leatherkind

I am sorry for the delayed response, my problem was the presser foot tension. It was too low. Bob actually told me to check the tension but I thought it was OK. Leather was sliding under the foot. I was using oil tanned leather and it is quite slippery to begin with because of oil. On top of it the feed dog and the presser foot are very smooth and naturally do not provide a lot of traction. It is a trade off: you get traction with teeth on the feed dog and the presser foot or you get no "bulldozer" marks on leather. In the attempt to make less presser foot imprints on my work i decreased the pressure and that created the problem... It seems to be OK when the tension knob is above the machine head by about an inch. I do not know about others. To test your tension please take a test piece and start stitching forward, then while you doing that switch in reverse. Pull the piece slightly towards yourself at all times. If the tension is too low you will see significant difference in stitch length forward vs. reverse. I believe you should be able to switch in reverse at any time of stitching cycle.

I jinxed it... vent back to the machine and the very first back stitch got longer again. I almost ready to blame the machine!

Thank you MADMAX22, there is really only one easy to get to bolt under the cover on the back of the machine. After i tightened it a bit the stitches in back and forward direction became equal in length and the stitch lever became somewhat tighter to operate. I am attaching a picture of that bolt. Is it the same thing you have done?

Ultimately what was the root cause of the problem?

You can glue oil tan leather grain side to grain side if you rough up both surfaces.

You can probably make a flatbed attachment to any cylinder arm machine. http://leatherworker.net/forum/index.php?showtopic=34847&view=findpost&p=218917

My Cowboy 4500 arrived in about 2 weeks (if not less) this summer. 4 months sounds a bit too long... doesn't it?

Can you please post a picture of it?

This is probably the best method out there. Awesome result!

I have an improvised flatbed attachment. I thought of getting a factory built one, but i needed one really quick and made this one out of laminated particle board. It turned out that this completely separate unit works very well. It takes no time to move it away with all the sewing on it if necessary and use the machine as a cylinder arm as designed. It is also very easy to check on the bobbin or change the height of the table. I however have not used the factory built one so i can not tell which one is better.

I like making bags out of thick leather and I had troubles with corners too. The leather is rather stiff and hard to handle. Here is how I stitch gussets to the middle compartment separator of a handbag. The bag is made out of 2mm oil tanned leather. 1. Prepare the edge of the pieces for the glue (this is oil tan and glue will not adhere if you do not rough up the surface) 2. Start gluing the gussets. As you approach the round corner fold the edge of the gusset and then while folded bend it to mimic the turn. I do it quite hard so the leather flexes, becomes more pliable and takes needed shape. 3. Glue pieces together and secure them with clips. (i should have wrapped them with something... they leave some impressions) 4. Stitch it all. I hope it helps. Equipment and materials used: 2mm oil tan leather, Cowboy 4500 sewing machine, round punch http://leatherworker.net/forum/index.php?showtopic=7801&view=findpost&p=216263, needle #25, bonded nylon #346, fabri-tack glue, rotary tool with sandpaper cylinder.

Thanks Rick. I will try pins. I was under impression that it is easy to ruin the surface with pins. I will try to put them exactly where the stitch will go. My plan B was to skive a little bit just enough to expose the fibers so the glue can adhere. That can get messy though for i have no good skiver and i was trying to avoid it.

Hi everyone, i wonder if anyone knows how to glue oil tan lather top side to top side. I have tried several different glue types and nothing sticks to it. I need to secure three layers of oil tan for machine stitching and two of the layers are going top side to top side. Thank you.

I would like to add a good word about Cowboy 4500 I have purchased from Bob. I am new to sewing but always wanted to make something out of leather. I did not even know what i wanted to make... After spending countless hours chasing "industrial" leather machines on Craigslist I found this website and soon after decided that Cowboy looks good. I did not see a difference between Cobra and Cowboy but Toledo is 1000mi closer and their phone was first in the list and they picked up the phone... Bob spent significant time with me on the phone explaining all the pros and cons. Of course most of the stuff was new to me. The more I new about the machine the more confident i was that i am choosing the right one. Look how solid every part of it is. There are no wimpy screws on this equipment and all rods are like an inch in diameter. You will need help to mount the head on the table it is that heavy. This is no nonsense machine. I am not even sure if you can knock it off timing! It seems like it will go through anything you stick in to it as long as it is not thicker then 1 inch. You will stitch a zipper to thin leather or go through 5 layers of thick oil tan... no difference. Amazing. I used 130 thread and 346 ... no difference! Do they call 346 a rope? Just change the tension and a needle. I do not even oil the tread and I am using same thread on both sides. The bobbin on Cowboy 4500 takes about 47 feet of #346 thread! It took me a while to figure out the tension though but once i knew how it was just pure enjoyment. The thing is that this machine with thick threads needs a lot higher tension then regular boxstore $70 model but those are... different, and i did not know any better. Here is one of our first bags. http://leatherworker.net/forum/index.php?showtopic=25239&view=findpost&p=213686 Whatever extras i needed Bob shipped them to me same day. Awesome service! Good luck! PS. I am not affiliated with any one seller and do not work for any. Just in case it may appear i am doing a sale here

Thank you Dwight for your suggestion. I was looking for something that would allow me to make repeatable and high quality cut. Followed your instructions I was able to make a 75 mm diameter (3 inch) corner rounding punch. http://leatherworker.net/forum/index.php?showtopic=7801&view=findpost&p=216263 It works very good.

