Single needle industrial sewing Machine Model 3914 Set up and Operating Instructions Visit our website at: http://www.harborfreight.com Read this material before using this product. Failure to do so can result in serious injury. Save this manual. Copyright© 2005 by Harbor Freight Tools®. All rights reserved. No portion of this manual or any artwork contained herein may be reproduced in any shape or form without the express written consent of Harbor Freight Tools.
Specifications Machine Type Heavy duty, industrial sewing machine; high speed, single needle-lock stitch Drive V-belt driven (size 41 replacement belt) Action Foot pedal operation, along with a knee and manual lifting arm for presser foot.
inhibit rust. Always lock up tools and keep out of reach of children. 5. Use the right product for the job. Do not attempt to force a small product or attachment to do the work of a larger industrial tool. There are certain applications for which this product was designed. It will do the job better and more safely at the rate for which it was intended. Do not modify this product and do not use this product for a purpose for which it was not intended. 6. Dress properly.
to supply the correct current to the tool without heating up. Otherwise, the extension cord could melt and catch fire, or cause electrical damage to the tool. This tool requires use of an extension cord with up to 10 amps capability (up to 50 feet), with wire size rated at 18 AWG. Longer extension cords require larger size wire. If you are using the tool outdoors, use an extension cord rated for outdoor use (signified by “WA” on the jacket). 18. Maintenance.
Grounding To prevent electric shock and death from incorrect grounding wire connection: Check with a qualified electrician if you are in doubt as to whether the outlet is properly grounded. Do not modify the power cord plug provided with the tool. Never remove the grounding prong from the plug. Do not use the tool if the power cord or plug is damaged. If damaged, have it repaired by a service facility before use. If the plug will not fit the outlet, have a proper outlet installed by a qualified electrician.
. 7. 8. the required minimum cord size. (See Table A.) Symbology If you are using an extension cord outdoors, make sure it is marked with the suffix “W-A” (“W” in Canada) to indicate it is acceptable for outdoor use. Double Insulated Make sure the extension cord is properly wired and in good electrical condition. Always replace a damaged extension cord or have it repaired by a qualified electrician before using it.
of the machine, depending on the user’s preference. Assembly Sewing Machine Hinge Indentations in Tabletop Table Stand and Top (not provided) Back of Sewing Machine Power Switch Motor Knee Lifting Arm for Presser Foot Oil Pan (1g) Figure 1 The assembly instructions describe mounting the Single-Needle Sewing Machine (Model 03914) to the Table Stand (Model 03929), not included. In order to complete this procedure, you must first purchase and assemble the Table Stand Kit (Model 03929).
Knee Press Lifter Rod (2g) Oil Pan Magnet (22g) Oil Sight Window (1f) Mounting the Motor Note: The Motor is heavy. You will need a helper to hold the motor in place while tightening the Nuts (67j) on the Carriage Bolts (70j) in step 5 on the following page. Motor Rotation Switch Always keep to right Hand Wheel (7b) Figure 5 7. Tilt the machine back to expose the Oil Pan (1g). Insert the Knee Press Lifter Rod (2g). Place the Oil Pan Magnet (22g) in the lowest portion of the Oil Pan. 8.
Hand Wheel (7b) Sewing Machine Carriage Bolts (70j), Flat Washer (69j), Spring Washer (68j), Nut (67j) Belt (71j) Set Screws (8b) (One on each side of the Pulley) Main Shaft (32b) Figure 7 3. Figure 9 5. Slot in Tabletop for belt Bobbin Winder Assembly Slide the Sewing Machine Hand Wheel (7b) onto the Main Shaft (32b) of the Sewing Machine. Align one of the Set Screw holes (on the side of the Pulley) with the flat section of the Main Shaft.
and turn it around. Move the belt by hand to verify that it is aligned and tracking correctly. Caution: Do not tighten the Belt so much that the left side of the Sewing Machine begins to lift up from the Oil Pan. 2. Once you have the Pulleys aligned, remove the Belt from the Sewing Machine Hand Wheel (7b), and tighten its Set Screws (8b). Replace the Pulley and tighten the Motor Set Screw (7j). 2.
