OfiTE 800 User manual

Model 800 Viscometer
#130-10-C/#130-11-C - With Carrying Case and Power Supply
#130-10-L - With Retractable Legs (For Kits)
Instruction Manual
Updated 3/16/2022
Ver. 11
OFI Testing Equipment, Inc.
11302 Steeplecrest Dr. · Houston, Texas · 77065 · U.S.A.
Tele: 832.320.7300 · Fax: [phone] · www.ote.com
©Copyright OFITE 2015

OFITE, 11302 Steeplecrest Dr., Houston, TX 77065 USA / Tel: [phone] / Fax: [phone] / www.ote.com 1
Introduction.....................................................................................2
Description......................................................................................2
Components ...................................................................................3
Specications .................................................................................5
Safety...............................................................................................8
Setup.............................................................................................. 11
Calibration.....................................................................................12
Operation.......................................................................................15
Calculations ..................................................................................17
Disassembly .................................................................................17
Maintenance..................................................................................18
Warranty and Return Policy ........................................................23
Table of
Contents

OFITE, 11302 Steeplecrest Dr., Houston, TX 77065 USA / Tel: [phone] / Fax: [phone] / www.ote.com 2
The Model 800 8-Speed Electronic Viscometer is designed and exclusively
manufactured by OFI Testing Equipment, Inc. It is extensively used worldwide
in both the eld and laboratory for the precise measurement of rheological
properties of uids.
The OFITE Model 800 Viscometer determines the ow characteristics of oils
and drilling uids in terms of shear rate and shear stress over various time
and temperature ranges at atmospheric pressure. Speeds are easily changed
with a control knob, and shear stress values are displayed on a lighted
magnied dial for ease of reading.
The viscometer’s motor RPM is continuously monitored and automatically
adjusted by the OFITE Pulse-Power electronic speed regulator to maintain
a constant shear rate under varying input power and drilling uid shear
conditions. The eight precisely regulated test speeds (shear rates in RPM)
are as follows: 3 (Gel), 6, 30, 60, 100, 200, 300, and 600. A higher stirring
speed is also provided. Speeds may be changed with a control knob
selection, without stopping the motor.
The Model 800 is suitable for both eld and laboratory use and uses a
motor-driven electronic package to provide drilling uid engineers with
an extremely accurate and versatile tool. The Model 800 operates from a
13–16 VDC power source. The electronic regulator continuously monitors
and automatically adjusts the rotational speed to maintain a constant shear
rate under varying uid shear conditions and input power variations that are
commonly found on-site.
Introduction
Description

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#130-10 Model 800 8-Speed Viscometer
#130-10-2 Speed Reference PC Board (For 130-10 Model Only)
#130-10-3 Speed Control PC Board (For 130-10 Model Only)
#130-10-5 Switch Plate
#130-10-6 Wiring Harness
#130-10-8-1 Encoder Disc
#130-10-14 Motor (For 130-10 Model Only)
#130-10-16 Belt
#130-10-17 Cover
#130-10-18 Lens for Cover
#130-10-20 Torsion Shaft
#130-10-22 Card Guide for PC Boards
#130-10-61 Light Assembly
#130-21 Cup, Stainless Steel
#130-76-28 Motor (For 130-11 Model Only)
#132-50 Rotor Drive
#132-56 Rotor Sleeve, R1, 303 Stainless Steel
#132-57 Shield
#132-58 Bob, B1, 303 Stainless Steel
#132-59 Bearing Retainer
#132-71 Bearing
#132-74 Locking Ring, 1.653"
#132-75 Locking Ring, ½"
#132-76 Locking Ring,    "
#134-05-2 Shielded Bearing for Bob Shaft
#134-10 Torsion Spring Assy, F1
#134-39 Clamp Sleeve for Torsion Spring
#134-40 Shim, ⅝" × ⅜"
#135-02 External Retainer Ring
#135-18 Socket Set Screw
#142-63 Locking Screw
#163-26 Small Clip
#170-21 Stand Support Rod
#170-44 Rubber Foot, ½"
#171-32 Midget Knob
Case:
#130-10-13-5 Carrying Case with Custom Foam Insert (For 130-10 Only)
#130-11-13-5 Carrying Case with Custom Foam Insert (For 130-11 Only)
Components

