Uwe

As you turn the wheel, the outer presser foot is supposed to start lifting up the moment the vibrating presser foot presses against the feed dog (or against the material if there is any). There must be something that prevents that from happening. Your foot lift linkage is not working properly. I have strong feeling it has to do with how you adjusted the feet for same lift. What exactly did you do to adjust the foot lift?

Floyd, you are correct - the clamping arm itself (where we loosen the screw) is indeed fixed in its position by its connection to the feed cam arm on the main shaft. But we're really rotating the shaft that the clamping arm holds on to, not the clamping arm itself. It's hard to explain in words without writing a novel. Might be a good video topic.

Things may actually bind on the housing, not the fed dog. I've had a few machines where I managed to get the adjustment so out of whack so that the foot lift linkage was touching the cast body and causing a bind. Make sure your foot lift linkage looks something like this: The linkages are all connected and it may be tricky to get it into the right position. Sometimes you can adjust the linkage like shown below to get it back into the correct range of motion: This arm should be vertical in the middle of its range of motion: If things are really out of whack you may need to re-set all the linkages as as shown in this video where I replaced the thread tension release guide:

I managed to overcome my fear of drilling holes into perfectly good sewing machines yet again to install a swing-down edge guide on my Cowboy 4500. It was the logical next step after making the extended hand lever. I used the KG-967 edge guide in this video. The KG-967 is the extended version of the KG-867 and has 20mm more reach (the adjustment range is offset by 20mm). Both guides actually work on a Juki TSC-441 class machines. Here's the video for your entertainment:

I made a video that shows the rest of the installation. I'll start a separate topic for that, but it makes sense to include it here as well:

I tried out a concept I had in mind to extend the manual foot lift lever on 441 class machines. The topic had come up with folks installing a swing-down edge guide on their Cobra Class 4 machines. The offset of the hand lever to the right avoids interference with the edge guide and you can use both at the same time. My experiment is more of a proof of concept and looks a bit crude, but it works quite well and feels very solid. The gravity based automatic release when you press the foot pedal works too, which is important I think. My threads are 1/4"-20 which is a bit coarse for this application and wants to work itself loose over time as you operate the lever. A drop of Lock-Tite on the threads might help with that. Here's the original hand lever on my Cowboy 4500: Here's the extended version I made. I used a 3/8" connecting rod nut, drilled out one end with 10mm bit to fit the protruding shaft stub and then drilled and tapped holes for the set screw and the ball lever. The extension could be executed in a more elegant and polished fashion, but I was on a mission to just try and see if it works at all. A "proper" version could be made from a 10mm bushing sleeve like this one sold by KarTek for $4.99: or a 10mm sway bar bushing like this sold by IRO for $1.99 Of course if you have a lathe in your garage, you can just make one from scratch.

Can you please post some close-up pictures of your hook and also the spec page of your manual? If your hook as a part number referenced anywhere in a parts list or diagram, that would be super helpful, too. I am curious to see how the specs differ from the Juki LS-341 original. You're one of the few people who have access to this exceedingly rare Cobra Class 26. The Leather Machine Company for some reason is almost secretive about that machine. A postage stamp size image is all the info they offer online. It is possible that your machine's clone manufacturer made some modifications and perhaps used a hook that is different from the original Juki design. Some Juki machines (e.g. Juki LU-563) support two interchangeable versions of their hook, B1830-563-0A0 and B1830-563-BA0, the latter designed for "thick" thread. Perhaps there's a comparable thick thread version of Juki LS-341 hook design available.

This Ebay seller (Jim Taly) has the needles you need in all sizes: http://r.ebay.com/7z3Umx I've ordered needles from Jim Taly on several occasions and I've had good experiences buying from him. I'm sure several of our banner vendors carry them, too. Your machine may need to be adjusted to make it work with these needles.

None that I can see for us slow-sewing folks. If you're using the motor without the brake to drive a racehorse garment machine at 4000 stitches per minute, the machine's momentum may cause it to run on for a few stitches after you let go of the pedal. High-speed machines that need to stop on a dime the instant you let go of the pedal will need the brake pad on this motor. My count-along sewing pace does not require a brake pad.

Some servo motors have a built-in brake pad that will keep the motor from spinning unless you depress the pedal a little bit to release the brake. This brake also makes it hard to turn the handwheel unless you depress the pedal. If your motor looks like this: it will have a break pad that looks like this: When I use one of these motors, the first thing I do is remove the brake pad. Just remove the plastic cover on the left (three screws) and then you'll see an arm with that curved metal+cork brake pad that presses against a wheel. Two screws hold that pad in place. Just remove those two screws and the brake pad. If you have a different motor, the tightness may be due to gummed-up bearings from dried-up-oil-turned-varnish glue or general crud in works. I've had machines that barely turned when I started working on them. A few thorough oilings often help: drip oil everywhere you see (or suspect) parts moving against each other as you move the hand wheel. Work the hand wheel back and forth to let the oil get pulled into tight spots by capillary action. Let it sit for few hours to soak in and liquify dried up oil varnish, then repeat. Things often improve dramatically after a day or so. I sometimes spend a few days just oiling and moving the hand wheel whenever I walk past a project machine I plan to work on. If it does not improve, there may be something physically worn, or something's rubbing or touching that shouldn't (like teenagers.) For belts, try an non-big-box old-school hardware store. They sometimes have a rack of general purpose V-belts in one-inch increments. Look for size 3L (3/8" wide) and then the length you need.

