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DeWALT Owners Group « DEWALT POWER TOOL DISCUSSIONS « DEWALT FAQ's « Circular Saw Electric Blade Brake
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« on: October 13, 2011, 09:24:32 PM »

Looking at buying the DW368 or the DW369 saw.  The 369 is a more expensive model because it comes with a case, blade brake & heavy duty base.

How does the Electric Blade Brake work & what are the components of it?
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« Reply #1 on: October 14, 2011, 02:18:23 PM »

The switch send's a reverse current through the motor to stop it.
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« Reply #2 on: October 15, 2011, 08:26:02 PM »

On universal motors it usually just shorts the leads, no reverse current.  So if you let off the switch and unplug it at the same time, the brake still works.  Could be safer that way.  You really want the brake, I'm I have a left hand Milwaukee saw that's great, but no brake and really frustrating.  Takes a very long time to spin down.
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« Reply #3 on: October 17, 2011, 10:04:25 AM »

Yes, must have the brake.  The 368 is at Lowes for $100 & the 369 is online at Home Depot for $140.  $40 more to prevent injury, well worth it.  Thanks.
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« Reply #4 on: October 25, 2011, 06:59:53 PM »

Bought the DW369CSK.  This saw does blow away my 10 year old 11-amp Skillsaw in every way.  The blade brake does slow the blade down faster versus a saw without the brake, but not as quick as I thought it would.  The case is nice, you can store blade(s) under the saw & it has a spring type clamp to hold them in place.  Also comes with a 18-tooth framing blade, wrench & manual.  The black 'heavy duty' base that is advertised as being able to withstand a 1-story drop is made out of plastic?   Hmmmm.... 
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« Reply #5 on: October 25, 2011, 08:24:26 PM »

It will flex as opposed to bend like a metal base.  I have this circular saw and also the DC390 cordless.  I've dropped both many many times.  The base on the corded saw is 100% true while my cordless is slightly warped (I am unable to straighten it).
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« Reply #6 on: October 25, 2011, 08:49:52 PM »

I am not familiar with that model, as out here on the west coast where I live, we pretty much exclusively use warm drive saws.  However, I would not be concerned on the plastic base, if that is what is on it.  DeWALT uses a xenoi plastic, which is extremely durable and flexible, so it is able to take abuse/shock and flex back to square.  I know that consumers are wary of plastic (and in many cases, they should be) but the plastic that DeWALT uses is high quality, and well placed.  Hope you like your saw!
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« Reply #7 on: October 27, 2011, 08:45:06 AM »

I think you can rest assured that the base on the DW369 is pretty tough.  In a 2007 Tools of the Trade article, the reviewer offered the following about composite bases and the DW369:

"For those skeptical of composite plastic bases, let me tell you that I was, too, when they first came out. After trying unsuccessfully to break a DeWalt base with a framing hammer, I became a believer. No other base type could stand up to that much abuse and still remain serviceable."

The article is available at the following link:  http://www.toolsofthetrade.net/industry-news.asp?sectionID=1492&articleID=685600

Saws with electric brakes have a secondary set of motor field windings which are shorted out when the trigger is released.  Essentially this winding configuration turns the motor in to a generator with a heavy electrical load (a dead short) that makes it hard to turn, causing the dynamic braking effect.  The gauge of wire and the number of turns used in the secondary winding determine the current generated during braking and the aggressiveness of the brake.  From my experience, I have found that tools with extremely aggressive brakes often exhibit severe brush arcing (when braking) resulting in extremely short brush and commutator life.  Dewalt has likely designed the brake on the DW369 to be slightly less aggressive in order to maintain long motor life while still providing the convenience of an electric brake.
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