A recent addition to my little herd is this promising 1960 freearm version of the 319K.
These machines were fitted with 206×1 needles originally & many have been ‘messed with’ to ‘convert’ them to the standard, universal 15×1 type which has a huge range of choices. (The original 206×1 needles are still available but only in a very restricted range) So buying one of these machines can be chancy, & you do take a risk. Be aware: )
In good working order they are wonderful machines which use the standard Singer A type flat cams of the period, with 5 inbuilt cams, plus zig zag & are all metal construction, no plastic gears or vulnerable parts. It does have a cleated belt, normally reliable but problematic if it needs replacing. (Rubber replacement belts are available, but expensive) No drop feed, you need a cover plate for free motion work. This one has a 75 watt motor & it is fast. You either like the colour & style or don’t. I love it! This one is in great cosmetic order for a 65 year old, I’m still checking its mechanics currently but it does a perfect straight stitch at full speed, with a 15×1 needle! I believe it has been ‘converted’ so it is getting a close check over in the bobbin/hook area before I proceed, carefully, with ZZ & cams: )
The bobbin case fitted to this machine is an Alfa (as fitted to Alfa 102 & 109 machines I believe) & has enough clearance to allow single 15×1 needles to be safely used to the maximum ZZ width. Trying 15×1 twin needles also has enough safe clearance up to the Singer recommended maximum byte of 3 on the stitch width indicator. So it does appear to be a good alternative bobbin case to the original Singer version to allow general use of 15×1 needles without further modifications. A straight swap in other words. Hook Assembly on this one is Simanco 173292 inner, Simanco 173191 outer. Has the dimple at 4 o’clock to locate the bobbin case.
Note no evidence of needle strikes using 15×1 needles, single & twin. Photos of the clearances using the Alfa case, with needles at BDC, are below:
Maximum & minimum bobbin case movement on left throw (showing the bobbins max movement left & right to allow for the thread to pass the bobbin fixing)
On the right throw the same procedure.
The needle is well clear of striking the bobbin case in any of the 4 positions. Only extreme needle flex would cause the needle to strike the case. All with 15×1 needle, not 206×1. For me that is visual proof that this Alfa bobbin case is perfect for converting the 320/319 machines safely to the universal 15×1 needles. I’ve used it at maximum speed on various cams & never a hint of a problem.
Similarly with twin 15×1 needles, with Singer recommended maximum byte of 3:
Plenty of clearance on left throw, needles at BDC.
Same on right throw:
It may well be possible to use byte 4 & still leave enough clearance to be safe? I have not tried that yet: )
So whoever decided to use the Alfa bobbin case knew exactly what they were doing. I have never come across mention of this option online before, so I don’t think it is generally known. I have also got another bobbin case to compare. The modern Taiwanese version of the Singer 173058. Branded as Maya, & well engineered.
I have tried this one with single needle & twin needle & it works OK, but hasn’t got quite as much clearance as the Alfa option! I have found one more Taiwanese version of the 173058 with a wider ‘jaw’ which does look to have a good chance to provide as good clearances as the Alfa. If not slightly better. This one:
This one looks to be as good, if not better, than the Alfa!? It may well enable full width double needle ZZs etc. I’m intending to buy one & try it: ) https://www.ebay.co.uk/itm/176739624523?
This new bobbin case arrived during the week & is now undergoing tests & photo examples of it will be shown here when all done. It looks to be the best in terms of needle clearances. With twin needles it is the width of the ZZ throat plate gap that limits ZZ width. (It rubs on slightly more than 3!) Open it up a fraction & the ZZ width could safely be 4 I reckon. Possibly 5, which is full width: )