Quade

If she knows what she's doing then that's great. I imagine you have to find out what kind of CPU it uses then reverse engineer the EEPROM. See how the code works then change it to do what you want it to do. Maybe you can just re-write some of the tables and not look at the code itself.

Being able to read and burn is just the first step. Do you know how it's all laid out inside the EEPROM? I'm actually working on operating a sewing machine with a Raspberry Pi4. Going to replace the stepper motor driver and main drive motor controller with my own hardware. I wouldn't if that wouldn't be easier than trying to reverse engineer Juki's eprom? https://semsi.com.mx/Manuales/JUKI/AMS-215C engineer manual.pdf Looking at page 169. I wonder if it would be easier to reverse engineer the contents of the floopy.

That's a good idea. On the 211 the numbers are printed on the hand wheel so there's nothing to change.

Same. There are YT video's showing how to "detune" a 1541 to work with thinner material. I use a 1541S for making bags mostly. It'll sew through everything I've needed it to sew through. It's hard to beat that machine. I got mine from "Goldstar Tools". My only complaint was the table and the servo were the cheapest you can find. They work, they just aren't as good as my other machine table and servo I got from Amazon. The 1508 is the next step up in heavy duty I believe from the 1541. I looked at them both and the 1541 seemed like the best machine for me. I don't particularly like horizontal hook the 1508 uses.

On my 211, the successor of that machine. I did test stitches into paper with no thread. Then made a chart that showed what each number represented. My 211, the numbers didn't correspond to stitch length either.

I like the Juki.

Yeah. Middle is zero stitch length and up is typically reverse. The thumb-screw lets you lock it so forward and reverse are mostly the same stitch length.

The mechanism of sewing requires that you only turn the crank forward. It has to do with how the hook moves to catch the thread. When you turn the crank backwards, the hook goes backwards and can no long hook the thread and make stitches. "Reverse" changes how the feed dogs and needle feed move. The machine is still sewing forwards but the feed dogs and needle are pushing the cloth backwards. You can stop with the needle down. rotate the whole work around and drive over some of the stitches you just made. I've also seen people get the hook into the "release" position then move the work backwards a bit then put the foot down and sew over the existing stitch. That seems like an interesting method to know.

They're about $45 on Amazon. It keeps oil from dripping on you and your pedal. These machines are oiled by filling a felt filled chamber on the top. The oil then works its way down copper felt lined tubes. Eventually it drips off into the pan. Juki's oiled this way have a drip pan with included catch bottle that catches the oil. You have to empty it periodically. Not having a reverse is the kiss of death in my mind. Yes you can work around it but, it's not fun. I'm getting rid of a needle feed consew primarily because it doesn't have reverse. Price isn't that great for a machine with no reverse. I paid $300 for the consew. I really just wanted the table.

Delrin comes in black too. I use black Delrin mostly.

I love Delrin. That's some quality work there.

My Singer 211 and Jiki 1541NS both do. A needle feed only Consew 224 was smooth as silk. I did the KGG test. Pulled the feet off the 1541 and most of the resistance went away. I can still feel some additional friction from when the eccentric pushes the lever to move the walking feet. The 1541 only shows the pressure when the foot is down. When the pressure foot is up, it's pretty smooth.

Haha I've been working with stepper motors and sewing machines lately... "Walking foot" of course. I'm curious? None of you with walking foot/compound feed machines feel it tighten when the inner foot presses down on the needle plate? I thought it was just normal for these machines? I think I'll try KGG's idea.

I was running guard-less too. I just keep things away from the action end.

I assume it's a stepper foot machine? I've worked with 2 stepper foot machines and they both get tighter right at the point the inside foot presses down and lifts the outer foot. When the needle just enters the foot is about the time the inner foot starts to press down on the plate. I adjusted my foot pressure to be much lighter but still enough to clamp the cloth and it reduced the tightness. You still feel it when the feet start their walk. Out of the box the pressure foot pressure was set pretty high.

I use a lathe for everything. It's a universal tool I'd damaged a PCV part when fixing a pool pump and didn't want wait till a new part showed up. I used the lathe to clean up the old part. Basically shaved off the old coupler so I could re-glue to it. It's a tool you don't realize you needed till you have one. I've made suspension bushings with it out of Delrin for one of my cars. I needed curtain rod hangers and didn't want to go to home depot. Made some out of aluminum stock. They look pretty good. If I can chuck it in there, I can cut it to size I agree that the sewing machine arms sizes aren't that critical.

My singer is like this. Top feed and vertical hook. I agree I could never tell if the thread was positioned properly. The case opener was normally in the way. I had more thread jamming problems with that machine than any other. I'm pretty sure I wasn't getting the thread into the right slot when it would jam. The Juki I use now, the bobbin holder comes out and you feed both in at once. It never seems to jam up.

On my 211 I had to rig up a puller. The hand-wheel bearing isn't glued in but it acted like an interference fit. It got tighter the deeper it went. I made an aluminum plug to give me something to push on that didn't bugger up the threads. Sometimes the old oil acts like glue too.

1 - The guide to the right of the tension assembled looks like it's flipped upside down. 2 - From my research in the past, it should have the double-tensioner. You can buy the double-tensioner and install it of you want to. I might wait to see if you can get sufficient tension with the single tensioner for what you're doing before I considered changing it out. https://stanleysewing.com/shop/machine-by-function/walking-foot/juki-1508/ Here's another with a single tensioner. Maybe the original ones were all singles?

I sort of feel the same about my 211. It works but it's old and I hate how you set the stitch length using the hand wheel. On the other hand it's a tank of a machine. The modern equivalent is probably the Juki 1508. Mine has the larger bobbin. The 211 is an old finicky design. I don't think I ever got my forward and reverse direction matched up. The reverse lever is clunky and requires more effort than a modern machine too. I'd probably avoid the machine with the cracked belt. It's a bit of a pain replacing the belt assuming you can get one. The hand wheel has to come off and you then fish the belt around the shaft and then down. I don't regret messing with my old machines like the 211 but, I have two newish Juki's I use now. One I got for free. I can get parts for both and they just work.

One of my Juki's has the screws for the guide, one of them doesn't. You need to look on the back of your machine and see if you have the threaded holes needed to mount the guide.

I bought mine from Goldstar. Came in original well packaged box. I will say the table and server were both...underwhelming. I think they save money by sending the cheapest table and servo. They both work fine but, compared to the servo I bought from Amazon and the tables I have, they just weren't as good. I don't really need after-sale support. The shop and user manual are readily available and I don't mind messing with my tools.

Looks like both arms would be relatively easy to fab up. Some tube, and flat stock. Might need a lathe to get ID's correct.

I've given up on old machines. I like the creature comforts of newer machines. Like being able to set stitch length with a knob instead of having to turn the hand-wheel. I never found it easy to find parts for old machines too. Even though it's commonly said they're easy to find. So it's not likely an answer you want to hear. I've never stopped looking for a crank arm for my 211 so I can convert it to a conventional walking foot. It was designed to use an air-cylinder for raising the walking foot but, I just want a conventional manual adjustment. The air cylinder setup gets in the way of a conventional knee lift. These days I enjoy being able to sew without having to jerk with the machine first.

I'd say it's more a guide than a tensioner. https://www.ebay.com/itm/162628519811 or https://www.ebay.com/itm/165279974669 If you can't find the actual part, you might be able to cannibalize the part off a new China tensioner. It wouldn't surprise me if it sewed just fine without it.