The bag and separate cord may be a little different, but the CS20 is pure Bosch quality. Click image to enlarge

Bosch CS20 7 ¼" Circular Saw

Accurate, versatile and tough

Text & photos by Tom Hintz

   Circular saws are valuable tools in even the best-equipped woodworking shops. Whether cutting boards to more easily handled lengths or rough-sizing sheet stock, a quality circular saw brings accuracy, speed and safety to the job.

Initial Impressions

   The first thing I noticed about the Bosch CS20 was that it had no cord, just a socket at the butt of the handle. Though initially a bit disconcerting, the reasons for this variation from the norm actually make a lot of sense, as we will see later in this story.

The overall appearance of the Bosch CS20 indicates a well built, tough saw with quality parts manufacture and fit throughout.

Plenty of Power

The 15-amp motor has a removeable cover to allow servicing the brushes. Click image to enlarge

   At the heart of the Bosch CS20 is a 15-amp motor that produces a no load 5800 RPM at the blade. To keep that power coming for many years to come, the motor has a removable end cap that allows access to the brushes for inspection or replacement.

   Incidentally, the sticker on the motor that usually has little useful information for the user includes a chart listing common roof rafter angles, including those for hip and valley rafters. Though woodworkers may not need this info often, it could come in handy when your simple doghouse or shed design mysteriously evolves into a small palace, with a hip roof.

Blade Clutch

The Vari-Torque Clutch looks like most other blade bolts, but could prevent serious injury. Click image to enlarge

   Kickback is always a concern with a circular saw. To reduce the chances of this potentially dangerous occurrence Bosch developed a Vari-Torque Clutch system that allows the blade slip on the arbor if the resistance suddenly increases, like when pinched in a board.

   The Vari-Torque system is remarkably simple and is "adjusted" when installing the blade. The outer blade washer is specially designed to create varying amounts of friction, controlled by how the bolt is tightened. The instructions call for 1/8-turn beyond finger tight but also describe altering that setting when cutting tougher, high-friction materials.

The dust blower vents help keep the cut line clear of debris. Click image to enlarge

Dust Blower

   Bosch came up with a unique idea for keeping dust off the cut line. A rather powerful fan is built into the housing between the motor and the blade guard with vents aimed at the cutting path.

Drawing air into the motor to cool it is an old idea. Accelerating and directing that air to clear sawdust from the cutting path is new and helpful thinking.

Tough Footplate

   The Bosch CS20 is equipped with an ultra-tough composite footplate that resists damage and distortion exceptionally well. Overall dimensions of the footplate are 12"-long and 6 5/8"-wide. The footplate extends 1 3/8" to the right of the blade and 5 1/8" to the left. The leading edge of the footplate is rounded to help it glide over irregularities in the surface being cut. Cut alignment notches are provided at the front of the footplate for 90 and 45-degrees.

The footplate is very tough, very slick on wood and the adjustments well thought out. Click image to enlarge

   The bevel and depth-of-cut locking handles are large, easy to use and can be quickly repositioned on their shafts. The bevel scale has detents at 22.5 and 45-degrees (56-degree maximum) and an adjustable zero position. The depth scale also has detents at ¼" – ½" – ¾" and 2" depths. Maximum cut depths are 2 7/16" at 90-degrees, 1 5/8" at 50-degrees and 1 7/8" at 45-degrees.

Blade Guard

   The stylish blade guard is cast from magnesium for strength while reducing weight. The retractable lower guard has an anti-snag lip to keep that action smooth and automatic. A large handle is provided for manual retraction of the lower guard for plunge cuts.

The blade guard has an effective rear dust exhaust. Click image to enlarge

   To help control dust, the aerodynamics of the blade guard have been massaged to direct sawdust to and out of a port at the rear of the upper guard housing. Shooting the sawdust where you have been, not where you are going is a simple but very effective idea.

Cordless?

   If you have never cut through or damaged the cord on a circular saw, consider yourself lucky. This is a not-so-uncommon occurrence that takes an otherwise healthy saw out of commission until a new cord is wired in or you do a patch-job that can be dangerous and will mysteriously seek out every snag in sight from that day forward.

   The Bosch CS20 has no cord attached but does have a socket and cord retention hook in the handle in which an extension cord can be plugged. This idea has a couple of benefits for the user.

   The idea of using a long cord (properly rated, 12AWG SJ - 50-feet) presents many possibilities on the job site or around the shop where outlets are seldom where we really need them.

   The Bosch CS20 I have came with a 25-foot-long cord, listed as a bonus on the box. Having a 25-foot-long cord seemed like it could be more of a liability than an advantage, until I used it. I never realized how limiting normal cords could be.

Handles

   Though not as eye-catching as the lack of a cord, the handles on the Bosch CS20 were afforded no less attention by the Bosch design folks. They are comfortable to the hand and give a solid sense of control. The primary grip has a rubber insert that is both anti-slip and vibration absorbing. Both grips are adequately sized for use with gloves or bare hands with no sacrifice of control.

Hang It High

Why haven't more manufacturers thought of this??? Click image to enlarge

   The Bosch CS20 features a built-in hook above the handle intended for hanging the saw on a 2-by-whatever rafter. This is such a more civilized idea than trying to balance a 10-pound saw on a 2-by-whatever stick of wood 20-feet above your working buddies, it makes one wonder why nobody thought of it before?

   For when you don't need it, or if you don't care about the folks below you, the hook folds down out of the way.

It's in the Bag

   In place of the common plastic carrying case, Bosch includes a tough canvas bag to protect the Bosch CS20 when not in use, or on the way to and from the job. The bag has a heavy-duty zipper and a framework that helps keep its shape, making it easier to use.

In The Shop

   The Bosch CS20 is remarkable in how unremarkable it is to use. Most of the technology that makes the Bosch CS20 accurate and easy to use does so without fanfare. It does what you want, when you want so easily the how and why it happens can go unnoticed.

   I was a little concerned that with all the power the Bosch CS20 has, the blade clutch system would slip unnecessarily. In all of my testing, including several heavy cuts in hardwood, the blade never slipped. Then, when cutting down a sheet of ¾"-thick ply the waste dipped, pinched the blade and the clutch released right on cue. I like automatic stuff that actually works when it is supposed to.

   One of the Bosch CS20 features Bosch touts is a clear view of the cutting line, not a common feature of right-bladed circular saws, and the main reason I switched to left-bladed models years ago. After using the Bosch CS20 in my shop, I can say that Bosch has once again done their homework. The motor, blade guard and bevel adjuster are arranged to provide a clear line of sight from the operator to the cut indicator notches in most cutting positions.

The cord retention system is easy to use and out of the way during use. Click image to enlarge

   The effective dust blower system, along with the rear exhaust dust chute means you can see the cut line notches and the layout line clearly. Making straight, accurate cuts freehand has never been easier.

   The composite footplate has remarkably little friction as it slides over wood, follows a guide fence very well, is perfectly aligned with the blade and doesn't leave marks behind. Index the footplate to 22.5 or 45-degrees and that's exactly what you get. The detents are right on the money.

   I was interested in how cumbersome the cord retention mechanism would be in use but found it is not a factor. The way the cord is retained keeps it securely plugged into the saw with no loops to snag on obstacles during use. The plug-in cord is a good idea that you need to use a while to fully appreciate.

   The Bosch CS20 has all the bells and whistles you need and none you don't. Bosch has a tradition of skipping the glitz and gadgets in favor of building solid, accurate and very tough tools. The Bosch CS20 is a prime example of that Bosch tradition and represents a very good value in circular saws.

   If you need a good circular saw, the Bosch CS20 deserves a hard look before you buy.

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