Singer 29K72 Stitch Length Problem

[Constabulary]

Sorry about pulling this old thread again but I actually have found a working link to the DOC file about the restoration of the Singer 29K13 in the Needlebar forum. Just for the case someone is interested in it:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CC0QFjAB&url=http%3A%2F%2Fneedlebar.org%2Fmain%2Frestoration%2FSinger29K13.doc&ei=OTClU6nBKKWL0AXW64HQAQ&usg=AFQjCNEA0DvpI_cgnioBfZRNQbNTqgeKbQ&bvm=bv.69411363,d.d2k

So you can safe it on your PC

[SARK9]

Thanks for that link!

I don't have a 29K at the moment, but I fully expect one to follow me home at some point.

Yours turned out great, BTW!

-DC

[Ornito]

Sorry tu reup this old post...

I've just got a Singer 29k71 and it seems I have the same "problem" (no less than 7 stiches...)

Is there a way to disassemble the bell crank  without removing the whole head?

thanks in advance.

Edited September 10, 2017 by Ornito

[Wizcrafts]

2 hours ago, Ornito said:

Sorry tu reup this old post...

I've just got a Singer 29k71 and it seems I have the same "problem" (no less than 7 stiches...)

Is there a way to disassemble the bell crank  without removing the whole head?

thanks in advance.

I normally remove the 4 screws securing the revolving head assemble, plus the needle clamp, then pull the head away from the arm and down. I suspect that you'll have to do this too. This gives you complete access to the parts inside the head. You'll just have to remove the presser foot and stitch length regulator, then unscrew two screws inside the bottom, and lift out the bell crank. Use bronze brazing rod to build up the little puck on the end of the crank, shape and polish it for a good fit without binding and put her back together.

[Ornito]

2 hours ago, Wizcrafts said:

I normally remove the 4 screws securing the revolving head assemble, plus the needle clamp, then pull the head away from the arm and down. I suspect that you'll have to do this too. This gives you complete access to the parts inside the head. You'll just have to remove the presser foot and stitch length regulator, then unscrew two screws inside the bottom, and lift out the bell crank. Use bronze brazing rod to build up the little puck on the end of the crank, shape and polish it for a good fit without binding and put her back together.

Thank you so much, Wiz.

I was hoping it could be done without removing the head....

[Wizcrafts]

10 hours ago, Ornito said:

Thank you so much, Wiz.

I was hoping it could be done without removing the head....

Why? Removing the 4 screws is almost effortless and takes about three minutes. You just need a long flat blade screwdriver to turn the screws out. Two are near the top and two near the bottom of the machine body and revolving head assembly. Remove the presser foot, regulator and needle clamp assembly, unscrew the 4 screws and the head can be pulled down and away. The needle bar will simply come out the top as you lower the head. There is no need to disconnect the needle bar from the top mechanism.

[Ornito]

3 hours ago, Wizcrafts said:

...There is no need to disconnect the needle bar from the top mechanism...

 

Thank you again, Wiz.

I didn't get it from the previous post.

 

[Ornito]

Sorry to bother again....

I'm getting some missing stitch...(here and there)

Could you kindly help me?

What's the problem origin and how I could fix it?

thanks in advance for any info provided.

[Wizcrafts]

4 hours ago, Ornito said:

Sorry to bother again....

I'm getting some missing stitch...(here and there)

Could you kindly help me?

What's the problem origin and how I could fix it?

thanks in advance for any info provided.

I also own a Singer 29k71 and have done everything I am about to describe for you. You can view or download and save/printout the official Singer Service Manual and Parts List, here - for the 29k-71, 72 and 73. It will make everything below more understandable.

Before adjusting anything, make sure the needle is the correct system (29x3, 29x4, 135x16, or 135x17) and that it is all the way up in the mounting clamp, and that the scarf is on the dead right and the rib is on the dead left. Also, make sure the needle size is correct for the thread you are using. For most users, that equates to a #18 needle for #69 thread, or a #19 needle for #92 thread. Finally, make sure the thread is bonded and stays that way throughout the sewing cycle.

