Walking foot - feed dogs marking leather

[jakc3]

Hello,

I have a question regarding feed dogs marking leather.

I have a Pfaff 335 sewing machine with walking foot feed. On softer leather the feet marked it as well but I solved that by gluing thin leather on the bottom of the feet. 

I still have issues with the bottom feed dog marking the leather. It's smooth, without teeth and it moves only horizontally (maybe just a little bit vertically but it is a negligible amount - 0.05mm). What it does is it leaves a line, which can't be rubbed off, on the bottom side of the leather.  First I thought this is because the plate covering it was slightly higher than the feed dog so I sanded it down to the same height. This however didn't solve the issue.

Are there any solutions/workarounds to this?

Many thanks,

Jakob

[Uwe]

Try lowering your presser foot pressure. Many people have the foot pressure set much too high for what they're sewing. Many people don't even know how to change that setting (perhaps because the manual does not talk about it!) Dial back the screw on top of the head to the least amount of pressure that keeps the material from moving when it shouldn't.

Support the material with your hands as you sew so the machine needs just a little bit of force to move the material. Don't push or pull on the material, let the machine do the feeding. 

[Uwe]

So it turns out I don't know how to lower the foot pressure on a Pfaff 335 either! I removed the foot pressure adjustment screw on my Pfaff 145 and it made almost no difference at all in how strong the feet press down. This needs further investigation . . .  

[JerseyFirefighter]

 

So it turns out I don't know how to lower the foot pressure on a Pfaff 335 either! I removed the foot pressure adjustment screw on my Pfaff 145 and it made almost no difference at all in how strong the feet press down. This needs further investigation . . .  

I've never had any success with backing off the presser foot pressure on my ferdco either. One of those minor annoyances I have come to accept in life. Still curious on further insight. 

[dikman]

It was pointed out to me that the pressure screw was missing on my 335 when I posted pics here, so I found something that would fit to replace it. Funnily enough, it didn't seem to make any difference to foot pressure, so I figured I needed the correct screw. From what Uwe said it  now appears it was missing because it didn't make any difference.

Now I'm curious to find exactly what, if anything, does affect the foot pressure.

[CowboyBob]

Is the marking worse or only on the leftside of the needle?

[Uwe]

The Pfaff 335/145 series machines have two presser foot springs, one nested inside the other.  It appears that on the old casting machines the outer, strong spring is not adjustable. If it is adjustable, I don't really see how. The inner spring is adjustable with the thumb screw, but that spring makes almost no difference. Either I'm missing something or I don't understand the design intent here (other than purposely locking the operator out from making that adjustment for some factory/production reason or saving $0.50 in production cost by not threading the hole and the sleeve.)

Only my Pfaff 593 was cooperating in being taken apart to show the thin inner spring (pulled a little). On this machine the sleeve does not have a knurled top. I was able to loosen the set screw that appears to lock the sleeve in place, but the extension sleeve would not budge or move at all after loosening the set screw. 

 

On my Pfaff 145, the extension sleeve has a knurled top, which makes it look like it's intended to be manipulated somehow. Unfortunately the set screw that holds that extension sleeve in place is messed up and I can't loosen it. Maybe you are able to move that sleeve up and down to adjust the outer spring, and then lock the sleeve in place again with the set screw. None of my machines were cooperating in testing this theory. 

On the modern casting of Pfaff 335, the outer spring is adjustable and you can adjust foot pressure:

This archive picture of my former Adler 69 shows how on that machine the inner and outer spring on that machine are adjustable with independent, nested, lockable adjustment screws. This seems how it should be, quite frankly. Maybe Adler filed a patent on that design to keep Pfaff from doing it.

 

 

[jakc3]

 

Is the marking worse or only on the leftside of the needle?

As you noticed, the screw doesn't really affect the foot pressure. 

The markings appear only on the left side of the needle.

A temporary fix I found is to sew the piece with baking paper underneath and then simply tear it away. It is extra work though and would be nice if the leather wouldn't get marked in the first place.

[CowboyBob]

Well I was thinking since the feed dog doesn't go down as it goes foward & you have just the left toe foot on when the inside foot goes up the outside foot goes down & the feed dog goes foward the top left edge of the feed dog is being pushed into the leather underneath.The only fix would be to round off the whole edge or top corner of the feed dog.

