Pfaff 335 h3 doesn't sew properly

[Gia]

Hello!

I am new to leather working, and this is my first sewing machine. I have an old Pfaff 335 h3, with which I sewed perfectly for a while - the tension and the stitch were flawless. Suddenly  it started to punch holes in the leather without making any stitches or just making them from time to time.
My question is: why this happened and what should I do to make it work again? 
Any help will be much appreciated. 

I am attaching a video and a photo for a better understanding. Thank you in advance!

Gia

https://imgur.com/DHCHz5T

[Constabulary]

Often the problem is just an not correctly adjusted needle bar but hard to tell from the distance. First thing I would do is checking the correct threading and the needle hook timing. Are you sure the needle is insert correctly and using the correct needle system? I guess you have a manual for your machine, right?

[jimi]

Hi and welcome, did you change anything or did it just start to not sew??

[Constabulary]

Since I see a white machine I guess it is the current 335 model. Here is a service manual for the current 335 model. It should help you with the settings:

 

Pfaff 335 Service manual.pdf

Edited July 6, 2020 by Constabulary

[Constabulary]

settings should be the same I think. Are you sure you interst the needle correctly?

Edited July 6, 2020 by Constabulary

[Gia]

49 minutes ago, Constabulary said:

Often the problem is just an not correctly adjusted needle bar but hard to tell from the distance. First thing I would do is checking the correct threading and the needle hook timing. Are you sure the needle is insert correctly and using the correct needle system? I guess you have a manual for your machine, right?

Everything is done right, it worked perfectly until yesterday. 
I use these needles https://imgur.com/4YbcAnU with 20/3 thread. Sometimes it does a couple of stitches, and then none. 
 

6 minutes ago, Constabulary said:

Since I see a white machine I guess it is the current 335 model. Here is a service manual for the current 335 model. It should help you with the settings:

 

 

Pfaff 335 Service manual.pdf

It is the old model, from the 60s I guess. It was painted for a better look.

Edited July 6, 2020 by Gia

[Gia]

55 minutes ago, jimi said:

Hi and welcome, did you change anything or did it just start to not sew??

I didn't change anything, it just started to not sew. 

[Gia]

10 minutes ago, Constabulary said:

settings should be the same I think. Are you sure you interst the needle correctly?

Yes, it is inserted correctly. I did sew a lot without any problems before this happened.

[Gia]

Is there any change to give me any guides to check if the timing works properly?

[Constabulary]

Sometimes needle bar rise a little bit so w/o sitting in front of the machine I would guess you have to lower the NB a little bit. As I said before I would check the needle hook timing. Procedure is in the manual I have liked above.

Edited July 6, 2020 by Constabulary

[Gia]

I did another try and this is how the stitching looks like. 
Seems to be a problem with hook but I don't guess which.

 

 

Edited July 6, 2020 by Northmount
replaced 3rd party links with the pictures

[Constabulary]

that looks like a tension problem - Which picture is top and which is bottom side? I guess the flesh (rough) side is the top side right?

[Gia]

7 minutes ago, Constabulary said:

that looks like a tension problem - Which picture is top and which is bottom side? I guess the flesh (rough) side is the top side right?

The rough side is the bottom side. It sews nice on top and it tangled the thread on the bottom.

Update: the hook timing seems to be perfect.. the hook meets the needle about 1.8mm after it starts rising. Here is a video with the timing:

 

[jimi]

can you send a picture of the thread path from the start to finish?

[Gia]

7 hours ago, jimi said:

can you send a picture of the thread path from the start to finish?

Threaded like in the manual:
 

 

Edited July 6, 2020 by Northmount
replaced 3rd party links with the pictures

[jimi]

I would pull out the thread and start again, if it is still the same then start to increase the top tension little by little? The only thing i can think of just now is the top tension is too slack??

[Gia]

13 minutes ago, jimi said:

I would pull out the thread and start again, if it is still the same then start to increase the top tension little by little? The only thing i can think of just now is the top tension is too slack??

I did that already, and nothing happened..

I notice that sometimes the thread got stuck between the tension discs. 

[jimi]

Is the tension release pin working when you lift the foot up? If the thread is sticking then take off the disks and see what is causing it to stick?

Edited July 6, 2020 by jimi

[jimi]

In your picture the thread is not going through the first pin? it looks to be going around the outside, (see picture) also it looks like you have little tension compared to my machines??(see picture)

can you send a picture of your tension unit from the side also?

Edited July 6, 2020 by jimi

[Gia]

5 hours ago, jimi said:

In your picture the thread is not going through the first pin? it looks to be going around the outside, (see picture) also it looks like you have little tension compared to my machines??(see picture)

can you send a picture of your tension unit from the side also?

I took off the tension but I can tell why the thread gets stuck..

The machine is threaded just like yours, as you can see:
 

 

 

 

Edited July 6, 2020 by Northmount
replaced 3rd party links with the pictures

[jimi]

I think the parts were maybe changed or this is not a pfaff tension assembly, anyway the first post where the thread passes on the assembly is not the same? you have the thread outside on the pin instead of inside the small ring?? See 1st red arrow in the pictures.

[Gia]

4 hours ago, jimi said:

I think the parts were maybe changed or this is not a pfaff tension assembly, anyway the first post where the thread passes on the assembly is not the same? you have the thread outside on the pin instead of inside the small ring?? See 1st red arrow in the pictures.

here is a better picture:
 

I did the threading following its manual.

[Pintodeluxe]

It doesn't look like the thread is snapped behind the pre-tension disc before the main tension discs.  

Additionally, if you need more upper tension you can thread right to left through both holes leading up to the pre-tensioner disc.   

[Gia]

7 minutes ago, Pintodeluxe said:

It doesn't look like the thread is snapped behind the pre-tension disc before the main tension discs.  

Additionally, if you need more upper tension you can thread right to left through both holes leading up to the pre-tensioner disc.   

I'll try, thanks.

My main problem was that the machine doesn't stitch at all or when it does, it looks like in the pictures. 
Given the fact that the timing is perfect, could the tension be the reason why it punches the leather without making any loops?

[Pintodeluxe]

If the thread was forced into the wrong slot, and not really threaded correctly, it would certainly cause problems.  You were right to suspect timing issues.  That's the first thing I'd check if it wasn't forming stitches at all.  If it's leaving loops on the bottom, you need more upper tension.  Assuming the bobbin tension is okay, try rethreading it, and make sure the thread snaps in the pre-tension disc.  With Pfaff's you can actually hear it snap into the disc. 

 

If you're out of tension disc adjustments, then look to add more passive upper tension IE: go through both guide holes before the pre-tension disc (threaded right-to-left on both holes).  

Good luck with it.