Adler · Bobbins

3D printed bobbins jamming in the heat

Is it too hot to be sewing? The temperature is 30C (86F) – we’re having a heat wave. My new 3D printed bobbins for Adler 87 suddenly started jamming. My old plastic bobbins for computerised Pfaff 7510 are also suddenly jamming! I blame the heat which makes the plastic expand.

With Pfaff and other machines that take standard bobbins, the solution is simple – switch to metal bobbins. You’d need to be on the surface of the Sun before those start jamming. Well, may be not quite on the Sun, but still in a rather hotter place than my sewing room. But these 3D printed bobbins have been printed exactly because metal bobbins are lacking! So, what to do?

Find a metal worker who can make them for you in steel. Yeah, right. ๐Ÿ˜ฃ

Instead, I found some tricks for Adler 87 that allow me to use 3D printed bobbins even though they expand a little.

Here are the bobbins. You see how they are supposed to fit into the bobbin case – sinking into it a little. At the moment some of them are rising above the surface slightly. ๐Ÿ˜’

Winding the bobbin

First, I discovered that when the bobbin is being wound in the heat, its sides move outwards under the pressure of the thread building up. Adler 87 has a rather high thread tension for winding.

The tensioner has a spring under the big screw, so first of all I took it out.

That improved the situation but not by very much. This zig-zagging of the thread around the pins already puts a lot of tension onto it. If you don’t mind that your bobbins hold a lot less thread than they should, you can re-route the thread with fewer zig-zags and that solves the problem.

But I do mind, so I choose to restrict the thread closer to the bobbin.

This helps and the bobbin almost doesn’t expand.

Threading the bobbin case

If you have a slightly expanded bobbin and you thread it the usual way, you might find that although the machine sews perfectly, you cannot pull out bobbin thread when you stop sewing. ๐Ÿ˜ค This is impossible to work with!! But don’t panic.

First, I put the bobbin into the bobbin case the wrong way around. ๐Ÿ˜ฏ Yes, I know, completely illegal, but hey – 3D printed resin bobbins are also not exactly regulation issue. So where you normally put the bobbin in so that it spins clockwise, I put it in so that it spins anti-clockwise. It makes it nearly impossible to thread the shuttle though, so what I do is put the bobbin in properly, thread the shuttle and then pop the bobbin out and flip it.

This positioning reduces zig-zagging in the thread path and is often sufficient to allow you to pull the bobbin thread when it is fully threaded through the needle hole. I noticed no issues with sewing and did not have to adjust thread tension on the bobbin case either.

Change your habits

If the above tricks are not quite sufficient, there is another thing you can do, and this only applies to machines with the same hook as Adler 87 – the Wheeler & Wilson D9 type.

If you pop the bobbin case in, leave the slide open and slowly rotate the balance wheel, you can observe that the hook pressure on the bobbin varies throughout the cycle. And it so happens that the usual “stop” position with the needle and the take-up lever both at the highest point corresponds to high pressure on the bobbin from the hook. Hence if the bobbin is a little too thick, it jams when you try to pull the thread.

However, just before that, when the needle is already up but the take-up lever is still down, the bobbin is spinning freely! ๐Ÿ˜ƒ

So here is my solution to a new sewing routine:

  1. When you want to stop sewing, bring the needle and the take-up lever to the highest point as usual.
  2. Now rotate the balance wheel backwards (towards you) a little – just to bring the take-up lever to its lowest point. Observe that the needle stays in the top position!
  3. Lift the foot and remove your sewing – the bobbin is now spinning freely.
  4. You are not done yet! Hold the threads firmly (mostly the thread coming off the needle) and rotate the balance wheel forward to bring the take-up lever back up ready for stitching. This will pull a length of thread off the spool, and if you don’t hold the thread, it will slink out of the needle instead.

With this method I can use even those bobbins that expanded quite a lot and are noticeably rising above the bobbin case edge. I found that even 1.5mm too high still works without the need to adjust bobbin tension for sewing!

I declare this a workable solution. But next time when I decide to get 3D printed bobbins done, I’ll start looking into different materials that can be used to make them. I know that ABS plastic would have been better as it is much harder, but the cost was prohibitive. I’ve got a good working compromise, so I’m happy with it.

Happy sewing! Even during a heat wave. ๐Ÿ˜Š

13 thoughts on “3D printed bobbins jamming in the heat

  1. Another bit of amazing information. Never thought of anything like that happening. BTW, it’s gonna be about 95F here . . . 86 is cool!

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      1. Interesting. I read that England is in a bit of a heat wave . . . we are for sure here. Yesterday Death Valley in CA was 130 F (55C) and where I live, 100 F (38C). Windows closed, lots of water, fans and air conditioning, metal bobbins, and stay inside!

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  2. Very interesting point. What a modern problem! I like the way you expose the alternatives, thanks!! Another option, but maybe a little expensive too, it’s to make a room very very cold to work in. But I don’t know if this would work if it is too much hot outside, don’t know if air condition machines would work so well. I hope the weather can calm down. Meanwhile, time to enjoy ice cream!

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    1. Ice cream it is! ๐Ÿ˜ƒ We have no air conditioning at home, just one small unit that we keep in the bedroom. It doesn’t make it really cold but at least helps to sleep. The sewing room and the rest of the house will have to stay hot. But hopefully the weather will cool down in a few days.

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  3. Keeping empty bobbins in the fridge might be another alternative way to prevent them distorting during a heatwave?

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  4. Well I guess it is for the very same reason that I choose specs with metal frames – those plastic sunglasses were always falling down my nose! It has been exceptionally hot here and quite unbearable for me. I feel sorry for the lambs who are now sporting chunky fleeces in the field below us. You are very clever to work out a way to adjust to a situation. Nothing to lose and lots to gain. If it works then whoohoo, you are up and running!

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  5. My Jeans were a bit tight yesterday, perhaps I’ve expanded in the heat? Great info, thanks for sharing.

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  6. Sorry to read of your troubles with the bobbins. I would be suspect of the heat being an issue though if the proper resin was used. My resin printed parts and bobbins seem to do fine with engineering resin.
    For metal bobbins, have you tried finding your local Model Engineer’s Club or a local Maker Space? Those old retired guys would probably be happy to have something to do! While stainless would be best, aluminum would be OK of you boiled them in salt water or washing soda to oxidize them.

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    1. I contacted 3D Print Shop about that jamming issue and they too thought there was something wrong with the resin. They are going to redo all the bobbins for me. ๐Ÿ™‚
      As for making metal ones, I’ll see if I can locate any of those clubs but I’ve never heard of them.

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