Consew 226 - feed timing issue

[RWL2]

The 'fabric' (actually a piece of cardboard) moves back and forth but doesn't progress in either direction.  The needle just goes through the same hole.  This was a completely frozen machine and needed a near complete disassembly.  About the only things I didn't take apart were the middle shaft for the reverse on the bottom of the machine and the shaft on the bottom that controls the feed dog, and the rock shaft in the upper arm part of the casting.  I have no idea if it was working properly before I took it apart.  The needle comes down and passes through the vibrating foot and fabric when it's in a rear position and moving forward.  The needle lifts and the vibrating foot follows the feed dog and pulls the fabric back.  

Here is how I assembled it.  What do I have out of time and how do I fix that?  Do you need other photos to diagnose the problem?

The "front" set screw of the timing collar on the right is in the groove of the lower shaft.  Which set screw should be in the groove?

I slid the feed eccentric back to show that both of its set screws had been in the grooves.  The two timing marks on the right are aligned and the thread takeup arm was in its highest position

The set screw of the feed dog's eccentric was in the groove.

 

 

 

Edited August 9, 2020 by RWL2
Changed a word

[Uwe]

In general, on Singer based machines the set screw marked with “S” is the one that goes into the groove on the shaft. Other manufacturers have different rules. Make sure you tighten the set screw in the groove first (to properly seat it,) before you tighten the other set screw.

The set screw that goes into the groove also generally has a pointy or domed tip, whereas the other set screw usually has a flat tip. If you remove the set screws, pay attention to that when re-inserting them.

You also have (or had) a loose set screw on one of the timing pulleys poking holes into your timing belt, by the way.

What we really need is a video, not still images, to debug the feed timing. Take a short close-up video of your feed dog and needle moving very slowly, upload it to YouTube and share the link here (easier said than done, I know - it’s the price you pay for crowd sourcing help.)

On many machines the key feed timing position for maximum forward feed is as follows:

When the feed dog is in the very front and rising, it is supposed to reach the top of the throat plate at the exact same time that the descending needle and vibrating presser foot also reach the top of throat plate.

If that’s not the case, you have to figure out which of these movements is out of synch and adjust that. Sometimes it’s more than one thing out of synch. Again, we need to see the movement to give meaningful advice.

 

 

Edited August 11, 2020 by Uwe

[RWL2]

Uwe, thanks for tackling this problem.  I've never made a video to upload, so it may take a little longer, but I'd appreciate your expertise after watching how my machine operates. 

I looked back at the photos I took before I disassembled the machine and noted that the feed eccentric wasn't in the same orientation when the timing marks were aligned.  I loosened the set screws for the feed eccentric and rotated the "top" set screw down to the "bottom" groove in the arm shaft and the lower set screw of the feed eccentric now rests on a round part of the shaft.  This mostly corrected the motion of the feed dog.  I used your previous video on adjusting the Juki LU-563 to adjust the location of the presser feet. I'm not sure if I have the eccentric on the upper arm shaft oriented in the best position for the timing of the presser feet, but at least the vibrating foot goes down when the needle goes down and moves the test fabric back in the correct direction at this point.  Video to come.

[RWL2]

I uploaded a video of the motion of the feed dog and presser feet.  It should be available at this link:  

When I orient the feed eccentric with both set screws in grooves and with the "bottom" set screw of the timing collar in the groove, this is the action that is produced.  The main problem to my eye is that the feed dog comes up at an angle rather than up, back and down.  The effect is that the 'fabric' is fed to the rear and then slid in reverse toward the front, leading to short stitches.  If I orient the feed eccentric so that its "top" set screw is in the bottom groove and its lower set screw is on the rounded part of the shaft, and the "lower" set screw of the timing collar is in the groove, the motion appears correct to my eye and material feeds normally.  This latter setup doesn't seem correct though - why would there be two grooves for the feed eccentric if only one of them were in a groove?  What adjustment should be made?

 

[Uwe]

thanks for that video! It looks to me like the front to back movements of both feed dog and needle are just about right. It’s the up/down movement of the feed dog that’s not right.  I’d recommend rotating the feed dog lift eccentric to have the other set screw seated inside the groove. 

 

It’s possible that both the feed lifting eccentric  and hook driving gear have the wrong set screw inside the groove on your machine.

The difference is that the hook driving gear can be adjusted to make it work correctly in either position, since you can “disconnect” the large hook driving gear from the small gear on the hook shaft by sliding them apart to rotate the hook into the correct position before re-engaging the gears.

The feed lifting eccentric on the other hand can only work correctly in one position relative to the groove on the hook driving shaft.

Remove each set screw entirely, one at a time, and inspect the tip. Make sure that the set screw that will rest inside the groove has the pointy or domed tip, the other should have a flat tip. Make sure you tighten the set screw inside the groove first, before the other one. 

The second screw on each gear with the float tip that rests on the rounded part of the shaft just adds additional holding power to the gear to make sure the main set screw inside the groove doesn’t easily wiggle loose.

Since you disassembled the shaft, you may also have inadvertently re-installed the feed lifting eccentric backwards (flipped 180 degrees around the vertical axis) which may be a problem if the eccentric isn’t symmetric relative to the groove. I’ll have to look at my machine in storage to see which way the feed lifting eccentric is oriented on my machine.

 

 

 

 

Edited August 12, 2020 by Uwe

[RWL2]

Your thought of flipping the feed lifting eccentric 180º is a good thought.  When I installed it I couldn't see a difference in how it should be oriented, but maybe it's subtle.  I'll try that.  I don't recall any of the set screws along that shaft having domed or pointed ends but I will go back and look at all of them.  

[RWL2]

I flipped the lift eccentric but there was no change in the feed.  I pulled out the set screws and more closely examined them.  There are domed and flat set screws, with one of each in the feed eccentric.  Same combination of one flat and one domed in the index collar to the right  .....But why would Consew take the time to machine two grooves in the lower arm shaft for the feed eccentric if only one set screw was supposed to be in a groove?  In my tinkering, with both set screws of the feed eccentric in grooves, I believe there was one orientation of the set screws in the index collar that led to the machine feeding in reverse without the reverse lever being pressed.  It did occur to me that it might be possible to adjust the reverse mechanism so that it fed forward but I didn't want to fool with the reverse feed mechanism because that had been untouched.

[RWL2]

Follow up.  In the end, I moved the "top" set screw of the feed eccentric, marked with the "S" to the bottom groove and left the top set screw of the index collar on the right in the groove.  The feed dog feeds normally now.

[Uwe]

Yay, I’m glad to hear you got it resolved!

[Jorge700]

Gracias 

[Pintodeluxe]

As always, Uwe offers good comprehensive help.  

Glad it all worked out.

[Kzulu]

Hello, I’m having the exact same issue of the back and forth motion never advancing to the next stitch. I bought the machine used so there’s that of “who knows what’s been done to it”. However, the first issue was needing a new belt (check), taken care of now everything’s moving. Now my issue is what this discussion is about. The only thing I’ve done is take the set screws to look at them and not switch them; ensuring that the set screw was pointed and the other screw was flat which they were in their correct spots. Also, I haven’t adjusted anything yet because I don’t know what l ready correct and what’s not. I don’t want to adjust something and not know how to reverse it.