If all the above are positive, yet the machine skips stitches, there are only a few items left to check. First, make sure there is sufficient presser foot pressure to hold down the leather as the needle begins its ascent. If you see the leather lifting, screw down the pressure spring until it stops lifting with the needle. While you're at it, take a look at the thread on top and make sure it isn't binding, or coming out of the tensioners.

Another cause of skipped stitches could be the tape or glue holding layers together for sewing. I use titanium coated needles to help fend off problems caused by leather tape and contact glue.

If none of the above stops the skipped stitches, the machine is either marginally out of time, or the check spring is badly worn, or the gears in the bolt on gear box are very badly worn. The first step you take should be to slide open the throat plate and face it sideways, across the gear box, so you can see the hook and needle. Put a representative piece or pieces of leather (that are having skipped stitches) under the foot, lower the foot and slowly rotate the hand wheel in the forward direction (counterclockwise if on the end of the body; clockwise if on the right front). Observe the size and quality of the loop as the needle goes down, then raises up and stops. There should be a visible thread loop on the right side of the eye. The point of the hook should be about 1/8 inch away from the needle and loop. As you continue moving the hand wheel, that hook should move to the center of the needle and pick off the thread loop. Skipped stitches happen when something prevents a good loop from forming and staying intact until picked off.

If a loop forms  and holds, but the hook has passed the needle too soon, the timing needs to be retarded. If the hook is so far back that the needle and loop have moved up past it, the timing needs to be advanced. If the hook seems to be intersecting the needle at the proper time, but the loop has gone away, the check spring needs to be replaced. Timing is adjusted through a hole in the right front of the base of the machine. You'll need to loosen a nut on the back of the rack-to-down crank combination, then use a straight blade screwdriver to turn the eccentric screw one way or the other to get the hook in the best position to pick off the thread loop. Once you find that position, tighten up the locking nut to secure the timing.

If timing the hook doesn't stop the skipped stitches, there is either a lot of play in the gears in the gear box, or the check spring needs replaced. You can see how much wear is in those parts by holding the wheel in place and using you fingers to turn the hook one way and the other. There is bound to be some slack, but too much will create crazy timing. These racks and gears can be replaced with aftermarket parts, which will probably need a bit of tweaking to get a good fit with the least binding or slack.

I left the check spring replacement for the last item. This spring, which is inside the needle bar, above the needle mounting bracket, is tiny and has a paddle shape on the lower portion. The top is shaped like a T and has two tiny screws that secure it to the inside of the needle bar. You are going to have to remove the head again to see if this spring is the culprit. The spring eventually wears out and stops holding the thread in place, causing the loop to dissolve. Sometimes, you can bend the paddle end back in to get more life out of the check spring. Or not. If you've gone to the trouble of removing the barrel head, you might as well replace the spring.  Just make sure you set the tiny screws aside in the same right/left alignment as they came off. You should reinstall them in the exact same positions.

With the check spring off, examine the needle bar to see if a deep groove has been worn into the area where the paddle is supposed to squeeze the thread. If this has occurred, nothing you do about the spring will improve the situation. You would probably have to replace the entire needle bar to fix this.

Good luck with your repairs!

[Ornito]

1 hour ago, Wizcrafts said:

I also own a Singer 29k71 and have done everything I am about to describe for you. You can view or download and save/printout the official Singer Service Manual and Parts List, here - for the 29k-71, 72 and 73. It will make everything below more understandable.

Before adjusting anything, make sure the needle is the correct system (29x3, 29x4, 135x16, or 135x17) and that it is all the way up in the mounting clamp, and that the scarf is on the dead right and the rib is on the dead left. Also, make sure the needle size is correct for the thread you are using. For most users, that equates to a #18 needle for #69 thread, or a #19 needle for #92 thread. Finally, make sure the thread is bonded and stays that way throughout the sewing cycle.

