Hunter BL Series User manual

BL Series Drum / Disc Lathe
7674-T, 09-22
© Copyright 2019-2022 Hunter Engineering Company
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1.1. Owner Information
BL Series Drum / Disc Lathe
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1.2. Getting Started
1.2.1. Introduction
This manual provides operaon instrucons and informaon required to operate the BL Series Drum/Disc
Lathe. This manual assumes that you are familiar with the basics of brake lathes. Secon 1 provides me-
chanical and electrical safety informaon as well as basic informaon about the BL Series Drum / Disc
Lathe. Following secons contain more detailed informaon about equipment, procedures, and maintenance.
Italicized references (for example, Refer to “Equipment Components” page 5.) are used to refer to specic
parts of this manual that provide addional informaon or explanaon. These references should be read for
addional informaon to the instrucons presented.
The owner of the BL Series brake lathe is solely responsible for arranging technical training. The lathe is to
be operated only by a qualied Hunter trained technician. Maintaining records of personnel trained is solely
the responsibility of the owner or management.
For further operaon instrucons for BL6x and BL7x lathes with ACT / Digi-Cal, refer to “Chapter 3. ACT /
Digi-Cal” of these instrucons.
1.2.2. For Your Safety
Hazard Definitions
Watch for these symbols:
CAUTION
Cauon: Hazards or unsafe pracces, which could result in minor personal injury or product
or property damage.
WARNING
Warning: Hazards or unsafe pracces, which could result in severe personal injury or death.
DANGER
Danger: Immediate hazards, which will result in severe personal injury or death.
These symbols idenfy situaons that could be detrimental to your safety and or cause equipment damage.
Important Safety Instructions
Read all instrucons.
All visitors and children should be kept a safe distance from the work area.
BL Series Drum / Disc Lathe
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To reduce the risk of re, do not operate the equipment in the vicinity of open containers of ammable
liquids (gasoline).
Do not let cord hang over edge of table, bench or counter, or come in contact with hot manifolds or moving
parts.
Do not operate the equipment with a damaged cord or if the equipment has been dropped or damaged -
unl it has been examined by a qualied service technician.
If an extension cord is necessary, a cord with a current rang equal to or more than that of the equipment
should be used. Cords rated for less current than the equipment may overheat. Care should be taken to
arrange the cord so that it will not be tripped over or pulled .
Always unplug equipment from electrical outlet when not in use. Never use the cord to pull the plug from
the outlet. Grasp plug and pull to disconnect.
Remove adjusng keys and wrenches. Form a habit of checking to see that keys and adjusng wrenches are
removed from tool before turning it on.
Keep the work area clean. Cluered oors, benches and areas around the lathe invite accidents
Do not use in a dangerous environment. Do not use in damp or wet locaons, or expose them to rain. Keep
the work area well lighted.
Wear proper apparel. Wear no loose clothing, gloves, neckes, rings, bracelets, or other jewelry which may
get caught in moving parts. Non-slip footwear is recommended. Wear protecve hair covering to contain
long hair.
Do not overreach. Keep proper foong and balance at all mes.
Always WEAR OSHA approved safety glasses. Everyday eyeglasses only have impact resistant lenses; they
are NOT safety glasses.
Also use face or dust mask if cung operaon is dusty.
Never stand on the tool. Serious injury could occur if the tool is pped or if the cung tool is unintenonally
contacted.
Keep guards in place and in working order.
Unplug tools before servicing, when changing accessories such as blades, bits,cuers, and the like.
Secure work. Use clamps or a vise to hold work when praccal. It is safer than using your hand and it frees
both hands to operate tool.
Do not force a tool. It will do the job beer and safer at the rate for which it was designed.
Use the right tool. Do not force a tool or aachment to do a job for which it was not designed.
Maintain tools with care. Keep tools sharp and clean for best and safest performance. Follow instrucons for
lubricang and changing accessories.