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Optional:
#132-56-C R1 Closed-Cup Rotor; 316 Stainless Steel (For completion and
fracturing uid testing.)
#130-45-1 Calibration Instrument
#132-80 Calibration Fluid, Certied, 100 cP, 16 oz
Additional Bobs, Sleeves, and Springs:
#132-58-1 B2 Bob, 303 Stainless Steel
#132-58-2 B3 Bob, 303 Stainless Steel
#132-58-3 B4 Bob, 303 Stainless Steel
#132-58-4 B5 Bob, 303 Stainless Steel
#132-58H B1 Bob, Hastelloy®
#132-56H R1 Sleeve, Hastelloy®
#134-10-2 F0.2 Torsion Spring Assembly (Green)
#134-10-3 F0.5 Torsion Spring Assembly (Yellow)
#134-10-4 F2.0 Torsion Spring Assembly (Red)
#134-10-5 F3.0 Torsion Spring Assembly (Purple)
#134-10-6 F4.0 Torsion Spring Assembly (White)
#130-10-SP One Year Spare Parts
#130-10-18 Lens for Cover
#130-10-503 Fuse, 4 Amp, Qty: 4
#130-10-61 Light Assembly
#130-48 Retaining Ring Pliers, Internal
#130-76-47 Retaining Ring Pliers, External
#132-59 Bearing Retainer
#132-71 Bearing, Qty: 2
#132-75 Locking Ring, ½"
#132-80 Calibration Fluid, 100 cP, 16 oz
#132-81 Calibration Fluid, 50 cP, 16 oz
#134-05-2 Shielded Bearing for Bob Shaft, Qty: 4
#134-10 Torsion Spring Assy, F1
#135-02 External Retainer Ring, Qty: 2

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Specications Instrument Geometry True Couette Coaxial Cylinder
Speed Accuracy (RPM) .1
Motor Speeds (RPM) 8 Fixed Speeds (600, 300, 200, 100, 60,
30, 6, and 3)
Readout Direct Dial
Power Requirements 13 – 16 VDC
Weight (kg) 6.0
Dimensions (cm) 15.2 × 17.8 × 40.6
Shipping Weight (kg) 20.4
Shipping Dimensions (cm) 55.9 × 25.4 × 40.6
Range of Measurement for Model 800
Rotor - Bob R1B1 R1B2 R1B3 R1B4 R1B5
Rotor Radius, RR, (cm) 1.8415 1.8415 1.8415 1.8415 1.8415
Bob Radius, RB, (cm) 1.7245 1.2276 0.8622 0.8622 1.5987
Bob Height, L, (cm) 3.8 3.8 3.8 1.9 3.8
Shear Gap, (cm) 0.117 0.6139 0.9793 0.9793 0.2428
R Ratio, RB/RR 0.9365 0.666 0.468 0.468 0.8681
Shear Rate Constant kR(sec-1
per RPM) 1.7023 0.377 0.2682 0.2682 0.8503
Shear Stress Constant for
E󰀨ective Bob Surface kS(cm-3)0.01323 0.02610 0.05290 0.10600 0.01541
Overall Instrument Constant,
K, with Standard F1.0 Spring,
ŋ=KfƟ/N
300 2,672 7,620 15,200 349
Max. Shear Stress,
SSMAX, (Dyne / cm2)
Constant
kT
R1B1 R1B2 R1B3 R1B4 R1B5
F 0.2 (Green) 77.2 330 651 1,320 2,644 384
F 0.5 (Yellow) 193 840 1,657 3,359 6,730 977
F 1.0 (Blue) 386 1,680 3,314 6,717 13,460 1,955
F 2.0 (Red) 772 3,360 6,629 13,435 26,921 3,910
F 3.0 (Purple) 1,158 5,040 9,943 20,152 40,381 5,865
F 4.0 (White) 1,544 6,720 13,257 26,870 53,841 7,819
F 5.0 (Black) 1,930 840 16,571 33,587 67,302 9,774
F 10.0 (Orange) 3,860 16,800 33,143 67,175 134,603 19,548

