UPDATE 7/3/14: I recently purchased a refurbished Consew 226 to work alongside the Sailrite. For several tasks, I am finding the Consew to be a better fit, especially on projects in which I am not always sewing through the same number of layers. With the Consew I am exclusively using a TEX 45 bonded nylon thread (see these bags), and am mostly using a TEX 40 polyester thread with the Sailrite (like I use on these wallets and pouches). This combo is working well for what I am doing. If I was to continue only using the Sailrite for all my production, I have a feeling it would eventually start causing a lot more problems. It just doesn't seem like these machines are made for production work (it's not a fully industrial machine after all). But for less intense work, it seems to be just fine.
My sewing machine and I have been together a little over a year now, so I think it is high time to talk a bit about this lovely beast. She's a Sailrite Ultrafeed LSZ-1, a semi-industrial machine made especially for sewing through multiple layers of heavy materials like canvas, leather, upholstery fabric, or in my case, bike tubes. I tell ya, without this machine, I wouldn't have gotten as far as I have with my bike tube adventuring.
Before I had this machine, I had very little experience with and did very little research into industrial and semi-industrial machines, so I don't have much to compare this to other than all the many home machines I have used. That being said, just the fact that it has a walking foot (the most amazing thing ever!) and a more powerful motor than the old home sewing machine I had been using, has made it indispensable for my business. Once I played around with it for a bit and figured out all the settings, the ease with which I could get professional looking seams was amazing. Just getting decent looking seams out of my first machine was a struggle (not the machine's fault, surely its makers never intended it to be used for sewing rubber).
I read about this machine in Make magazine and I knew someone who had one, so I had done a little bit of research. Practically all the reviews I found were overwhelmingly positive, which made me a bit suspicious (with the exception of one reviewer who, while admitting it was a good machine, said that Sailrite's choice to go with a plastic flywheel was akin to wearing cheap shoes with a thousand dollar suit). But, it seemed like a pretty decent machine for the price. Plus my friend had good things to say about theirs so I was seriously considering the investment. THEN...the day before my birthday I was presented with my very own bright and shiny Ultrafeed sitting in a custom made table built by a good friend and one of my biggest supporters! After some difficulties with skipped stitches (which was determined to have been caused by some minor adjustments that were made soon after I got it) I was off and sewing! And I will say that it has been a great machine ever since, and now I understand why everyone was raving about it. It has worked very well for me, and has made a huge difference in my business.
There are a couple things that have irked me that I want to mention. Yeah, the plastic flywheel feels cheap, but so far I've had no problems with it. There's no light, which took some getting used to. Also annoying was the fact that the electronic foot pedal that comes with the machine is cheap and makes speed control difficult. I was lucky enough to have someone around who knows how to fiddle with electronics and wiring. He replaced the cheapo pedal with an older resistive style pedal, which made it much easier to control the speed of the machine. The circuit board from the electronic pedal was put into a custom 3D printed case and is wired to the new/old resistive pedal, which allows for some fine-tuning. This makes it really easy to go super slow if I need to.
It do think that there are some features that should be automatically included, but are add-ons, and they aren't cheap. During Sailrite's holiday sale last December, I caved and bought an LED light and their reverse stop & lock knob, which allows you to lock the stitch length lever in place (seems that should be a standard option, is that just me?) I also went in for a right angle binder, which really has nothing to do with the overall operation of the machine, but I have really loved it. Since the machine has been working so well for me and the add-ons I got have been pretty useful, I won't complain about this, but I think it's worth at least mentioning.
One last thing I want to mention is that I exclusively use TEX 45 bonded nylon thread and TEX 40 polyester thread. They both work beautifully with a little bit of tension adjustment when switching between them.
Overall, I'd say it's definitely a good machine, and I'm finding that it's still a great fit for what I am doing, especially with a few modifications (the new pedal, adding a light, and the stop & lock knob). Now, for some videos!