Use only Hunter recommended accessories. Consult the Brake Lathe Packages and Accessories Brochure
Form 3947-T for recommended accessories. The use of non-recommended accessories may cause risk of
injury to persons.
BL Series Drum / Disc Lathe
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Check for damaged parts. Before further use of the tool, a guard or other part that is damaged should be
carefully checked to determine that it will operate properly and perform its intended funcon - check for
alignment of moving parts, binding of moving parts, breakage of parts, mounng, and any other condions
that may aect its operaon. A guard or other part that is damaged should be properly repaired or replaced.
Never leave the tool running unaended. Turn the power “OFF.” Do not leave the tool unl it comes to a
complete stop.
Reduce the risk of unintenonal starng. Make sure switch is in “OFF” posion before plugging in.
SAVE THESE INSTRUCTIONS
1.2.3. Specific Safety Precautions / Power Source
Specications for Extension Cords
When using an extension cord, be sure to use one designed to carry the current your product will draw.
Make sure your extension cord is in good condion. An undersized cord will cause a drop in line voltage
resulng in loss of power and overheang. Table 1 shows the correct size to use depending on cord length
and name plate ampere rang. If in doubt, use the next heavier gauge. The smaller the gauge number, the
heavier the cord.
Power Source Grounding Instructions
In the event of a malfuncon or breakdown, grounding provides a path of least resistance for electric current
to reduce the risk of electric shock. This tool is equipped with an electric cord having an equipment-ground-
ing conductor and a grounding plug. The plug must be plugged into a matching outlet that is properly
installed and grounded in accordance with all local codes and ordinances.
Do not modify the plug provided - if it will not t the outlet, have the proper outlet installed by a qualied
electrician.
Improper connecon of the equipment-grounding conductor can result in a risk of electric shock. The
conductor with insulaon having an outer surface that is green with or without yellow stripes is the
equipment-grounding conductor. If repair or replacement of the electric cord or plug is necessary, do NOT
connect the equipment-grounding conductor to a live terminal.
Check with a qualied electrician or service personnel if the grounding instrucons are not completely
understood, or if in doubt as to whether the tool is properly grounded.
BL Series Drum / Disc Lathe
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Use only 3-wire extension cords that have 3-prong grounding plugs and 3-pole receptacles that accept the
tool’s plug.
Repair or replace damaged or worn cords immediately.
The Lathe is intended for use on all grounded supply circuits having a nominal rang less than 110VAC or
220VAC. An example of an 110VAC outlet on this type circuit is illustrated below.
The lathe has a grounding plug that looks like the plug illustrated above. Do NOT use adaptors that allow you
to bypass required equipment electrical grounding.
1.3. Operation Information
1.3.1. Equipment Components
Major Operang Controls
BL Series Drum / Disc Lathe
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Disc Tool Bit Micrometer Controls
Disc tool bit micrometer controls are used to make accurate cung insert depth adjustments. Rotang
the controls clockwise feeds the cung inserts into the disc fricon surface, rotang the controls counter
clockwise moves them away from the disc surface
Drum Crossfeed Control
Rotate the drum crossfeed control handle clockwise, and the boring bar extends to move the cung insert
toward the inner edge of the drum diameter. Rotate the handle counter clockwise, and the insert moves
toward the outer edge of the drum diameter.
Feed Selector Handle
Select “DRUM” or “DISC” automac feed control with the feed selector handle
Control Panel
BL Series Drum / Disc Lathe
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“FEED RATE” dial is used to change feed rate from slow to fast. Slow is labeled as FINE. Fast is labeled as
COURSE. The recommended range of feed rates for One Cut Pass is also specied. One Cut operaon is
the method of cung a drum or disc in which, a single cut is used to remove fricon surface material and
provide the desired nish. This is a deep cut made at a slow feed rate.
“RETRACT DRUM BAR” indicator is a red LED that glows when the drum bar is NOT fully retracted in its
home posion.
“LIGHTS” buon turns the two LED work light ON and OFF.
“POWER” toggle switch turns the spindle motor and controls ON and OFF.
