DW734 locking head problem

[Matt Day]

I've had my DW734 for about 5 years and it's been a great planer.

But I've noticed lately that the cutter head seems to creep upward and the lock doesn't quite lock it in place. For instance, I'm trying to plane down some 8/4 maple and purpleheart to the same thickness for some cutting boards, ala woodwhisperer. I'll put the first board through and it will cut 1/16" on the front of the board, and I can hear the cutter head slipping up so by the end of the board (we're only taking a 2' board here) it's not taking as big of a cut.

After the board goes through, I can unlock the cutter head and see the head drop down back to where I wanted it to be for the whole cut.

Is there anyway to adjust the tightness of the locking mechanism? Or is there anything else I can do?

Thanks

[glenn bradley]

I have that planer and had a similar experience. The cure was a very good cleaning of the four posts. Final step was a wipe-down with Denatured alcohol so that they were very clean and dry.

[Matt Day]

I took the planer partially apart this afternoon. I pulled the cover and saw a little bit of build up on the columns. I also took off the locking mechanism and found some buildup (pith I suppose) where it contacts the columns. Thinking positively, I thought this was the culprit and I thoroughly cleaned it all with DNA.

Since I planed both sides of all my wood while the planer head was slipping, I figured there wasn't a true flat face anymore, and proved this to myself at the jointer. So with a freshly jointed face it was back to the newly cleaned planer. With the head locked down I put a board through and it cut the first part of the 2' board but not at the end (I put pencil marks on the wood to make sure). To test it, I unlocked the head, then locked it right away without adjusting the depth of cut up top. To my dismay, the head dropped down like it was doing before and when I put the board through, it cut more at the front of the board and a little more toward the back. I did this about 5 times and each time it cut more wood until finally all my pencil marks were gone, again, with no adjusting of the depth of cut. I'm not going to pass each board through 5 times just to get a parallel face, especially when I need to get 8 pieces all the same thickness.

I don't know what else to do, but I'm not going to keep thinning my $100 worth of purpleheart and maple testing it. My next step is to call Dewalt and see if they can help.

This DW734 has given me years of good service, but I fear it's giving up the ghost.

[glenn bradley]

Good effort. Sorry the behavior is unchanged. I cannot see any method of adjusting the pressure. If my lock applied much more pressure it would bow the columns. I think you are on target calling DeWalt. Unfortunately the only assistance I have ever gotten out of that outfit is being told to "bring the unit to the nearest service center, that is all, beep". Perhaps the lever/collar mechanism is available as parts and can be replaced if just plain worn out ;-)

[Dan Friedrichs]

Are you sure the cutterhead lock is slipping? For instance, can you place a board between the cutterhead and bed (to use as a lever to try and pry the head up), and with the lock engaged, observe the lock mechanism friction piece sliding up/down on the posts?

If so, the problem is obviously the head lock failing to hold tightly enough.

I had a DW733 that exhibited a similar problem, but the problem was not the lock, but rather the two threaded rods that raise/lower the cutterhead. They had worn against the bearing they ride on at the bottom, causing lots of slop.

[glenn bradley]

Dan's a genius. I didn't think about that.

[Matt Day]

Dan,

Thanks so much for the suggestions - after work I'll try lifting the head with a board to see what it does.

Have you ever taken the cutter head assembly off the treaded rods? Do you just keep moving the assembly upwards until it comes off the threaded rod (after taking of the locking mechanism of course)?

[Dan Friedrichs]

Yes, I took my cutter head assembly off the threaded rods to replace the rods. I don't recall exactly, but I believe you are right: it just threads off the top. The rods have a slot towards the bottom of the shaft that rides in a metal bearing-type-thing, allowing them to turn but keeping them fixed in the vertical plane. In my case, that slot had worn and elongated significantly in the vertical direction, allowing both the cutter assembly and rod to move up and down. I never thought the head lock did much to stop movement, but once I replaced those threaded rods with new ones, performance was much better. Obviously this is a different problem entirely than just a slipping head lock, but maybe something to investigate if you planer has had a lot of use...

[Matt Day]

So I pretty much disassembled the planer this evening. I noticed the threaded rod was not locked from moving vertically upward. The C shaped plates have been ground down a bit from the rod, and the slot the C shaped plates goes in appears to be wider than they should be. See the attached pictures. Is this slot in the threaded rod supposed to have a tight fit wtih the C shaped plates?

I'm going to try and bring it by the Factory Service Center tomorrow or the next day to talk with the helpful tech I talked to on the phone today.

[Norman Hitt]

Ummm, I don't see any slop at all, must be REALLY Tight, 'cause I can't see the pictures either.:rolleyes::D

[Matt Day]

oops, thanks Norman.

You can actually see a sliver of metal in the pictures.

[Dan Friedrichs]

Matt, that's basically what mine looked like, but maybe a little worse. I believe the C-shaped piece should rather tightly fit in the slot - I'd guess the play between the two pieces should be around 1/32" or less. I bought new threaded rods and plates from DeWalt service's website for ~$20/pair, IIRC.

[Matt Day]

Well, after waiting on some parts that my local factory service place didn't have, I'm finally back in business after about $60 in parts. Since I had the whole thing apart I decided to replace just about everything it could be. I started with new threaded rod and the C shaped pieces that hold them in place which cost about $20 for all. I also replaced all four of the arms of the locking mechanism that contact the posts (the ones with the half circles) for about $20. These seemed to develop some play at the rivet that holds the half circle to the arm, which may have made the "lock" not as good. After replacing them, it still feels about the same so I'm not sure how much this did but didn't hurt. Then I replaced the 4 square silver bushings that hold the rollers in place for about $20 - after talking to the repair guy he said these ovalize over time and could be allowing the rollers to raise.

While I was at it, I put in some new knives I had around and waxed the tables, and made sure the knives are parallel with the table. It feels like a new machine and cuts beautifully again!

If anyone has an older DW734 that's not working like it used to, I highly suggest this overhaul. For $60 and about 3 hours of time you'll have a new machine.