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How to tell when planer blades dull? DW734 keeps overheating

by ppg677
posted 05-03-2017 12:58 AM


20 replies so far

View TungOil's profile

TungOil

1304 posts in 947 days


#1 posted 05-03-2017 01:06 AM

1/16” is likely too heavy a cut in maple. I never take more than 1/32” off with my 735.

These lunchbox planers have universal motors so they don’t have a lot of power to begin with. If you ever get the opportunity to work with a heavy industrial planer, something powered by a 3+hp induction motor you will immediately know what I mean. you can plow 1/8” off of a 12” wide piece of cherry no problem.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

View Rich's profile

Rich

4695 posts in 1042 days


#2 posted 05-03-2017 01:45 AM

If the blades can shave hair, they’re plenty sharp. I routinely shave off 1/16” per pass with my DW733 without a hitch. Cherry, maple, pecan, even mesquite. I’m sorry that I can’t say for sure what the problem might be, but it surely doesn’t sound like an issue with blade sharpness or the depth of your cuts.

When you say it’s overheating, do you mean it’s shutting down and has to be reset, or it just seems abnormally hot?

-- My grandfather always said that when one door closes, another one opens. He was a wonderful man, but a lousy cabinet maker

View ppg677's profile

ppg677

216 posts in 1308 days


#3 posted 05-03-2017 01:48 AM

It shuts down. I have to wait a couple minutes before the breaker is able to be pressed down.

I usually take off 1/32 to 1/16

View papadan's profile

papadan

3584 posts in 3821 days


#4 posted 05-03-2017 02:32 AM

Can you post a pic of your setup. I’m thinking there is another problem. Do you have DC connected and operating.

View Matt Hegedus's profile

Matt Hegedus

147 posts in 1245 days


#5 posted 05-03-2017 02:40 AM

Yea my 734 is plugged into a 25 ft extension cord and it never overheats, even running a hard lumber through. It slows down w wide stuff (12”) but I get a good finish and no trip.

May want to look into how to tell if that motor is going bad. Or have an electrician double check your breaker? Or… what if your blades are sticking out farther than they should be? That could bog it down enough to trip. So I mean the distance between the rollers and the cutter knives could be off and you’d never know it without measureing.

Just throwing out some ideas

-- From Pittsburgh, PA

View Lazyman's profile

Lazyman

3697 posts in 1840 days


#6 posted 05-03-2017 03:30 AM

If it is tripping the breaker, it is possible the breaker itself is faulty. After tripping the breaker on my old table saw when I bogged down the blade it kept tripping even when it wasn’t overloaded and replacing the breaker fixed the problem. On many machines it is pretty inexpensive to replace so might be worth a try. The manual does say that blade dullness is a primary cause of tripping the breaker.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View papadan's profile

papadan

3584 posts in 3821 days


#7 posted 05-03-2017 04:33 AM

I’m thinking air flow around the machine. I’ve run thousands of bd ft through my Ridgid and the only thing that shows dull blades is lousy finish on the wood. I have never overheated it on any kind of wood. I used to have a DC hooked up that pulled a lot of air through it, now I use it outside without the DC shoot attached and it runs great.

View Rich's profile

Rich

4695 posts in 1042 days


#8 posted 05-03-2017 04:49 AM

If I understand ppg’s explanation, it’s not tripping the breaker at the power source, it’s doing a thermal shutdown at the machine. It’s frustrating to explain because I run hundreds of feed of board through my DW733 in the Tucson summer heat without a problem.

I was wondering the same thing as papadan regarding airflow. When I turn my planer on, I leave it on for the duration of my planing operation. That keeps the air flowing through the motor. There’s no reason to turn it off to adjust the head, or anything. I’ve done a dozen door stiles, planing 80” boards from 8/4 down to 1-3/8”, in one session. The planer is running for an hour-plus, never turned off.

I’d recommend contacting DeWalt. That’s a quality planer. Much nicer than my DW733, so it shouldn’t do a thermal shutdown like that in normal conditions.

-- My grandfather always said that when one door closes, another one opens. He was a wonderful man, but a lousy cabinet maker

View Lazyman's profile

Lazyman

3697 posts in 1840 days


#9 posted 05-04-2017 01:32 AM



If I understand ppg s explanation, it s not tripping the breaker at the power source, it s doing a thermal shutdown at the machine. It s frustrating to explain because I run hundreds of feed of board through my DW733 in the Tucson summer heat without a problem.

I said breaker but I meant the thermal breaker built into the machine. It might not be replaceable as it was on my table saw but I’ve found that once you trip it, they sometimes trip more easily. If it is the motor overheating and not overloading as my table saw did, it could be a faulty motor.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View ppg677's profile

ppg677

216 posts in 1308 days


#10 posted 05-04-2017 04:07 PM

Unfortunately DeWalt wants me to ship this to one of their service centers. That’s not gonna be cheap, and I’m skeptical of them “fixing” a problem that only rears its head after planing boards for 10 minutes.

View bigblockyeti's profile

bigblockyeti

5834 posts in 2173 days


#11 posted 05-04-2017 04:24 PM



I’d recommend contacting DeWalt. That s a quality planer. Much nicer than my DW733, so it shouldn t do a thermal shutdown like that in normal conditions.

