kgg

I looked at your first video as the second video seems to be not working. A couple of points I see: i) you are not holding the bobbin thread and the top thread you seem to be holding it forward ii) the top thread should go through the last guide just before going to the eye of the needle. Suggest checking your top thread path. What size of thread and needle combination are you using. I'm assuming you are using the same size thread in the bobbin as for the top thread. kgg

You could try a automotive supply house or a local body shop. A couple of manuals that may help you in the future: kgg 111w152,153,154,155 (2).pdf Singer_111W155_Parts.pdf

I would try holding it at a different angle and see if that works better. If the holding angle works better the question is it uncomfortable for you to use in comparison to your other edger or is it that the new one isn't sharp. If the holding angel is uncomfortable you will probably revert back to your other edger and the new one will just gather dust. If it wasn't properly sharpened at the factory I wouldn't do any resharpening. I think when you pay a premium price for a hand tool it should be ready to work right out of the box. For me the bottom line if it is uncomfortable to use or the edge wasn't sharpened properly I would return it for a refund, but that is just me. kgg

As with all of us as we get older things get more difficult. It does sound like a interesting project and if you can figure out a system I would be interested in seeing the setup. A cable system may work on thinner materials but on thicker / tougher items is where getting enough power transferred from a foot operated setup I think will be a problem. You maybe able to be overcomed that with using a weighted wheel in a treadle setup but then you will have to contend with overrun momentum of the wheel. Why not sell the Boss and move into something like a CB3200 type machine and save the shoulder? kgg

Found this as it sparked my curiosity : Leather Bag with Wooden Sides https://www.instructables.com/Leather-Bag-With-Wooden-Sides-/ kgg

I would suspect the leather is glued to the wood with a contact cement type glue and then nailed. kgg

You may want to first compare the parts list for the H2 and H3 and see what parts are the same that you need. It maybe cheaper to buy the H2 just for the parts rather then buying new parts. kgg

To me a custom boot would mean constructed to fit my two pegs perfectly. Just like having a tailor made suit, it fits only one person perfectly. By "volume" to me is just another way of saying "off the rack". Have you search for a boot-maker close to your location or maybe ask a pedorthic clinic for recommendations on who could make a custom boot for your needs. kgg

To be sure drop Atlas Levy ( atlaslevy.com ) an email or phone call. To me it appears to some clone of the the older Juki LH-1182 expect for the oil level window. kgg

I would also do a test in combination with the kevlar lining and thread that you are plan on using. Personally I think the domestic sewing machine is going to struggle if it will do the job at all. Remember the thicker the leather the better the protection. Yes the thicker the leather the heavier weight wise the jacket will be but the last time I dumped a bike in a bend the pavement burned through the chaps, jeans, medium duty leather jacket and the 4mm thick belt I was wearing. Road rash is a nasty thing. kgg

What machine are you planning on using? kgg

I'm going to assume your "Heavy Leather" measurement is in inches so 0.175" is 4.45mm which is about 11.5 oz thick leather. The needle size for V138 (T135) thread should be good for thick/tough leather. However the bobbin thread being 75 which I'm going to assume is T70 which is V69 is the smallest size really for industrial sewing machines. I think some of your problem is your bobbin thread is two sizes smaller and flimsier then the top thread. This I feel is causing / related to your stitching problems. Why are you using a smaller bobbin thread? Normally the bobbin and top thread should be the same size and type of thread (bonded nylon or bonded polyester). The left twist thread is the standard twist direction sold today also known as Z-Twist, or Standard Twist. Mixing thread colors and types of thread can also pose problems as darker threads like black are stiffer then lighter colors like white and bonded nylon is also stiffer then bonded polyester. kgg

Measuring any thread is difficult at the best of times let alone cotton which can absorb moisture and swell. That doesn't even account for what changes it has be exposed too for the last 30 (??) years. kgg

A true flat felled seam not the mock flat felled seam sometimes referred to as a military seam. An example can be see in this video as the first seam done with jeans materials (www.youtube.com/watch?v=E1vJzVW2lLk) kgg

My understanding is that for cotton thread it is converted to sort of Tex measurement by dividing 1000 by the size of the thread. So in this case it would be 1000/24 = Tex 41.7 or somewhere around V40. Braking strength for cotton is less then bonded nylon or polyester. kgg

