Dewalt 734 undercut

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Forum topic by Midway posted 10-04-2015 10:03 AM 635 views 0 times favorited 4 replies Add to Favorites Watch
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62 posts in 1483 days

10-04-2015 10:03 AM

I have a Dewalt 734 and have done everything i can think of to stop the under cutting 2” from each end and

approx .03 deep.

-- Midway wichita,ks.

4 replies so far

View poospleasures's profile


833 posts in 2998 days

#1 posted 10-04-2015 10:49 AM

I have the same planer and have very little of this problem. My rule is to have the tables adjusted for the outer ends to be just slightly raised from level. Have sharp blades. Take very small cuts for your last cuts to the thickness you want. Butt shorter pieces end to end as you send them through. Last if the board is long and heavy use your hand to lift the end just a little is it is coming under the last cutter. Good luck. Hope this helps.

-- I,ve had amnesia for as long as I can remember. Vernon

View Tennessee's profile


2901 posts in 3028 days

#2 posted 10-04-2015 11:20 AM

All that Vernon says are good answers and will work.
For me, raising the outfeed table outer edge and raising the board myself when it comes to the end of the cut work the best for me,

-- Tsunami Guitars and Custom Woodworking, Cleveland, TN

View JeffP's profile


573 posts in 1905 days

#3 posted 10-04-2015 12:32 PM

I think to really solve this you would need to figure out which one of two possible “reasons” is causing this on your machine.

Seems it is one of these two:
1) front rollers not in perfect agreement with back rollers
2) back rollers plus outfeed table not adequate to keep board level after leaving front rollers

Clearly, all of the common answers focus on #2 above. If that is the right reason, then to the previous posts, you can add the idea of putting a much longer and very flat board underneath your work-piece. This would (hopefully) act as a “built in outfeed table” to keep the work-piece perfectly level well past the cutter head.

If even that doesn’t improve the situation, then have a look at #1. If you’re sure that the board is not changing angle after it leaves the back rollers…then it pretty much proves that the cutter head is changing position slightly once it is no longer supported by the front roller.

I haven’t ever take a planer apart, but thinking through the process suggests that perfection would only be achieved if the front roller and back roller were offset by the same amount as the depth of cut. The front roller rides on the “un-cut” board as it comes in, and the back roller rides on the “cut” board after it goes past the cutter.

Unless the rear roller is slightly deeper than the front, there would be a natural unloading of the springs and soft roller material and any play in the height adjustment mechanism. Not surprising then, that a 30 thou. shift in the height of the cutter could come from that.

BTW, all possible disclaimers apply here…this is just an engineer doing arm-chair figuring, not deep experience with a planer. FWIW, my 735, which has only a few hours of use so far does not exhibit this issue at all…and I didn’t even bother to put the cheesey in and outfeed tables on the machine. If there is an adjustment for tension on either the front or rear roller, maybe yours needs some tweaking after it has become an “experienced” machine?

Also, the common practice of feeding another workpiece or sacrificial piece right behind your workpiece would tend to remove the issues caused by #1.

-- Last week I finally got my $*i# together. Unfortunately, it was in my shop, so I will probably never find it again.

View Midway's profile


62 posts in 1483 days

#4 posted 10-04-2015 01:34 PM

I have the planer mounted on a 5’work bench. the planer is mounted in the middle with 2’ of table on each end
the 2’ tables on each end are mounted with 4 ea bolts to adjust the tables up and down. I have tried all the
ups and downs of the tables, but when i think i have the problem solved it startts haponeing again.

The best way that i have found is like youall said a piece of wood in front and behind the board being cut.

It is just a cheeep planer so i will have to live with it.

ps: I have made a jig to hold the cutting blades so i can sharpen them with a big hone stone.

-- Midway wichita,ks.

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