For the addional buons on the act / Digi-Cal control panel, refer to“Chapter 3. ACT / Digi-Cal” of these
instrucons
1.3.2. Drum and Disc Mounting
Typical Drum/Disc Mounting Congurations
These gures illustrate how typical hubbed and hubless drums and discs are mounted on the arbor. Adaptors
and / or collets t into the bearing seats or center holes as outlined below. Adaptors may be used as spacers
as needed. It is important that all surfaces contacted by adaptors are as clean as possible.
BL Series Drum / Disc Lathe
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Hubless Discs and Drums
Care should be taken to ensure the following:
All contact surfaces on the arbor, the centering cone, and the adaptors are clean.
Verify that the centering cone and the adaptors are free of nicks and burrs. If the contact surfaces are not
smooth, at, and making full contact, sand with ne emery cloth or replace.
BL Series Drum / Disc Lathe
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Verify that the arbor runout is no more than .0015 inch (.381 mm). The arbor should be cleaned prior to
installing. If the arbor is bent, replace with a new one.
Verify that the mounng surfaces on the disc are clean and free of any high spots. These high spots may be
eliminated by ling.
Proper mounng is important to ensure a correct nish.
Hubbed Discs and Drums
Care should be taken to ensure the following:
All contact surfaces on the arbor and split collets must be clean.
All grease, dirt and chips must be removed from grooves in split collets.
Verify that the arbor runout is no more than .0015 inch (.381 mm). The arbor should be cleaned prior to
installing. If the arbor is bent, replace with a new one.
All grease and dirt should be cleaned from the disc or drum hub prior to mounng.
Proper mounng is important to ensure a correct nish.
1.3.3. Spindle Speed Adjustment
Variable Speed Motor (Models BL6x or BL7x with ACT / Digi-Cal)
Pressing “SPEED” buon located in center of control panel toggles between high,medium and low speed,
indicated by the green LED switching to HIGH, MED or LOW.
Pressing “ACT” buon located in center of control panel will automacally vary speed, indicated by the green
LED. The ACT feature oscillates machining speed top prevent buildup of vibraon (chaer), requiring no
bands or other devices.
Belt / Pulley System (Models BL0x or BL1x)
1. Disconnect the power to the lathe.
2. Li the motor access cover to expose the motor and two pulleys
3. Release the belt tension by liing the handle on the motor base.
4. Move the ribbed belt to the desired set of pulleys, then release the handle on the motor base.
The recommended spindle speed is determined by measuring the diameter of the workpiece. The chart
below indicates the posion of the belt on the pulleys.
BL Series Drum / Disc Lathe
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1.3.4. Disc Resurfacing
Measure the total indicated runout to determine the deepest cut necessary toresurface the disc. Refer to
“2.7 Measuring Total Indicated Runout (T.I.R.)” onpage 17.
BL Series Drum / Disc Lathe
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BL Series Drum / Disc Lathe
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1. Choose the proper spindle speed. Refer to “2.3 Spindle Speed Adjustment” onpage 9.
2. Using a micrometer, check the thickness / parallelism of the disc from at least three points around the
circumference, about 1 inch (25 mm) in from the outer diameter. If the disc thickness variaon is out
of specicaon, it should be machined. However, if the thickness is less than the minimum thickness
established by the manufacturer, or if it will be less aer resurfacing, the disc should be replaced.
3. Mount the disc on the arbor using the appropriate adaptors and spacers. Refer to“2.2 Drum and Disc
Mounng” on page 7.
4. Stretch the silencer band around the disc.
5. Turn the power switch “ON.” The spindle and the disc will begin to turn.
6. Check the setup accuracy and workpiece condion. Refer to “2.6 Achieving Setup Accuracy and Deter-
mining Workpiece Quality/Condion” on page 15.
7. Turn the knob on the detent assembly unl the roll pin is aligned with the slot in the detent locking nut.
8. Rotate the twin cuer up to posion unl the detent pin pops down, roughly aligning the twin cuer on
center.
