Thread gets caught under hook occasionally

[Uwe]

So I spent a few hours checking on things that folks had suggested (thanks to all!). Alas, I really could not find any adjustment that was out of spec or one that I could tweak to reliably resolve the problem. The springy-ness of the bonded polyester may exacerbate the problem. Nylon and Cotton may not want to"spring" downward as readily as this polyester thread does. Alas, when sewing for outdoor applications, Polyester is among the few durable choices.

I started considering the hook design itself and comparing it other hooks I had on hand. I recently got a Pfaff 545 which has a notably different hook design, that I think makes a big difference for this particular problem.

I decided to make a slight modification to the Consew's Kobani hook and add a very thin stainless steel plate that keeps the thread from "falling down" if it goes slack for some reason. Other hook designs have this type of plate and it seemed like a good thing to try. My fix is reversible with simple nail polish remover and in a worst case scenario the hook itself is cheap at around $30 in case we need to go back to square one.

I had actually sold the machine a few weeks ago and the new owner, being a novice, ran into trouble quite frequently with this particular issue, causing frustration with an otherwise perfectly good machine.

I think the fix is a good one for my particular situation. I'm not suggesting that anybody else should do this.

Below is the updated video with footage added at the end to show the fix I decided on. Sorry about the occasional muffled voice. I know I need to step up my microphone game if I am going to be doing more talkies.

 

Edited June 5, 2016 by Uwe

[gottaknow]

Clever fix for a diy'er, but using superglue on the hook of a machine I had sold isn't something I'd ever do. First good big birdnest, a wandering screwdriver, tweezers, etc. and your fix pops off or gets bent down still pinching the thread. I've seen things like this attempted many times and they always fail. Sorry Uwe, just being honest. If I had bought this machine and discovered the work around later, I'd be upset. If you're going to rebuild and sell machines, this is one of those things you should avoid doing. Again, just being completely honest. 

Regards, Eric 

[brmax]

I found the old singer 212,  I have has the plate on the bottom of the hook also it is probably smaller if it did match in thickness. I think that one your working on has a bigger bobbin. Maybe a good time to measure as its in the "proto type staging".

It sure has my interest especially seeing the threaded holes that I could see being used, possibly a bigger singer or other model big 255 consew.

I did notice the 1508 I mentioned didn't have the plate so will take a look next time for results when I put poly in.

 projects for the new month always busy

Good day

Floyd

 

[Uwe]

I appreciate your feedback and honesty Eric. Time will tell if the fix lasts and you may very well be right about it not lasting. But it's not quite same as painted-over bondo on a car to hide evidence of an accident. I'm always upfront with what I do or did to a machine. I'm on good terms with the buyer and we both investigated the problem together. We were delighted when we finally could reproduce the problem to know how it happened, and agreed that it was basically a design flaw. I think he'll appreciate the fix (I even sent him a link to the video) but if the fix doesn't last, I'll install a new hook for him. Alas, with an unmodified hook, we're back to getting thread caught under the hook, which is super annoying. Is this simply an unavoidable design flaw of this class of machines and hooks? The more modern hook designs all seem to have some design element in the hook to minimize or prevent this failure mode.

Are there any hooks out there that fit the Singer 111W155 class of machines and don't have this flaw? I bought the Koban hook because I thought they're one of the better brands for hooks. I'd prefer to just install a new hook that doesn't get thread caught on the underside by design, rather than operator skill or luck.

Edited June 5, 2016 by Uwe

[gottaknow]

1 hour ago, Uwe said:

I appreciate your feedback and honesty Eric. Time will tell if the fix lasts and you may very well be right about it not lasting. But it's not quite same as painted-over bondo on a car to hide evidence of an accident. I'm always upfront with what I do or did to a machine. I'm on good terms with the buyer and we both investigated the problem together. We were delighted when we finally could reproduce the problem to know how it happened, and agreed that it was basically a design flaw. I think he'll appreciate the fix (I even sent him a link to the video) but if the fix doesn't last, I'll install a new hook for him. Alas, with an unmodified hook, we're back to getting thread caught under the hook, which is super annoying. Is this simply an unavoidable design flaw of this class of machines and hooks? The more modern hook designs all seem to have some design element in the hook to minimize or prevent this failure mode.

Are there any hooks out there that fit the Singer 111W155 class of machines and don't have this flaw? I bought the Koban hook because I thought they're one of the better brands for hooks. I'd prefer to just install a new hook that doesn't get thread caught on the underside by design, rather than operator skill or luck.

I'll take a look at my spare hooks and see what I have.  Stay tuned. 

Regards, Eric 

[Uwe]

2 hours ago, brmax said:

I found the old singer 212,  I have has the plate on the bottom of the hook also

Great find! I think you may be onto something here. The Singer 212 hook design has a special hook thread guide "bridge" that get screwed into place. My hook actually has threaded holes on the bottom as you noticed - I didn't know what they were for. It would be NICE if the Singer 212 hook thread guide bridge would fit my hook (it's actually a Hirose HSH-11-55, not a Koban, as I stated earlier). Clearance may be an issue tough - it's super tight. But a screwed-in-place bridge would certainly be more confidence inducing than a glued, cantilevered tab.

 

[Uwe]

I had also considered putting on a full circular ring on the underside of the hook instead of just a cantilevered tab, but I was worried about covering up the threaded holes, haha! There are spacer shims available (intended for machinists)  that would be a perfect match size-wise, available in various thicknesses from several millimeters to 1/10th of a millimeter: 

[brmax]

I hope it works out for some parts, with Eric and some measures its a go.

Good work guys

Floyd

[gottaknow]

Uwe, what is the diameter of that hook shaft?

Regards, Eric

[Constabulary]

Now that I see the pictures... I´m using an original OEM DUERKOPP hook with replaceable shaft in my 111G156 which also has a "deflector tin" under the hook. Maybe some Companies have discovered this problem earlier. Thats probably why I never ran into this problem. The DUERKOPP 239 and 241 and the like are using a lot of Singer 111 compatible parts.

Pic 1 Singer hook on the right in Pic 2 on the left. All other parts are DUERKOPP

 

Edited June 6, 2016 by Constabulary