Pfaff 191-5 timing

[mollieelle]

Hi all. I have a new to me Pfaff 191-5 in the shop that needs timing and was wondering if anyone has experience timing this machine? I cannot locate a service manual for it and am having trouble identifying the screws to free the hook to rotate. I’ve compared to post bed manuals I can find with no luck. 
 

Any help is much appreciated. 
 

[trash treasure]

Here's a link to the manual, I think, but you have to pay for it :

https://www.paypal.com/webapps/shoppingcart?mfid=1576761307702_cfa11ca903db8&flowlogging_id=cfa11ca903db8#/checkout/shoppingCart

It came from here - Lots of Pfaff manuals :

http://www.pfaffmanuals.com/Pfaff_Industrial_Manuals.htm

 

[mollieelle]

Thanks @trash treasure That is, however, the instruction or operating manual. Which does not include any information about timing the machine unfortunately. 

 

I would need what is called the service or adjustment manual. Which I have scoured for and cannot find. 

Edited December 19, 2019 by mollieelle

[Michiel]

If you cannot find an service manual

i would try it with an other brand postbed sewing machine

the adler 68 looks not verry different to me

 http://www.duerkopp-adler.com/commons/download/download-text-attachments/Vintage_Manuals_Adler/Manual_Adler_68.pdf

if that doesnot work you could use the partsmanual for your machine and for the adler to find out how it is for your machine

it might be a puzzle but if you print them all and do some close reading you can do it (for me this method works)

http://www.duerkopp-adler.com/commons/download/download-text-attachments/Vintage_Parts_Books_Adler/68.pdf

 

[mollieelle]

Thanks @Michiel That is my usual strategy as well. I’ve read the Adler 68 manual and watched a video of that machine being serviced and timed by @Uwe. I’ve also read every pfaff post bed service manual. While they are close, there seems to be a critical screw that requires loosening on my machine that I am not finding by puzzling. 

 

With the screws loose I can see to loosen from the cumulative manuals, the hook is still not free to rotate. 

Edited December 19, 2019 by mollieelle

[Constabulary]

I haven an english language Pfaff 141-5 Manual. The head part is the same as on you 191 (permanent wheel feed + roller foot), the bed section is of course different. The file size is to big to attach here so when you send me your email address by PM I can forward the PDF to you. Maybe that helps you.

You only say "that needs timing" so what particular problem do you haven or what problem is not covered in the other manuals. What screw do you mean? Please post pictures (not too small please).

[mollieelle]

@Constabulary Thanks so much. Is it an operators/instruction manual or a service manual? Unfortunately the operators/instruction manuals do not have the info I need. 

 

The hook is not meeting the needle at the correct time. The hook needs to be rotated  in the post to time it to meet the needle correctly. There are generally a set of screws that need to be loosened in order to allow the hook shaft to rotate independently. I’ve loosened the screws I know to, however, the hook shaft is not free to rotate. So I’m missing a screw or a step to free thehook shaft to rotate. 

Your machine could well be quite similar and if you had a service/adjustment manual that would be super useful  

[Constabulary]

instruction manual - no service manual, sorry!

Maybe this pictures gives you an idea - its from a 595 parts list and it should pretty much the same as on your machine I think.

[trash treasure]

If I had to do it without a manual, I think I'd loosen that large bevel gear (In the lower left view), and then you could turn the hook shaft, to adjust. But maybe I'm missing something - Probably ......

[mollieelle]

@trash treasure That's exactly what I thought would do it but no such luck. It definitely seems there's a sneaky screw or novel mechanism that im missing.

[trash treasure]

It must be just stuck to the hook shaft - The parts schematic just shows those 2 set screws ....... Unless there's a screw-under-a-screw, Singer-style.    I don't see what else could be stopping  the hook shaft from moving.

Anybody else with guidance here?

[mollieelle]

@trash treasure I too share your suspicions that the gears are indeed just stuck. They just must be   I’ve loosened every other screw I could find to try. But afraid to go prying the gears loose unless I know that for sure - though it may come to that. This machine is an odd subclass of the pfaff 191. So it does vary a bit from the general 191 schematic. 

[jimi]

Hi, I must be missing something with this machine?? is it not possible to adjust the needle bar??

[Scoutmom103]

I had a stuck bobbin case assembly.  I used PB Blaster, heat and then unwaxed dental floss to literally floss between the stuck parts to loosen the gunk that was binding the parts.  I went slowly and just kept at it over days to not harm the parts with heat or force.

Edited December 20, 2019 by Scoutmom103
The floss was used after I had removed the screws. The screw removal took a while do to the build up of hardened oil.

[trash treasure]

Maybe try some heat and penetrating oil on that gear - All the machines I buy are old and crusty, never a new one :~) , so I often need to free stuck parts, using chemicals and heat (sometimes) - I like to use Kroil (Best, but smelly), or Blue Creeper (2nd best, but less smelly), but try something like that -

For heat, if you have a heat gun, that'll work well, or even just a hair drier (I have even been known to use a micro torch at times) - The heat will soften old grease, and make the penetrating stuff penetrate better - The gear WILL come loose eventually , and you won't hurt anything.

As far as jimi's suggestion of just re-setting the needle bar - That will work, IF that was the cause of the original out-of-time problem (A driven-up, or shifted needle bar), but you can really wind up chasing your tail with this stuff, if you're not careful - The normal procedure for timing a machine is to set the needle bar FIRST (To correct spec for the needle system, etc), and THEN time the hook to it.  If you just set the needle bar to accommodate the hook timing (whatever it happens to be) .......... Well,  It wouldn't be my first choice for a solution - Just sayin'.

[mollieelle]

Thanks so much @trash treasure and @Scoutmom103  I’ll work today to de grease those gears and free them. Probably a good thing to do anyway. 

Ive read the service manual for the 591, the 191s contemporary counterpart carefully and I am positive the hook itself is not timed correctly according to the timing requirements of the machine.

@jimi Unfortunately adjusting the needle bar alone is not enough to remedy the situation. The hook and needle bar each have timing requirements they have to meet. Changing the needle bar to meet the hooks out of time position is not fixing this timing issue. The needle bar needs to be at a specific place in its path (2mm from bdc in this case) to have time to form a loop that the hook can catch properly. I can change the height of the needle bar to meet the hook, however, the hook then meets the needle a hair after bdc (bottom dead center) which does not give it time to form a loop. The hook then barely catches the loop sometimes, slices and splits the thread sometimes because the loop is tiny and too tight to catch, or misses it altogether sometimes. 

[CowboyBob]

On most Pfaff's & I'm sure this one is the same way you loosen the screws on the smaller gear,the screws on the large gear go into a slot on the shaft,so re-tighten the large gear screws ,loosen the small ones & if it's stuck,very carefully put a screwdriver under the hook to hold it from turning & turn the handwheel & it should break free.

[mollieelle]

Thanks so much @CowboyBob I'm cleaning them up and will give that a go. To make sure I'm after the right thing - below is a photo. The smaller vertical gear is connected to my hook shaft. When the screws are loosened on that gear the hook shaft should rotate freely without turning that small gear - correct? So that should really be the only gear I need to loosen to free the shaft to rotate independently?

[mollieelle]

I got it!! That did it. Some fishing line, pb blaster, cleaning, and loosening the small gear only. I can properly time my machine now. Thanks for the early Christmas present all. Wohooo!

[CowboyBob]

Great, I'm glad to hear you got it loose.

[trash treasure]

I'm glad that someone who actually knew what they were talking about (Bob), finally chimed in :~)