unionattic Report post Posted October 29, 2019 (edited) Experimenting with my Pfaff 471. I can dependably(?) stitch 2 layers of leather, but when I attempt to stitch four layers (2 layers & 2 skived-layers glued together), the top thread struggles and starts to tear itself up. I have the servo set pretty slow, but I don't think that should affect the torque of the needle press. My first guess is that the needle is undersized. I'm using #30 Venus V-Spun thread. The needle is a #14 1134 LR Schmetz. As a double-check I show a diagram of the needle orientation and thread feed direction. I believe the scallop should face right and that the top thread should enter from the scallop side. Below I link to an album that demonstrates sewing 2 layers and 4 layers. Album showing that I can stitch 2 layers of leather ok, but 3.5/4 layers the stitch fails. Edited October 29, 2019 by unionattic update needle description & thread name Quote Share this post Link to post Share on other sites
Constabulary Report post Posted October 29, 2019 since the hook is on the left side of the needle the scarf of the needle has to face left (toward the hook tip) - yours is facing right according to your drawn picture. Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted October 29, 2019 Check to see if you threaded the needle backwards. Your drawing shows it threaded from right to left, from the scarf side to the rib side. That is backwards! You should be using bonded nylon thread to sew leather. The Venus thread you have is for cloth garments. Your needle is very small as well. To sew 2 layers of soft to medium temper leather you should use #69 (T70) bonded nylon thread with a #18 leather point needle. Sewing 4 layers calls for moving up to #92 bonded thread with a #19 or #20 needle. This assumes that the leather pieces are each about 2 ounces thickness. Quote Share this post Link to post Share on other sites
Constabulary Report post Posted October 29, 2019 Wiz, right to left threading is correct when the hook tip is on the left side. Problem is the needle scarf facing right instead of left. With other words turn the needle 180° and start again. Quote Share this post Link to post Share on other sites
unionattic Report post Posted October 29, 2019 7 hours ago, Constabulary said: Wiz, right to left threading is correct when the hook tip is on the left side. Problem is the needle scarf facing right instead of left. With other words turn the needle 180° and start again. Ah thanks. I was wondering about this. I felt like the scallop (scarf?) should face the hook, instead of away from it, but I thought i was reading the opposite in the manual (who's pictures are impossible to see) Quote Share this post Link to post Share on other sites
unionattic Report post Posted October 29, 2019 (edited) 7 hours ago, Constabulary said: Wiz, right to left threading is correct when the hook tip is on the left side. Problem is the needle scarf facing right instead of left. With other words turn the needle 180° and start again. 8 hours ago, Wizcrafts said: Check to see if you threaded the needle backwards. Your drawing shows it threaded from right to left, from the scarf side to the rib side. That is backwards! You should be using bonded nylon thread to sew leather. The Venus thread you have is for cloth garments. Your needle is very small as well. To sew 2 layers of soft to medium temper leather you should use #69 (T70) bonded nylon thread with a #18 leather point needle. Sewing 4 layers calls for moving up to #92 bonded thread with a #19 or #20 needle. This assumes that the leather pieces are each about 2 ounces thickness. Hi there. Regarding Bonded Nylon Thread... I am in Singapore, so I'll need to find something here. Are there other names this thread would go by? One thread I have access to is Serafil, which they call 'polyester continuous filament' and recommend it for things like shoes. From the makers of Serafil, there is also Strongbond, which sounds more like the type of thing you're talking about. Edited October 29, 2019 by unionattic found some other thread possibilities Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted October 29, 2019 I have a few spools of Serafil bonded thread. It isn't as strongly bonded as Cowboy thread. The stitches look looser to me. The Strongbond looks comparable to what most of us in the US are using for sewing leather. Quote Share this post Link to post Share on other sites
unionattic Report post Posted October 30, 2019 On 10/23/2019 at 1:34 AM, Gregg From Keystone Sewing said: 471 takes system 134, or 135X7 When the designate a cut point, as in this case, the system needle changes for example here 134LR, 135X8 RTW, In this case, LL is a cut point needle with an hour glass shape. CR I'm not sure and can look this up later. 134-35 are very different needle, but the needle shank will will fit the same with the 134. 11 hours ago, Wizcrafts said: I have a few spools of Serafil bonded thread. It isn't as strongly bonded as Cowboy thread. The stitches look looser to me. The Strongbond looks comparable to what most of us in the US are using for sewing leather. Thanks. When you refer to the 'bonding' of the thread, what physical characteristic are you describing? I'm guessing it's how tightly the filaments that compose the thread are 'stuck together' somehow? Or maybe how easy it is to tear the thread? Quote Share this post Link to post Share on other sites
unionattic Report post Posted October 30, 2019 23 hours ago, unionattic said: Experimenting with my Pfaff 471. I can dependably(?) stitch 2 layers of leather, but when I attempt to stitch four layers (2 layers & 2 skived-layers glued together), the top thread struggles and starts to tear itself up. I have the servo set pretty slow, but I don't think that should affect the torque of the needle press. My first guess is that the needle is undersized. I'm using #30 Venus V-Spun thread. The needle is a #14 1134 LR Schmetz. As a double-check I show a diagram of the needle orientation and thread feed direction. I believe the scallop should face right and that the top thread should enter from the scallop side. Below I link to an album that demonstrates sewing 2 layers and 4 layers. Album showing that I can stitch 2 layers of leather ok, but 3.5/4 layers the stitch fails. I am able to get Groz-Beckert 134 LL CR 90/14 100/16 and 110/18. The heavier gauge needles, 134 LL CR/134 KK LL CR 120 and 134 LL CR/134 KK LL CR 130 apparently have a shorter shank. They're gong to give me some samples of those two, I'm not sure if there is flexibility to adjust the Pfaff-471 to use shorter-shank needles, but at least a #18 size should be a helpful start. Quote Share this post Link to post Share on other sites
unionattic Report post Posted October 31, 2019 Hey guys... Today I tested out a #18 134 LLCR on the same trouble 4-ply leather (and I rotated teh needleso that the scallop faces the hook of the machine). And it sewed well. I have uploaded a video of the successful stitching to the same album above. Quote Share this post Link to post Share on other sites
Gregg From Keystone Sewing Report post Posted October 31, 2019 On 10/29/2019 at 11:39 PM, unionattic said: When you refer to the 'bonding' of the thread, what physical characteristic are you describing? I'm guessing it's how tightly the filaments that compose the thread are 'stuck together' somehow? Or maybe how easy it is to tear the thread? I made a short video, hope this helps. No other way to describe it. YouTube of bonded and non bonded thread example Quote Share this post Link to post Share on other sites
unionattic Report post Posted November 1, 2019 15 hours ago, Gregg From Keystone Sewing said: I made a short video, hope this helps. No other way to describe it. YouTube of bonded and non bonded thread example Perfect! (and a great soundtrack) Quote Share this post Link to post Share on other sites
