A hand-cranked cutaway demonstrator of a single-needle lockstitch machine in a 250x120x220 mm welded/sheet frame with transparent covers: upper arm shaft driving a 15 mm crank (30 mm needle stroke), take-up lever, needle bar in guide bushes, a 2:1 toothed-belt drive to a horizontal rotary hook with bobbin case, and an eccentric-driven feed dog with adjustable 0-4 mm stroke.
| Needle stroke | 30 mm (crank r=15) |
|---|---|
| Hook drive ratio | 2 : 1 belt |
| Feed length | 0-4 mm adjustable |
| Enclosure | 250 x 120 x 220 mm |
| 0 deg | Needle TDC, take-up rising, feed advancing |
| 90 deg | Needle 15 mm down in fabric, feed dog below plate |
| 180 deg | Needle BDC, hook approaching |
| 200 deg | Hook point at needle eye, loop pick-up, clearance 0.1 mm |
| 270 deg | Needle clear, feed dog rises, take-up pulls |
| 300 deg | Take-up top: stitch set |
| Overall size | 280 × 124 × 229 mm |
| Parts | 38 |
| Material | Steel (S235) |
| Mass (calculated) | 9735.7 g |
| General tolerance | ± 0.2 mm (ISO 2768-m) |
| Process | welded |
| 4× | Deep groove ball bearing 6001 ISO 15 |
| 4× | Socket head cap screw M4x10 ISO 4762 |
| 01 | base_plate 250 × 120 × 8 mm · 1884.0 g |
| 02 | frame_left 8 × 120 × 212 mm · 1497.3 g |
| 03 | frame_right 8 × 120 × 212 mm · 1497.3 g |
| 04 | upper_arm 234 × 20 × 15 mm · 551.1 g |
| 05 | cover_front 250 × 4 × 220 mm · 1542.8 g |
| 06 | main_shaft 280 × 12 × 12 mm · 248.6 g |
| 07 | hook_shaft 280 × 12 × 12 mm · 248.6 g |
| 08 | bearing_1 8 × 28 × 28 mm · 24.8 g |
| 09 | bearing_block_1 14 × 40 × 40 mm · 108.2 g |
| 10 | bearing_2 8 × 28 × 28 mm · 24.8 g |
| 11 | bearing_block_2 14 × 40 × 40 mm · 108.2 g |
| 12 | bearing_3 8 × 28 × 28 mm · 24.8 g |
| 13 | bearing_block_3 14 × 40 × 40 mm · 108.2 g |
| 14 | bearing_4 8 × 28 × 28 mm · 24.8 g |
| 15 | bearing_block_4 14 × 40 × 40 mm · 108.2 g |
| 16 | handwheel 15 × 80 × 80 mm · 578.6 g |
| 17 | pulley_main 12 × 40 × 40 mm · 107.7 g |
| 18 | pulley_hook 12 × 20 × 20 mm · 18.9 g |
| 19 | belt 10 × 42 × 130 mm · 40.8 g |
| 20 | crank_disc 8 × 40 × 40 mm · 71.8 g |
| 21 | con_rod 5 × 6 × 40 mm · 9.4 g |
| 22 | needle_bar 8 × 8 × 75 mm · 29.6 g |
| 23 | needle 1.4 × 1.4 × 30 mm · 0.4 g |
| 24 | needle_guide 20 × 24 × 30 mm · 70.7 g |
| 25 | take_up_lever 8 × 4 × 54 mm · 10.1 g |
| 26 | presser_bar 6 × 6 × 70 mm · 15.5 g |
| 27 | presser_foot 25 × 12 × 2 mm · 4.4 g |
| 28 | throat_plate 234 × 110 × 3 mm · 604.1 g |
| 29 | feed_dog 12 × 14.5 × 6 mm · 2.8 g |
| 30 | feed_bar 80 × 18 × 6 mm · 67.8 g |
| 31 | stitch_lever 8 × 4 × 50 mm · 8.8 g |
| 32 | rotary_hook 12 × 36 × 36 mm · 40.4 g |
| 33 | bobbin_case 9 × 28 × 28 mm · 43.5 g |
| 34 | timing_screw_1 7 × 7 × 14 mm · 2.0 g |
| 35 | timing_screw_2 7 × 7 × 14 mm · 2.0 g |
| 36 | timing_screw_3 7 × 7 × 14 mm · 2.0 g |
| 37 | timing_screw_4 7 × 7 × 14 mm · 2.0 g |
| 38 | thread_path 0.8 × 0.8 × 125 mm · 0.5 g |