- RichTaylor

The only significant differences between the DW733 & DW734 are the three knife cutter head on the 734 and the paint, the motor and virtually everything else is identical.

I’ve driven my 734 pretty hard even after the knifes are quite dull and only caused it to kick off once. I would check your voltage at the plug while under load, if it’s dropping too low it will draw enough amperage to heat the motor faster than it can cool itself causing it to trip the overload.

-- "Lack of effort will result in failure with amazing predictability" - Me

View pintodeluxe's profile

pintodeluxe

5970 posts in 3266 days


#12 posted 05-04-2017 04:30 PM

1. Decrease cutting depth to 1/32”
2. Treat planer bed and tables with Bostik Glidecote. This will greatly decrease sliding friction.
3. Make sure you have good dust collection, and that it isn’t clogged anywhere. Maple is notorious for clogging up dust chutes. Extra chips inside the machine can generate friction and excess heat.
4. Try a different outlet that is known to be on a different circuit. If the problem goes away, it’s not a problem with the planer. Even if it’s the internal trip switch, it could be an indication that the circuit is overloaded (perhaps due to sharing with light circuits etc.).

Blades don’t look or feel much different when they are dull. The most common symptom of dull knives is the boards don’t feed well. I would get about 150-200 b.f. between blade changes on my 735 factory blades. Granted that is not a very good way to express blade life, because taking 5/4 down to 3/4” takes a lot more passes than 4/4 down to 3/4”, but you get the general idea.

I switched to a Shelix head with carbide inserts for better blade life.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Rich's profile

Rich

4695 posts in 1042 days


#13 posted 05-04-2017 05:16 PM

If you decrease the cut depth by half, you’re going to be running the motor twice as long to get the job done.

Nathan’s suggestion that the internal thermal breaker is bad could well be the case. You can order the part for under $20 and replace it yourself. It might be worth a try, since shipping to a service center will cost at least that much.

-- My grandfather always said that when one door closes, another one opens. He was a wonderful man, but a lousy cabinet maker

View pintodeluxe's profile

pintodeluxe

5970 posts in 3266 days


#14 posted 05-04-2017 05:51 PM



If you decrease the cut depth by half, you re going to be running the motor twice as long to get the job done.

- RichTaylor

I don’t think running time is the most important factor here. It’s load on the motor, friction, and heat buildup.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View HorizontalMike's profile

HorizontalMike

7792 posts in 3366 days


#15 posted 05-04-2017 06:00 PM



If you decrease the cut depth by half, you re going to be running the motor twice as long to get the job done.
- RichTaylor

I don t think running time is the most important factor here. It s load on the motor, friction, and heat buildup.
- pintodeluxe

+10 IMO

-- HorizontalMike -- "Woodpeckers understand..."

View Rich's profile

Rich

4695 posts in 1042 days


#16 posted 05-04-2017 06:27 PM


If you decrease the cut depth by half, you re going to be running the motor twice as long to get the job done.

- RichTaylor

I don t think running time is the most important factor here. It s load on the motor, friction, and heat buildup.

- pintodeluxe

It might or might not be a factor. That is pure speculation. I made a factual statement that halving the cut depth will take twice as long to get the job done. If it’s a problem with the motor, its bearings, or the thermal overload, runtime will matter.

If it’s load, friction and heat, why can I plane four interior doors worth of 8/4 alder down to 1-3/8” on my DW733, taking 1/16” per pass, non-stop in a 90ยบ-plus shop here in southern AZ without a problem? My 733 is over 20 years old, and the internal breaker has never popped. Actually, I kind of wish the motor would fry so I’d have a reason to get a nicer one :)

Again, all you and I can do is guess. For $20 the OP can eliminate one possibility. Seems like a no-brainer to me compared to packing up and shipping to a service center, where the final cost will be far greater, and might involve nothing more than them replacing the breaker that the owner could have done himself.

-- My grandfather always said that when one door closes, another one opens. He was a wonderful man, but a lousy cabinet maker

View Loren's profile

Loren

10477 posts in 4100 days


#17 posted 05-04-2017 06:52 PM

I used to have one of those planers and as
I recall I did manage to trip the breaker
by running it on an extension cord.

I would suggest as well that the issue may
be with the wiring in the work shop. I had
old wiring once and my air compressor
wouldn’t restart when it had air it it… too
much load.

View ppg677's profile

ppg677

216 posts in 1308 days


#18 posted 05-06-2017 02:47 AM

Any idea where to source a thermal breaker? That said, the motor casing definitely feels warm when it trips.

I tried no extension cord tonight. Still tripped after 5-10m of operation.

I have a decent dust collector attached.

I don’t see any obvious dust clogs in the air holes around the motor housing.

Maybe I just got a dud. Or maybe I try a blade change.

View MrUnix's profile

MrUnix

7448 posts in 2651 days


#19 posted 05-06-2017 02:56 AM

Is it a thermal overload or a circuit breaker? Here is one listed for the 734 ($11) at ereplacementparts:

5140000-19 Circuit Breaker

(they can be found at lots of other places as well.. all around the same price)

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View JBurt's profile

JBurt

8 posts in 2316 days


#20 posted 12-19-2018 07:05 PM

Did you ever figure out the problem with the planer?

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