I have a Pfaff 1295 for sale in the Detroit, Michigan area. Earlier in life this machine was set up as a full-function binding station running on three-phase power and an air compressor. It shows signs of only moderate use and the original Pfaff hook is in very nice shape. It's now ready for a simpler, yet still productive life with all manual controls and a new Consew CSM550-1 servo motor. I fabricated some custom parts to make the thread tension release work with the manual foot lift mechanism. The demo video below should tell most of the story.

Sigourney Weaver probably knows.

Machines not only vary in where their intended application range falls, i.e. light/medium/heavy duty, but they also differ in how wide a range of needles sizes they handle well. Some machines are generalists by design and support a wide range of needle and thread sizes. For example, Consew 225 specs supports needles from size 12-24 (Nm 80-180) and threads Tex 35-138. Another generalist, the Juki LU-341 supports needles 14-24 (Nm 90-180) and threads Tex 40-138. Other machines are specialists by design and tuned for a very narrow range. For example, the Pfaff 335 specs officially call for needle sizes 12-16 (Nm 80-100) and threads Tex 35-69. In the heavy duty category, the Juki TSC-441 class has a fairly wide design range of needle sizes 20-28 (Nm130-280) and threads from 92-415. Many machine designs can extend their design range to some degree on either end, but the basic design range they start from does make a difference in how versatile they are in supported needle and thread sizes.

If your main goal is saddle and tack repair as indicated in your profile, then the "field plowing" Cobra Class 4 (or any other Juki TSC-441 class machine) would be a good candidate to cover a large range of your sewing projects. If you need to extend that range downward towards more delicate "Sunday church trip" projects, get a companion Juki LS-341 class machine (e.g. Cobra 26). Neither will win the hill climb race, but at least they'll get you to the top to enjoy the view.

The Nm (Number metric) needle size number is in 1/100th of millimeters, so a Nm 100 is 1.00 mm thick, a Nm 200 is 2.00mm thick, etc. The other number 20,21,22, etc. are usually Singer size designation and do not represent any actual dimensions.

The Adler 104 Operator's manual (Manual_Adler_104_105.pdf) may give you some additional information. It also specifies the 328 Needle system to be used. Here's a picture of the Groz Beckert Version of the 328 leather point needles, which show the various names this needle system goes by. The usual suspects in the banner ads will have them in stock and they tend to offer more guidance than the Ebay sources.

I stumbled across a suitable set of measuring cups at a local surplus retailer and decided to have a go at a stainless steel cap for my Mitsubishi CU-865. $10 for a set of four measuring cups and the 1/4-cup in that set was the right candidate. Here are some pictures. It turned out almost as nice as the $125 Pfaff version, I think.

Sewpro does not have the SP-1100 motor (or SP-1100 NPFL with needle position and foot list) on their website yet, I'm not sure why. They had brought the motor to the TexProcess trade show in Atlanta last May, which is where I first met Sergey (Mr. SewProUSA) and we talked about the motor at length. Excellence in sewing technology and webmastering don't always go hand-in-hand. You basically have to call and inquire about the motor, something rather common in the sewing machine world. One key feature I like about this motor system, aside from the power and low speed torque, is actually the control interface. You can control the needle position function with a simple button that cycles through Up/Down/Off states, which is how it should be. Motor top speed is adjusted via simple "+" or "-" buttons, which is also how it should be. Other, more esoteric functions are set via a crude menu system that is just as cryptic as other controllers. The needle position sensor is optional and runs about $25, I think. I'm not connected to SewPro in any way other than having talked to Sergey and ordered two of his SP-1100 motors. I just like the motor, that's all. I took a few pictures of my SP-1100 NPFL motor, which is currently serving mobile test setup duty. The motor body itself measures about 4" square on the mounting faceplate and 6" long (not counting the pulley).

Most hooks of that style have a tension spring that can be adjusted. The bobbin usually spins counter-clockwise. The thread gets pulled through the slot in the bobbin case and under the blade of the tension spring. The thread needs to emerge from under the tip of the tension spring. The bobbin case tension spring has two screws, one fixed and one for adjusting tension. An eyeglass repair screwdriver from the drug store works well for working on these tiny screws. Bobbin tension should be very light - just barely noticeable when pulling out the thread with your fingers.

The left side looks better, if not quite good. Perhaps you were listening to Les Miserable and when she said "There was a time when it all went wrong" your top thread popped out of the tension discs.

Maybe your hook is correct after all. This picture from MooseTrading shows details and (slightly wrong, but workable) top threading path (visit http://www.moosetrading.com/sites/default/files/products/img_20150310_131615127.jpg for high-resolutuion image) I need to make one of those cool see-through slide covers!

It's hard to tell, but the machine looks a bit incomplete and slightly messed up. There may be a reason it was so cheap. This machine isn't even close to worry about the bobbin thread tension. It's like worrying about tire pressure when you're missing the steering wheel and seats in your car. Post a couple of pictures of the head from different angles and underneath. We may be able to figure what you're missing or what needs fixing. Don't hook up a motor until you can hand turn perfect stitches. A lot of damage can be caused under motor power if parts are missing or wrong.

The hook does not look like a Pfaff hook for that machine. The original would have a bobbin cap. A hook from a different machine may not work at all. The Pfaff 1445 Parts Manual will be a good reference for finding out which parts may be missing or wrong. Your hook and bobbin case/cap should like similar to this:

Those pictures are smaller than the bobbin itself! I can't see much of anything. When re-sizing a picture, aim for a pixel count of around 1000 in the long dimension.

It doesn't look like the Juki TSC-441 (Cowboy 4500 etc. ) style throat plates will work, at least not without modification. I took a picture of my 441 plate and sized it to match the scale of your photo. I lined up the needle slots on both plates, so you can see where the other dimensions line up or not. The Cowboy holster and stirrup plates are not exactly cheap at $160 each - a bit expensive for experiments.