proper top and bottom tension

[esantoro]

I've been meaning to ask about this for some time, and now the issue has raised its head again.

I'm having problems again getting proper top and bottom tension. Bobbin thread (207) is pulling top thread (277/#25 needle) to the bottom when the top tension is already pretty tight and the bobbin tension already rather light. Leather used is one layer of 7/8 oz belting leather or veg retan.

I've loosened the bobbin tension screw to the point where the top thread is now catching on the tab portion of the bobbin case tension spring. This isn't the first time this has happened, so I'm beginning to think I should tweak that bobbin case tension spring somehow so that I can screw down that tab far enough that the top thread doesn't catch on it but that bobbin tension won't be too tight.

Thanks for any suggestions.

Ed

[Art]

Hi Ed,

I guess the bobbin tension spring could be worn out, I've never worn one out though. See if you can get a Japanese part instead of a Chinese one. Orrrr, crank it down till it clears and then crank some adjustment into the secondary tension (first of all make sure you have two wraps around it counterclockwise -- we're talking about the tension knob that is closer to the needle), and you aren't using those funky Neel's bobbins are you?

Art

I've been meaning to ask about this for some time, and now the issue has raised its head again.

I'm having problems again getting proper top and bottom tension. Bobbin thread (207) is pulling top thread (277/#25 needle) to the bottom when the top tension is already pretty tight and the bobbin tension already rather light. Leather used is one layer of 7/8 oz belting leather or veg retan.

I've loosened the bobbin tension screw to the point where the top thread is now catching on the tab portion of the bobbin case tension spring. This isn't the first time this has happened, so I'm beginning to think I should tweak that bobbin case tension spring somehow so that I can screw down that tab far enough that the top thread doesn't catch on it but that bobbin tension won't be too tight.

Thanks for any suggestions.

Ed

[esantoro]

Hi Ed,

I guess the bobbin tension spring could be worn out, I've never worn one out though. See if you can get a Japanese part instead of a Chinese one. Orrrr, crank it down till it clears and then crank some adjustment into the secondary tension (first of all make sure you have two wraps around it counterclockwise -- we're talking about the tension knob that is closer to the needle), and you aren't using those funky Neel's bobbins are you?

Art

Hi Art,

Last night I bent the tab so that it wouldn't be a problem, but the result was more bobbin thread tension. Then I went to bed. I think I need to get more creative in how I bend this spring/clip, not just the tab.

I've been wrapping the thread 1.5 times around the secondary tension wheel (closest to the needle). If I take a bird's eye view of the wheel I see one strand of thread. If I take a worm's eye view (from underneath the machine looking up) I see two strands of thread. If I wrap the thread once more around this wheel, there will be two and three strands respectively.

Thanks,

Ed

[Art]

Hi Ed,

That's what I call two wraps, well almost two.

Art

Hi Art,

Last night I bent the tab so that it wouldn't be a problem, but the result was more bobbin thread tension. Then I went to bed. I think I need to get more creative in how I bend this spring/clip, not just the tab.

I've been wrapping the thread 1.5 times around the secondary tension wheel (closest to the needle). If I take a bird's eye view of the wheel I see one strand of thread. If I take a worm's eye view (from underneath the machine looking up) I see two strands of thread. If I wrap the thread once more around this wheel, there will be two and three strands respectively.

Thanks,

Ed

[esantoro]

I thought I had had this tension problem licked. But it's still here.

Bobbin tension is still too tight and pulling the top thread to the bottom of 8/12 ounce leather , 1/4".

This is the case even when I have primary and secondary top tensions tightened to the point where i really shouldn't go beyond: primary tension has 9 screw threads showing and secondary tension has 7 threads showing.

I can remedy this if I loosen the bobbin tension screw to the point where the bobbin tension clip/spring is so loose that the top thread catches on it as it goes around.

In these tests the top thread is aways 277 and bobbin thread has been 207 and 277 with the same results. needle is organ #25 diamond point.

If I add a third layer of 5/6 oz leather, for a total thickness of @3/8", the problem is remedied.

To my understanding, I should still be able to adjust tension so that I can pull the knot to the top of 8 oz leather, or any thickness.

My next step is to start bending up the forked tip of the bobbin tension spring, requiring the bobbin tension screw to be tightened further, insuring that the top thread never catches on the bobbin tension clip/spring, even when loosened quite a bit.

It is about now that I should be remembering the rule never to work with leather or machines when tired. But will I listen.................

AhhhhHAAAAAhaaaaaaaaaaa.......noooooooooo.

[Art]

Ed,

Start over. Increase the bobbin tension until there is a pound or two of bobbin tension on the bobbin thread. Then leave it alone and adjust the top tension to put the lock where you want it. Start from square one, throw in a new needle and bobbin for baseline, make sure the bobbin turns clockwise as you look from the open end of the bobbin case and that the thread is clicked in under the tension spring, one or two pounds pull should be just fine.

Art

I thought I had had this tension problem licked. But it's still here.

Bobbin tension is still too tight and pulling the top thread to the bottom of 8/12 ounce leather , 1/4".

This is the case even when I have primary and secondary top tensions tightened to the point where i really shouldn't go beyond: primary tension has 9 screw threads showing and secondary tension has 7 threads showing.

I can remedy this if I loosen the bobbin tension screw to the point where the bobbin tension clip/spring is so loose that the top thread catches on it as it goes around.

In these tests the top thread is aways 277 and bobbin thread has been 207 and 277 with the same results. needle is organ #25 diamond point.

If I add a third layer of 5/6 oz leather, for a total thickness of @3/8", the problem is remedied.

To my understanding, I should still be able to adjust tension so that I can pull the knot to the top of 8 oz leather, or any thickness.

My next step is to start bending up the forked tip of the bobbin tension spring, requiring the bobbin tension screw to be tightened further, insuring that the top thread never catches on the bobbin tension clip/spring, even when loosened quite a bit.

It is about now that I should be remembering the rule never to work with leather or machines when tired. But will I listen.................

AhhhhHAAAAAhaaaaaaaaaaa.......noooooooooo.

[esantoro]

I think I've got it under control now and have a better idea of how the Bobbin tension clip/spring reacts to various tweaking. Till today I had been lightly bending only the tab that screws down, no other part of the clip. I had to experience with very lightly bending the forked tip of the clip.

Thanks for listening to all of my thinking out loud.

Ed