Bosch 4100DG-09 10" Worksite Saw
The best in class just got better - and safer
Text, photos & video by Tom Hintz
Posted - 9-26-2007
When I reviewed Bosch 4000-09, the previous version of the Bosch 4100DG-09 several years ago, I was very impressed. However, a few of my viewers thought my mental saw had run into a knot because this was a mere worksite saw. But then woodworkers (and contractors) began trying the Bosch 4000-09 and emails full of praise started coming in, vastly outnumbering the NaySayers.
Since then, Bosch has been tweaking that already impressive design. The result is the Bosch 4100DG-09 seen here. Once again, Bosch steps out in front of the competition. The extensive features and capabilities may well have put the Bosch 4100DG-09 in a class of its own.
The Bosch 4100 is available without the digital fence system and without the Bosch Gravity-Rise stand.
From the Top
The first thing you notice about the Bosch 4100DG-09 is the large 21 1/2"-deep by 29"-wide aluminum table surface. Flip the locking lever under the front edge and the table extension opens to increase the surface to a maximum of 40 1/2"-wide. The fence guide rail expands along with the table for a maximum fence to blade distance (right) of 25". Measure up your favorite "full sized" table saw and you will find that for many woodworking purposes the Bosch 4100DG-09 is equally capable.
The table has a pair of full sized 3/8"-deep by 3/4"-wide, T-shaped miter slots that accommodate the included full-featured miter gauge. They also make the Bosch 4100DG-09 compatible with many shop-built jigs or the wide range of aftermarket accessories currently on the market without modification.
A round plastic insert between the blade and front edge of the table acts as a Pre-Cut Indicator. This plastic disk accepts pencil lines, allowing you to draw marks indicating the edges of the blade. These marks allow aligning a cut very accurately without having to move the wood up to the spinning blade.
The aluminum table and extension are very flat and have a glass beaded finish. This surface tends to make sliding wood effortless without applying wax or other preparations though their use does not appear to be problematic as long as they are compatible with wood and aluminum.
The table is mounted to a very tough, plastic cabinet and a sub base below that. Very little space is wasted on the cabinet. Three sides are used up with mounts for the included equipment that comes with the Bosch 4100DG-09, providing secure storage while moving the saw from one location to another. The forward side of the cabinet has the operating controls and On/Off switch.
The sub base has molded in handholds that make carrying the 60 LB (99LBS with the Gravity-Rise stand) Bosch 4100DG-09 easy. While very tough, the sub base material resists marring the surface on which it stands. However, as with any power tool, it should be secured to the surface before operation for safety. Holes for fasteners are provided in all four corners for this purpose, or to secure the Bosch 4100DG-09 to the Bosch Gravity-Rise stand.
Motor, Trunion and Dust Collection
The Bosch 4100DG-09 is powered by a 15-amp motor (4Hp max developed as per Bosch literature). The blade is mounted directly to the motor shaft, commonly called direct drive and turns at 3650 RPM (no load). The motor is equipped with Soft Start and Constant Response( Circuitry that make the Bosch 4100DG-09 smoother starting and stabilizes RPM while cutting.
The motor is mounted directly to a special assembly below the table that is a kind of trunion. The height adjustments move the motor/blade vertically on this assembly while bevel adjustments pivot the entire assembly. Describing it sounds far more complicated than this simple mechanism really is.
The major portion of the under-table mechanism forms a shroud that surrounds most of the lower two thirds of blade. This shroud is shaped to help direct air and dust back to a 2 1/4"-diameter port that fits most shop vac hoses at the rear of the saw. This shroud remains aligned with the blade through height and bevel changes and drastically reduces the area being evacuated. That means that dust collection starts out very good and stays that way even when hooked to a good sized shop-vac. Naturally, the power of a full-on dust collector will work better but this system is very effective regardless. Even dust escaping above the table is substantially reduced.
This entire assembly mounts to the cabinet and top at two adjustable pivot points. These pivots are accessible from the outside of the cabinet and make aligning the blade with the miter slot as easy and accurate as it is on many cabinet saws. Loosen four hex head socket screws, bump the assembly into alignment and re tighten the screws, all without ever seeing the underside of the saw.
