescribed maintenance and inspection works should be performed in time.
The DVS gives the advice of inspection works after 1 year.
For machines with a specially high usage percentage the testing cycle should be
shortened.
The works should be performed at the WIDOS GmbH company or by an authorized
partner.
2.9. Dangers Caused by Electric Energy
Only skilled persons are allowed to work at electrical appliances !
The electrical equipment of the machine has to be checked regularly.
Loose connections and damaged cables have to be replaced immediately.
If works at alive parts are necessary, a second person has to assist who can disconnect the
machine from the mains if necessary.
All electric tools (heating element, planer, aggregate) have to be protected from rain and dropping
water (if necessary use a welding tent).
According to VDE 0100, the use on construction sites is only allowed with a power distributor with a
FI-safety switch.

Safety Rules Chapter 2
30.08.19 Working Instructions WIDOS 4600 Page 13 of 32
2.10. Dangers Caused by the Hydraulics
System parts and pressure hoses should be made pressureless before beginning of
any repair works. Even if the machine is switched off, pressure may be in the
hydraulic accumulator!
There is the danger of injuring the eyes by hydraulic oil squirting out
Damaged hydraulic hoses have to be immediately replaced.
Make a visual inspection of the hydraulic hoses before each work beginning.
The hydraulic oil is inedible !
2.11. Special Dangers
2.11.1 Danger of Catching Clothes by the Planer
There is the danger of cutting yourself or even breaking bones !
Only wear clothes tight to the body.
Do not wear rings or jewellery during work.
If necessary, wear a hair-net.
Always put the planer back into the reception box after and before each use.
Transport the planer at the handle only.
Do not touch the planer surfaces.
Switch the planer on only for usage. Otherwise the planer will start every time when the security
microswitch is pressed.
2.11.2 Danger of being burnt by Heating Element, Reception Box and Welding
Area
You can burn yourself, inflammable materials can be ignited!
The heating element temperature is heated up to more than 200° C!
Do not touch the surfaces of the heating element.
Do not leave the heating element unsupervised.
Take enough safety distance to inflammable materials.
Wear safety gloves.
Always put the heating element back into the reception box after and before each use.
Transport the heating element at the handle only.

Safety Rules Chapter 2
30.08.19 Working Instructions WIDOS 4600 Page 14 of 32
2.11.3 Danger of Stumbling over Hydraulic and Electric Wires
Make sure that no person has to step over the wires.
Lay the wires in such a way that the danger is kept to a minimum.
2.11.4 Danger of Squeezing by Clamping Devices and Guideways
There is the danger of serious injuries:
on the one hand between the inner clamping devices and on the other hand between the
outer clamping device and the end of the guideway.
Do not stand or put hands between clamped pipe ends.
Do not stand or put hands between the inner clamping devices with not yet clamped pipes.
Do not block opening and closing of the machine slides.
2.12. Structural Modifications on the Machine
No modifications, extensions or reconstructions may be made on the machine without permission
of the manufacturer.
Machine parts which are not in a perfect condition are to be replaced immediately.
Only use original WIDOS spare and wear parts.
In case of purchase orders please always state the machine number.
2.13. Cleaning the Machine
The used materials and tissues are to be handled and disposed of properly, especially:
when cleaning with solvents
when lubricating with oil and grease
2.14. Warranty and Liability
Fundamentally our "General Sales and Delivery Conditions" are valid.
They are at the owner's disposal latest when signing the contract.
Guarantee and liability demands referring to personal injuries or damages on objects are excluded if
they are caused by one or several of the following reasons:
not using the machine according to the prescriptions
inexpert transport, mounting, starting, operating and maintenance of the machine
running the machine with defective or not orderly mounted safety appliances
ignoring the information given in this manual
structural modifications on the machine without permission
unsatisfactory checking of parts of the machine, which are worn out
repairs performed in an inexpert way
in case of catastrophes and force majeure.

WIDOS Einsteinstr. 5 Phone [phone]
Wilhelm Dommer Söhne D-71254 Ditzingen Fax [phone]
GmbH E-mail: [email protected] Webside: www.widos.de
30.08.19 Working Instructions WIDOS 4600 Page 15 of 32
3. Functional Description
Basically, the international and national process guidelines are to be
followed.
The plastic pipes are clamped by means of the clamping devices.
Then the front sides of the pipes are cut plane and parallel by means of the planer and the
misalignment of the pipes is checked.
The heating element is inserted and the pipes are pressed against the heating element under defined
adjusting pressure. This process is called "adjusting".
After the prescribed bead height being reached, pressure is reduced, the heating time begins. The
function of this time is to heat up the pipe ends.
After expiration of the heating time, the slides are opened, the heating element is removed quickly and
the pipes are driven together again. The time gap from the removal of the heating element to joining
the pipes is called change over time.
The pipes are joined under prescribed welding pressure and then cool down under pressure (cooling
time).
The welded joint can be unclamped, the welding process is finished.
Heating element heats the pipes up
t
o welding temperature
Finished welding with internal
and ex
t
ernal bead