Mounting the Thread Stand Thread Hanger (28i) 7. Upper Spool Rest Rod (30i) Column Pipe Connector (33i) Lower Spool Rest Rod (36i) Spool Pins (40i) Note: The Support has tabs that hold onto the corners of the Nut to make tightening easier. When assembling, place the Nut on the side with these tabs. Figure 13 Note: The Thread Stand is designed to be mounted on the Table Stand Kit (Model 03929-sold separately).
Cap over the end of the Upper Spool Rest Rod. Washers (27i). Leave the Screws just loose enough to allow the Base to slide. Less than 1/8” gap between Belt (71j) and Wheel (3i) Mounting the Bobbin Winder The Bobbin Winder is used to wind thread onto the Bobbin (17h). It is mounted so that it contacts the Belt (71j) when needed for bobbin winding.
moderate to slow speeds for the first 15 minutes of use. WARNING: Shut the machine off completely before working around the needle or other moving parts. BASIC SETTINGS You will need to make the following adjustments on a regular basis when using the machine. Attaching the Needle The needles supplied with the Sewing Machine are size 90/14 (DBX1). The shank is size 16 x 257. For leatherwork use a 16 x 95 needle. This machine can accommodate a needle up to size 22.
Winding Thread Onto the Bobbin Setting the Bobbin into the Bobbin Case and into the Machine Thread Guide Hole (43i) Bobbin (17h) Thread Tension Bracket (18i) Thread from Spool Tension (not Discs shown) (21i) Bobbin Case (21c) 1. Route the Thread from the Spool, up through the Thread Guide Hole (43i), through the hole in the Thread Tension Bracket (18i), then over and under between the Tension Discs (21i). 2.
Threading the Top Thread Thread Hanger (28i) Set the spool of thread (sold separately) onto the top thread Spool Pin (40i), (the left Spool Pin), and thread it through the eyelet directly above on the Thread Hanger (28i). Guide the thread through the machine, following the steps and photos below. Note: There are two Spool Pins (40i).
pulling it to the top of the machine. Pull both threads behind the Presser Foot, leaving at least 4” of excess thread. Adjusting the Bobbin Thread Tension Adjusting the Stitch Length Increase Tension Stitch Length Dial (46e) Tension Adjustment Screw Decrease Tension Bobbin Case (21c) Figure 26 To increase or decrease the stitch length, turn the Stitch Length Dial (46e) to the desired number (in millimeters) as indicated at (A) above.
ADVANCED SETTINGS Raises Presser Foot The Sewing Machine is set at the factory for using with jean weight materials. The following adjustments are needed only when using the machine for unusual types of fabric or when changing machine components. These procedures should be performed only by a qualified sewing machine technician. Presser Foot Lever (18d) Lowers Presser Foot Adjusting the Feed Timing Figure 29 1. To raise the Presser Foot, turn the Presser Foot Lever up.
Feed Lifting Shaft Crank (1e) Bolt (2e) Feed Bar Body Subassembly (4e) 0.03”~0.033” ( ) 0.028”~0.031” ( ) 0.037”~0.041” ( 1. Loosen the Bolt (2e) of the Feed Lifting Shaft Crank (1e). 2. Move the Feed Bar Body Subassembly (4e) up or down to make the adjustment. 3. Tighten the Bolt (2e), being careful not to overtighten.
pulled out by the Thread Take-up Spring. Adjusting the Presser Bar Height c. The normal setting is when the marker on the Thread Guide is aligned with the center of the Bolt. Figure 34 Rubber Plug (37a) & Presser Bar Set Screw (32d) 1. Remove and set aside the Rubber Plug (37a), and loosen the Presser Bar Set Screw (32d). 2. Manually adjust the Presser Bar height, and the angle of the Presser Foot. 3. After adjusting, securely tighten the Set Screw and replace the Rubber Plug.
Adjusting Sewing Speed with Pulleys (sold separately) This machine is a fast running machine. It can be adjusted to a slower running machine by changing the pulley on the motor to a smaller diameter pulley. Consult a qualified sewing machine repair shop to replace the pulley with a 1-3/4” or 1-1/2” pulley to slow the speed of the machine. Maintenance 1. Advanced Machine adjustments should only be performed by a qualified technician. 2. Check the oil level weekly when the machine is used daily.
