Race shuttle Cap?

[Leatherphase]

I have an old Singer 78-3 that I’m hoping to start working with, I think it’s needle bar is a bit off, because the needle intermediately hits the little cap on the the race shuttle. Removing the cap seems to relieve the problem, what does the Shuttle Race Cap do? Does just keep dust/debris out of the bobbin and race assembly? Is it important enough that I should bend/replace the needle bar in order to keep it on?

[Constabulary]

That's (afaik) the loop spreader, you find this thingy on many (if not all) CB hook machines and some machines with oscillating barrel hooks (like Singer 45K flat bed). Is you cap looking like the one in the picture or has it narrower cot out? The 78 is a needle feed machine and when someone installed a drop feed cap f.i. form a 31K (for what ever reason) it will not work (very wild guess but who knows).

I´m not sure if it works w/o but I think it´s there for a reason. Where does the needle hit this cap - front, back, left side? Does the needle hit the cap in a particular stitch length or permanently?

Some pictures may be helpful.

Edited September 28, 2020 by Constabulary

[Leatherphase]

24 minutes ago, Constabulary said:

That's (afaik) the loop spreader, you find this thingy on many (if not all) CB hook machines and some machines with oscillating barrel hooks (like Singer 45K flat bed). Is you cap looking like the one in the picture or has it narrower cot out? The 78 is a needle feed machine and when someone installed a drop feed cap f.i. form a 31K (for what ever reason) it will not work (very wild guess but who knows).

I´m not sure if it works w/o but I think it´s there for a reason. Where does the needle hit this cap - front, back, left side? Does the needle hit the cap in a particular stitch length or permanently?

Some pictures may be helpful.

It’s hitting the side of the cap nearest me. It looks bit different with a notch on the side it hits and now i notice it’s a different part number as well, maybe I should grind the opening a bit more since I can’t find a replacement? Its hitting just the edge 

Edited September 28, 2020 by Leatherphase

[Wizcrafts]

Is the needle going through the center of the slot in the cover plate? If not, the needle bar may need to be loosened and turned slightly. However, this will change the alignment of the needle clamp and thread guide. If the needle is already centered, then the shuttle assembly position may need to be tweaked to clear the needle.