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Shear Rate Range R1B1 R1B2 R1B3 R1B4 R1B5
Shear Rate Constant, KR,
(sec-1 per RPM) 1.7023 0.3770 0.2682 0.2682 0.8503
Shear Rate, (sec-1 or 1/s)
3 RPM 5.11 1.13 0.80 0.80 2.56
6 RPM 10.21 2.26 1.61 1.61 5.11
30 RPM 51.07 11.31 8.05 8.05 25.54
60 RPM 102.14 22.62 16.09 16.09 51.07
100 RPM 170.23 37.70 26.82 26.82 85.12
200 RPM 340.46 75.40 53.64 53.64 170.23
300 RPM 510.69 113.10 80.46 80.46 255.35
600 RPM 1021.38 226.20 160.92 160.92 510.69
Viscosity Ranges<a>
(cP) R1B1 R1B2 R1B3 R1B4 R1B5
Minimum Viscosity<b>
@600 RPM 0.5<c> 4.5 12.7 25 1.2
Maximum Viscosity<d>
@3 RPM 33,000 293,920 838,200 1,672,000 38,390
<a> Computed for standard Torsion Spring (F 1.0). For other torsion springs, multiply by F factor.
<b> Lower viscosities can be measured by the Model 800, however one must take into account the
e󰀨ect of bearing drag, Taylor vortices, zero o󰀨set, etc. when looking at the expected accuracy of the
reading.
<c> For practical purposes the minimum viscosity is limited to 0.5 cP due to Taylor Vortices.
<d> Maximum viscosity is based on Maximum Shear Stress and Minimum shear rate (RPM). However,
due to practical and physical limitations, it may be di󰀩cult to take these measurements.
Shear Stress Conversions
To convert from units on left side to units on top, multiply by factor @ intercept.
Centipoise
(cP) Poise (P) g/(cm*s) (mN*s)m2mPa*s (lb*s)
100 ft2
Centipoise
(cP) 1 0.01 0.01 1 1 0.002088
Poise (P) 100 1 100 100 100 0.2088
g/(cm*s) 100 1 100 100 100 0.2088
(mN*s)m21 0.01 0.01 1 1 0.002088
mPa*s 1 0.01 0.01 1 1 0.002088
(lb*s)
100 ft2478.93 4.789 4.789 478.93 478.93 1

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Shear Stress Conversions
To convert from units on left side to units on top, multiply by factor @ intercept.
Dyne/cm2Pa lb/100ft2lb/ft2DR
Dyne/cm21 0.1 0.2084 0.002084 0.1957
Pa 10 1 2.084 0.02084 1.957
lb/100ft24.788 0.4788 1 0.01 0.939
lb/ft2478.8 47.88 100 1 93.9
DR 5.107 0.5107 1.065 0.01065 1
What Bob & Spring Should I Use?
There is often confusion or misunderstanding about what a viscometer can
actually measure. For example, a viscometer with an R1 B1 F1 combination
can measure water fairly well at 100 RPM and higher, but at 3 RPM, the
readings would be shaky at best. While on the other hand, a linear uid with a
viscosity of 15,000, could not get past 6 RPM with the same combination.
To estimate which spring might be best, use the formula below to calculate a
Minimum Spring factor, where one establishes the maximum RPM the uid
is going to be tested at, as well as what the expected “Apparent Viscosity”
of the uid at that RPM. If the Factor comes out as .87, then an F 1.0 spring
should be used. If it comes out as .16, then an F 0.2 spring would be best. To
cover all ranges, it may be necessary to use more than one spring.
Minimum Spring Factor (F) = RPM(max) * AV(max)
BOB(F)*90,000
Bob (F)
R1B1 1.0
R1B2 8.9
R1B3 25.4
R1B4 50.7
R1B5 2.4

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Safety
Explanation of Symbols
Caution: Risk of Danger - This symbol directs the operator to consult the
instruction manual for safety related warnings. (ISO-7000-0434)
Whenever this symbol is used on the equipment, the user must
consult the manual to determine the nature of the hazard and any
actions which have to be taken.
Fuse: This is the internationally recognized symbol for a user-replaceable
fuse. This symbol will be followed by information required to guide the
user to choose the proper replacement fuse.
Direct Current (DC): This symbol indicates an input (or output) that is
direct current only. (IEC 60417-5013)
Note: This symbol will indicate important notes and helpful hints for the
operation of the equipment.
Polarity: This symbol indicates that the equipment receives positive
voltage on the center pin of the connector and the return voltage is on the
outer case.
Tip: This symbol is used to identify operational information and best
practices to obtain the most reliable data.
Caution: Note - This symbol is used to indicate statements in the manual
which warn against actions which may cause damage to the equipment
during routine service or maintenance

