Gregg From Keystone Sewing

Your Singer 531B-8BL is a 1994 model, either 206RB-1 or -2. The variance is the oil system where the -2 has an oil tank for the hook and centralized lubrication. Some -1s had this oil system as well, but all of the -2s have the oil system.

Perhaps you can use one of these; Pfaff presser foot adapter for 138

I'm fist pumping behind my keyboard. Glad I was able to help.

CLICK HERE to download engineers manual. Sounds like it could be a connecting rod eccentric cam adjustment, see attached, 2.Adjustments page.

See attached, 138-115U appears to be same as -6 but with a triangular eccentric for garment or textile work "U" and with cording device "115". Hope this helps. Pfaff138-115U_SubClass.pdf

I have a l lot of Pfaff 138 books I'll see what I can find.

Consew 255RB Owners manual See above, black dial is part of the lubrication system, the silver knob is fine adjustment for the presser foot pressure.

Best thing to do in this case is cross reference the parts in the parts book and see what variances between classes there are. This is your best bet. Even though it may not give you the what the differences are, at least you know they are using something different to get there with a higher lift, longer stitch length or a larger bobbin hook.

Agree, top quality, not as well known brand wise.

That's a lot of work, good job.

Good stuff, like said report back.

Thanks for this, never heard of them until now. I'll keep this information on hand.

Pfaff comes to mind; you MUST have the machine's brochure, parts list, owners manual, engineers manual, all kind of stuff to piece together all of the specifications that you may want to have.

Really well done, great job, thanks for sharing.

It appears that you have a mismatch of parts; standard needle plate, binder presser feet set, binder feed dog. That feeder, also, has taken one too many needle strikes and can certainly snag the thread as you are sewing. Also, what size it that thread, it look really thick? What needle size is that also? Hope this helps get you started.

I made a short video, hope this helps. No other way to describe it. YouTube of bonded and non bonded thread example

Yes sir, that's exactly correct.

Silky, we add reverse by cutting and welding some parts and adding a lever seen here in this image. We then drop a chain down through the hole and connecting to a foot pedal for reverse.

I would think a needle size 16~20 would be a good start, I'd have to really see the whole job, not just the thread, but again try these sizes.

Here's the parts list section for the hook guard.

New to me.

This too, same idea that also works well.

471 takes system 134, or 135X7 When the designate a cut point, as in this case, the system needle changes for example here 134LR, 135X8 RTW, In this case, LL is a cut point needle with an hour glass shape. CR I'm not sure and can look this up later. 134-35 are very different needle, but the needle shank will will fit the same with the 134.

Anti backlash spring or bobbin case break as some may call this is used to prevent the bobbin from over spinning after the machine comes to a stop. The slower that you sew, the less that you have to worry about this. On a high speed machine with needle positioning, the machine will commonly come to abrupt stops and starts and can most easily do this. Especially on a large bobbin machine where the bobbin has more weight. This is why many machines come with anti backlash spring either built into the bobbin case, or a drop in bobbin case coil spring or star. Often the machine manufacturer will call for a bobbin made out of aluminum to keep the weight down and help prevent over spinning as well.

That's what comes up in the description. I don't envy anyone who gets into this part of the machine.