Sawstop Cabinet Saw

Executive Summary

SawStop LLC was started by an invention—a contact sensor and blade brake that stops the saw blade within 1/200th second after contact with the operator's skin. An injury has to occur for the brake to release, but the damage from that injury is then substantially minimized. Contact with the spinning blade becomes a trip to the Band-Aid® box instead of the emergency room.

SawStop released their first full production run of saws with this technology in December 2004. The saw is easy to assemble and adjust, and appears to be manufactured with quality materials to close tolerances. SawStop understands that safety alone does not sell saws, and they took the opportunity to reconsider and improve on many aspects of cabinet saw design.

The saw is solid and smooth running. Blade height and tilt adjustments are smooth, accurate, and free of backlash or flex. The brake system is almost transparent to the operator. You have to click an extra switch now and then, know how to spot and deal with conductive materials, and switch to a different cartridge when mounting a dado set. Other than that the saw operates much like a conventional cabinet saw. My initial experience with this saw has been quite positive. It is expensive, but you get what you pay for. I recommend it for consideration to anyone who is in the market for a premium cabinet saw.

Design Differences Relative to Conventional Cabinet Saws

Most operators run their saws without guards. SawStop believes this to be because OEM safety devices are awkward and inconvenient to use. They have equipped the SawStop Cabinet Saw with the most comprehensive, high quality, and convenient set of safety features available to date.

The blade brake is visible in the middle of the photograph. Twisting the red tab 90° clockwise releases the brake cartridge so it can be exchanged with the dado blade cartridge, inspected, or replaced. Rotating the gray steel handle 180° releases the riving knife to switch to the full guard. Once properly aligned, brake cartridge and knife/guard exchange is very quick and easy. The integral dust collection is visible toward the bottom of the photograph. What appears to be a plastic funnel to which the dust hose connects is actually the thick iron casting that spans between the trunnions. This picture was taken with the dust shroud removed. Other safety features include a convenient master disconnect (more convenient than unplugging the saw for maintenance or changing blades), magnetic starter, included zero clearance insert, hip-friendly on/off paddle, toespace at the cabinet front to reduce overreaching, and unusually large top (44" wide x 30" deep) to better support stock.

The photograph to the right is of the other end of the iron casting that connects the trunnions. The blade brake and riving knife required substantial reengineering of the North American cabinet saw design. It's about time; these machines haven't changed in about 50 years. A good starting point was provided by European saws that have riving knives. The key difference is that the motor/arbor carriage slides straight up along a massive front linear bearing, a smaller back linear bearing, and a large acme thread rod. A gas strut partially counterbalances the assembly weight during cut depth adjustment. This vertical movement is required by the riving knife. A conventional table saw has a single pulley run from the motor to the arbor. This saw transfers power with two pulley sets. The arbor rides in a separate cast iron block that pivots to drop the blade below the table when the brake is released.

Those are the highly touted mechanical design differences. Here are a couple of features that aren't seen on the average home shop saw:

• There is a master disconnect located just downstream of the junction box. This disconnect simply opens all power and ground connections, essentially the same result as unplugging the saw. This disconnect was provided to positively disconnect the saw for maintenance, blade changes, etc. It can accept a padlock. The master disconnect might be left on at all times except when the saw is being maintained or the blade changed. I suspect that many owners will leave this disconnect on 24/7.
• Downstream of the master disconnect there is a main power switch. The saw systems go through their self-diagnostic routine every time this switch is turned on. This main power switch is commonly turned on at the beginning of a shop session.
• Further downstream yet is the on/off paddle switch that actually turns the saw on. The on/off paddle is, of course, only turned on when you are running the saw.

Operational Differences

Operation of the SawStop Cabinet Saw is very much like a conventional North American style saw. Blade height and tilt controls are identical to other saws except that the height adjustment may take a few more turns. This was designed to keep the action light despite the extra mass. My saw requires about 19 handle revolutions to go from below the table top to full 3 1/8" cut depth.

This photograph shows the underside of the table top just in front of the blade. The trunnion arc, top of the height adjustment acme thread screw, and lower motor/arbor carriage stop are visible. The fairly large gap in the dust collection shroud at this point closes up as the saw is tilted over to 45°.

