Newbie questions (lot of them!)

[kgg]

10 hours ago, RaSk said:

Regarding the stitching I'm doing, this is what I called a "felled seam" but I'm not sure it's the correct term.

From your sketch I would say it is a British Standard 3870 class 2 lapped seam. Look at the  2.05.02 in the Coats Reference Guide to Different Seam Types under Numerical Designations of Seam Types ( www.coats.com/en/information-hub/Seam-Types ) or ( www.coats.com/-/media/Coats/Information-Hub/Seam-Types_tcm35-155172.pdf?rev=ab977c6d9977486f8312d07387f20bf3 ) for a better / clearer view of the seam types. I would suggest changing to a 2.02.01 or for more strength a 2.04.01 that way you should be able to get an attachment to do the seam in one pass. 

4 hours ago, dikman said:

Your servo appears to be a fairly generic design, nothing special, but these really need some sort of mechanical speed reduction to get the control that most of us want for leatherwork. I'm surprised that the seller didn't suggest this.

I agree but not surprised at what the seller is suggesting. Speed reducer either by replacing the hand-wheel or an intermediate speeder reducer between the motor and the existing hand-wheel probably costs less then $200 or put an EFKA servo motor on for $1000 plus. I agree with Wiz that a good start would be to replace the existing servo motor with a good old fashion analog brush motor with the speed rheostat for about $150.

My opinion is follow the KISS way, analog servo motor, drive belt, sewing machine. Once you put electronic controls in for the drive motor and needle positioning there are more things to go wrong. I don't use speed reducers, needle positioner's or electronically controlled servo motors on any of my machines. If I needed to lower the sewing speed I would seriously consider installing an intermediate speeder reducer but if I needed to add a speed reducer to get extra punching torque I would say I am using the wrong machine for the job.

kgg

[Constabulary]

Too many different questions fro just 1 thread I think.

I run 2 750W JACK servos (same as yours but with more power), on both I have a 40 / 50mm pulley installed and also a 1:3 speed reducer. I guess yours still has the original 75mm pulley so I would replace the pulley with a smaller one (easy task usually). You find them on Ebay quite cheap (come from China) - BUT - these pulleys have a 15mm bore some JACK servos come with a 13mm and some with a 15mm bore. If yours has a 13mm shaft so can use a piece of 15mm tube with 1mm wall to adapt it. You can also make adjustment on the starting speed. 500rpm is the lowest you can set BUT the motor will actually start at 200rpm (shown in the display) - at least my 2 JACK servos do.

cheap small pulleys:

https://www.ebay.com/itm/323356609027

Motor speed adjustment:

https://www.youtube.com/watch?v=hi09g49JksA

Speed reducers can be DIY made from some simple parts or you can also buy them from certain dealers. Not sure what sources you have in France but in Germany you can get them from SIECK. They sell internationally and they speak English.

https://www.sieck.de/en/machines/sewing/shoe-upper-sewing-machines/diverse-machines/?produkt=9237

But as mentioned before with a speed reducer installed the needle position will not work any more however the machine can be run very slow then and you don´t really need a needle petitioner. But depends on your preferences. I don´t need the NP.

Find more info about all kind of speed reducers here:

https://www.google.com/search?client=firefox-b-d&q=speed+reducer+site%3Aleatherworker.net%2Fforum

https://www.google.com/search?client=firefox-b-d&q=speed+reducer+site%3Aleatherworker.net%2Fforum

Other than a speed reducer you can do what TOXO did (see above).  Also a question of preferences but both speed reducer or larger hand wheel work well.

The foot pressure on the 239 will be adjusted with a knurled screw in the center of the top of the machines - same as on Singer 111. The 239 Dürkopp has a lot in common with the Singer 111 but certain things are different.

If you need a manual for your machine you can use the Singer 111G156 manual partially (as I said it has a lot in common but is not the same) - other than that I can send you a Dürkopp 239 manual in German language if that helps.