MOTOR WIRING DIAGRAM REV 07g, 10b SKU 3914 For technical questions, please call 1-800-444-3353.
A - ARM BED PARTS LIST Part Description Qty 1a Arm Bed Assembly 1 2a Tension Complete Subassembly 1 3a Tension Adjustment Knob 1 4a Thread Disc Rotation Stopper 1 5a Thread Tension Spring 1 6a Thread Release Disc 1 7a Thread Tension Disc 2 8a Tension Screw 1 9a Take-up Spring 1 10a Thread Tension Post Socket 1 11a Set Screw 1 12a Tension Release Pin 1 13a Oil Packing Subassembly 1 14a Oil Packing Cover 1 15a Oil Wick 1 16a Screw 17a Part Description Qty
A- ARM BED ASSEMBLY DRAWING 46 Motor (DOL 12-Ha) (Not Shown) SKU 3914 For technical questions, please call 1-800-444-3353.
B - MAIN SHAFT PARTS LIST Part 1b 2b 3b 4b 5b 6b 7b 8b 9b 10b 11b 12b 13b 14b 15b 16b 17b Description Thread Take-up Eyelet Needle Bar Crank Set Screw Bolt O-Ring Thread Take-up Lever Link Hand Wheel Set Screw Sealing Ring Main Shaft Rear Bushing Sub-assembly Plate Feed Drive Cam Snap Ring Bolt Set Screw Main Shaft Thrust Collar Main Shaft Middle Bushing Qty Part 1 1 1 1 1 1 1 2 1 18b 19b 20b 21b 22b 1 1 1 1 2 2 1 1 23b 24b 25b 26b 27b 28b 29b 30b 31b 32b 33b 34b Description Qty Set Screw Thread T
REV 10b B - MAIN SHAFT assembly DRAWING SKU 3914 For technical questions, please call 1-800-444-3353.
C- Stitch Drive PARTS LIST Part Description Qty Part Description Qty 1c Bolt 1 19c Rotating Hook Sub-assembly 1 2c Rotating Hook Positioning Finger 1 20c Rotating Hook 1 3c Upright Shaft Lower Bushing 1 21c Bobbin Case 1 4c Set Screw 8 22c Bobbin 1 5c Bevel Gear 1 23c Needle 1 6c Upright Shaft 1 24c Needle Bar Thread Guide 1 7c Bevel Pinion 1 25c Bolt 1 8c Bolt 2 26c Wire Needle Bar Thread Guide 1 9c Hook Driving Shaft Rear Bushing 1 27c Needle Bar L
C - Stitch Drive ASSEMBLY DRAWING SKU 3914 For technical questions, please call 1-800-444-3353.
D - PRESSER BAR PARTS LIST Part Description Qty Part Description Qty 1d Bolt 1 18d Presser Foot Lever 1 2d Bolt 1 19d Presser Spring Regulator Nut 1 3d Spring 1 20d Presser Regulator 1 4d Washer 1 21d Tension Release Lever 1 5d Washer 1 22d Lifting Lever Presser Rod 1 6d Bolt 1 23d Lifting Lever Rear Crank 1 7d Snap Ring 1 24d Lifting Lever Presser Rod 1 8d Pin 1 25d Pressure Lever 1 9d Presser Foot 1 26d O-Ring 1 10d Bolt 1 27d Presser Spring
D - PRESSER BAR ASSEMBLY DRAWING SKU 3914 For technical questions, please call 1-800-444-3353.
E - FEED Control PARTS LIST Part Description Qty Part Description Qty 1e Feed Lifting Shaft Crank 1 33e Bolt 1 2e Bolt 1 34e Connecting Rod 1 3e Bolt 1 35e Rocker Slate Return Board 1 4e Feed Bar Body Subassembly 1 36e Bolt 1 5e Feed Dog 1 37e Reverse Crank Subassembly 1 6e Snap Ring 1 38e Connecting Rod 1 7e Bushing 1 39e Feed Regulator 1 8e Thrust Collar 1 40e Feed Regulator Stud 1 Connecting Rod 1 9e Set Screw 1 41e 10e Feed Drive Shaft 1 42e
E - FEED Control ASSEMBLY DRAWING SKU 3914 For technical questions, please call 1-800-444-3353.