9. Loosen the lock knobs located over the tool holder bars.
10. Adjust the twin cuer unl the cung inserts are posioned at the inner diameter of the disc’s inboard
and outboard fricon surfaces.
11. Tighten the 1 inch detent locking nut slightly ghter than hand-ght.
12. Perform a scratch test to verify setup and condion of the disc. Refer to “2.6 Achieving Setup Accuracy
and Determining Workpiece Quality/Condion” on page 15.
13. Measure the total indicated runout to determine the deepest cut necessary to resurface the disc. Refer
to “2.7 Measuring Total Indicated Runout (T.I.R.)” onpage 17.
14. Turn the tool holder bar micrometer controls unl the cung inserts just contact the shallowest secon
of the disc face. (This may or may not be in a deep groove.)
15. Rotate the slip collar of the micrometer dial to zero.
16. Retract the cung inserts away from the face of the disc.
17. While observing the micrometer dials, turn the tool holder bar controls and set the depth of cut for
approximately .004 inch (1.01 mm) more than that required to resurface the disc. Lock the cung inserts
into posion by ghtening the locking knobs located over the tool holder bars.
18. Set the feed rate according to the desired nish of cut, as noted on the feed control dial.
19. Shi the feed selector handle to the “DISC” posion. (If the lathe does not automacally feed, check to
see if the Drum Retract light is on. If the light is on, manually retract the drum boring bar unl the light
goes out and automac feed is engaged.)
20. Allow the cung inserts to travel past the outer edge of the disc.
21. Disengage the feed selector.
BL Series Drum / Disc Lathe
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22. Turn the power switch to “OFF.”
23. Remove the disc from the arbor and clean with brake cleaner or warm soapy water.
1.3.5. Drum Resurfacing
Check the setup and workpiece accuracy. Refer to “2.6 Achieving SetupAccuracy and Determining Work-
piece Quality/Condion” on page 15.
BL Series Drum / Disc Lathe
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1. Choose the proper spindle speed. Refer to “2.3 Spindle Speed Adjustment” onpage 9.
2. Using a brake drum diameter gauge, check the drum diameter from at least three points around the
circumference, about 1 inch (25 mm) in from the outer diameter. If the drum diameter is greater than
the maximum diameter established by the manufacturer, or if it will be greater aer surfacing, the drum
should be replaced.
3. Loosen the detent locking nut and rotate the twin cuer so the cung inserts point down.
4. Mount the drum on the arbor using the appropriate adaptors and spacers. Refer to “2.2 Drum and Disc
Mounng” on page 7.
5. Wrap the drum silencer band snugly around the drum and secure it by sliding the buckle nger under the
top layer of the band.
6. Turn the power switch “ON.” The spindle and drum will begin to turn.
7. Check the setup and workpiece accuracy. Refer to “2.6 Achieving Setup Accuracy and Determining
Workpiece Quality/Condion” on page 15.
8. Extend the drum boring bar by turning the drum crossfeed control on the right side of the feed housing.
Posion the boring bar cung insert over the most worn secon of the drum face. This may be a deep
groove or bell-mouthcondion.
9. Perform a scratch test to verify setup accuracy and drum condion. Refer to “2.6 Achieving Setup
Accuracy and Determining Workpiece Quality/Condion” on page 15.
10. Measure the total indicated runout to determine the deepest cut necessary to resurface the drum. Refer
to “2.7 Measuring Total Indicated Runout (T.I.R.)” onpage 17.
11. Turn the drum crossfeed control unl the cung insert just contacts the shallowest secon of the drum
surface. (This may or may not be in a deep groove.)
12. Set the depth-of-cut dial to zero and lock it with the thumbscrew.
13. While observing the feed control dial, turn the handwheel and set the depth of cut for approximately
.008 inch (2.03 mm) more than that required to resurface the drum.
