Techsew 441

[Silverd]

Hi All,

 

I have a two year old Techsew 441 that periodically will make a cluncking noise, skip a stitch then break off the needle.  Typically this is when sewing thick leather,  10oz or so but has also done it on lesser material.  I understand it has to do with how the needle path into the hook zone is influenced by the material but the problem appears to be getting worse not better.  A recent project resulted in 8 or 10 broken needles and remaking of several components.  Ive checked the timing using the Uwe system and it's spot on. I have renewed the hook assembly but have not made any lateral adjustmentso or shimming.

Is anyone familiar with this behavior and its causality?

 

Silverd

[Wizcrafts]

Make sure you have sufficient foot pressure to fully hold down the leather as you sew. If it is too loose the leather can lift with the needle and cause problems like skipped stitches and bent needles.

Take the cover off the end and handwheel slowly, watching the needle and hook for actual contact. The hook should just miss the scarf in the needle on the upstroke. If the needle touches the hook, the needle bar needs to be checked for looseness at the top and re-positioned, then tightened in place. There's a tapered pin holding the needle bar in place and set screw on top the locks down the lateral position of the needle bar pin.

How often do you remove the faceplate and oil every crank and oil hole in the left end of the head? While you're doing that, check all set screws for tightness. Raise and lower the feet with the hand lifter to ensure that there is no binding or excess slack.

If these simple things don't make any difference, contact Ron at Techsew. Make a video, with audio, to show what is happening.

[kgg]

Which model of Techsew? I can't seem to find any reference to a Techsew 441.

kgg

[Wizcrafts]

9 hours ago, kgg said:

Which model of Techsew? I can't seem to find any reference to a Techsew 441.

kgg

A 441 machine is a general description of a clone of a Juki TSC-441. In this case, the current Techsew 441 clones are the models 4100 and 5100. The OP may have forgotten the model number, or the machine is in a different location than his home at the time this was posted. My machines live in a shop that I am not in when I do my posting on this forum (too busy sewing).

[RockyAussie]

Another thing may be worth a check is that the 2 screws with springs that hold the shuttle race body are not screwed in all the way or too far. The springs should be just showing visible and the shuttle can be pulled in and out a little by hand. Also check that the bobbin is unwinding smoothly and not catching intermittently.

[Silverd]

Great advise.

Techsew model 5100

Presser foot presser does not appear to be a causality.  I keep it as light as possible but normally dont allow the work to lift.

There is a gap between the needle and hookI as you describe.  But I have not measured the gap.  Machine normally sews well.

I'll check set screw tightness and hand lever presser foot lift mechanism as suggested.

Two shoulder  screws with springs that retain the hook shuttle into the casting are tight.  I can loosen them a bit.  That said.  The shuttle assy does not freely translate in the arm casting at least on this machine. You are suggesting is not normal?  I'll work on this to free it up.  

Bobbin appears to operate normally.  Thread pulls evenly.

 

Many thanks.  I'll follow up a little later.

 

Siverd 

 

 

 

 

[DrmCa]

Does it correlate at all with the wear on the needle? I.e. does a new sharp needle work better than an older dull needle?

[Silverd]

No.  I've never put so many new needles in a machine!  

I'm thinking the work piece is a contributing culprit since the machine will sew perfectly on another piece of leather immediately before and after a breakage.

Silverd

[RockyAussie]

5 hours ago, Silverd said:

Two shoulder  screws with springs that retain the hook shuttle into the casting are tight.  I can loosen them a bit.  That said.  The shuttle assy does not freely translate in the arm casting at least on this machine. You are suggesting is not normal?  I'll work on this to free it up. 

For the screw tightness check this Solar Leather link                         

 

[Silverd]

Hey

 

Great video!  Typically,  shoulder screws like the ones with the springs holding the hook assembly in place are designed with sufficient shoulder length such that they can be fully seated.  Not the case here apparently as you have pointed out.  Definitely I'll loosen mine as they are installed tight.  

 

Thank you

 

Silverd

[RockyAussie]

Another thing that may be causing the problem is if you are hitting different layers while sewing close to the edge in which case have a read in this post I did awhile ago. 

They sold in Australia here some time back some Q stitch machines (Colt and Stallion if my memory is correct) and they came with only the slotted needle plate with no actively working dog foot. I recently did  put on a servo motor on one of these for a saddler friend and noticed that they still had a dog foot under the slotted plate and that,that served to act as a sort of needle guide. If you had a spare dog foot you could grind it down to suit. I did find that it was quite reliable in the stitching and the only reason I mention this is the slotted needle plate gives a better support under the feet than when using the standard dog foot needle plate as shown in my post above. Other than that if you can track down the same feed dog and needle plate I did, I think you will be more than happy.

[Silverd]

Rocky 

Without exception,  my problem is stitching multiple layers close to edge applications. Halters and Bridle work or the like.   I think reducing the standard feed dog needle hole width as you suggest may be a really good way to ensure the needle is correctly aligned with the hook when it exits the material.  If the needle deflects one way or the other in its travel thru the work,  a narrow slot in the feed dog would prevent the needle from entering the hook zone out of position. If the slot in the feed dog were chanfered, it might correct the situation good enough to make a stitch without allowing a needle / hook collision.  Or it would stop the needle travel altogether...which is better done by the dog than the hook.

I'm now wondering why narrow slotted dogs are not already offered. It would allow maintaining the compound feed feature of the 441 which is valuable. But   is there a down side to this idea?  

Ill post photos of what I come up with to this end.  

 

Silverd

[DrmCa]

What size needle and thread are you using, by the way?

[RockyAussie]

3 hours ago, Silverd said:

But   is there a down side to this idea?  

Ill post photos of what I come up with to this end

I have not found ANY yet except that perhaps the sellers hope to be able to sell other machines that this one has trouble doing in its (present)standard form. I look forward to seeing any improvements you come up with.

[Silverd]

17 hours ago, DrmCa said:

What size needle and thread are you using, by the way?

They range from 22 to 25 size mostly.  

Silverd

[Silverd]

On 6/18/2019 at 2:36 AM, RockyAussie said:

Another thing that may be causing the problem is if you are hitting different layers while sewing close to the edge in which case have a read in this post I did awhile ago. 

They sold in Australia here some time back some Q stitch machines (Colt and Stallion if my memory is correct) and they came with only the slotted needle plate with no actively working dog foot. I recently did  put on a servo motor on one of these for a saddler friend and noticed that they still had a dog foot under the slotted plate and that,that served to act as a sort of needle guide. If you had a spare dog foot you could grind it down to suit. I did find that it was quite reliable in the stitching and the only reason I mention this is the slotted needle plate gives a better support under the feet than when using the standard dog foot needle plate as shown in my post above. Other than that if you can track down the same feed dog and needle plate I did, I think you will be more than happy.

Loosened the shoulder screws with springs as you suggested and lubricated the entire head workings,  checked all hardware for tightness and reset bobin pull out tension using the 16 fluid Oz method.  Reassembled and finished a few multilayer stirrup leathers without incident.  I noticed the shuttle plate moves around as the shuttle occilates.  This could have been the root cause but it's a little early to tell and sewing buckles onto stirrup leather is quite stable compared with sewing a padded halter together.  

I also ordered three feed dogs from Bob Kovar and a flat / narrow slot needle plate.  That's the only plate I didnt have for this machine!  I work in the machine tool industry and can have the modifications made to the feed dogs as I described done.  Photos to follow.

Thanks for your help.  Everything you have told me makes good sense.

Silverd