Cordless Reciprocating Saws - Part 1

Understand 18-volt cordless reciprocating saw features & functions.Subject:  Cordless Reciprocating Saws, Part 1Topic:  Features of cordless reciprocating saws


DeWalt’s lever-action keyless blade chuck operates by raising or lowering a lever mounted on the outside of the saw. Lifting the lever releases the blade clamp, lowering the lever secures the blade in place.

The material being cut is contacted by the shoe of the reciprocating saw. With a fixed mount shoe, the saw uses only the nearest inch of the blade, an area which wears out long before the rest of the blade has even cut any material. By designing an adjustable shoe feature, Milwaukee lets the saw operator use more of the saw blade. With an adjustable shoe, the operator moves the shoe further from the end of the saw. With the shoe adjusted to any of its three extended positions, different teeth of the blade contact the material being cut. With an adjustable shoe, it is possible to use each saw blade much more efficiently.

While the shoe on the DeWalt saw is not adjustable, it does pivot back and forth to match the angle of the saw against the material being cut. The Milwaukee shoe, although with adjustable positions, is fixed at a permanent angle.

The 18-volt batteries that power the saws are attached to the base of each saw’s handle. DeWalt uses a prong-type design that inserts up into the inner hollow of the handle base. Milwaukee features a slide rail design allowing the battery to slide into and out of the handle base on large alignment grooves. Both saws use a high-impact polycarbonate plastic to mold the body of the saw.

University Of Extrication Product Review

At first glance, these two saws appear similar in all their basic features and operation, differing only in their color and shape. There are no major design flaws or unusual quirks with either saw. A fire-rescue purchaser would be satisfied with either tool in the rescue inventory. Through our endurance testing and actual fire rescue applications, however, the weaknesses and strengths of each saw became apparent.

Our work with the DeWalt saw continues to be an ongoing learning experience. The company is continually upgrading and modifying its product as evident during the last 18 months, improving with each new version of the tool. The current model DW938 saw is much improved over earlier models.

The slow and cumbersome manual chuck key feature found in the original 1998 version of the DeWalt 18-volt saw has been replaced by a keyless lever chuck. This lever-action design performed significantly better under our rescue applications than the twist barrel keyless chuck design of the Milwaukee tool.

We were able to close the DeWalt blade clamp even when debris was present inside the clamp. Dirt, plastic and wood shavings, mastic glue from roof pillars and cloth from roof headliners continually caused the Milwaukee twist barrel to fail. The barrel spring return either would not release the dirty blade or would not accept a replacement blade because it could not fully clamp down onto the blade itself. This was the most serious challenge encountered with the Milwaukee product.

Releasing the 18-volt battery while wearing fire rescue gloves was difficult with the DeWalt saw. All rescuers involved in our field testing preferred the large release button design of the Milwaukee Sawzall battery. These large buttons released easily every time while the tool operator could keep their rescue gloves on. DeWalt was aware of the problem with their small battery release buttons and moved to address it. DeWalt’s latest generation of 18-volt batteries, the XR2 NiCad model, now have improved release buttons. The new battery’s performance is comparable to that of the Milwaukee.

We did experience a battery release problem with one Milwaukee battery. After being secured in place on the saw, this battery would slide forward from its’ position when the saw encountered severe vibration during cutting. The problem turned out to be a defective battery, which was quickly replaced by Milwaukee. All Milwaukee batteries currently being tested remain secure in the handle during use and abuse.

In Part 2 of our series, we’ll attack the myths that surround rechargeable batteries and look at alternative power sources for cordless reciprocating saws.

SAW SPECIFICATIONS
  DEWALT MILWAUKEE
Weight of saw with battery 7 pounds 8 pounds
Length of saw w/o blad 17 inches 18 inches
Stroke length 7/8 inch 1 inch
Strokes/minute 0-2, 800 spm 0-2,000 spm
Trigger safety lock feature Yes Yes
Reversible blade capability Yes Yes
Keyless chuck type Lever type Twist barrel
Shoe/foot adjustable No (flexible) Yes (3 positions)
Battery type 18 volt 18 volt
Housing/handle Plastic Plastic
Battery shoe design Prong inserts into handle base Slide rail design
Battery release button Twin buttons on sides of battery Twin buttons on sides of battery