Help! Skipped stitches

[robert2891]

Hi all, and thanks in advance for any help with this.

For about a week now, I've been getting skipped / missed stitches . 

I'm sewing leather on a consew 206rb walking foot. 

I've rethreaded, changed bobbins, and changed needles. It happens regardless of whether using ball point or cutting needles. I've got the correct needle size for the thread (100nm and 69t thread - I've tried 110 and 120nm too).

What else could it be? Its killing me on productivity (and cost of leather) :-(

[RockyAussie]

1. is it just the same leather and or job application? Sometimes I have run in to a leather or a particular job section where this might happen like turning a corner. 2. Would it help to increase your foot pressure a bit?  There are a lot of reasons as well which may include a dulled off hook or slightly out of timing. I'd try a little more foot pressure first then also if it happens mostly in the one area of a job see if your needle is being deflected to the left a bit. If it is alter how you hold it or go for a bigger needle perhaps. If it happens just anywhere then check you timing and be sure the loop is well formed when the hook is getting to come through it. Does your tensions stay constant when stitching or is there a tendency for the tension to come high when it misses? Brian

[robert2891]

Thanks Brian, I'll try and replicate it while hand turning to see if there's more tension over the missed stitches. It does it when just going in a straight line. What do u mean by more foot pressure?

Also, its all leathers, 1.4mm - 2.8mm

[robert2891]

Hi Brian,

so I took off the plate and checked the timing and indeed it's out-  in fact, I don't think that so much the timing is out as the needle is in too far. I'm missing the screw for the thread guide and I believe that is resulting in the needle going to high in the needle bar thus having the effect of the needle coming up to soon on the hook and hitting. When I drop the needle to the height it would be if there was a screw through the needle bar, it's perfect. However, I can't for the life of me find a parts manual for a consew 206rb-2 - anyone any ideas? (will it be the same screw parts as the 206rb-5?)

Thanks Again

[ljk]

Hi Brian   I've had over 25 206-rb, the Japanese,Chinese and Taiwanese.  All worked well and never had to mess with hook other

sliding for and aft to match correct distance to needle.  I've fixed many for friends and associates, all because of hacking including

dealers.  Your on the right track with needle bar timing.  On thick material the thread tension may start to release causing

multiple problems.  There is a fix for that, by dimpling the tension washer.

 

These machines are metric and the hardware store probably  has a screw that works.  I know somebody who used

one of these machine daily for 25yrs. and never oiled it.  Still working today (it gets oiled know.)                    tx Lynn

 

[robert2891]

Thanks Lynn - can you explain what you mean by thread tension start to release and what dimpling the tension washer is. This is my first machine and only been sewing for 2 months, so still very much wet behind the ears.

[RockyAussie]

5 hours ago, robert2891 said:

Hi Brian,

so I took off the plate and checked the timing and indeed it's out-  in fact, I don't think that so much the timing is out as the needle is in too far. I'm missing the screw for the thread guide and I believe that is resulting in the needle going to high in the needle bar thus having the effect of the needle coming up to soon on the hook and hitting. When I drop the needle to the height it would be if there was a screw through the needle bar, it's perfect. However, I can't for the life of me find a parts manual for a consew 206rb-2 - anyone any ideas? (will it be the same screw parts as the 206rb-5?)

Thanks Again

Hi Robert, I had a quick google check and found this manual. You can see all the pages on line --https://www.manualslib.com/manual/1226154/Consew-206rb-5.html

I have a lot of different machines but not that one sorry. I would study the hell out of it particullarly with regards to the timing. Take some pictures of any parts you have trouble with and post them on here. That will often give the best feedback. Brian

[ljk]

There is a black washer just behind the conical tension spring it goes over the post, than the spring

and than the nut you turn to change tension.  The center cross bar on the washer can be dimpled

slightly outward.  This means more travel for the tension release rod and keep proper thread

tension on thick material.  If your knee lift is properly adjusted you will get thread release

at full travel.  I dimple with small screw driver a hammer on a soft piece of wood.  My

favorite machine, although I have a Nacajima 280L that will lift higher, sew longer stitches.

and use 277top  and 207bobbin thread.   tx Lynn

[robert2891]

Thanks Lynn & Brian. Regarding the manual, I did find that one, but wasn't sure if the parts would be the same as my 206-RB-2. In fact, I don't think all the parts are the same as I just ordered needle bar screws from that manual and they are the wrong fit.

Regarding the problem I had, it is now resolved - although I think I need to tinker with the tension as Lynn said as I do stitch some very heavy sections and can never get it right.

The problem was in the timing. I adjusted the needle bar until the hook stroke was lined up, but then found that the needle was hitting the bobbin case, so I rotated the hook assembly instead and it was way out. I've run a load of test pieces and no missed stitches, so perfect

Thanks for your help, 

Rob