WIDOS Einsteinstr. 5 Phone [phone]
Wilhelm Dommer Söhne D-71254 Ditzingen Fax [phone]
GmbH E-mail: [email protected] Webside: www.widos.de
30.08.19 Working Instructions WIDOS 4600 Page 16 of 32
4. Operating and Indicating Elements
4.1. Elements on the Hydraulic Aggregate
No. Name Function
1 Pressure gauge, digital Digital display of the hydraulic pressure
2 Valve lever Opening the slides. There are 4 different positions:
- to the left side: slides close.
- in the middle (usual position): the pressure which
is currently achieved is kept (also by means of the
built-in hydraulic accumulator)
- slightly to the right side (position pressureless):
a possibly existing pressure is released without
moving the slides. Due to the hydraulic accumu-
lator, it takes about 10 s until the pressure is
completely released.
- to the right side: slides open
3 Setting screw for pressure
relief valve
- Limitation of the pressure to the desired value.
4 Hydraulic connection for
closing the slides
- Non-dropping quick-acting coupling
5 Hydraulic connection for
opening the slides
- Non-dropping quick-acting coupling
6 Screw with oil dipstick - checking the oil level
- oil filler neck
1
2
4
5
3
6
Label „opening / closing“
Indicating label „Setting the
pressure relief valve“

Operating and Indicating Elements Chapter 4
30.08.19 Working Instructions WIDOS 4600 Page 17 of 32
4.1.1 Hydraulic aggregat with pressure gauge analog
4.2. Elements on the side of the aggregate
No. Denomination Function
7 Plug socket 230 V / 50 Hz Possibility for connecting the planer / heating element
8 Plug socket 230 V / 50 Hz Possibility for connecting the planer / heating element
9 Mains cable 230 V / 50Hz Power supply
4.3. Separating device for heating element
There is a tear-off bar mounted between the movable and
the fixed clamping shells on the basic machine. It
prevents the heating element from sticking to the heated-
up pipe ends.
When inserting the heating element take care that it lies
in the zone of the throat of the tear-off bar (see arrow).
(6)
(3)
(5)
(4)
(2)
Pressure gauge
analog (version)
7
8
9

Operating and Indicating Elements Chapter 4
30.08.19 Working Instructions WIDOS 4600 Page 18 of 32
4.4. Elements at heating element and planer
No. Denomination Function
10 Control lamp green - There are three different states:
off: signalizes that the heating element is not
heated up at the moment or that it cools down
blinking: the heating element temperature is
maintained by a certain pulse-position ratio
on: signalizes that the heating element is heated up at
the moment. It has not yet reached the desired
temperature
11 Setting screw - For regulating the temperature of the heating
element
12 On/off-switch with red lamp - As soon as the heating element is switched on,
the red control lamp lightens
13 Locking lever with protection switch - Protection against unintended running of the
planer
- Protection of the planer against jumping out of the
machine
- Planing is only possible if the security micro
switch is pressed
14 On/off-switch for planer - The planer can be switched on with the switch
and the associated fixing knob.
- The planer has to be switched off before and
after each use.
14
13
10
11
12

WIDOS Einsteinstr. 5 Phone [phone]
Wilhelm Dommer Söhne D-71254 Ditzingen Fax [phone]
GmbH E-mail: [email protected] Webside: www.widos.de
30.08.19 Working Instructions WIDOS 4600 Page 19 of 32
5. Starting and Operating
The instructions of this chapter are supposed to initiate in the operation of the machine and
lead during the approppriate starting of the machine.
This includes:
the safe operation of the machine
using all the possible options of the machine
economic operation of the machine.
5.1. Starting
The machine may only be operated by trained and authorized persons.
For the qualification, a plastic welding exam can be taken according to
DVS and DVGW.
In situations of danger for persons and the machine, the mains plug has to
be unplugged immediately.
In case of power failure, there may still be pressure in the hydraulic system.
Therefore release pressure if need be.
After completion of the welding work and during breaks the machine has
to be switched off. Further take care that no unauthorized person has
access.
Protect the machine from wetness and moisture !
According to VDE 0100, the use on construction sites is only allowed with a
power distributor with a FI-security protective switch.
Check the oil level of the hydraulic system before each starting of the control unit in
order to avoid damages on the pump. The oil-level must be between the two marks at
the oil dipstick.
Connect the hydraulic aggregate to the mains (230 V / 50 Hz).
Connect the heating element and the planer to the corresponding plug sockets of the aggregate.
Connect the hydraulic hoses of the basic machine to the quick-acting couplings of the hydraulic
aggregate.
Lay hydraulic and electric wires carefully (danger of stumbling) !
Take into account the surrounding conditions:
The welding may not be performed under direct sun rays influence.
Use a welding umbrella if necessary.
If the surrounding temperature is under 5° C, measures have to be taken:
Use a welding tent or preheat the pipe ends if necessary.
In addition, take measures against rain, wind and dust.

Starting and Operating Chapter 5
30.08.19 Working Instructions WIDOS 4600 Page 20 of 32
5.1.1 Replacing the Reduction Inserts
Unscrew the mounted reduction inserts by means of the provided Allan key.
Screw the reduction inserts with the corresponding diameter into the clamping devices.
If necessary (e.g. for T-pieces) the outer fixed clamping device can be dismantled by unscrewing
the three hexagon socket screws.
Dismantling of the outer fixed clamping device
5.1.2 Using Small and Large Reduction Inserts
Small Reduction Inserts:
Pipe fittings often have only a short straight surface area on which they can be clamped.
Fittings mostly need to be clamped in the inner clamping devices with the small reduction
inserts.
When fittings are to be welded (bends, T-pieces etc.), the inner small reduction insert can also be
used flush to the inside or to the outside.
Small reduction insert, centered (for pipes)
Large Reduction Inserts
They are mainly used for a good tightening and are generally mounted on the inner
clamping devices.
Super large reduction inserts have a specially high guidance quality and are mainly
used during the welding of fittings with long legs which can only be clamped with a single
clamping tool.
Shown here:
Small reduction insert,
flush to the inside
(for bends, T-pieces)