Delta DJ30 12" jointer

Christopher, I owned an RJ42 for many years. Models or brands of jointers don't make much difference, most straight knife jointers are basically the same. The cutterhead has bearings mounted in pillow blocks on each end. There isn't a lot of clearance between the end of the cutterhead and the block. You do not want knives in your jointer that may hit these blocks. Typically, the ends of the knives are not 90 degrees, they are angled back a few degrees, sometimes only on the outside edge where you would be doing rabbeting. If you want to rabbet and use the ledge as a guide, the ends of the knives are set even with the rabbet ledge. Normally, the fence is also used. Keeping against the fence controls the width of the rabbet but, if the knives are not even with the ledge, the cut won't pass on to the outfeed table. It's your depth that is limited to 3/4", you can cut a rabbet as wide as the jointer.

I think I originally wrote, the short point of the sharpened bevel should stick above the gib about 1/16". I should have said between even and 1/16" above the cutterhead, the gib goes on the back side of the long point of the knife, towards the infeed side, the short point of the knives face the outfeed side.The relationship between the top of the knives to the cutterhead is pretty close to 1/16", .0625".  I don't know why the manual says .015", the knives would be so deep in the grooves that there wouldn't be enough gullet to evacuate the chips.

If you set jointer blades perfectly even with the outfeed table, after a cut or two, the tips will be worn so that the jointer won't be able to do it's job. You need to set the outfeed table just a small amout below the tips, .015" would be a bit too much in my opinion for precision work, about right for flat surfacing rough stock. Maybe this is what they meant. If your ends of the knives are even with the rabbet ledge and still long enough to hit the pillow block at the other end, you have the wrong length knives. The end can be ground down but this would be very unusual, in my experience.

Lots of folks turn the locking bar bolts the wrong way by mistake. They work opposite of normal even though the threads are normal. You tighten them clockwise to loosen the gibs, back them up to put pressure against the gib and hold the knives. The heads of the bolts do not hit the knives, the heads press against the groove in the cutterhead. De-laminated the knives? I think some portable planers have laminated knives but it would be something new for a DJ30. Who knows if someone tried to use something they shouldn't have and busted things up?

I would set the knives as I said before. Roll the head by hand to make sure there is no contact anywhere. It should only be a matter of fine tuning the outfeed table to have one very sweet jointer. I hope you have the quiet model, you could hear the RJ42 a block away. Make sure you tighten the infeed table lock before using. Pressure on the heavy infeed table can cause it to sudenly drop to full depth, otherwise. Use the handles on the fence when tipping so you don't get pinched. Good luck.