When sewing, my fabric will get hung up in the feed and if I don't stop in time it will snag so badly the I need to pry it out with my seam ripper. It has often completely ruined my projects

• If you don't keep the buttonhole foot level, the feed dogs may fail to feed the fabric.

Keeping the buttonhole foot flat can be somewhat tricky. The reason is the buttonhole foot is different from the presser foot. It is longer and wider.
That's why it is not easy to keep it flat as you sew. So many times, we have uneven layers of fabric on the seam allowance while we sew. Besides, we also sew too much near the edge of the seam allowance.
Uneven layers in the seam allowance cause the buttonhole foot not to stay flat too. Sewing near the seam allowance also causes the same problem. These two causes can even tip the foot. Thus, it will result in the feed dogs losing their traction. As a result, they fail to feed the fabric properly.
In the end, it also causes the fabric to stop moving, and the needle gets stuck on one spot. The result is a lot of stitches appearing on the spot the needle stops.
Solution ; The solution is to keep the buttonhole foot as flat as possible. It may be challenging, but it is necessary. It will help the feed dogs have even traction throughout the sewing process.
If the fabric or seam layers are uneven, you need to compensate for different layers. It means making them even by adding fabric to the side with fewer layers. For example, balance the equation if you have four layers of buttonhole fabric on one side and two on the other side.

I've been sewing for over 30 years, if it were me & I bought a Bernina & that happened I'd take it back & find out why it happened.
I'd take a piece of the fabric & thread & let them sew it & see what happens.
a machine like that should sew so good, you'd be saying look what I sewed, instead of this can't be happening...

A walking foot is a foot with feed dogs, or a similar fabric moving mechanism. This is useful when there are many layers of fabric or slick fabric. Then the top layer of fabric can be made to travel at the same rate as the lowest layer (the feed dogs) or an slightly different rate. Then the fabric layers will stay even for the entire length of the seam.

A walking foot sewing machine has this feature built in. Thus you don't need to adjust extra hardware to keep your fabric aligned. (On some, specific feet are needed to use the feature. However, it is easier to adjust than the separate walking foot that I have for my older Singer sewing machine.)

I hope this helps.

Cindy Wells

Feed dog lever should lower the feed dogs, these are the teeth that grip and move the fabric foward and backwards as the needle goes up and down, they are under the needle plate.

Only time you would lower the feed dogs is if you want to do free motion embroidery or darning perhaps.

So no, don't touch for normal seam stitching. If you are sewing very heavy fabric you may want to lessen the pressure on the presser foot a little (if your machine has this adjustment it will be a knob on top of the head above the pressure foot area).

You may find that your machine doesn't really like very thick fabrics. Sewing something like upholstery weight with a domestic machine is pretty ambitious; an industrial strength machine is best bet.

You could try using a seam jumper when crossing bulk, this is a little plastic device that you put in front and behind the pressure foot to keep it level as it goes over the bulk. This then means the machine can keep feeding the fabric evenly. WIthout it, the feed dogs arent getting enough pressure, the machine slows and can't feed the seam, your needle may deflect and strike the foot, and broken needle may be the result.

Here is a link to one called a Jean a Ma Jig, http://sewing.about.com/gi/dynamic/offsite.htm?site=http://www.clotilde.com/store/

Also, try bashing the seam you are wanting to sew across first with a hammer and always trim the seam allowances inside the seam if you can. If sewing denim, use a denim needle with blue coating, it helps it pass between the densely woven fibres in this fabric.

However, it may be that your machine just hasn't got the strength to stitch through more than 6 layers, many wont. Especially if you use buttonhole twist thread to get the read to wear jeans seam finish. I often resort to using my old SInger 20U industrial straight stitch when altering jeans.

Machine breaks needles
1.make sure you are using the right needle for your type of sewing machine.
Most machines can use generic Schmetz needles. There are cases where the machine will only use ones specified in the owners manual.
2.the presser foot may not be installed properly
3.use the correct needle for the type of fabric you are working with. To fine of needle on heavy fabric or to course a needle on silk or jersey can damage fabric.
4.let the feed dogs guide the fabric & the feed dogs will work with the presser foot .
5.the needle is not all the way in -push all the way up against the stop

also make sure to use the right tension for what your sewing
also clean under the needle plate & bobbin area for lint or loose threads

if these suggestions don't work & stop the needle breaking then it may be neccessary to have the machine serviced

If you take a look at this website you'll see the different feet for some makes
http://www.sewingpartsonline.com/sewing-machine-presser-feet.aspx

I assume you mean what are the different feet used for?
General purpose foot will have room for the needle to swing through wide stitches, but enough foot to hold the fabric and move it through against the feed dogs. This is the one you use most.
A straight stitch foot will have a little hole so that the needle only goes through a small area and the fabric can't move to give a neat plain straight stitch.
Plastic wide toe foot is good when you need to see what you are sewing onto such as applique (sewing a piece of fabric onto another with a wide satin stitch).
Teflon coated foot is good for slippery fabrics, it grips well.
A roller foot is great for textiles like leather and vinyl which don't feed nicely.
Then there are lots of feet for turning the fabric to sew it such as a rolled hem (these come in different widths so you can turn 2mm, 4mm or 6mm for example).
Felled foot (like the side seam on your jeans) joining two fabrics in a felled seam
Then there are feet for quilting and darning where you need to move the fabric smoothly in different directions, these will be small foot area and open stitching space usually.
Walking foot is a special one, part of the foot moves because a part of it clips around the needle bar and the up and down movement then activates the foot so its little teeth help to move the fabric from the top to supplement the normal feed dogs below. Pfaff machines actually built this function into their machines some years ago to give even feed from top and bottom. Great for quilting thick fabric sandwich or sewing together fabrics that want to slip or not feed smoothly.

There is also similar info here http://sewmamasew.com/blog2/2009/06/feet-feet-feet/ which may help you to see the different uses and feet available.
Most manufacturers will sell their machine with 4 or 5 of the most used feet but often have more to buy aftermarket. And many feet between companies look very alike so if you have a clip on foot from one brand it may work on another machine with a clip on foot.

I hope that this is what you were asking.

Found the manual here on features page http://jukihome.com/products/mo644d.html
Differntial feeding is covered on page 25, and the diagram showing location of the differential feed knob and stitch length knobs inside the cloth plate is on page 2.

So swing open the left cover (cloth plate) to access these controls.

Differential feed means you change the feeding speed of the two feed dogs so the front one feeds at a different speed to the back one. Effectively, this either streches the fabric as you seam, or pushes the fabric together as you seam. So if you want to do a rolled hem "lettuce" edge you are stretching the fabric with the differential feed to achieve this, turn the numbers up. If you are sewing a loose knit and it is "waving" then turn the diff feed down to 0.7 or so to squeeze the fabric back together.

That's basically it! Like anything on an overlocker, test sew, adjust, test sew, adjust until you are getting the right effect.

I don't think you can adjust the feed pressure on this machine. I have the same machine and the same problem and my solution is the same as you've already mentioned - raise the foot and move the fabric by hand. I would do it by turning the wheel by hand until the seam is clear of the foot to prevent breaking a needle or sewing my fingers.

You should take it for service. It could be slightly out of time.