Pfaff 145 H3 Maximum Thread Size?

[MurraySmith]

Hi There

I need to see if I'm trying to do the impossible, and could use some help.

My wife's 145 H3 is has a BSN configuration: medium weight fabric materials.  I would like to sew heavy leather (5-6 oz) on it using #207 thread, and it's not going well.  The machine will pierce the leather reasonably well (especially after I've added a servo motor), but the machine won't pull the top thread up consistently.  I've played with the tensions to no avail.  It will work for a few stitches, but eventually a loop will stay under the feed dog and jam.  I've had to re-time it a dozen times as it will just slip the .  I'm thinking the thread is too large to fit in the space between the needle plate and the rotary hook "keeper" that goes into the slot on the plate.

Now, looking at the parts manual, I can see there are differences between the fabric and leather models beyond torque, so perhaps I'm trying to fit a square peg in a round hole.  I know the rotary hook is different and, the flywheel too.

Any suggestions?  Can I make this machine work as is?  Should I find the parts to convert it to a leather machine?  Or just sell this machine as is and start again?

Thanks

Murray

 

 

 

 

[chrisash]

Use 138 thread on the bobbin, what size needle are you using

[MurraySmith]

Thanks Chris

We're using a 134-35 size 24 needle.  We started trying to sew with 277 thread, then 207, then 138.  The 138 worked best, but still had jams.  Perhaps I need to put in a smaller needle with the 138?

 

[shoepatcher]

Will not sew anything bigger than #207 on top only.  The smallest needle you can use with #138 thread is #22/140.   I prefer to use #23 or #24 with #138 thread depending on what I am sewing,.  The machine is jamming -  could be timing, bobbin case opener set wrong or the slot on the underside of the the throat plate that the finger from the bobbin case may not be deep enough to give you the proper clearance for the thread to clear it as it goes around the hook. If that is the case, the slot on the throat plate has to be made deeper to accommodate the #138 thread.  I have deepen that slot on a few machines!!

glenn

[MurraySmith]

Thanks Glenn.  What I'm hearing is that it is possible to get this machine to work. 

How do I time the bobbin case opener?  I know that it is adjusted by the screw at the 4 o'clock position relative to the bobbin, but I don't know when it should be "opening". 

I will open up the throat plate slot and see how that works.

 

Murray

 

[shoepatcher]

I time the bobbin case opener by hand.  Remove the right slide plate. With machine threaded, turn balance wheel towards you while watching the hook pick up the the needle thread.  Follow it as goes from 9:00 o'clock where it pick up thread to 12:00 o'clock. when it gets to about 5:00 0'clock should release from hook and be very close to bobbin case opener.  Loosen adjustment for bobbin case opener and move it so thread just goes past the opening at the opener.  Tighten adjustment.   Turn balance wheel again and watch the thread as it nears bobbin case opener. Should clear it without being held up.  If it does, great.  If not, redo this procedure again by hand until your adjustment is good.  Now turn machine on, hold the needle and bobbin thread in your hand and sew a few stitches.  Should be good to go.

glenn

[MurraySmith]

Glenn:

Thank you very much for your help.  The machine is getting closer and closer to working for me.  Using a smaller needle and having a deeper slot on the throat plate has done a lot.

Now I'm just working on reducing the speed, and will hopefully be able to get a "standard" speed reducer somewhere, otherwise I need to build one.

Murray