Mixer blade is chipping

Hi, Put your mixers head in upright position and adjust the screw between the head and the stand. This will rise the head (one rotation is about 1 mm) and the attachement will not scrape the bowl.

Find the screw in the picture as shown and screw it counter-clock-wise which will drop the bowl level down when it is in the raised position and the mixer paddle will not rub on the bowl.
http://www.fixya.com/uploads/images/07F1BE1.jpg

There's an adjustment screw as shown in the picture.
http://www.fixya.com/uploads/images/07F1BE1.jpg
Screwing this screw clockwise will raise up the bowl so the mixer paddle reaches closer to the bottom. Don't go too far, the paddle will start hitting the bowl.

Tip the mixer up and look for a screw on the hinge underneath the top part. Turn this screw counterclockwise about 2 turns and the paddle will clear the bototm of the bowl.

Tegan, sorry to hear you tilt mixer head is drooping and causing rubbing problems with the mixing bowl. This should be pretty easy to fix, if you?ve got a small blade screw driver and a small hex driver (or jewelers screw driver). First, do you still have the K45SS Parts List? If not, you can download a PDF version from the KA website. Click on Customer Care>Locate Manuals & Guides> Enter the 6 character model number (in your case, use KSM90P) and select one of the files that appear under Parts List. Turn to page 4 - Case, Gearing and Planetary unit, which shows the exploded view diagram and locate Illus. Nos. 29 & 30. Page 5 lists the parts as Adjusting Screw and Set Screw respectively. What?s probably happened is that over 12 years of operation, the vibrations from your mixer has caused the set screw to loosen and drop, hence the lower mixer head. Both screws will need to be ?adjusted? to move the head back to its original position. Now the problem is removing the head from its pedestal. Turn to page 8 and gently remove Illus. No. 7, Hinge Pin, with a hammer and pin driver. With the hinge pin removed the mixer head and pedestal can be separated and you should have access to adjusting and set screws. I would inspect them for wear and tear, and replace them, if you deem appropriate. It may take a few trial reassemblies to get the mixer head back to the original factory position, but once there, everything should be OK. I hope this helps! Howard, Burke, VA

It is going to low down. the adjustment should at the back of the unit.

The solution provided by luannej is useful only if your mixing attachment is striking the surface of the bowl. By adjusting the screw located at the junction of the head and base, you are actually controlling how far the head is allowed to tilt forward and, thus, the height of the attachment above the bottom of the bowl. Although the attachment striking the bottom of the bowl will lead to wobble (and noise!), it isn't usually the root cause of the wobble. In fact, the wobble may be causing the bowl strikes and adjusting the head height only hides the problem.

The head of the mixer is secured to the base by a large steel pin. Any play between the head and base comes from this hinge and its resulting tolerances. To "tighten" the sloppy tolerances causing your wobble, follow these steps: 1) Lock the mixer's head down and turn the entire mixer upside down. 2) Looking deep into the hollow base, find the small slotted set screw. This screw actually presses against the pin and takes up the slop between the head and pin. Note that this screw is not the large slotted screw I mentioned earlier visible when you tilt the head back. 3)Tighten the small set screw as much as you can. Your wobble should be greatly reduced or eliminated now. 4) Lastly, you may want to readjust the large screw controlling the head's tilt to optimize the distance between attachment and bowl. Hope this helps.

Using one of the bowls, filled it with hot water up to the shaft and where the paddle is hooked up. Using a cotton cloth, wrap it around the paddle and shaft, let it soak for 30 to 40 min. After 30 min, twist the paddle back and forth to loosen up whatever got stuck inside the shaft and paddle. Put a little of mineral oil so that the paddle will be easily remove and it will just slide out from the shaft. 

Read the instruction manual. There is a screw to adjust the beater height, it is where the mixer joins to the stand.

There is an adjustment screw and a system for setting it. You can find a video of it here (or just a ton of people who know all about these mixers). I just found it while trying to troubleshoot the same problem for my wifes mixer.

http://forum.kitchenaid.com/forums/forum.asp?FORUM_ID=196