 

Quote

Bobbin thread - I've read around here and seen on some videos, that it's better to use the same thread for the needle and the bobbin. I've also heard that you can use a thinner thread for the bobbin and it will make a better seam aspect. What is your experience regarding that last statement? And what are the downsides/benefits of both solutions?

Depends on your project. Usually a smaller bottom thread is used when you have problems with centering the thread knot in the center of the material but IMO thats a very rare occasion and mainly is when you sew thicker or dense (or both) materials but it depends. In lets say 90% of the cases I use the same thread size top and bottom. I rather go up with the needle size than using a smaller bottom thread. It just depends...

 

Quote

"Reversible" sewing - As I'm borrowing the small CNC from my wife (Cameo 4 Pro), I was trying to digitize some patterns and then draw seam lines & cut on the backside of the vinyl with some nice results. Following the previous question, if I use the same thread for the bobbin, is there a world where I can sew from the backside of the vinyl? Mostly for a purely decorative seam, like drawing something on the back and stitching it from the "back" side. My understanding of lockstitch makes me think it is possible.

Usually the needle entry hole (on the top side) looks better / cleaner than the needle exit hole (on the bottom side) so it may depend on your project. But I would generally sew from the side where the seam is visible on the finished product.

 

Edited July 7, 2022 by Constabulary

[Constabulary]

Quote

Presser foot guide - I've also bought (by recommendation of the vendor) a presser foot with an edge guide, exactly this one but 3 times more expensive, to do the decorative seam mentioned above, my issue is that it does small stitches. I've tried reducing the spring tension but still not very effective. It's probably not a good idea to use it for felled seams, is it?

 

Not sure what you mean with small stitches in regard to the edge guide...

However it maybe be better to use a drop down guide which you can adjust sideways and in height.

Like this one here:

https://www.ebay.de/itm/143603133045

it mounts to the backside of your machine and you may need an adapter for mounting it (requires drilling and taping t

 

Edited July 7, 2022 by Constabulary

[dikman]

3 hours ago, kgg said:

My opinion is follow the KISS way, analog servo motor, drive belt, sewing machine. Once you put electronic controls in for the drive motor and needle positioning there are more things to go wrong. 

kgg

I agree, simplicity in electronics is always nice, particularly for people who aren't well-versed in the subject. I wonder, though, if being in France he will have the same problem I had - availability. Those analog speed control servos don't appear to be too difficult to get in the US but here in Australia they are not common and are expensive - if you can find one.

[RaSk]

13 hours ago, toxo said:

Those presser feet with the blades are meant to be used on an edge.

This is the enlarged pulley on my Durkopp Adler 69  (Similar on the 239).  It's 270mm diameter with a 40mm pulley on the servo motor. Total cost about £50 iirc. Note the needle positioner doing it's job.

What do you mean by edge? These were the only feet provided with the machine.
Regarding changing the handwheel pulley, I've read on this forum that it was not the most recommended solutions for several reasons. What are the pros & cons? Or why did you choose this over other options?

12 hours ago, SARK9 said:

Have a look at:   About 3:12 for a couple of things to check. At the point in the cycle where the presser foot should be holding the material down, try to wiggle it from side to side to check the hold down force. Also test when the presser foot lifts to see if the walking foot is pressing the material to the feed dog firmly,  and its moving in unison with the needle & feed dog. You may need to reset the heights & timing as is shown in the video to accommodate non-OEM feet and different materials.

-DC 

I've checked it is firmly held down at almost every moment of the cycle. There is a very slight position where the material can slip (pulling it with a lot of force), it is just before the needle penetrates the material when it switches between foot.
Overall it seems to be holding very firmly. Should I care/try to tune it because of this very slight position? I can do a video if you want.

(Fun fact: Your nickname is almost like mine, my favorite number is 9 and I have a Malinois -that stays at my parent's house-. )
 

10 hours ago, dikman said:

Have you tried reducing the overall speed in the servo menu? This should make it easier to control at slow speed, but to get accurate slow speed control you need to fit a speed reducer of some sort. Replacing the handwheel with a larger pulley, as toxo suggested, performs the same function as a speed reducer, I've done this on several machines. 

