I have a craftsman chipper / shredder and it doesn't do a very good job - is there a piece to change or a blade to sharpen?

I dont think you need to remove the fly wheel to sharpen blades. Remove the housing an the blades are visible an removed that way. Not a hard job at all.

The flywheel takes a puller, but you should not have to do that just to sharpen the blades.

there's a website that has all this informationthere are many actually but I personally like few .. let me know if u need help
thanks

the chipping blade use a knife sharpening hone the shredder side you can flip some over

In your browser type in http://www.mtdparts.com/webapp/wcs/stores/servlet/Home_10101_19502_-1?cm_mmc=MSN-_-MTD-_-Yard%20Machines%20Parts-_-Sponsored

I would check with an MTD dealer. I look online and found a site for the chipper blades and they wanted $40.00 USD for each. It may be worth your time to take the other ones out and get them sharpened.
Good Day.

The blade(s) should have usually two bolts on them depending how many blades you have. Mine only has one blade held on with two bolts and that is only on the side that cuts the larger branches up to two inches in diameter and should be sharpened on a grinding wheel because it has a specific angle to it. The other side that chips smaller branches and twigs it a type of flailer, meaning pieces of metal just swinging around to mash up the sticks and do not need sharpening.

http://manuals.mtdproducts.com/mtd/public/list.jsp?BrandCode=10151

above link will provide a pdf of manual

I’m happy to assist further over the phone at https://www.6ya.com/expert/rolandw_c013176d62ee17ae

It takes me about 5 minutes to Remove, Sharpen, and Re-install my chipper blade for my Bolens mc2500. First, If your using a screen or rollers in the discharge, then remove them. Look underneath, and you will see the thick flywheel. Make sure the spark pug wire is disconnected, then slowly turn the flywheel by hand until you see the two hex head bolts that hold the chipper blade to the flywheel. Also remember which way you take it off, so it goes back together the same way. using an open end or combination wrench remove the two hex bolts. Now to sharpen, I use a medium/ coarse honing tool made for lawnmower blades. I clamp the blade to the top edge of my Bolens with a pair of visegrips, then a little oil, and the sharpening tool, and I'm done sharpening in about 2 minutes, and then re-installing, reversing the removel process. I hope this helps.

Maintenance (excluding the power plant) Your primary maintenance concern with chippers and shredders is their knives. You can re-sharpen chipper knives, whereas you can reverse shredder flail-type knives when dull but you can not re-sharpen them. You must sharpen chipper knives with special sharpening equipment because they are made of high-carbon steel. Maintaining sharp knives can lengthen their life and the life of the machine by keeping power requirements low. An over-dulled or chipped chipper knife will need extensive sharpening, which will remove a large portion of the blade. This obviously will shorten its life. As soon as a blade is slightly dull, you should sharpen it to minimize the amount of blade-material that you remove. All knives need sharpening at the same time to keep them in balance-even if only one is worn or chipped. Also, you must use matched sets to keep the knife the same distance from the anvil for proper chipping and feeding. After removing the knives, clean the area where they are fastened with a wire brush to make sure they will align correctly. Be sure to torque the knife bolts to their proper specifications. You will need to examine the anvil and be sure it maintains a good, square edge. Occasionally, you may need to remove and sharpen it.