need help changing knives on dewalt 734 please

[Bob Riefer]

Well, I put knives into the planer for the first time this past weekend, and something went wrong. We thought we followed the instructions, but the blades were set too far in I think because the cutter head was rubbing on the wood (while the knives were barely touching the wood) and now I have scuffs on the cutter head (which theoretically shouldn't cause any harm) and a damaged blade clamp to replace.

The model I have has little magnets that your are supposed to use to set the knife depth perfectly. However, the manual doesn't clearly show how to use the magnets, so I think that's where we went wrong perhaps. I'm thinking we put the magnets in the wrong place and therefore it was depressing the knives too far in when we tightened everything up.

I've searched for pictures/videos and haven't found anything yet. I would appreciate if anyone has any pictures showing how to change the knives so I can be sure I don't damage the machine further.

Thanks!

[Ken Fitzgerald]

Bob,

I'm getting ready to leave for a doctors appointment so I don't have time to research this but theoretically I'd place the magnets on the edge of the outfeed table and adjust blades to the height and parallel with the outfeed table.

[Dan Friedrichs]

Bob,

You must have the DW733, not the 734 - the 734 has indexed knives. I'm not sure if you've seen this, but here's the page from the 733 manual showing how to use the knife setting jigs. As I recall, the only trick is to notice that the magnet jigs aren't totally concave - one side has a flat that is supposed to align to the cutterhead.

[Bob Riefer]

Boy oh Boy Dan, you are on the money! I do indeed have the 733 it appears. The unit was gifted to me by a former coworker, he called it a 734 and I never questioned it. Ha ha, I'm so embarassed

Ok, so yes, those are the jigs that I have. When you say "aligned to the cutterhead" can you explain that in as plain english as possible so that I can try it when I get home later? It's a tight space in there and I'm new to this so please forgive my elementary questions. Much appreciated!

[Dan Friedrichs]

It's been awhile since I did this, but if I remember right, it's just like the middle picture above - the non-flat side of the magnetic jig goes towards the knife, and the "flat" on the magnetic jig goes on the flat section of the cutterhead (opposite the side you are changing the knife on). I remember staring at the jig for a few minutes, but once you figure out where it sits, the rest is trivially easy - it's a great system, and it's a shame DeWalt abandoned it (although from their perspective, non-resharpenable indexed knives must be good for sales...)

[Bob Riefer]

Thanks for not picking on me for my mistake on the model number

Ok, so it looks like the "flat side" of the jig is a little "catch" or "foot" that should engage the portion of the cutter head that is cut out. That cut out portion has a flat area, a corner so to speak.

The magnet portion of the jig then hugs the curved portion of the cutterhead that is between the two knives.

When positioned like this, the non-flat side of the jig should push the knives inward to proper alignment, and then I tighten down the two outside screws with the supplied wrench.

With those two outside screws tightened, I can then rotate the cutter head forward to put the remaining screws in and tighten them all.

Does it sound like I'm now understanding it correctly?

[Dan Friedrichs]

Sounds right!

[Danny Hamsley]

Yep, that is how you do it. I will warn you that if you tighten the bolts to what you would normally do by feel, you will shear the bolt head off. Don't ask me how I know this! Just snug them down, then go order some extra bolts!

[Bob Riefer]

Well, I'm waiting for my replacement blade clamp part to arrive, but I figured I'd attempt to set the other knife last night. The way the magnetic jig works, it sticks to the cutter head and provides a stopping point that keeps the knife at the proper position. The other part of the knife positioning process is that there's a spring loaded arm that's trying to push the knife out... so the out pushing motion, and the stop of the jig work together (rather, they counter against each other) to create proper setting depth.

However, what I'm seeing is that the spring is not pushing the knife out fully, and therefore it doesn't meet the jig on the left side (but does meet the jig on the other side). So I'm thinking I'll need to manually pull the knife out far enough to meet the jig. Perhaps a small piece of tape, some needle nose pliers, or a handheld magnet.

What do you think?

(btw, this planer was a free gift from a coworker.. "free" is starting not to seem like such a great deal!)


edit: So, I was just checking the parts diagram again and noticed that the spring they recommend is different than what was installed in mine (and would explain why my knives aren't being pushed out evenly).

Their spring pushes out on both the left AND right side of the blade. Mine only pushes out on one side. Perhaps an outdated design, or a broken spring..

Here's what theirs looks like, I ordered two of them

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