For a start the 160 (#23) needle is only good for V138 thread in thinner materials. If you want to use V207 you need to go to at least a 180 (#24) needle and maybe a 200 (#25) in thicker / tougher / sticky materials. If you use an underside needle like the V207 thread with a 160 needle the hole the needle punches isn't big enough to allow the top thread to form a proper loop on it's upstroke so the hook can catch it. You may be able to use one size of needle up from the machines rating but two sizes or more probably not. My take on thread is V69 is the largest thread for domestic sewing machines and the smallest thread size for industrial sewing machines. The V138 thread is generally the max rating for most upholstery class machines while the V207 thread seems to be the cross over point from upholstery class machines to the heavy stitchers of the 441 Class machines. kgg

I agree with @Constabulary that this motor is not safe and should be replaced with what in North America is generally referred to as a Universal sewing machine motor or a servo motor. My experience is when a motor has the plug cut off like what is shown in your first photo it means the motor has a problem not worth fixing for one reason or another. kgg

Under the section Hints in the manual " In operating the machine always turn the wheel from you." From that statement I would assume the hand-wheel turns in the clockwise direction. I have attached the manual. kgg 46k15.pdf

The Juki LS-1341 or similar clones should fit what you want to make. When the time is right it and you feel you can use a machine, manual or motorized, at least now you have a starting point of information. kgg

Have you check your manual for your machines sub class. The information I have the max size needle thus the max thread depends on the sub class. The max needle the machine is rated for is 180 (#24) but mostly 140 (#23) or under. The 180 needle will be able to handle V207 in thinner thickness but you may have to go up to a 200 (#25) in thick or tough stuff. A good cross reference for needle size to thread size can be had at: https://www.tolindsewmach.com/thread-chart.html The machine information I referenced can be seen in the attached manual pages 2 & 3. kgg 268_instructions_for_operating.pdf

Yes those machines are all manual machines. Singer no longer and hasn't for many years made industrial sewing machines that I'm aware of. This narrows the field down for sewing machines. If you only want one machine a sort of all rounder machine would be a cylinder arm machine with a flatbed attachment. You can do items that are best done with a flatbed sewing machine (example: wallets) as well as items done with a cylinder arm that are circular. Then there is the dollar factor. Depending on how thick your leather will be including the seams an excellent machine would be a Juki LS -1341 or a clone machine. The Juki LS-1341 new will cost about $5200 USD while a clone of the older Juki LS-341 will cost about $2500 USD. Juki is the typical machines that the clones copy. So accessories like binding attachments and parts are readily available at reasonable prices. Then there is the used market for both brand name and clone machines which can be had from either a dealer / repair shop or the owner directly. I would suggest getting one from a dealer that has been gone over unless you or you know someone that can properly evaluate a used machine. The only thing is the footwear part of what you want to make as this has a very broad range from slippers to workboots and everything in between ????? kgg

I would definitely investigate getting a machine particularly since hand stitching will probably aggravate your arthritis. My mother use to love to sew all sorts of garments, hand knitted everything from socks to heavy real wool sweaters and use sign language for her day job. When she turned about 50 her arthritis got so bad she could hardly sign anymore let allow sew or knit. My advice is put the needles down and get a sewing machine to reduce the stress on your hands. Determine what items you would like to sew and what items you eventually would like to sew and purchase a motorized sewing machine accordingly. I think the one armed bandits like the Tippmann Boss ($1000 - $1575 USD) , Cowboy Outlaw ($1400 USD) and the Master Tool Cub by Weaver ($2000 USD) will also aggravate your arthritis but not as bad as hand stitching will eventually. I look at the bottom rating reviews for items, the ones giving the bottom end reviews. I think those probably give a more accurate view of what to expect. kgg

If you enjoy hand stitching you still can do that it for your own or special projects but when doing large quantity projects mechanizing the work process is the way to go. To me it's like hand sawing versus using a circular saw, one piece of 2x4 no big deal but a 100 I'll use the circular saw. Doing those sheaths all by hand will I bet quickly lose the enjoyment of doing that many similar items. How mechanized you want or can afford will be the question. Just adding a proper sewing machine will as @Dwight mentioned from however long it takes to hand stitch to about five minutes for sewing as will as reducing the hand and mental fatigue. kgg

I would figure out i) an average cost for materials like leather, dye, thread, etc including wastage ii) an average time to complete a knife sheath from cutting the leather to the finished sheath iii) a fair hourly rate you want to charge iv) a profit margin Just as an example would be $10 for materials plus $15 hourly labor rate (say 1 hour to just to keep it simple for the math) plus say 40 percent for profit for a total: $25 for labor / materials plus $25 x0.40 = $35 per sheath. The only two areas you can really save on the cost per sheath is the labor cost which could be reduced using equipment and the profit margin. kgg

Have a look at this video of the Consew 226 being converted to the larger bobbin it should answer you questions and the parts you will need. kgg