Hi,
I got my very old tensioner but it was from 1931-1940 and had no tension release pin mechanism. It had a completely different tension release.
I decided this tensioner was probably made in 1937 based on the serial number and model AE in the listings.
After some thought, I made a tension double D release disc for my 1952-53 tensioner post. The 1937 mounting post had no hole in the mounting screw or the tension post.
So, I made the double disc out of #14 copper wire hammered slightly flat to fit the tension post split gap between the thread cut post halves.
This was bent into a curved S disc and works fine. It pushes the 'beehive cup plate' away from the flat face plate when the presser foot is raised and the original 1953 release pin is pushed.
The thread is now actually released by raising the presser foot and lift lever.
Long story short, my New Home LLC Model sews beautifully and fairly smooth now at any speed. No popping. No snapping. No stalls. No jams. No cut threads.
The current brand new standard needle works totally fine and clearances are not a problem with this longer needle available now.
The hook timing gap is still at 3.5 mm and that needs to be decreased with a 1 mm cut off modern needle, IMO.
I sewed a superman red S on some jean material. Then, I doubled it over and it sewed fine. I doubled that to four layers and it sewed fine.
I added one more single layer and the needle made a very slight noise at slow speed. I quit that test. Four layers of jeans is the limit for this machine.
There were no clearance issues with the feed dog or its movements, and so I am not messing with the feed dog timing.
Here are some measurements of various parts on my LLC, 'New Home' Rotary. AKA, Free Westinghouse and Elgin.
Bobbin with many holes like a current class 15: diameter: 21.85 mm or 0.286".
Height or thickness: 7.23 mm or 0.284".
OD of spool at the thread core: 6.09 mm or 0.239".
Bobbin core hole ID: 6.10 mm.
Bobbin case center post hole ID: 3.95 mm.
Bobbin case center post hole OD: 5.76 mm or 0.227".
Bobbin case inside and much larger diameter ID: 22.13 mm.
NH motor shaft OD: 7.26 mm or 0.286"; has two drilled mounting holes for a set screw. So, the rubber tire can be offset a few mm further out.
NH old rubber OD: 28.7 mm or 1.109" or about 1-7/16".
NH LLC rubber pulley has an integrated bobbin winder shaft on the outer end and the new Janome ones at supply houses don't have that outer shaft bobbin winder feature.
HTH,
Stefan