Thank you AndyL1, I like your advise and especially the step # 7 I like simple solutions and what can be easier then a washer? I however was looking for something that would produce a very repeatable quality result. After searching leatherworker.net some more i found this suggestion http://leatherworker.net/forum/index.php?showtopic=25656&view=findpost&p=161712 $13 bucks later and three hours of work in my shop i arrived to the following solution. The monster punch! it is a 3 inch (75mm) large round corner leather punch made out of steel pipe. I got it in plumbng supply store. One whack does it all. Notice that just like it was suggested in the link above i have bent the sticking out parts outwards to form 90 degree corner. Works great. Thank you for your time. Round punch for leather. Corner cutter punch. Cutting leather corners. Semicircle punch. 90 degree punch.

I am having a similar problem. I need to cut round corners on brief case and i would like to get it done as accurate as possible. Attempts to use a thick paper pattern and exacto knife or a metal pattern do not produce professionally looking cuts. They do not match very well and... look like someone just cut them with exacto knife There are corner cutting machines and i am curious if anyone used them and what is important to know about them to make a good choice? Thank you very much.

I just received and installed a drop down roller fabric guide for Cowboy 4500 from Bob Kovar. Thank you Bob for great advise and speedy shipment. I am not sure i did it perfectly but it works great and it is surprisingly rigid. I have attached it with 6mm bolts for which holes were drilled and tapped. It is installed as low as possible so that I did not have to change the angle of the manual presser foot lift handle. There are two modifications to existing parts however. 1. The ball handle of the manual presser foot lift is grinded by about 1/4" so it would not hit the roller guide mechanism. 2. Roller guide altitude limiting bolt is shortened and the nut that secures it is put on the other side of that back fixture. That too was done to avoid it being an obstacle.

Thank you Bob very much for your expertise! Considering the high quality of this machine and my inexperience I knew I am doing something wrong. Can you please also comment on the tension. 4 lbs on top thread isn't it a bit too much? (assuming i am working with thicker stuff) Although I was not able to set it to much less then that because the bottom thread is getting almost free of tension. Thank you again for your time.

I had so mach fun trying to figure out correct tension... It seems to be more difficult to adjust with thin soft leather then with thick and stiff. For example i was stitching the zippers to soft leather and you can tell that the leather side looks shrunk compare to the zipper. I guess the tension was too high. Unfortunately I could not find anywhere numerical specifications on what the tension should be. At best it is "a little more" or "too much" so i had to guess. Maybe i just did not look in the right place? Please let me know if you have it. I also realize that if you try to make a complete chart that is probably going to be enormous. Just imagine now many different tension mechanisms are out there, how many different threads and coatings, and how many different materials... Nevertheless, one problem at a time. Here is my example of thread tension. I would greatly appreciate if you tell me if I have it correct or not. I measured the thread tension by pulling the thread to the back of Cowboy 4500 with luggage scale. The leather is 1,2 , and 3 layers of 2mm (3/32") oil tan which is not very soft. All together they are about 1/4". In all three stitch samples the top thread is at constant tension of 1800g (4lb). The bottom tension is changing three times 200g (7oz), 850g(1lb 14oz), and 2kg (4lb 8oz). Thread is bonded Nylon #346 (about 1mm in diameter) made by Linhanyl and the needle is #25 leather point. I have circled obviously bad spots with red (horror) and yellow (outrageous). As you can see there is little difference for thick material but not so for thin. I would like to mention that to change the bottom tension so much i had to turn the bolt only 1/2 of a turn.

Very cool style! What kind of machine are you using?

Hi Chouinardragon. I was in similar situation this spring when i was trying to make a choice of the machine. Please do not underestimate the requirements for the machine. I just finished a bag and was surprised how thick some folds can get. http://leatherworker.net/forum/index.php?showtopic=25239&view=findpost&p=213686 I found these Wizcrafts' comments very helpful too: http://leatherworker.net/forum/index.php?showtopic=25239&view=findpost&p=159571 In case you have seen it already or not interested please forgive me for wasting your time. Good luck with your projects!

I used #22 ball point needle and T135 nylon thread and harness presser foot assembly. This choice was made after #20 needle bent on a first try and #22 was the largest ball point I had on hand at that time. I had larger needles but those were all for leather and i have heard somewhere that they will cut the fabric and the seam will not be strong. T135 was used because i like thick threads but bigger thread would adversely affect gentle feel of this very soft leather. I used Harness Foot because this is the only one i have. Your question however prompted me to investigate effects of different needles on nylon fabric. For the experiment I used 0.15 mm nylon fabric (0.0065"), #22 ball point, #23 spade point, and #25 triangular point needles. It is not exactly apples to apples comparison but i think it is enough to prove my original assumptions wrong. None of the needles seem to inflict any damage on the fabric which was a total surprise to me. Only the largest needle caused threads to pull in cross shape which i do not think can be considered a mechanical damage. I do not see any evidence of cutting. It seems that i was wrong and I could have used leather point just as well and achieve different type of stitch. The experiment is not ideal however because i did the puncturing by hand. I will try it on the machine under normal conditions if I do not forget. PS Thank you question and for your opinion about the backpack.

I am glad i found leatherworker.net and I enjoy reading it very much. It was difficult for me with no experience in sewing to make a sewing machine choice. Thanks to all contributors here and especially to Wizcrafts' posts I was able to make an informed decision. This summer I acquired a Cowboy 4500 from Bob Kovar and it was a lot of fun making different items on this machine. Here is one project that proved to me that i got the right machine. It is a leather and jeans backpack. (please see the attachment) Even though it is relatively light duty bag there are several tough spots in it. There are folds of thick leather on top of heavy nylon fabric together with some thick jeans folds. Many of those layers are with glue between them. Some spots are at least 1/2 inch of very stiff material to get through and the machine showed no stress at all. Just do not press the pedal too hard or it will go too fast to properly control the material. I am very glad that i got this machine.