14. Set the feed rate according to the desired nish of cut, as noted on the feed control dial.
15. Shi the feed selector handle to the “DRUM” posion. Let cung connue unl the cung insert has
cleared the edge of the drum.
16. Disengage the feed selector.
17. Turn the power switch to the “OFF” posion.
18. Remove drum from the arbor and clean with brake cleaner or warm soapy water.
1.3.6. Achieving Setup Accuracy and Determining Workpiece Quality/Condition
Checking For Setup Accuracy
BL Series Drum / Disc Lathe
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1. Determine if there is excess setup runout by inserng the box end of the5/16 inch (8 mm) wrench,
221-604-2 (provided with lathe), into the center drill end of the arbor while the spindle is turning and
lightly hold the opposite end. Any detectable side-to-side movement (wobble) in the wrench indicates
excess setup runout. Excess runout must be eliminated before proceeding with resurfacing.
2. If side-to-side wobble is observed, excess runout is present. Check the following for possible causes:
• A damaged or dirty disc or drum.
• Improper mounng technique.
• Damaged or dirty mounng adaptors.
• Excessively ght arbor nut.
• Damaged arbor.
Checking For Workpiece Quality/Condion
1. Bring the cung insert up to the workpiece surface to be cut.
2. Feed the cung insert in unl it just scratches the surface.
3. Back the cung insert away from the workpiece surface and turn the appropriate feed control one turn
to feed the cung insert to a new posion on the workpiece surface.
4. Turn the lathe “OFF.”
5. Loosen the arbor nut and rotate the workpiece 180 degrees. Tighten the arbor nut.
6. Turn the lathe “ON.”
7. Inscribe another scratch on the workpiece surface as described in steps 1-2.(The scratch marks will be
oset by the amount that the feed control was turned.)
Interpreting Scratch Test Results
BL Series Drum / Disc Lathe
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1.3.7. Measuring Total Indicated Runout (T.I.R.)
1. Feed the cung insert in unl it just scratches the surface.
2. Zero the depth-of-cut micrometer dial.
3. Find the maximum permissible runout for the vehicle being serviced. This value will be .003 inch (.762
mm) to .005 inch (1.27 mm) for most vehicles.
4. Turn the depth-of-cut knob to feed the cung insert into the workpiece this amount.
5. If your workpiece and setup runout is within specicaon, your scratch will go all the way around the
workpiece. Stop this test and proceed with resurfacing the workpiece.
6. If the scratch does not connue around the enre surface of the workpiece, connue feeding the cung
insert by turning the depth-of-cut knob unl the scratch is 360 degrees.
7. When this is completed, the amount of T.I.R. can be determined from the micrometer dial.
1.4. ACT / Digi-Cal
1.4.1. ACT / Digi-Cal Controls
A
BL Series Drum / Disc Lathe
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Pressing “ZERO” buon set current posion to 0.0000.
Pressing “CAL” buon starts calibraon mode.
Pressing “TOGGLE DISP” buon toggles between three dierent display modes asindicated by the green
LED next to DRUM or ROTOR located above the numbersand the green LEDs next to DIAMETER, THICK-
NESS or DEPTH below the numbers:.
• Rotor Depth / Depth Display Mode,
• Rotor Thickness Display Mode.
• Drum Diameter / Depth Display Mode.
Pressing “IN / MM” buon toggles between inches or millimeters. Green LED next to IN. or MM indicates
mode. The display units may be changed at any me during the operaon of the Digi-Cal unit.
Pressing “ACT” buon located in center of control panel will automacally vary speed, indicated by the green
LED. The ACT feature oscillates machining speed to prevent buildup of vibraon (chaer), requiring no bands
or other devices.
Pressing “SPEED” buon located in center of control panel toggles between high,medium and low speed,
indicated by the green LED switching to HIGH, MED or LOW.
1.4.2. Calibration
When is Calibration Required?
When is Calibration Required?
Calibraon is required for measuring disc thickness and drum diameter.
Calibraon is not required to measure disc and drum depth-of-cut and total indicated runout.
