Singer 45K Open & Closed Frame Shuttle - Whats The Difference???

[Constabulary]

I always wanted to ask this...

What is the difference (beside the obvious) between an open frame and closed frame shuttle for the Singer 45K / Adler 4 & 5 and the like?
I notice that the up to date 441 clones all have closed frame shuttles as it seems but even in old 45K parts list from the 1920´s or so they show open frame and closed frame shuttles for the same machine. I have a (very) rough idea but I´m not sure and wondering what the "old school" LW and dealers know about it.

[CowboyBob]

The larger thread works better when sewing leather with the open frame,there is less  metal to  for the thread to drag against so the thread slides through easier.

[Constabulary]

Thanks Bob! My thought was just the opposite. The closed frame puts more dragon the thread (agree) but I thought thats better for thicker thread / thick materials. But maybe I´m wrong. So with other words closed frame for thread up to 138 / 207 and open frame for 207 and up?

[Uwe]

I had been wondering about the same thing some time ago. I have a dozen or so aftermarket 91774 open frame 45K shuttle hooks. I suppose there's bit of tight spot on the corner of a closed frame hook ( similar to my Adler 205 video.) There's probably a smoother ride for the thread to drag along the smooth edge of a closed frame hook as opposed to bouncing down a few steps on a open frame hook. The closed frame hook likely is more rigid and dimensionally stable, less likely to twist or bend. 

I'm wondering if open and closed frame versions are interchangeable in Singer 45K models. If anybody recognizes the manufacturer's mark on my aftermarket hooks (looks like an H inside a G) please let me know - I've not been able to find a reference. 

 

[Constabulary]

I meanwhile have a 45D and a couple of open and closed frame shuttles (different brands and condition, some orig Adler and some quality after market shuttles from NÄMATAG and so forth but not all have a brand stamp). Yet I have not tested them all but both types work in the machine. At the moment I THINK the open frame works better my 11/3 SYNTON thread and 10mm resin coated nylon webbing. But I have not used the machine very much so atm it´s just a "feeling".

I just thought there's a reason why there are 2 different types of shuttles....

EDIT:

Uwe, your Videos are always excellent - haven´t seen this one before but its great to see in slomo

Edited November 16, 2016 by Constabulary

[jimi]

I would imagine it was just a design change, nothing else. remember at one point they were OBSOLETE in the parts manuals. if you look at a manual you will almost always find the illustrations in pairs. one hook for thin thread and one hook for thick thread. this can be seen when you compare the heel, they are slightly different. try and trace one then compare to the other beside it and there should be one with the heel slightly smaller. in this case the #91044. here are two open shuttles, one for thick and the other for thin? just my opinion..

 

[Uwe]

I think that diagram shows the exact same parts, just assembled and separately, from a slightly different angle. 91046 is the complete hook assembly, 91044 is the frame that is part of the 91046 assembly. 

The page from the 45K68/69/71 parts book shows hook assembly 91774, which consists of individual parts 91772, 91771, 91043, 91795

Edited November 16, 2016 by Uwe

[jimi]

mmm? yeah i think you are right Uwe

[Constabulary]

You still can buy both types.

[jimi]

So Bob that is probably the reason the Frobana use the open frame type??