Your two questions are interrelated, the "corkscrew knob" controls the amount of pressure the foot places on the fabric while it is between the presser foot and the feed dogs. Two much pressure or too little is no good. The feed dogs should grab the fabric and pull it evenly under the presser foot. Righty-tighty - more pressure, lefty-loosey - less pressure. All you need to do with your hands is to gently guide the fabric under the foot.

The chromes knob top left is probably the presser bar tension (for the presser foot). It should be in the manual too. It should be tight enough for the feed dogs to grip the material. The general rule is the heavier the fabric the more tension you need. If it's very loose the fabric will not feed at all. These parts have oil points.

Snapping, twisting or balling can be bad quality thread; some threads have lumps and bumps, and are uneven. If you need a referance to a good standard I hold Gütermann in high regards, but there are others with just as high quality threads. To small a needle (needle hole) makes this problem worse, if you can up the needle a size or two it might help. It's important to match needle and thread size correctly.

Some emphasize the way the way the thread is wound on the spool, cross wound thread tend to give more twists than straight wound thread on a vertial spool pin. I get this problem now and then too, but I haven't managed to make sense of the theories about it. It doesn't always happen regarless of wounding or if I have the spool on a tread stand behind the machine, horizontally or vertiacally it can happen. It can happen to the best of threads, and you can try the various advice to sort it out. one is to keep the thread in a glass behind the machine in stead of on the vertical spool pin.

Thanks again! I will adjust as needed. So far its been sewing just fine. Every once in a while the machine skip stitches, but I believe that's because the wife is running over her pinned needles with her foot. I told her to remove the pins first, she hasn't had an issue since. I think the machine is fine, the wife just needs to get over the learning curve.

It should be able to stitch over pins (straight across only, not alongside or diagonally), but yes it might cause a skipped stitch, I'm not sure how reliable it is. It's one of those things we really should not do, but we do it anyway. It's not as much the machine as the needle type that allows this. If you happen to have a package of very old needles they will break. I think this was a new feature some time in the late 1950s (at least well established by 1965).

Skipped stitches; double check for needle in the correct way, correct threading of the needle and bobbin case, correct needle type (130 aka 705 aka 15x1), cleaning of the groove behind the needle clamp and bobbin - feed dog area in general.

I have backed off on adopting more of the mechanical sewing machines, running out of room. One of the problems I have seen is finding parts of a broken needle down in the area of the bobbin case. When I have been sewing with a group, and someone is using the sewing machine that belongs to our hostess, I encourage using a tissue or small piece of white fabric to cover the bobbin area when changing a needle.

I agree with cashs-mom on the 301. I have never found anything negative about that model of machine.

I wanted to update and let everyone know I upped my needle size and the machine sews through material like butter now! Having the right needle paired with the thread and fabric was a huge deal with this thicker fabric. I am using a 16 Guage jean needle and wow I wish I would have started with it. Night/day difference now, especially when lock stitching.

This is the largest needle I have found. You have to search a bit more to find size 19 (120), but 18 (110) is in the standard selection where they sell needles. The older machines take these needles fine. There is a Chinese brand that carries up to size 122 (140), but not all machines can take them. These needles are of reasonable quality. I know the old cast iron straight stitchers take them, as well as my Elna Supermatic (beige and tan as well as the green ones). The cocrete grey Pfaffs take them too. My 730 Bernina does not. If you ever should be tempted to try them out, make sure there's enough clearing for the hook and race as the needle goes up and down.

Using the right size needle for the job will help with a myriad of issues.

I sew over pins all the time with my vintage machines and rarely have a problem other than a bent pin. The hinged presser foot was invented specifically for sewing over pins, did you guys know that?

Cari

Great info! I purchased some 110/18 needles for $8 off ebay in a lot. Three 5 packs. Should be here tomorrow. I have a greyish pfaff machine (360). But it's too fast of a machine for the wife currently and the motor is starting to smoke after light use. I am assuming it's the capacitors smoking and not the motor as the machine runs great.