The Digi-Cal unit requires calibraon when:
- Insert holders are replaced or moved.
- Aer cung inserts are replaced or rotated.
The Digi-Cal unit may be re-calibrated at any me. Disc and/or drum thicknesscalibraon may be performed
at any me.
BL Series Drum / Disc Lathe
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Prepare for Calibration
1. Connect the BL power cord to an AC outlet.
2. Verify that the BL power switch is in the "OFF" posion.
3. Locate the supplied calibraon tool, 25-115-1.
4. Locate the "CAL" buon and both "ZERO" buon on the Digi-Cal unit.
Calibration Steps
Calibration Steps
Use of the Calibration tool during the Following Calibration Steps.
BL Series Drum / Disc Lathe
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1. Press the “CAL” buon on the DigiCal unit.
2. Display will now show “CAL” and “rot” on the Digi-Cal displays, indicang it is ready for disc thickness
calibraon.
3. Move the twin cuer to the disc cung posion..
4. Place the curved recess of the calibraon tool against the arbor sha and ush with the arbor face.
5. Hold the end of the calibraon tool between the cung inserts. Slowly turn each micrometer control
knob unl the cung inserts just touch the calibraon tool,suspending it between them. The cung
inserts should be at approximately the same posion on each side of the calibraon tool. (See rst gure
above.)
6. Press the right, “ZERO” buon to calibrate the Digi-Cal for disc measurements.
7. Display will now show “CAL” and “dIA” or “CAL” and “dru” in display, indicang it is ready for drum
diameter calibraon.
8. Rotate the twin cuer out of the way, such that cung inserts are poinng up.
9. Place the curved recess of the calibraon tool against the 1 inch arbor sha and ush with the arbor
face. The p of the calibraon tool should face the spindle.
10. Posion the calibraon tool and the drum cung insert so the end of the calibraon tool extends just
beyond the drum cung insert.
11. Using the drum depth control, slowly feed the drum cung insert out unl it touches the inside of the
calibraon tool. Gently swinging the calibraon tool up and down should produce a slight scraping sound
between the calibraon tool and the cung insert. (See second gure above.)
12. Press the le “ZERO” buon to calibrate the Digi-Cal for drum measurements.
13. The unit will automacally exit the calibraon mode when calibraon is complete.
1.4.3. Measuring the Disc Total Indicated Runout (T.I.R.)
Measuring the Disc Total Indicated Runout (T.I.R.)
1. With the disc mounted on the spindle, posion the twin cuer so the cung inserts are on either side of
the disc, near the outer diameter.
2. Place the BL power switch in the “ON” posion, and verify that the disc is rotang.
3. Press the “TOGGLE DISP” buon unl “ROTOR” and “DEPTH” is indicated by the green LEDs. Numeric
values will be displayed in each window of the disc display.
4. Slowly turn either disc micrometer control knob clockwise, unl the cung insert is near the disc. The
“high point” of the disc fricon surface is located where the insert scratches the disc.
5. Press the disc “ZERO” buon of the disc micrometer control knob used in step 4. The disc display should
read “0.000.”
6. Turn the disc micrometer control knob unl the cung insert scratches a circle around the enre disc
fricon surface.
7. The “zeroed” disc display now shows the T.I.R. for the disc.
1.4.4. Measuring True Minimum Disc Thickness for a One-Cut Cleanup Pass
Measuring True Minimum Disc Thickness for a One-Cut Cleanup Pass
With the data provided by the Digi-Cal, the technician can determine the necessaryamount of material to
remove from the disc for a one-cut resurfacing operaon, orreplace the disc if it is undersized.
Using this unique procedure, the Digi-Cal can measure and combine the deepest wear points on opposite
sides of the disc, with total indicated runout (T.I.R.), to calculate the true minimum disc thickness.
This also, allows the technician to determine beforehand, if the disc will be undersized aer resurfacing and
eliminates:
- The need for mulple passes on the disc.
BL Series Drum / Disc Lathe
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