[RockyAussie]

I will try and take some pics tomorrow of a 335 I have put away in a storage container. From what I can see it looks as though I have lifted the as Uwe calls the extension up about 1/4 to 3/8" and run with that. From memory I think it required vice grips and ample swearing.My 331 has a far nicer set up (Like the modern one a bit)  but inside of it there is a rod that when you screw the extension down it pushes the inner  spring down. As I use very small feet and on light duty leathers I take that rod out thus making the inner spring do nothing. I gauge the tension by lifting the foot by hand first then adjusting the pressure until the job will just not lift when the needle pulls up.When I use heavy veg I put it back in.

[RockyAussie]

Just found a pic that shows the 331 and it's adjuster.

[RockyAussie]

Here's the pics of the 335 with the sleeve pulled up about 3/8". This still allows the screw when wound down to come into play and have some meaning I guess. Note the sleeve is no longer visible from inside against the outer spring. Sorry the pics are not the best, it is quite dark down the back in that container.

[dikman]

Poor little machine, all neglected and lonely in the dim dark recesses of that storage container.

[RockyAussie]

It deserves it. It's got one foot tooo many for my liking..

[dikman]

. Well, I'm prepared to give it a good home where it will be appreciated and let it see the light of day!

Anyhow, I got curious and just had a closer look at mine. The outer spring is fixed and is non-adjustable, the inner spring provides the adjustment (not that it seems to make much difference in the normal setup). The mod you did, however, can allow the inner spring to have more effect. By raising that "sleeve" it reduces the tension applied by the inner spring when the adjusting screw is all the way out so when you adjust the top screw it should have more effect. Of course, to get the best out of it an awfully long screw will be needed . Seeing that I haven't really been able to find a screw with the right thread size I might run a tap through to use a more standard size and then make a decent adjuster, now that I know how it works.

[RockyAussie]

I think by raising it as I have done the outer spring has less tension on it and the inner spring then allows more of an adjustment. As I did this for wallet type work I would say if you wanted it to do heavier type work you would only take the sleeve up 1/4"(6mm).In the location I have this one the adjustment bolt does not feel to touch the inner spring until about 3/4 way down. As for my 335.... its staying in the sin bin.The Adler 69 as Uwe pointed out has a more logical adjustment system and I only every use that when I want to do thick bag handles and such. The 331 does most things just right, It's just a shame they stopped making them.

[Gregg From Keystone Sewing]

I think Pfaff may sell various springs for this?  I'm not sure at all, just speculating.  I was looking in the books for 1245 and 335s with this type of two spring pressure foot setup, with nothing for sure.  I've seen different subclasses with different spring part numbers, maybe that's it?  

[dikman]

Rocky, on my 335 raising the doo-hickey (technical term) on top doesn't have any effect on the outer spring, as the spring pushes against the top of the housing regardless of the doo-hickey's position. All it does is change how much additional tension can be applied via the inner spring.

Gregg, what you say makes sense, although I don't know if that's what they do.

[RockyAussie]

OK. I did it quite a few years ago and the pics above of Uwe's 145 may have made me think that the spring rested on the doo hicky. As long as it works,as it did for me that's the main thing.

[dikman]

That's ok, the memory starts to go as you get older .

[jimi]

On 4/23/2017 at 7:32 PM, jakc3 said:

Hello,

I have a question regarding feed dogs marking leather.

I have a Pfaff 335 sewing machine with walking foot feed. On softer leather the feet marked it as well but I solved that by gluing thin leather on the bottom of the feet. 

I still have issues with the bottom feed dog marking the leather. It's smooth, without teeth and it moves only horizontally (maybe just a little bit vertically but it is a negligible amount - 0.05mm). What it does is it leaves a line, which can't be rubbed off, on the bottom side of the leather.  First I thought this is because the plate covering it was slightly higher than the feed dog so I sanded it down to the same height. This however didn't solve the issue.

Are there any solutions/workarounds to this?

Many thanks,

Jakob

Hi Jakob, just saw this post? dont know if you fixed the problem or not?? this also happened to me on my 335 and the solution was to put a little bit of tape under the needle plate to bring it up to the feed dogs level. that stopped marking lines underneath the leather for me. hope this helps. regards jimi.

[buko]

On 4/25/2017 at 11:26 AM, Gregg From Keystone Sewing said:

I think Pfaff may sell various springs for this?  I'm not sure at all, just speculating.  I was looking in the books for 1245 and 335s with this type of two spring pressure foot setup, with nothing for sure.  I've seen different subclasses with different spring part numbers, maybe that's it?  

First off, I know very little about sewing machines so take what I say with a grain of salt. But my first thought when I saw Uwe's post was maybe you could buy a spare spring and shorten it to reduce the pressure.