Blade height is controlled by a traditional handwheel on the front of the cabinet. Bevel adjustments are made by releasing a locking lever located behind the handwheel, tilting the trunion assembly to the desired bevel angle between -2 and 47-degrees according to the scale and then flip the locking lever to secure the blade at that setting.
The Bosch 4100DG-09 is equipped with a 5/8"-diameter arbor to work with most common blades and accessories. The arbor length is 1", measured from the back washer. That length will accept many 6" and 8"-diameter stacked dado sets but depending on the thickness of the individual plates, the maximum width attainable will vary slightly. A dado insert plate is available for the Bosch 4100DG-09 as an accessory.
The Bosch 4100DG-09 has a lever operated arbor lock that makes blade changing a one tool (wrench included) operation. This system also prevents having to wedge a piece of wood in the throat to hold the blade when loosening or tightening the arbor nut. The arbor lock makes blade changing safer for you and the blade.
Squarelock Rip™ Fence
Based on the tried and true T-square design, the Bosch Squarelock™ Rip fence moves along its rails easily but locks solidly (at both ends) making it very stable during use. The fence arm is adjustable for parallelism to the miter slot and during my evaluation, proved to hold this adjustment very well. I aligned the fence to the miter slot during assembly (very small adjustment needed) and when measured again at the end of the evaluation, found that the fence had not moved.
The 2 3/4"-tall by 1 3/4"-wide extruded aluminum fence rail is straight, strong and has slots in both faces that accept common bolts for attaching shop-built jigs and accessories. The rectangular shape of the fence rail makes using slip-over jigs easy as well.
Digital Measuring Display
This easy to use electronic display makes setting cut widths exceptionally precise on the Bosch 4100DG-09. The built-in functions provide interesting capabilities to go along with the extreme accuracy.
The Digital Measuring Display is easy to set up initially and use. It can be connected to or disconnected from the rip fence using built-in magnets rather than tools. When not in use it "parks" at the left end of the fence rail, also secured by a magnet.
To make reading the Digital Measuring Display easy for everybody a Unit button cycles through numbering formats. You can choose from 1/16" and 1/32" graduations of an inch scale, a decimal-based inch scale and a decimal metric scale. The Units button can be pushed at any time to change the current display to one of the other formats that might be more accurate or easier to read in that situation.
Another interesting function is the Reset. Push this button and wherever the fence is at that moment becomes "Zero". This has interesting possible uses, especially since this unit reads into negative numbers with equal accuracy. Lets say you want to cut 1/8"-thick strips from a large piece of wood. Make an initial cut to clean up the edge and be sure it is parallel to the fence. Push Reset and move the fence so the display shows - 1/4" (with a 1/8"-kerf blade) and lock the fence down. Making the cut produces an accurately sized 1/8"-thick strip and still allows you to use safe push devices between the blade and fence. Repeating this simple procedure allows cutting several pieces that are virtually identical in thickness.
Once the Digital Measuring Display is set up, setting the rip fence to the exact cut width wanted is fast and very accurate. Judging by its stability during the near constant setting and resetting during the evaluation, it is also repeats very precisely.
The Digital Measuring Display is included in the Bosch 4100DG-09 package but is also available as an accessory to upgrade the base model of this saw.
Though still a rarity on high-end cabinet saws, Bosch 4100DG-09 developed their new, fully modular Smart Guard system for the Bosch 4100DG-09. This guard system features a fully articulated blade guard assembly, adjustable riving knife and a completely tool-free design. Yes, on a "worksite" saw!
The Smart Guard has independent side panels that can rise over wood individually or together depending on the width of the material being cut. When making a narrow cut, the side without wood under it stays flat on the table surface for additional safety. Both side panels can be lifted up to engage individual snap locks to provide access to the blade for measuring or aligning cuts. The side panel assembly as well as the anti-kickback pawls use quick-release, tool-free mounts, making their removal from the riving knife fast and easy.
The riving knife itself can be locked at any of three heights for using the full blade guard system, the riving knife on its own for grooving type cuts and a fully withdrawn position to park the riving knife below the table surface entirely. A finger-operated lever at its base locks the riving knife in any of these positions. Also, because the riving knife mounts to the same assembly as the blade arbor, it, the guard and anti kickback pawls follow the blade exactly, maintaining critical alignments and clearances to maximize safety and performance.