Your servo appears to be a fairly generic design, nothing special, but these really need some sort of mechanical speed reduction to get the control that most of us want for leatherwork. I'm surprised that the seller didn't suggest this.

I've tried tweaking every parameter of the servo motor using this manual
The V setting for max speed just limit the max speed/RPM, no effect on low speed. I've already chosen the lowest settings: 5.
The M setting for synchronizer mode as said previously has only a small effect on the final needle position (when stopping)
Z/L settings seem to be only a technician setting that impacts the V setting, so also no effect on low speed
C setting for torque, I haven't noticed any significant change
N low-speed setting (positioning speed according to manual) also has no significant effect

I've read here on the forum that it's common that sellers don't understand the need for speed reduction as 99% of the market wants speed. I asked for speed reduction, he got me speed limiting, not exactly what I needed.

5 hours ago, kgg said:

I agree but not surprised at what the seller is suggesting. Speed reducer either by replacing the hand-wheel or an intermediate speeder reducer between the motor and the existing hand-wheel probably costs less then $200 or put an EFKA servo motor on for $1000 plus. I agree with Wiz that a good start would be to replace the existing servo motor with a good old fashion analog brush motor with the speed rheostat for about $150.

My opinion is follow the KISS way, analog servo motor, drive belt, sewing machine. Once you put electronic controls in for the drive motor and needle positioning there are more things to go wrong. I don't use speed reducers, needle positioner's or electronically controlled servo motors on any of my machines. If I needed to lower the sewing speed I would seriously consider installing an intermediate speeder reducer but if I needed to add a speed reducer to get extra punching torque I would say I am using the wrong machine for the job.

kgg

As I said previously, I'd rather not change the whole motor for now. Buying an EFKA at 800$ for a machine that cost me 600$ (with a new servo motor) doesn't make a lot of sense to me and I do have not a budget for it yet.
 

3 hours ago, Constabulary said:

Too many different questions fro just 1 thread I think.

I run 2 750W JACK servos (same as yours but with more power), on both I have a 40 / 50mm pulley installed and also a 1:3 speed reducer. I guess yours still has the original 75mm pulley so I would replace the pulley with a smaller one (easy task usually). You find them on Ebay quite cheap (come from China) - BUT - these pulleys have a 15mm bore some JACK servos come with a 13mm and some with a 15mm bore. If yours has a 13mm shaft so can use a piece of 15mm tube with 1mm wall to adapt it. You can also make adjustment on the starting speed. 500rpm is the lowest you can set BUT the motor will actually start at 200rpm (shown in the display) - at least my 2 JACK servos do.

cheap small pulleys:

https://www.ebay.com/itm/323356609027

Motor speed adjustment:

https://www.youtube.com/watch?v=hi09g49JksA

Speed reducers can be DIY made from some simple parts or you can also buy them from certain dealers. Not sure what sources you have in France but in Germany you can get them from SIECK. They sell internationally and they speak English.

https://www.sieck.de/en/machines/sewing/shoe-upper-sewing-machines/diverse-machines/?produkt=9237

But as mentioned before with a speed reducer installed the needle position will not work any more however the machine can be run very slow then and you don´t really need a needle petitioner. But depends on your preferences. I don´t need the NP.

Find more info about all kind of speed reducers here:

https://www.google.com/search?client=firefox-b-d&q=speed+reducer+site%3Aleatherworker.net%2Fforum

https://www.google.com/search?client=firefox-b-d&q=speed+reducer+site%3Aleatherworker.net%2Fforum

Other than a speed reducer you can do what TOXO did (see above).  Also a question of preferences but both speed reducer or larger hand wheel work well.

The foot pressure on the 239 will be adjusted with a knurled screw in the center of the top of the machines - same as on Singer 111. The 239 Dürkopp has a lot in common with the Singer 111 but certain things are different.

If you need a manual for your machine you can use the Singer 111G156 manual partially (as I said it has a lot in common but is not the same) - other than that I can send you a Dürkopp 239 manual in German language if that helps.

