PHONE: (360) 734-1540 • www.southbendlathe.com
Chucks are heavy! Get assistance when installing or removing the chuck from the lathe. Wear heavy duty leather boots for foot and toe protection, and keep hands and fingers away from all pinch points. Ignoring this warning can lead to a severe crushing injury or finger amputation!
Hardened steel jaws for durability and extreme clamping force and grip Universal plain back mounting Scroll gear design provides single chuck key control of all jaws
• OD Clamping .................. 0.16"–7" (4–180mm) • ID Clamping ............ 2.20"–6.69" (56–170mm) • Chuck Bore Diameter ................2.28" (58mm) • Chuck Outer Diameter ............7.60" (193mm) • Front Mounting Cap Screw Torque ...29 ft/lbs • Rear Mounting Hex Bolt Torque ........53 ft/lbs • Maximum Chuck Key Torque ............72 ft/lbs • Maximum Gripping Force (at Full Jaw and Scroll Gear Tooth Engagement) .....5620 ft/lbs • Maximum Speed ...........................2000 RPM* • Mounting Type ............. Universal Plain Back • Construction ..................Fine-Grain Cast-Iron • Chuck Weight ......................................... 33 lbs • Country of Origin ................................ Taiwan * The maximum speed listed above is ONLY possible with the chuck jaws and the workpiece in complete rotational symmetry. The workpiece weight must be within the limits of the lathe, and the workpiece mass must be of equal density throughout to prevent centrifugal imbalance or radial runout—even if a tailstock or other support is used for additional support.
Front or rear mounting bolt pattern Fine-grain cast iron body Manufactured with high-tech German CNC machinery
DISCONNECT LATHE FROM POWER!
Mount the back plate on the spindle.
Accurately measure the inside of the back relief bore on the chuck. This dimension is critical and should be ± 0.001''.
Face the entire surface of the back plate.
Turn a shoulder into the back plate face that is 1 ⁄ 8 '' deep and 0.001" to 0.002'' larger than the relief bore that is on the mounting side of the chuck. (Remember, a press fit must exist between the two.) Slightly chamfer the edges to prevent any burrs when installing.
Copyright © November, 2010 by South Bend Lathe Co. WARNING: No portion of this manual may be reproduced without written approval. #CR13312 Printed in Taiwan
I N S T R U C T I O N S
Mfg. Since 5/10
Set the chuck on the back plate, and align the shoulder with the relief bore. Use a transfer punch to mark the mounting holes in the back plate. Or you can use a drill bit of the same diameter as the mounting holes in the chuck. Lightly tap on the bit, rotate it 90°, and tap it again to form an X.
A chuck key left in the chuck can become a dangerous projectile when the spindle is started. Always remove the chuck key after using it. Develop a habit of not taking your hand off of a chuck key unless it is away from the machine.
Remove the back plate from the lathe, drill the chuck mounting cap screw holes though the back plate, and then tap the holes.
Clean and stone all mating surfaces until they are perfectly clean and free of burrs. •
Disconnect the lathe from power before installing and removing the chuck or doing any maintenance or adjustments. Accidental lathe startup can cause severe injury or death.
Place the back plate into a freezer for 30 minutes; place the chuck in an oven at 100°F for the same amount of time.
Put on insulated leather gloves and fasten the chuck to the back plate with the mounting cap screws only finger tight, then install the assembly onto the lathe spindle. If the chuck is loose, or is crooked on the shoulder, it will be necessary to recut the back plate face and shoulder again.
If you are also installing the chuck by threading the hex bolts into the chuck from the back side of the mounting plate, repeat Step 11 on these bolts, but torque them to 53 ft/lbs.
When installation is complete, lightly stamp alignment marks in the chuck and back plate to ensure that the chuck will be re-installed in the same position if ever removed.
A thrown workpiece may cause severe injury or even death. When swapping the chuck jaw positions, keep in mind that maximum gripping force is attained at full jaw and jaw screw engagement. If only one is partially engaged, overall clamping force is reduced.
Tighten the chuck mounting cap screws in a star pattern in three progressively tighter sequences until you reach a final torque of 29 ft/lbs. Alternating the tightening process insures the chuck will be pressed on straight. Repeat this step until the chuck seats with back plate. •
Operating the lathe where maximum chuck speed is exceeded, or at too high of a speed for an unbalanced workpiece, can cause the workpiece to be thrown from the chuck. Always use the appropriate feed and speed rates. A thrown workpiece may cause severe injury or even death.
Large chucks are very heavy and difficult to grasp, which can lead to crushed fingers or hands if mishandled. Get assistance when installing or removing large chucks to reduce this risk. Protect your hands and the precision ground ways by using a chuck cradle or piece of plywood over the ways of the lathe when servicing chucks.
Often chuck jaws will protrude past the diameter of the chuck and can contact a coolant nozzle, tooling, tool post, or saddle. Before starting the spindle, make sure the workpiece and the chuck jaws have adequate clearance by rotating it through its entire range of motion by hand.