Most worksite and portable table saws either come with or can be combined with some sort of stand but the Bosch Gravity-Rise takes this concept to a whole new level. I was very impressed with the original Gravity-Rise stand during my initial review of the Bosch 4000 several years ago. Thankfully they have not done anything to compromise this very trick piece of equipment. The only real change I can find is the addition of a couple parts-identifying stickers that make assembly easier.
The Gravity-Rise stand is the product of innovative engineering that uses balance and leverage to produce a very stable, easy to use stand for the Bosch 4100DG-09. The design of the mechanism makes raising or lowering the Bosch 4100DG-09 very easy for one person. A single lever near the handle unlocks the wheels from their stowed or extended positions. The large 8"-tall by 2.5"-wide pneumatic tires make moving the saw and stand over rough terrain surprisingly smooth and controllable. In the opened mode, the Gravity-Rise stand puts the Bosch 4100DG-09 table surface at a comfortable 37.5"-above the floor. Adjustable (tool free) leveling feet keep the stand/saw stable for use.
The overall size of the Gravity-Rise stand with the Bosch 4100DG-09 attached shrinks into a surprisingly small package in the stowed configuration. The package requires a space just 28 1/2"-wide by 30"-deep and 45"-tall for storage. This can be a huge benefit for many woodworkers with space-challenged shops or shared space work areas.
In the Shop
Perhaps most surprising about the Bosch 4100DG-09 is that its capabilities are very close to many contractor style saws in useable size and power. It won't pass as a 3 HP cabinet saw but with a good quality blade and common sense feed rates, the Bosch 4100DG-09 handles the vast majority of woodworking chores without a problem.
I made a bunch of rip and cross cuts during this evaluation in various woods from junk pine to oak. The Bosch 4100DG-09 handled them all with ease and a surprising level of accuracy. The carbide tipped 40-tooth, narrow kerf Bosch combination blade supplied with this machine did a nice job of making smooth cuts in all directions. Feed rates may be slightly slower than a full sized machine but they are completely manageable.
Between the quality of its construction and the accuracy of the fence system, the Bosch 4100DG-09 is entirely capable of making high quality woodworking projects. It lacks some of the sheer power and capacity of the full-scale machines but in most cases those deficiencies are small and have little impact on the majority of woodworking tasks. The ones they do impact can usually be overcome rather easily with outboard material supports, a shop-built jig or a little of the problem-solving thinking woodworkers are so adept at.
Dust collection is very good on the Bosch 4100DG-09 thanks to the shroud design. I tried a full range of cuts with the Bosch 4100DG-09 connected to my shop-vac and then my full-on dust collector. Understandably the dust collector won out, but not by as much as I expected. The internal shroud does a good job of making this a very effective system that will keep the Bosch 4100DG-09 and work area remarkably dust free.
The Gravity-Rise stand continues to amaze me. Made from 1 1/2"-diameter tubing, it is very sturdy and stable in both the stowed and open modes. The mechanism that actually lifts the Bosch 4100DG-09 makes full use of mechanical advantage so there is little operator effort required. If you can carry a medium bag of groceries, handling the Bosch 4100DG-09 on the Gravity-Rise stand will be a snap.
The Bosch 4100DG-09 is not intended as a direct replacement for contractor or cabinet saws. However, it does handle most woodworking tasks very well, which has endeared this machine to space-challenged woodworkers since it first appeared on the market. The new features will make the Bosch 4100DG-09 an even more attractive alternative. The power and capabilities will have some woodworkers considering the Bosch 4100DG-09 as a second saw to compliment their full-sized machines. I used the previous version of the Bosch 4100DG-09 as a backup/second saw in my shop for a long time and was often very glad I had it when a project demanded an additional cut I had not anticipated. The mobility of the Bosch 4100DG-09 give it a huge edge when it comes to breaking down large materials in the driveway or when taking the saw to the job is just easier.
With a street price of around $700 (9-23-2007) for the Bosch 4100DG-09 with the Digital Measurement display and Gravity-Rise stand, this can be a cost effective way to bring the capabilities of a table saw to your small shop. For many of us, having the Bosch 4100DG-09 as a second saw would not be hard to take either.
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