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Electrical Requirements
The Model 800 Viscometer is to be powered by a DC power source. The
power supply for the #130-10 Model is capable of providing between 13
and 16 volts DC. The power supply for the #130-11 Model supplies 24 volts
DC. The equipment is current limited to 4 amps by a user-replaceable fuse.
However, we suggest that the power supply be current limited to less than 4
amps to provide additional protection to the equipment.
Power (On/O󰀨) Switch
Input Connector:
13 – 16 VDC Power
Inlet / Emergency
Disconnect Device
Power (On/O󰀨) Switch
Input Connector:
24 VDC Power
Inlet / Emergency
Disconnect Device
When connecting the equipment to your power source, make sure that the
13-16 VDC is connected to the center pin of the connector.
The equipment is supplied with a user-replaceable fuse. This fuse must only
be replaced by a 250-volt, 4-amp, time-delayed fuse.
Environmental Conditions
The equipment is designed for use in normal environmental conditions:
- Indoors
- At or below an altitude of 2,000 m (6,562 ft)
- In temperatures between 5° and 40°C (41°–104°F)
- With a maximum relative humidity of 80% for temperatures up to 31°C
(88°F) decreasing linearly to 50% relative humidity at 40°C (104°F)
- This equipment has not been rated according to IEC 60529
Installation
The Model 800 Viscometer should be used in a location where it will not be
subjected to excessive moisture. It should be placed on a at, stable surface
in a well-ventilated environment.

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Caution – Risk of Danger: This equipment produces sound pressure
in excess of 85 dBA. Protective measures (such as hearing protection,
noise-reducing ba󰀪es, or a hood) should be considered.
Equipment Operation
Caution – Risk of Danger: The (13–16 VDC) power cord and the DC inlet
are the emergency disconnect devices. Do not position the equipment such
that it is di󰀩cult to operate the emergency disconnect devices.
Caution – Risk of Danger: In normal operation, this equipment may liberate
the potentially poisonous gasses listed below. However, the list below is
dependent upon the chemical makeup of the sample uids presented for
testing. Care should be taken to ensure that: no unexpected or anomalous
chemicals are contained or added to the test samples; the test environment is
adequately ventilated; and, when necessary, appropriate personal protective
equipment is employed.
- Hydrogen Sulde (H2S)
- Methane (CH4)
- Carbon Dioxide (CO2)
- Sulfur Dioxide (SO2)
Caution – Risk of Danger: The samples presented for testing may contain
ammable substances. The following risk-reduction procedures must be
followed to ensure the safe operation of the equipment.
- Always use in a well-ventilated area.
- Keep away from open ames.
Caution – Risk of Danger: If this equipment is operated in a manner not
specied by the manufacturer (OFITE), the protections provided by the
equipment may be impaired.
Caution – Risk of Danger: This equipment may operate unexpectedly if
the equipment is energized when the Speed Selector Knob and Power (On/
O󰀨) Switch are left in the “On” position. Care should be taken to ensure both
switches are in the “O󰀨” position prior to energizing the equipment. Also,
care should be taken to ensure that the Speed Selector Knob is in the “O󰀨”
position prior to turning the Power (On/O󰀨) Switch to the “On” position.
Speed Selector Knob

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Setup The Model 800 Viscometer is a precision instrument. Any damage to the bob
shaft, bearings, or transducer will greatly a󰀨ect the accuracy of the readings.
Always handle the Viscometer with care, especially when installing and
removing the bob.
Always remove the bob from the shaft before shipping the Viscometer.
Failure to do so will damage the bob shaft.
1. Connect the instrument to a 13–16 VDC, current-limited power source.
2. With the instrument turned o󰀨, place the splash guard onto the bob shaft
with the tube end pointed up towards the bob. Push up.
3. Screw on the appropriate bob with the tapered end up towards the splash
guard.
4. Place the sleeve onto the rotor over the bob. The threads assure the rotor
will attach evenly and uniformly each and every time.
5. The power switch is located on the back panel. Turn the unit on.
6. Place a properly prepared sample of test uid in a sample cup and
immerse the rotor sleeve exactly to the ll line on the sleeve by raising the
platform. Tighten the lock nut on the platform.
Rotor
Splash Guard
Bob
Sleeve
Platform