If all the above are positive, yet the machine skips stitches, there are only a few items left to check. First, make sure there is sufficient presser foot pressure to hold down the leather as the needle begins its ascent. If you see the leather lifting, screw down the pressure spring until it stops lifting with the needle. While you're at it, take a look at the thread on top and make sure it isn't binding, or coming out of the tensioners.

Another cause of skipped stitches could be the tape or glue holding layers together for sewing. I use titanium coated needles to help fend off problems caused by leather tape and contact glue.

If none of the above stops the skipped stitches, the machine is either marginally out of time, or the check spring is badly worn, or the gears in the bolt on gear box are very badly worn. The first step you take should be to slide open the throat plate and face it sideways, across the gear box, so you can see the hook and needle. Put a representative piece or pieces of leather (that are having skipped stitches) under the foot, lower the foot and slowly rotate the hand wheel in the forward direction (counterclockwise if on the end of the body; clockwise if on the right front). Observe the size and quality of the loop as the needle goes down, then raises up and stops. There should be a visible thread loop on the right side of the eye. The point of the hook should be about 1/8 inch away from the needle and loop. As you continue moving the hand wheel, that hook should move to the center of the needle and pick off the thread loop. Skipped stitches happen when something prevents a good loop from forming and staying intact until picked off.

If a loop forms  and holds, but the hook has passed the needle too soon, the timing needs to be retarded. If the hook is so far back that the needle and loop have moved up past it, the timing needs to be advanced. If the hook seems to be intersecting the needle at the proper time, but the loop has gone away, the check spring needs to be replaced. Timing is adjusted through a hole in the right front of the base of the machine. You'll need to loosen a nut on the back of the rack-to-down crank combination, then use a straight blade screwdriver to turn the eccentric screw one way or the other to get the hook in the best position to pick off the thread loop. Once you find that position, tighten up the locking nut to secure the timing.

If timing the hook doesn't stop the skipped stitches, there is either a lot of play in the gears in the gear box, or the check spring needs replaced. You can see how much wear is in those parts by holding the wheel in place and using you fingers to turn the hook one way and the other. There is bound to be some slack, but too much will create crazy timing. These racks and gears can be replaced with aftermarket parts, which will probably need a bit of tweaking to get a good fit with the least binding or slack.

I left the check spring replacement for the last item. This spring, which is inside the needle bar, above the needle mounting bracket, is tiny and has a paddle shape on the lower portion. The top is shaped like a T and has two tiny screws that secure it to the inside of the needle bar. You are going to have to remove the head again to see if this spring is the culprit. The spring eventually wears out and stops holding the thread in place, causing the loop to dissolve. Sometimes, you can bend the paddle end back in to get more life out of the check spring. Or not. If you've gone to the trouble of removing the barrel head, you might as well replace the spring.  Just make sure you set the tiny screws aside in the same right/left alignment as they came off. You should reinstall them in the exact same positions.

With the check spring off, examine the needle bar to see if a deep groove has been worn into the area where the paddle is supposed to squeeze the thread. If this has occurred, nothing you do about the spring will improve the situation. You would probably have to replace the entire needle bar to fix this.

Good luck with your repairs!

Wiz, I have no more words to say Thank you so much !!

the machine is working good (except the 7 spi issue...) 

I tested it many times and with many different type of leather without any issue..

today I faced my first attempt on a real project and I proceeded with glueing the edges of the project....

I think you've got the problem:

"Another cause of skipped stitches could be the tape or glue holding layers together for sewing. I use titanium coated needles to help fend off problems caused by leather tape and contact"

In fact I prevously tryied with different (not glued) pieces of leather and not a single stitch was missed....

Do you have a suggestion for titanium coated needles? 

I'm using Schmetz  120/19 332 LR (29x4 R TW) and Amann Serafil Polyester #20

thanks again.