UnionSpecial 39500 Series Instructions For Adjusting And Operating

ASSEMBLING AND ADJUSTING SEWING PARTS {Continued)NOTE: The adjusting instructions that follow will pertain to both the 503 and the505 stitch, the only difference is an upper spreader is used for the 503 stitch, whilean upper looper is used for the 505 stitch. All of the instructions are applicable fo rboth types of stitches, unless otherwise specified.SETTING THE NEEDLEWith throat plate assembled in position, needleshould center in the front end of needle slot. Whenneedle is at high position, needle point should be set15/32 inch above the throat plate (A. F i g. 3). Toalign needle or set the height above the throat plate,move needle driving arm (B, Fig. 3) by looseningclamp screw {C). After needle has been properlyset, tighten clamp screw and remove throat plate.If needle thread cam pull-off {A, Fig. 4) over- Fig. 3laps looper thread pull- off {B), separate by movinglooper thread pull- off back. When retightening loo-per pull-off screw, be sure to take up end play inneedle driving arm.At this point, in-sert lower looper {A,Fig. 5) into bar {B).With lower looper atthe left end of itsstroke, set looper point1/8 inch from centerof needle (Fig. 5), usingloor.ergaugeNo. 21225-1j8. Do nothave low-er looper deflecting Fig. 5Fig. 4 needle. Tighten nut{C). Now assemble differential {front) feed dog.SETTING THE REAR NEEDLE GUARDSet rear needle guard {A, Fig. 6) as high as possi-ble, without interferring with either lower looper ormovement of lower knife holder, but still in position todeflect needle forward . 002-. 004 inch. Screw {B) is usedto set rear needle guard. Make sure there is no interfer-ence between rear needle guard and lower looper.SETTING THE LOWER LOOPERNow finish lower looper adjustment. As lower loopermoves to the right, its point should be set into the needlescarf {A, Fig. 7) until the needle springs forward fromrear needle guard surface another. 002-. 004 inch. Tight-en nut {C, Fig. 5) securely.SETTING THE FRONT NEEDLE GUARD Fig. 6Assemble front needle guard {C, Fig. 6). When lower looper is springing nee-dle off back guard, set front needle gua:Pd as close as possible to needle withouttouching. Screw {D) is used to adjust and set front needle guard. After this settingmake sure there is no interference between needle guards and differential feed dog.9From the library of: Superior Sewing Machine & Supply LLC