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Calibration The Model 800 viscometer can lose calibration while in service if the bob
shaft bearings become contaminated or if the bob shaft itself is bent. If the
dial does not read zero when it should or if there is excessive dial deection
when the main shaft is turning, this may indicate that the bob shaft bearings
are sticking. If the spring appears to be non-linear, the bob shaft may be bent.
Your viscometer will require servicing if it exhibits any of these symptoms.
According to API Recommended Practice 10B-2, viscometers being used
for testing well cement should be calibrated quarterly. API Recommended
Practice 13B-1 and 13B-2 specify viscometers being used for drilling uids
should be checked monthly.
The OFITE Calibrating Instrument (Part No. 130-45-1) and the Calibration
Check Kit (Part No. 132-49) are available to facilitate calibration. The
Calibrating Instrument uses a dead-weight method of calibrating, while the
Calibration Check Kit is uid based.
130-45-1 Calibrating Instrument
132-49 Calibration Check Kit
Equipment:
#130-45-1 Calibrating Instrument for 8-Speed Viscometer (Requires a trained
technician)
#132-49 Calibration Check Kit
Calibration Fluids, “Certied”:
#132-84 Calibration Fluid, 20 CP, 16 oz (500 mL)
#132-81 Calibration Fluid, 50 CP, 16 oz (500 mL)
#132-80 Calibration Fluid, 100 CP, 16 oz (500 mL)
#132-83 Calibration Fluid, 200 CP, 16 oz (500 mL)
#132-82 Calibration Fluid, 500 CP, 16 oz (500 mL)

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Procedure:
1. Choose the certied calibration uid using the temperature-viscosity chart
supplied with the calibration uid to cover the viscosity range of interest.
Make sure the lot number on the chart matches the lot number on the
uid container. Each lot of standard uid is individually certied. The
viscosity will normally vary slightly from lot to lot.
2. Clean and dry the viscometer bob, sleeve, and cup. Place the viscometer
and the calibration uid side-by-side on the counter top in a room
with a reasonably constant temperature (variation of less than 5°F ±
2.5°F). Allow the viscometer and the uid to stand at least two hours to
equilibrate.
3. Operate the viscometer in air for two to four minutes to loosen up the
bearings and gears. Observe the rotor sleeve for excessive wobbling and
replace if necessary.
4. Fill the cup to the scribed line with calibration uid and place it on the
viscometer stage. Move the stage upward until the uid level is to the ll
line on the sleeve.
Never immerse the sleeve in uids above the ll line.
Fill Line
Viscometer Sleeve
5. Place a thermometer capable of ± 0.2°F (0.1°C) into the uid and hold
or tape it in place to prevent breakage. Operate the viscometer at a low
speed setting until the thermometer reading becomes stable to within ±
0.2°F (0.1°C) per 30 seconds. Note and record the temperature reading.
6. Once the temperature has stabilized, operate the viscometer at 600 RPM
and then at 300 RPM. Note and record the dial readings to the nearest
0.5 dial unit.

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7. Using the temperature-viscosity chart supplied with the calibration uid,
determine the certied viscosity to the nearest 0.5 centipoise.
a. Compare the 300 RPM reading to standard viscosity and record the
deviation plus or minus.
b. Divide the 600 RPM dial reading by 1.98, compare that to standard
viscosity, and record the deviation plus or minus.
8. Deviations exceeding 1.5 dial units are not acceptable. If the deviation
exceeds this tolerance, the viscometer will require adjustments or
calibration by a qualied technician.
9. Record the viscometer serial number, date, and deviation. Mark on
the viscometer the date of calibration and a general indication of the
calibration check status.

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Operation Measuring Viscosity:
1. Mix the sample on the “STIR” setting for 10 seconds while heating or
cooling the uid. Monitor the temperature with a thermometer. Continue to
mix until the sample reaches the target temperature.
2. Rotate the knob to one of the speed settings. When the dial reading
stabilizes, record the reading and the temperature. Repeat this step for
any other speeds that your test requires.
Always start with the higher RPM and work your way down to the lowest
RPM. For example, if you need readings at 100 RPM, 200 RPM, and 300
RPM, record the measurement at 300 RPM rst, then 200 RPM, then 100
RPM, then gel strengths (if necessary).
Measuring Gel Strength:
1. Mix the sample on the “STIR” setting for 10 seconds.
2. Rotate the knob to “GEL” and immediately shut o󰀨 the power.
3. As soon as the sleeve stops rotating, wait 10 seconds and turn the power
back on while looking at the dial. Record the maximum dial deection
before the gel breaks. This is the 10 second gel strength.
When measuring gel properties, the dial does not have to return to zero
during the quiescent period. Therefore, it should not be forced back to the
zero setting if it does not freely do so. When determining the maximum
dial deection, no allowance needs to be made if the dial did not start
at zero. Only the maximum dial deection is of interest. Rheological
properties and characteristics of the sample will determine if the dial
returns to zero during the quiescent periods of the gel measurements.
4. For the 10 minute gel strength, re-stir the uid and wait 10 minutes before
recording the maximum dial deection.

