# How to tell when planer blades dull? DW734 keeps overheating



## ppg677 (Jan 21, 2016)

Hi, I have a 1-year old Dewalt DW734 planer. I'm a weekend warrior and have done a few projects (a few chests of drawers which involved planing 4/4 maple down to 1/2" stock for drawer sides/backs).

I keep having overheating issues. I rotated the blades once and the overheating issues went away for a bit. Now they're back after probably sending another 75 Bd. Feet or so through the planer (perhaps taking a 1/4" off). I'm not taking off more than 1/16" (or less) at a time from 6" wide oak/cherry/maple boards.

I'm not terribly experienced with planer/jointer blades. Is there a way to tell how dull the blades are such that this is "working as intended"? FWIW, the blades remove the hair from my arm hair no problem with a couple "shaving" passes.

I checked the carbon brush and it is not anywhere close to the line closest to the spring.


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## TungOil (Jan 16, 2017)

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.


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## RichT (Oct 14, 2016)

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?


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## ppg677 (Jan 21, 2016)

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


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## papadan (Mar 6, 2009)

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


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## matthww (Mar 24, 2016)

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


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## Lazyman (Aug 8, 2014)

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.


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## papadan (Mar 6, 2009)

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.


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## RichT (Oct 14, 2016)

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.


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## Lazyman (Aug 8, 2014)

> 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.


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## ppg677 (Jan 21, 2016)

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.


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## bigblockyeti (Sep 9, 2013)

> 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.


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## pintodeluxe (Sep 12, 2010)

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.


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## RichT (Oct 14, 2016)

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.


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## pintodeluxe (Sep 12, 2010)

> 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.


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## HorizontalMike (Jun 3, 2010)

> 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


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## RichT (Oct 14, 2016)

> 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
> 
> ...


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 90º-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.


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## Loren (May 30, 2008)

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.


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## ppg677 (Jan 21, 2016)

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.


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## MrUnix (May 18, 2012)

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


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## JBurt (Apr 19, 2013)

Did you ever figure out the problem with the planer?


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## stop23 (Sep 16, 2015)

Did anyone find an answer to this? It sounds similar to my situation. l was recently running pine through my 734 for about 10 minutes 1/16" passes and the motor RPM started dropping (when not under load), then started smelling electrical burning. I let it cool down completely overnight, and the next day turned it on and let it run with no load. After 10 minutes or so, I got the same RPM drop and burning smell. It never tripped the thermal breaker.

I suspect either a bad motor or shop wiring. My outlets are on a 15-amp circuit, and 80' from the breaker. I was also stupidly running a 25' 16awg extension cord. Any idea how much current the motor pulls at no load? I'm letting it cool down now but will try again with no extension cord and will measure the voltage drop.


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## Unknowncraftsman (Jun 23, 2013)

Mr stop23 your post does read like your on the very thin edge of unpowering your planer.


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## Fresch (Feb 21, 2013)

That blade looks blue on my screen, so dull and overheated


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## david2011 (Apr 1, 2008)

> That blade looks blue on my screen, so dull and overheated
> 
> - Fresch


Agreed. If the blades got hot enough to develop color on one edge, chances are that they got too hot on the other edge and were annealed (softened). That would cause the second edge to dull very easily.


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## YouthfullMind (Dec 26, 2017)

I was having the same thing happen frequently and was considering upgrading to a different machine. I kept switching knives which would temporarily help, but not fix the problem. I switched the thermal breaker which didn't fix the problem either. I finally ordered a byrd helical head and that has fixed the problem.

I'm not sure if there was a problem with my machine or I had too high of expectations for the machine/stock knives. Regardless, the helical head made my machine function much better and I'm glad I didn't spend a lot more for a new machine.


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## stop23 (Sep 16, 2015)

FWIW-I measured the voltage drop under varying load conditions. 121 VAC at no circuit load, 116VAC w/ Planer on and at speed w/ no load, 117VAC w/ shop vac running, 112VAC w/ planer and shop vac running.

Planer made the same smell, hot motor, dropping RPM when plugged directly into the wall at 116VAC as it did at 112VAC. Was planning to upgrade the power in the shop w/ a 70A subpanel w/ 20A breakers on the outlets and add a couple 240VAC drops. Hopefully that will fix the problem. I'm a bit skeptical though. Doesn't seem like a 3% voltage drop should be a problem especially at no load speed.


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## splintergroup (Jan 20, 2015)

FYI

Semi-related. I just got a sales notice from Holbren and they list their own manufactured blades (735, not sure if the same as a 734) on sale

Possibly a better base metal than the OEM units (if they fit!)


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## mel52 (Sep 4, 2017)

734 and 735 have different length blades. 735 is longer by I think, around 1/2 inch. Mel


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## hkmiller (Mar 6, 2018)

> FYI
> 
> Semi-related. I just got a sales notice from Holbren and they list their own manufactured blades (735, not sure if the same as a 734) on sale
> 
> ...


Thanks for the post. I ordered a set. See how they compare to the Dewalt 735 blades. Planning alot of heart pine.


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## clagwell (Dec 20, 2018)

> FWIW-I measured the voltage drop under varying load conditions. 121 VAC at no circuit load, 116VAC w/ Planer on and at speed w/ no load, 117VAC w/ shop vac running, 112VAC w/ planer and shop vac running.
> 
> Planer made the same smell, hot motor, dropping RPM when plugged directly into the wall at 116VAC as it did at 112VAC. Was planning to upgrade the power in the shop w/ a 70A subpanel w/ 20A breakers on the outlets and add a couple 240VAC drops. Hopefully that will fix the problem. I m a bit skeptical though. Doesn t seem like a 3% voltage drop should be a problem especially at no load speed.
> 
> - stop23


You are correct. 112 V will not cause your motor to overheat. You have a universal motor. It's induction motors that can overheat with low supply voltage and full load.

Overheating with no load is an indication of a defective motor or too much mechanical friction.

Your power supply is not the problem.


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