Pfaff 138 Hook Adjustment

[TNcycling]

I have a Pfaff 138 sewing machine.   The hook is way out of adjustment.   I have been unable to find any service manuals for the pfaff 138 machine.  How do I adjust the hook?

[Tigweldor]

Are you sure that you are using needle 130/705 h and that the needle is fully inserted to its´stop in the needle bar ?

Pfaff recommends using a 110 needle in the 138 when making adjustments.

On the 138 you have to raise the needle bar 2mm from lowest point of needle travel when setting hook timing.

 

Here is a free copy of the user manual : https://manualsnet.com/pfaff/138

 

attached below is the service manual for the 138

 

Greetings

Hans

BA Pfaff 138.pdf

Edited May 3 by Tigweldor

[TNcycling]

Thank you Hans,

The hook is almost 180 degrees out of phase.  I loosened the 2 screws that are in the video, but I cannot turn the hook.  I think that it is stuck.  The bight control knob that controls the width of the stitch is very hard to turn.   The knob has a set screw, but I cannot loosen it because it is also stuck.  The widest setting on Pfaff 138 is 6 mm compared to 4 mm on the Pfaff 30.   I assume that 6 is the proper setting to adjust the hook.

Thank you, Doug.

[Tigweldor]

Sounds like your 138 has sat for a long time and is crying out for oil.

Unscrew the round knob for stitch length adjustment and oil everything - open the lid right above the adjustment knob and also oil every moving part from the top.

Actually, flood the whole machine with oil and keep working all moving parts until it operates and runs smoothly.

The 138 also does not have a timing belt - it is gear driven.

Now these gears are housed inside an upper and a lower plastic encasement - remove those housings, clean them and repack with good grease - the old stuff often resembles clay.

If a screw is stuck, insert a good and tight fitting screw driver into the head slot and hit the handle of the screw driver with a hammer/mallet to free the threads - a manual impact driver is sometimes necessary on really stuck candidates.

Soak stuck hook with penetrating oil or rust remover - throw the WD40 as far from you as you can - it is NOT a good solution for stuck threads or stuck anythings - in my eyes it is one of the most useless "wonder solutions" out there - a complete waste of cash.

Now Ballistol on the other hand, does work - many a gun owner has it in his arsenal.

Jup - 6mm is right.  The ZigZag setting knob also adjusts needle position placement (left, center, right) - you have to assure that the hook can grab the loop in all 3 settings. Be gentle with that big plastic knob - it becomes brittle with age - if you break it, replacement is expensive as well as rare.

 

Do NOT force things - take your time - haste often produces costly mistakes - avoid such.

Greetings

Hans

Edited May 4 by Tigweldor

[nejcek74]

Frozen zig zag knob is a known problem on this type of machines, here is a video of solving the problem with Pfaff 130.

Search this forum for Pfaff 138, there are already posts discussing various problems, including the one with ZZ know:

 

[TNcycling]

I have an original instruction book.   I also have a spare parts catalogue.   I don't a service manual.  The link to the service manual does not work.  It has sat for a long time.  It is a Pfaff 138-6/21-BS.   The SN is 139887.  I was able to loosen the screws and turn the hook and adjust it.  I first tested it by hand manually.  Then I tried the motor.  It makes a beautiful zigzag.  It is also extremely fast.  The video that nejcek74 provided describes the problem.  The bight control knob is loose.    I was able to free the bight set screw.  The knob partially backs off the shaft, but it is still stuck on the shaft.   The shaft is frozen as described in the video.   I will try to get anti-seize lubricants as Hans suggested and proceed as he suggested along with the description in the video.

 

[nejcek74]

i can download the "BA Pfaff 138-1" than Hans has attached. I guess some kind of safety check is preventing it for you.

Otherwise it is this one:

https://issuu.com/davidmannock/docs/pfaff_138_adjust_manual

 

[TNcycling]

Thank you.   Yes, it must have been a safety check.   

[Tigweldor]

Here is a review of the 138-6/21BS  - some good info.

https://www.ashleyandthenoisemakers.com/blog/2015/3/7/pfaff-138-review-1

 

Greetings

Hans

Who has both colour machines - and loves them for any fabric and vinyls and tarps -- just not the most favorite for leather  - I prefer a compound or walking foot for that.

[Tigweldor]

One more tip that I can give any Pfaff owner - buy yourself a GOOD 1/4 inch drive metric socket set.

With the better ones, each bit has its´own socket - the screw driver bits are sharp and short - the most important thing.

When removing needle plate screws - I want a real shorty - 1/4 inch bit with a stub handle - that´s all you need on a sewing machine.

Hand tight is enough for most screws.

I tapped the 2 on the bed for the edge guide to M4 and used short allenheads - beats the stock knurled "hour glass" style screws

Another tip - to keep the table uncluttered - buy some magnets.

On the 138, get rid of the stock spool holders - get a decent thread stand - and put a big magnet on the flat metal lid - it´ll stay  there all by itself.

Bobbins, scissors and other tools stay put on magnets and you know exactly where they are - should you need them.   That goes for every sewing machine.

Nother advantage - your screwdriver is always fully magnetized when you take it from the magnet - on some small screws that is downright handy.

 

Greetings

Hans