Mfg. Since 5/10 Model SB1236
I N S T R U C T I O N S
Always disconnect machine from power before performing maintenance or serious personal injury may result.
For optimum performance from your chuck, follow the maintenance schedule below. Never hammer on the chuck, jaws, or a workpiece that is clamped in the chuck; and never subject the chuck to abrasives, flame, or water.
• Check/correct loose mounting bolts.
• Keep the chuck clean and oiled.
• Use a vacuum, rag, or brush to clean the chuck after use. Never use air pressure to clean chips away from a chuck. • Avoid leaving the chuck clamped on a workpiece, unload the chuck jaws daily. • Make sure the chuck key is removed from the chuck when not in use.
If the chuck ever becomes stiff to operate, it may have been contaminated with metal chips or abrasives from incorrect or limited maintenance intervals. If this is the case, the chuck must be disassembled, cleaned, and re-lubricated.
DISCONNECT LATHE FROM POWER!
Unbolt and remove the chuck. Unless previously done, stamp alignment marks in the chuck and the mounting plate to ensure that they line up when reassembled.
Disassemble the chuck in the alphabetical sequence shown in Figure 1.
Back the jaws out of the chuck, and remove the grease fitting.
Unthread and remove the pinion retaining screw.
d e b c Note: Each jaw is marked 1, 2, or 3 to correspond to its marked slot in the chuck a Figure 1. Chuck sequence of disassembly.
Remove the pinion.
Remove the chuck backing plate screws and the back plate.
Remove the scroll gear from the inside of the chuck bore.
Using mineral spirits, clean and dry all components. Inspect all bores, teeth, pins, and mating surfaces for wear, burrs, galling, rust, or cracks, and re-dress as required.
Coat all parts with any automotive NLGI #2 grease, and carefully reassemble the chuck in the reverse order shown in Figure 1.
Rotate the chuck key clockwise until you see the tip of the scroll-gear lead thread just begin to enter jaw guide #1.
Insert jaw #1 into jaw guide #1, and hold the jaw against the scroll-gear.
Rotate the chuck key clockwise one turn to engage the tip of the scroll-gear lead thread into the jaw. Pull the jaw; it should be locked into the jaw guide.
Install the other jaws in the same manner, and install a new grease fitting.
Starting at Step 8 in Chuck Installation on Page 2, align and re-install the chuck as outlined.
I N S T R U C T I O N S
Mfg. Since 5/10
The chuck has hard spots or binds completely.
The workpiece slips in the jaws.
1. Jaw is in a poor position for clamping.
2. Lack of lubrication, rust, burr, or metal shavings inside of chuck.
3. Broken tooth on the jaw or the jaw screw.
1. Incorrect jaw or workpiece clamping position.
2. Insufficient pinion and scroll gear torque.
3. Chuck is binding before full clamping force is achieved, or a jaw or jaw screw is binding.
Clamping accuracy is poor.
4. Cutting overload.
1. Workpiece improperly clamped or workpiece is misaligned.
2. Chuck loose, mounting is off center, or it is improperly seated.
1. Re-install jaws in correct order and position on scroll gear.
2. Disassemble, de-burr, clean, and lubricate chuck.
3. Disassemble and rebuild chuck.
1. Re-position jaws and workpiece for maximum scroll gear and jaw engagement is achieved.
2. Tighten chuck key to 72 ft/lbs.
3. Chuck is loaded up with contaminants causing binding. Disassemble and service chuck. Loosen and retighten the chuck key several times to work lubricant in.
4. Reduce cutting depth or feed rate.
1. Remove jaws, clean, de-burr, and re-install, verify accuracy and recalibrate test/dial indicator.
2. Remove chuck, clean and de-burr mounting, and re install, or machine a new mounting plate.
3 4 12 7 5 11 10 6 1 2 8 9
REF PART # 1 2 3 4 5 6 7 8 9 10 11 12 PSB1234001 PSB1234002 PCAP115M PSB1234004 PSB1234005 PSB1234006 PSB1234007 PSB1234008 PCAP171M PSB1234010 PSB1234011 PB174M DESCRIPTION GREASE FITTING INTERNAL JAW SET OF 4 BUTTON HD CAP SCR M6-1 X 16 BACK COVER LOCK PIN PINION SCROLL GEAR CHUCK KEY CAP SCREW M10-1.5 X 80 BLK C12.9
EXTERNAL JAW SET OF 4 CHUCK BODY HEX BOLT M10-1.5 X 35 BLK C12.9
If you need help with your new chuck, contact us at: PHONE: (360) 734-1540 FAX: (360) 676-1075 (International) FAX: (360) 734-1639 (USA Only) EMAIL: email@example.com
Please Note: We included this parts breakdown for service purposes only. Since many of the parts shown are machined to
each individual chuck, they may not be available as replacement items.