friquant

@kgg Suggested a smaller needle. Here is a sample with a size 100 needle, front and back.

Here's one more sample of the 0.4mm canvas. This time I've marked the curly Q's with black marker To be clear, it's not the bottom thread showing through that I'm trying to fight. I understand that is a tough challenge on thin fabrics. But the curly Q's are new to me, and I'd like to know what is causing them, or how to make them go away. It reminds me of when I allow a long piece of thread to double over on itself, then the loop that is formed curls together.

Here are two samples on different materials The first is 0.1mm printer paper. The stitches are uniform. No curls The second is 0.4mm canvas. This one has curls. 125 needle, round point TEX 70 unbonded thread

These are round point needles. Organ MTX 190 (R) Reading up on Schmetz Serv 7 needles now...

Glad it's not just me, and sad there's no easy fix! 😁

The past week i notice my top thread is sometimes curling around the bottom thread. A few curly Q's along the seam. It seems most noticeable with thin materials. I'd like these stitches to be straight. (The bottom side actually looks better, which is rare for me.) Ive tried changing the bobbin tension and the top tension. I've tried adjusting the thread take-up spring. Needle is size 125 (Singer 20). Machine is pfaff 545 H4 Fabric in photo is a single layer of thin canvas-looking stuff (0.4mm thick). Thread in photo is TEX 70 polyester UNbonded but I get the same effect when using TEX 90 polyester bonded. First photo is top side Second photo is bottom side

Amazon sent me a replacement, and both units exhibit the same behavior. Still troubleshooting.

I have considered replacing the belt, but it still functions smoothly and it is old enough to no longer have a chemical smell, so I think I'll keep it for now. There is only one belt...from the 45mm motor pulley to the 80mm balance wheel pulley. (No other speed reducer.)

Using the Consew C1000 servo motor with needle position sensor from this website: https://www.amazon.com/dp/B01N6IYMCZ Also running this 45mm motor pulley: https://www.amazon.com/dp/B06ZZ42TGY It is quite convenient that it can do single stitches (the majority of the time). The majority of the time it does give exactly one stitch, and it completes the stitch at its slowest possible speed, which with the gear reduction is about 110 stitches per minute. But about 10 percent of the time, when I tap the gas pedal to ask for a single stitch, it instead does the following: Goes one full revolution at HIGH speed, then Makes a big THUNK sound, then Goes one more full revolution at its minimum speed Anybody else having issues like this? Here's a video. In this video, you can see a wave in the belt when the thunk happens. (Perhaps the thunk is a brake??) Here is a video:

Here are photos of the Pfaff 545, since they are somewhat different than what the 1245 service manual shows. To adjust timing: loosen the two screws at A. To adjust hook-to-needle distance: Loosen the two screws at B (to move the hook saddle) and also loosen the two screws at D and the two screws at E (to adjust the new mating distance of the bevel gears.) As for the two screws at C, they do not need to be loosened. One of the screws at C is resting on a flat spot ground into the hook driveshaft, so that's why you have to use the screws at A to adjust timing.

That makes sense...I've been focusing on the needle thread that I can see while the inner toe is in the air. Open toe would be visible more of the time

This looks good. Here is the unfurled link in case anybody needs it: https://www.supsew.com/download/Pfaff/Pfaff 245, 1245; 246, 1246 Service Manual.pdf Pfaff 245, 1245; 246, 1246 Service Manual.pdf

Is there a video on adjusting the hook to needle distance on a 545? After my original hook broke, I am installing an aftermarket hook and the new hook bumps into the needle so I'm adjusting. I have the hook saddle loose, but how to move the bevel gear so it still fits well against its mating gear?

Good to know the downsides of a roller feed machine. I set this at one point. I'll check and readjust. That sounds like a good idea. The lifting foot mostly rests toward the rear. What is an open toe inner foot?

I'm using a Pfaff 545.