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API Testing
1. Mix the sample on the “STIR” setting for 10 seconds.
2. Set the speed to 600 RPM. Wait for the reading to stabilize and then
record the dial reading and temperature.
3. Set the speed to 300 RPM. Wait for the reading to stabilize and then
record the dial reading and temperature.
4. Stir the sample again for 10 seconds.
5. Set the speed to “GEL” and immediately shut o󰀨 the power.
6. As soon as the sleeve stops rotating, wait 10 seconds and turn the power
on while looking at the dial. Record the maximum dial deection before
the gel breaks. This is the 10 second gel strength.
7. For the 10 minute gel strength, re-stir the uid and wait 10 minutes before
recording the maximum dial deection.

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Calculations Plastic Viscosity (PV), cP = 600 RPM reading – 300 RPM reading
Yield Point (YP), lb./100 ft2 = 300 RPM reading – Plastic Viscosity (PV)
Apparent Viscosity (AV), cP = 600 RPM reading / 2
Gel Strength, 10 second, lb/100 ft2 = the maximum dial deection after 10 sec.
Gel Strength, 10 minute, lb/100 ft2 = the maximum dial deection after 10 min.
ŋ=K F
ŋ= Viscosity (cP)
K= Machine constant for the bob and rotor combination
F= Spring factor
Ɵ= Dial readings
RPM= Rotational speed
Machine constants:
R1B1= 300
R1B2= 2,672
R1B3= 7,620
R1B4= 15,200
R1B5= 349
Clean the viscometer after every test.
1. Remove the sleeve from the rotor.
2. Remove the bob.
3. Once the bob is removed, remove the splash guard and wipe down the
bob shaft. Clean all removed parts with soap and water and dry them
thoroughly.
Keep the instrument upright at all times, especially when cleaning
so that water does not get into the bearings.
Disassembly
Ɵ
RPM

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Maintenance From time to time, the bearings will need to be changed. Complete the
following to determine if it is time to perform this maintenance procedure:
1. The viscometer should have a zero dial reading when placed in an upright
position with the sleeve not immersed in uid prior to running tests.
2. With the instrument in this position, rotate the sleeve at 600 RPM. The
dial reading in air should not exceed one.
3. Place water in a suitable container and immerse the rotor sleeve to the ll
line.
4. Rotate the sleeve at 600 RPM. The dial reading in water should be
between 1.5 and 3.0.
5. At 300 RPM, the dial reading in water should be between 0.5 and 2.0.
If the viscometer fails to pass any one of the above tests, the bearings are
bad and should be replaced by a qualied instrument technician.
Bob Shaft Bearing and Torsion Spring Replacement:
Tools Required:
Allen Wrench,   "
Phillips Head Screwdriver
Retainer Ring Pliers (small)
External Retainer Ring Pliers
Flat Screw Driver
Bob Shaft Wrench
Replacement Parts:
#134-05-2 Bearing for Bob Shaft, Shielded
1. Unplug the power supply and remove the sleeve and bob.
Use the bob shaft wrench to hold the shaft in place while unscrewing the
bob.
2. With the at-head screw driver, loosen the set screw in the speed control
knob. Remove the speed control knob from the unit.
3. Remove all four at-head screws on the outer housing cover and gently
lift the cover upward.
4. Loosen the set screw at the top of the Zero Calibration Knob one turn
counterclockwise.

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5. Loosen the two screws in the top of the Index Block. Pull the Index Block
straight back to prevent damage to the dial or stop pin.
6. Loosen the top set screw on the dial one turn counterclockwise.
7. Gently lift the torsion spring straight up.
Do not stretch the torsion spring.
If you are replacing only the torsion spring, discard the old spring, and
skip to step 21 to complete the process.
Set Screw (Step 4)
Bridge
Dial
Bearing Mount
Torsion Spring
Zero Calibration Knob
Set Screw (Step 6)
Index Block
Set Screw (Step 4)
Bridge
Dial
Bearing Mount
Torsion Spring
Zero Calibration Knob
Set Screw (Step 6)
Index Block
#130-10 Model
#130-11 Model