F - LUBRICATION PARTS LIST Part Description Qty Part Description Qty 1f Oil Sight Window 1 17f Bolt 1 2f Main Shaft Oil Tube 1 18f Bolt 1 3f Oil Return Tube Holder 1 19f Oil Pump Throughway 1 4f Oil Pump Installing Base 1 20f Rubber Joint 1 5f Lubrication Oil Pump Subassembly 1 21f Oil Pump Brace 1 6f Oil Pump Screen 1 22f Bolt 1 7f Bushing 1 23f Gasket 1 8f Impeller 1 24f Oil Tube 1 9f Lubrication Oil Pump 1 25f Bolt 1 10f Oil Return Pump Plunger
F - LUBRICATION ASSEMBLY DRAWING SKU 3914 For technical questions, please call 1-800-444-3353.
G - BASE ASSEMBLY DRAWING AND PARTS LIST Part Description Qty Part Description Qty 1g Oil Pan 1 14g Bolt 2 2g Knee Press Lifter Rod 1 15g Knee Press Lifter Crank 1 3g Rubber Cushion 4 16g Knee Press Plate Rod 1 4g Gasket 1 17g Knee Press Plate Cover Joint 1 5g Bolt 1 18g Knee Press Plate 1 6g O-Ring 1 19g Bolt 1 7g Stud 2 20g Knee Lifter Tube Holder 1 8g Nut 2 21g Knee Lifter 1 9g Bolt 1 22g Oil Pan Magnet 1 10g Spring 1 23g Rubber Pad 2 11g
H - ACCESSORIES PARTS LIST AND ASSEMBLY DRAWING Part Qty Part 1h Hinge Description 2 11h Belt Cover Support Description Qty 1 2h Hinge Cushion 2 12h Bolt 1 3h Tack 4 13h Bolt 1 4h Front Belt Cover 1 14h Screwdriver (large) 1 5h Belt Cover Cap 1 15h Screwdriver (medium) 1 6h Rear Belt Cover Assembly 1 16h Screwdriver (small) 1 7h Rear Belt Cover 1 17h Bobbin 3 8h Rear Belt Cover Assembly 1 19h Machine Rest Pin 1 9h Wood Screw 1 20h Oil 1 10h Belt Co
I - BOBBIN WINDER & THREAD STAND UNIT PARTS LIST Part Description Qty Part Description Qty 1i Base 1 25i Washer 1 2i Thread Winder Base Assembly 1 26i Wood Screw 2 3i Wheel 1 27i Washer 1 4i Bolt 1 28i Thread Hanger 1 5i Bobbin Winder Shaft 1 29i Column Cap 1 6i Connecting Rod 1 30i Upper Spool Rest Rod 1 7i Connecting Rod Pin 1 31i Bolt 1 8i Bobbin Winder Frame Rod 1 32i Washer 1 9i Bobbin Winder Frame Pin 1 33i Column Pipe Connector 1 10i Bolt
I - BOBBIN WINDER & THREAD STAND UNIT ASSEMBLY DRAWING SKU 3914 For technical questions, please call 1-800-444-3353.
J - MOTOR PARTS LIST Part Description Qty Part Description Qty 1j Pulley Safety Cover 1 37j Bearing 6203 1 2j Bolt M5 x 10 1 38j Rotor 1 3j Spring Washer Ø5 1 39j Bolt M6 x 15 1 4j Flat Washer 1 40j Lock Washer 1 5j Nut M12 1 41j Bearing Pressing Plate 1 6j Gear Spring Washer Ø12 1 42j Stator 1 7j Set Screw 5 x 14 1 43j Housing 1 8j Pulley 1 44j Plastic Cap 1 9j Inner Cover 1 45j Nut M10 2 10j Bolt 1 46j Spring Washer Ø10 2 11j Lock Nut M10
J - MOTOR ASSEMBLY DRAWING SKU 3914 For technical questions, please call 1-800-444-3353.
LIMITED 90 DAY WARRANTY Harbor Freight Tools Co. makes every effort to assure that its products meet high quality and durability standards, and warrants to the original purchaser that this product is free from defects in materials and workmanship for the period of 90 days from the date of purchase.
