UnionSpecial 63900 Adjustment Manual

Also see for 63900 Series: Instructions for adjusting and operating

Contents

UnionSpecial 63900 Adjustment Manual Manual pdf 15 page image

15TIMING THE HOOKRemove throat plate. Loosen three set screws (A) in the hook, andhold the hook and the bobbin case holder in such a position as toprevent interference with the needle. Turn handwheel in operatingdirection until the needle bar is at its lowest position, and continueto turn the handwheel until the needle is ascending and the middletiming make (Fig. 13) used in setting the needle bar is even with thelower edge of the needle bar frame (A).Turn the hook on the shaft until the point of the hook is even with thecenter of the needle and as close to the needle as possible withoutdeflecting it. A spacing of .003 to .005 inch between the needle andthe point of the hook is satisfactory. With the hook in this position,tighten the set screw opposite the hook point securely. Then,tighten the two remaining screws securely, and recheck the timingof the hook with the needle. At the hook timing position the top ofthe eye of the needle should be about 1/64 inch below the bottomof the hook point.Replace throat plate, allowing 1/32 inch clearance between the outsideedge of projection and the inside edge of bobbin case recess.NEEDLE GUARD INSTRUCTIONSIn the hook, at the right side of the needle hole in bobbin case holder (B,Fig. 15) is found a needle guarding surface (A, Fig. 15).The purpose of this guarding surface is to prevent the hook point (C) fromcoming in contact with needle (D) at loop-taking time, should the needlebe deflected toward the hook point. The needle guard will deflect theneedle slightly when needle is at bottom of its vertical travel if the hook isproperly timed. (At loop-taking time there should be little or no deflectionof needle by the needle guard.)For additional needle clearance, especially with use of larger needles,removal of some needle guarding surface may necessary.Before metal removal from the guarding surface all related settings should be checked as follows:1. See that the needle bar is set to correct height.2. Check for proper hook timing.3. Rotate the handwheel in operating direction by hand.Check for excessive needle deflection beyond what iscited on preceding page as a desirable condition.4. If needle deflection is excessive, follow steps (A) and (B)b e l o w .( A ) Remove bobbin case holder from hook.(B) Remove excess metal from the needle guardingsurface. This may be done by using a diamond fileNo. TT60 or fine emery cloth (#320), with one end secured to the bench, and rubbing theguarding surface back and forth until sufficient metal is removed. When metal is being removedfrom needle guarding surface, the bobbin case holder should be reinserted frequently andtested until proper needle guarding is obtained.