Sewing Machines
Welcome to the world of clones, industrial sewing machines and everything else sewing.
Let's say right off the bat that you could sew everything by hand! Ok, that takes too long so you want a machine.
Some of the qualities of a machine that would make your project more possible is a machine that has a longer arm, and has the ability to sew through the desired material, while pulling at least v69 thread and making a tight stitch. Forget Zig Zag at this point.
The arm length is that length between the needle and the machine's upright base, it limits the amount of and the ease of sewing materials on seams that are not along the edges. A technique to use for machines with smaller arms is to roll up the excess material and shove it under the arm while sewing the seam.
I define an industrial sewing machine as one that has a table with a motor underneath, with a clutch assembly, not any machine that has an electric motor attached to the head (or above the table).
Sailrites entire line of sewing machines, which are not industrial, can be purchased as a clone or a duplicate for much less money. their best feature is that they are portable and of reasonable stowage needs, and the custome service of Sailrite is a ten!
For your plans, this line of machines would certainly do the job.
For most of my tops and covers, I use v69 or v90 thread diameters. Some machines cannot pull thread of that diameter, punch through multiple layers of folded seam, or maybe even mount a needle that is necessary to carry the thread. Some machines can be forced to do this kind of work. If there is only a small section of this kind of sewing, perhaps you can turn the machine by hand until you reach a thinner section.
Metal gears: almost all of the smaller portables that claim industrial status, claim to have all-metal gearing, and this is a good thing. If you want to go one step further, look for all metal gears that have at least TWO set screws to hold the gear in place on the shaft.
If you routinely force your machine to sew heavier materials and threads, the gears will move on the shaft. The timing of the machine will change, and possibly cause problems with the seam formation. Something has to give, and sometimes you break a needle, but sometimes the timing changes. Having 2 set screws on the gears will reduce timing changes. I find that if I cause a timing change on my smaller portables, I can retime the machine myself, as long as only one gear slips at a time.
My current industrial machine is a Bernina 217. It is considered a medium weight commercial sewing machine. It will sew most things I want to sew, either straight stitch or zig zag. It was purchased used, but in like new condition for $1600. You can expect to pay at least $500 for an industrial machine that only has straight stitch and was made in China. If you go buy a machine off of craigs list, bring thread and a needle and the kind of material you expect to use, and make sure that the seller can sew it! I bought a heavy duty portable clone of a sailrite off of Ebay for $250 brand new. It was sufficient for my learing process and most top sewing, but occasionally I had timing movement.
I just sold a chinese industrial sewing machine, straight stitch only, and I kind of wish I had it back now. It formed a nice straight stitch, but I had to get it running right, with a trip to the local shop.
All right, now for zig zag. Zig Zag is only needed really for sewing some sails. It reduces "pucker" or the two pieces of material not laying flat and causing slight turbulence along the sail surface. Zig zag helps to reduce the pucker. One application of zig zag is for spinnakers and other light sails using rip stop nylon in light weights. If you look closely, you might find multi step zig zag used. I have an older portable Singer sewing machine that sews the multi-step zzag just fine, but more importantly it feeds the material better than my industral Bernina. If you are going to sew a Sailrite spinnaker kit, a home sewing machine with zzag will do just fine.