 

Thanks for joining in! I was reading some of your posts yesterday before bed time, glad to see you here :D 
Yep I thought it was maybe too many questions. As we've focused on machine, I'll probably do another thread in another section for the patterning/sewing questions.

You're correct, I just checked it is a 75mm pulley and it starts with "02" on the display so I guess it means 200 RPM.

I've tried unscrewing the pulley on the servo motor to check the shaft, but the pulley turns... Sorry I'm a real newbie on those topics 
Should I turn on the motor?

Thanks for the SIECK suggestion, it seems like a good option.

Reading a lot from this forum, I've found 3 solutions regarding pulleys:
- hand wheel pulley for a larger one
- servo motor pulley for a smaller one (I've seen even some 3D printed ones!)
- speed reducer 
I've also checked it's a 13mm shaft for the JACK motor.

I guess with those conditions DIY speed reducer or 3D printed servo motor pulley are the easiest/cheapest options?
I haven't seen long-term feedback regarding 3D printed pulleys, are they good?

Edited July 7, 2022 by RaSk

[RaSk]

1 hour ago, Constabulary said:

Not sure what you mean with small stitches in regard to the edge guide...

However it maybe be better to use a drop down guide which you can adjust sideways and in height.

Like this one here:

https://www.ebay.de/itm/143603133045

it mounts to the backside of your machine and you may need an adapter for mounting it (requires drilling and taping t

 

I've sent some pictures yesterday.
With the longest stitch setting, I cannot succeed to do stitches longer than 3 or 4 mm with the "edge guide presser foot" (it's not an edge guide like you sent, it's a presser foot with a guide in it).

I have a similar drop-down guide, not with a wheel but still a similar idea. The issue is for the type of seam I'm doing I'm not sure it's the ideal tool as it will have to lay on the material as well. I'll probably have to take a picture so you can see what I'm talking about.

[Handstitched]

Its a lot to read . I'm not an upholsterer, but   I used both ' felled seams & french seams '  when doing any upholstery . And while  you can't pin leather or vinyl like you would with fabric, canvas etc. to hold seams in place,  I use a basting tape when doing large jobs. . Thin double sided tape with a strong adhesive on both sides. Ideally  for thin leather or vinyl.   I tap/fold  the seams down with a flat hammer . 

HS

[dikman]

Those feet are edge-guide feet, they come in different widths designed to act as an edge guide to give a stitch line that is a fixed distance from the edge. In your first picture you can see drag marks next to the stitch line, caused by the guide part of the foot. It is spring-loaded so it can ride higher if the material is thinner than the depth of the guide.

As for pulley reducers, if you're handy you can make your own (I've made several different types). There have been quite a few posts about it on here, basically a shaft, a couple of pulleys and a couple of bearings. On one of my machines I replaced the handwheel with a large pulley, made a speed reducer too and could crawl the needle at one stitch every 2 1/2 seconds (servo was a generic type, similar to yours). Incidentally, I've found with my servos that although the speed setting does reduce the top speed it also has the effect of reducing the "sensitivity" somewhat as the movement of the actuating arm now covers a reduced speed range - if that makes sense.

[Wizcrafts]

2 hours ago, Handstitched said:

I use a basting tape when doing large jobs. . Thin double sided tape with a strong adhesive on both sides.

I too use Leather Tape to hold seams and patches in place. Know that if you sew through the tape itself, titanium coated needles work better than plain steel at resisting gumming up. I also keep a dauber handy and dip it into a 4 ounce jar of Goof Off to clean adhesive off the eye of the needle when it gums up.

[Handstitched]

21 hours ago, Wizcrafts said:

I also keep a dauber handy and dip it into a 4 ounce jar of Goof Off to clean adhesive off the eye of the needle when it gums up.

'Goof Off' . I had to google that . So far, I haven't had the needle gum up, yet. But  I do keep a good supply of acetone and a lot of Q tips ( ear buds)  , but thats a good idea. Thanks   

HS

Edited July 8, 2022 by Handstitched