Large bobbin (0f 5XX series) in Pfaff 145

[Pterytus]

Hi!

I plan to perform a heart transplant!
(had to say that, sounded too good ;-)

Well, it's the large shuttle of a Pfaff 541 which I want to put into my Pfaff 145 - and vice versa to be able to use the large bobbin of the 5XX series in the 145.
To make this possible I have to move (or replace) the lhs hook driving shaft bushing of both machines.
On the 145, I have to move it approx. 5mm to the right (away from shuttle) to be able to mount the larger shuttle carrier of the 541.

Now, I don't know how to do that "correctly". I have already loosened the set screw from below, but I don't seem to be able to move the bushing itself and I don't want to use excessive force on the bushing, which might be the wrong approach...

Does anyone know how the bushing is secured in the bedplate or how it can be (re)moved?

Thanx in advance,
cheers, Pete...

[chrisash]

Would you not need to change the gearing driving the hook to make allowance for the larger bobbin? 

[mikesc]

Is it possible that the bushing cannot be moved along the shaft to the right ? The screw may be merely to stop rotation of the bushing around the shaft ?
There is a better diagram than the one you posted available here
https://www.universalsewing.com/tek9.asp?pg=parts_pfaff
Scroll down to get to 145 and subclass.
In the pdf at page 21 ( diagram 11.80 ) the shaft sis shown with a "step" at the extreme left end..it may be that this "step" buts up against a corresponding "lip" inside the bushing? If so that would prevent any movement to the right..If that is the case ? you'd have to remove the bushing in a leftward direction, and then "machine" the shaft , so that the "step" was further to the right.The bushing itself may well have been heat set onto the shaft despite the presence of the "grubscrew / set screw" below and whatever that is ( oiling point ? ) above the shaft in the diagram 11.8.

Then again I could be entirely wrong, but if not it might explain why you cannot move it ( the bushing ) to the right ( along the shaft ) .

Note..that pdf file also shows the 545, and the bushing is the same as the 145, but the shaft that it sits on is not the same at the left hand end, maybe the 541 shaft is also different ?

Edited August 18, 2019 by mikesc

[Pterytus]

Thank you for your thoughts.

@chrisash

You do not need to change the gearing RATIO, because it is still two hook revolutions per stitch. The gears just have to be moved. But in my case I have to replace the drive shafts (shorter on 5XX series) and I also plan to change the gears as a pair although they seem to be the same on both my machines.

But all of that is not the problem and easily done, so I did not mention all necessary parts to change in detail, although you are right: It's more than just the bushings.

 

@mikesc

It is possible that I have to remove both bushings to the left completely first and exchange them along with shuttle carriers, shafts and gears (fortunately the bedplate measurements are the same in that area) - which would make machining unnecessary.

And that is exactly the question: Does the "oiling pipe" from above prevent the movement and/or is the bushing "just" heat set into the bedplate. All that is hard to tell from just looking at the parts... So I was hoping that someone had already removed those bushings of their machines at some point and could enlighten me with a nondestructive procedure to do so on my machines ;-)

Cheers, Pete...

[mikesc]

The only person who I can think of here who has done a lot of work on Pfaff ( besides Eric "gottaknow", who has not been around here for a long while now* ) is Uwe.

*I hope Eric is OK

Is that "oiling pipe" "slotted" at the end away from the shaft ?..I can't tell from the diagram. If it was, one would think that it would be removable ( and thus might be acting as a secondary "grub screw" albeit not intentionally, as being brass ( presuming it is brass, as most are ) it would be too prone to damage.

[Pterytus]

Ok, so I have this Pfaff 143, which was ridiculously cheap and out of tune but came barely worn and with some parts missing or in worse condition on my 145 and 541, so it became my "bad-part-accumulator-machine". It's still in working condition but it's, well, just a 143, what else can I say ...

... which makes it a perfect lab rat. First I tried to "pull" out the oil pipe from the top of the bed plate - which was not possible without much force so I left it there hoping it doesn't lock the bushing. Then I removed the grease housing and large bevel gear on the hook driving shaft which would otherwise prevent the bushing from being moved to the left and heated up the bushing and bedplate in that area to a point where I could barely touch them. I then used a hammer on the bushing from the right with still reasonable but real force which - Ta-Dah! - forced the bushing bit by bit to the left.

So much for the experiment. I hammered it back in place, replaced all parts and adjusted the hook so that the machine works again - no harm done.

But now I know how to remove the bushings.

I just have to decide whether I really want to perform that kind of blunt treatment on my machines or if I can live whith the smaller bobbin in my 145, but at least I now know that and how it can be done.

So thanks for your input which helped and encouraged me to try and learn a little more about the machines.

 

Cheers, Pete...

[CowboyBob]

To change it you need to get a hook saddle on the145 part # 91-010059-45,both gears ,bobbincase opener & take-up for the larger bobbin machine for this swap to work.Moving the bushing is the easiest part.

[Pterytus]

You are right, those parts are needed. Fortunately I do have a complete 5XX series machine (541) with all those parts and could "just" swap them while still keeping the 541 operational afterwards (with a smaller bobbin). Most of those parts however are bolted on and can be removed, replaced and adjusted using a screwdriver that's why dismounting/moving the bushing was incalculable for me at first.

 

Cheers, Pete...