Tacsew/juki 563 Hook Timing Problem: Stitch Length Affects Timing

[Gregg From Keystone Sewing]

1st things first, we really need to go in and replace the broken tension release slide.

After that, I'll bet someone here $1.00 I know what the issue is here with the needle bar frame feed dog hook thing. Seeing the video at 1:26 you can clearly see from the side the needle playing catch up.

View attached image, then remove the gib, turn this over by hand and you'll see this problem disappear. If so, this means the gib is too tight. It can take a few tries to get this set correctly.

On the longest stitch length setting, we set this by putting sewing oil all around the contact point between the gib and rock frame. When the gib is set correctly, you should be able to see an oil ooze out from around the gib with no real feel of side to side play by hand as the frame sweeps front to back. If you don't see this it means the gib is too tight, and is going to lock up and have to play catch up with the feed.

Hope this helps!!

Edited January 29, 2016 by Gregg From Keystone Sewing

[Uwe]

I certainly do enjoy blundering around in the dark, especially if the person I'm blundering with has great timing and knows how to adjust tension just so.

@TinkerTailor: it sure looks like a rubber O-ring but it's actually metal and part of the threaded post. Not sure if it's a manufacturing or a design issue. I suppose I could just use a dremel and grind down the bulging ring:

@ Gregg: Thanks for that suggestion. I checked that guide gib part on my machine and it appears to be doing exactly what it's supposed to.

I actually made a good deal of progress this morning. I decided to put things together but leave out the broken thread release part. It's not exactly a vital organ and I can't see any reason why the machine should not function properly without it in place. I'll deal with the foot-up thread release manually, not a big deal.

As I was putting things back together, I adjusted foot lift, timing of the inner presser foot (so it arrives at the material at the same time as the needle - it was way early before), re-timed the hook about four times with different top-bottom timing belt settings. Once I have it all figured out and can reproduce it reliably, I may make a little video showing how I made these adjustments.

The machine actually makes a very nice, even stitch now, so I' think I'm about 90% there. The one thing that's still bothering me is that the thread seems tight wrapping around the bobbin and it snaps a little as it's being released from the thread cast-off nib on the hook (i cleaned and polished the nib, no burrs or anything).

So it seems to me that I'm still just a little off on the timing to reach the buttery smoothness nirvana, but I'm not quite sure which adjustment will get me there. Should I advance hook timing a little or is this still due to an imperfect top-bottom timing belt position? I can't be far off.

Here's a little video that hopefully shows what I'm talking about:

[dikman]

I've only just learned about timing of the inner foot (is there no end to learning with these machines?). I'm pretty sure that was why I snapped two needles in the Pfaff, the needle was reaching the leather way before the inner foot, and I'm pretty sure it was causing the needle to deflect. In the process of adjusting it I managed to get the needle/foot to run in reverse .

Sounds like you're almost there, Uwe.

[Uwe]

All better now. I took the timing belt off one more time and advanced the bottom hook drive shaft one notch. Then I re-timed the hook for the seventh time today - I'm getting the hang of it.

Here she is sewing as well as I had hoped for:

I'm gonna give her (and me) a rest before I tackle that confounding reverse mechanism to balance forward and reverse stitch length.

[TZBrown]

It's looking real good. It is amazing what 1 cog on the timing belt can do, subtle change, dramatic result.

That's why I enjoy the search for perfection with these machines, and it is rewarding, at least to me