Consew RB-5 skipping stitches

[Brandedtack]

I recently purchased a new Consew RB-5 and have been pleased with it, however, recently I have had trouble with it skipping stitches. I was sewing leather with it with 207 bonded thread and a #23 needle. I have even switched to 138 with a 22 needle and it still skips stitches. I have included a photo of the leather I was using before it started acting up. I am certain that it is threaded properly.

Also, I wound bobbins today to try the smaller thread (obviously running at a higher speed) and after completing that, I attempted to sew and a small screw (pictured) fell off of the machine from somewhere and landed in the front of the machine. I can't figure out where it came from. It is very small and doesn't appear to have come off the exterior of the machine. Any help would be greatly appreciated.

Edited April 24, 2020 by Brandedtack
Add additional photo

[Constabulary]

the small screw could be from the tension unit but maybe too long... or it is from a presser foot but not sure though .

reg. skipping stitches - check the needle / hook timing , it often happens that the needle bar rises a little bit and the hook is not catching the thread loop. Adjustment values and procedure are all in the manual - guess you have one, right? If no you can download it here:

206RB-5 Instruction Manual - Consew

Edited April 24, 2020 by Constabulary

[ensitmike]

In addition to timing, check the hook spacing. If your machine wasn't setup for such large needles, chances are that spacing is completely off.

[Brandedtack]

Thank you Constabulary. That is exactly where that screw belonged.

 

[Pintodeluxe]

I wouldn't expect that machine to sew with 207 thread without modifications.  

138 would be the max thread size I would use.

I agree to check hook timing and spacing.  As a quick check, switch to 92 thread and a #19 or #20 needle.  This is a very common thread and needle choice for upholstery grade machines.  See if everything sews okay in a variety of situations with the lighter thread.  This will help you sort out thread and needle issues versus machine issues.  

[Brandedtack]

OK, I have switched needles and thread and continue to have the same problem. The hook timing and spacing is correct. Now I'm having trouble with it picking up the bobbin thread entirely. It works when I thread it but not when I sew. Can the thread tension effect this? If so, where would you set it to start? Everything else seems to be set correctly, but I'm obviously not setting something right. Right now I have a 22 needle and #138 thread and have tried sewing very thin leather as well as jean material...no luck.

 

[Pintodeluxe]

Ok, go back to basics.  Switch back to 90 weight thread and a #19 needle.  Work on your tension settings starting with the bobbin tension.  Set it for very light tension, with just a little resistance.  Thread should feed easily and consistently from the bobbin case.

Then adjust your top tension to match.  Make a small change like a 1/4 turn, and retest.  

If it won't even sew a row of stitches by hand, it will be impossible to set the tension, and points you back to re-checking the hook timing with a fine toothed comb.  

I hope you find success with your machine and find it quickly.  

Can you post a picture of your tension assembly with the machine threaded?

Thanks

Edited April 29, 2020 by Pintodeluxe