Wheel foot---that's cool! With the wheel directly to the side of the needle, it appears that turning the material continuously while the motor is ticking over would be consistent in "going where you point it". I could imagine the stitch length being longer for a left hand curve and shorter for a right hand curve since the needle is offset somewhat from the wheel&dog. Not that I'm planning to get a wheel right now, this is my first heavy duty machine and I'm still learning what I can do with it and how to drive it accurately

The current setup goes 110 stitches per minute at its lowest speed. That's using a servo motor and a 45mm pulley on the motor instead of the 75mm pulley it came with. In the tight corners I've been letting off the gas to rotate with the needle down.

How to develop the skills to accurately match curves? (You know, like a motorcyclist on a mountain highway) Attached is an image of my practice session. A paperboard box with a smooth curve drawn on it with ink, then my "follow the blue line" exercise with the triple-feed upholstery machine. While I ENJOY keeping the motor spinning the entire time, and taking the curves at slow, continuous speed, when practicing this way I notice that any time the outer toe is touching down, the paperboard tends to pivot about the rear (heel) part of the outer toe. Since the heel of the outer toe is NOT concentric with the needle, this leads to a couple of side effects. Side Effect A: Any rotation of the paperboard while the outer toe is down not only changes the direction of motion, it also moves the current position to one side or the other. Side Effect B: Any rotation of the paperboard while the outer toe is down increases the stitch length because in addition to the forward motion of the feed, it now has the additional lateral motion from my rotation pivoting pivots around the heel of the outer toe.

Got the remains of the hook out! Soaked it for a few hours in penetrating oil, tapped on it a lot with a smaller hammer and a long screwdriver, applied heat from a kitchen butane torch to the center portion, more tapping with the small hammer. Eventually I noticed it was budging a small amount one way then the other from the hammer taps.

I pried (gently I thought) on the hook from the left side, rotating the handwheel in between attempts, and the hook broke. I have now soaked it with penetrating oil (should have done that first!) in hopes to get the remaining part of the hook removed so I can install a new one.

Yes the machine was running before teardown. The user manual on page 14 says to "take out set screw 20 (Fig. 4) and pull the hook up out of the machine." Set screw 20 appears to be the screw at the center of the bowl that is removed in the photo. My guess is that the hook is rusted to its supports.

After carefully filing and polishing the end of the moving part of the hook, here is the new tip alignment (photo) The original symptom is much improved. It will even stitch with TEX 30 now, so long as I'm careful while hooking the bobbin thread.

Is there a secret way to knock the hook loose? I've removed the center screw, but the hook still seems to be stuck. I've even tied parachute cord around one side of the hook and pried up with a long screwdriver. The hook flexes somewhat, but does not budge.

Your photos are super helpful! I like those alignments a lot better, as there is no way for the thread to get stuck. The part numbers stamped on mine are pfaff 18348 (Cap), and pfaff 18346 (Base) As for checking the exploded view of parts, I found this document: https://www.diamondneedle.com/documents/Pfaff Parts Manual/145_545.pdf but the part numbers in there all start with "91-010".

How should the fingers of the bobbin case Cap align with those of the bobbin case Base? Attaching a photo of the alignment I've got. The alignment looks off to me on two accounts: 1. the hole one the Cap is offset form the hold on the Base 2. The longest protrusion of the Base sticks out farther than the longest protrusion of the Cap. The symptom is that when the thread comes around the bobbin, sometimes it gets caught on the outermost protrusion of the bobbin case Base, so instead of making a stitch in the fabric it has made a loop around the undercarriage. With TEX 90 or TEX 70 thread the machine is usable, as then the above-named conundrum only happens if you pull excessively on the needle thread while hooking the bobbin thread. But with TEX 30 it happens even during normal stitching...It might get five or six good stitches in before it locks up. (Not that I expect to be doing much stitching with TEX30, but we didn't yet have the color we wanted in a heavier thread.) I'd be interested to see photos of alignments on other 545s, and especially to hear if anyone has adjusted/modified their alignment to make it work more reliably.