This photograph shows the large tilt adjustment worm gear, bevel gears between the height adjustment wheel and acme thread screw, upper motor/arbor carriage stop, and the bottom end of the large linear bearing.

A few extra steps are required to turn the saw on and avoid unjustified release of the brake. Note that I use the term release regarding the brake because that is actually how the brake activates. There is a strong spring below the brake pawl. A stainless steel wire holds the spring in compression. When human contact is detected an electrical pulse melts the stainless steel wire and releases the spring, which in turn pushes the brake pawl into the blade. Below are some operational notes. Most of the notes have no impact on regular use of the saw.

• Before the saw can be used the main switch needs to be turned on. The saw electronics then take about ten seconds to boot up and run their self-diagnostic routine. Afterward the saw is turned on and off with a conveniently located paddle switch. The main switch and related ten second delay only need be done once per shop session.
• The blade brake will release when the blade becomes electrically connected to the operator or is electrically grounded to the saw top. Avoid making these electrical connections to prevent unjustified release of the brake. Check your lumber for nails and other embedded steel. Do not use accessories that place metal close to the spinning blade (of course some of these concerns apply to any brand of saw; ed.)
• Do not grab or touch the blade while it is coasting to a stop after the power is turned off. Coast down accidents are common, and the brake stays active to reduce their impact. The control panel will flash a green LED during coast down. Do not touch the blade until this LED has switched to constant on. My saw experienced a problem with this function. The LED continued to flash for about ten seconds after the blade had stopped. This occurred during the first few use cycles when the shop was below 50° F. The saw behaved normally after a change to the cartridge programming—a change that SawStop will make standard for future cartridges.
• Conductive material and extremely wet wood can cause the blade to connect electrically to the operator and/or saw top and release the brake. This can be avoided by running the saw in Bypass Mode. The operator enters this mode by holding the Bypass Key turned for more than one second while the saw is starting up. Then proceed with the cut normally. Afterward, check the control panel LEDs. They will flash a special pattern if the brake would have released. Further cuts in that stock can be made in Normal Mode if you don't see the special LED flash pattern. SawStop says that they have tested the wettest pressure treated wood they could find. There were some cases where the brake woudl have activated, but simply setting the wood aside to dry for an hour has reduced the water enough for Normal Mode cutting. I have not cut sopping wet PT yet, but plan to test it first in Bypass Mode if the surface is wet enough that it won't take a pencil mark.
• When cutting marginally conductive wood in Normal Mode the saw may shut down without brake release. I have not experienced this behavior. This happens when the sensor system notices a drop in the blade signal that is unusual but not severe enough to be caused by human contact. The motor is powered down in these cases because the reduced signal voltage would interfere with the system's ability to reliably sense human contact. Afterward the operator can allow the marginally conductive stock to dry further or cut it in Bypass Mode.

Packaging & Delivery

The whole assembly came to me in six packages. The saw (657 pounds gross in a 42" cube shaped crate), fence rails, fence, and accessories were shipped in four boxes via Yellow Freight. The standard brake cartridge, manual, cartridge key, and a ferrite filter were delivered by Fed-Ex. Additional cartridges and the dado insert arrived in a separate Fed-Ex delivery.

Shipping was fairly expensive because I live at the opposite side of the country from SawStop' distribution point. There really is quite a lot to ship, and SawStop does not yet have regional warehouses. I paid about $400 for shipping, an amount that would have been $100 more if Yellow Freight had delivered directly to my house. Big bucks, but I saved about the same amount by preordering the saw over two years ago. As of this writing SawStop is not set up to take credit cards. They did not ask for payment until the saw was ready to ship—I used a personal check. I took delivery at the closest Yellow terminal with the help of a good friend and his pickup truck and twelve part tackle. Rig the 657 pound box carefully and conservatively. It is top heavy and could go over on a bunch of guys in a blink.

Assembly

The saw came mostly assembled. Finishing the job was trivial. The shipment included all hardware and most of the required tools (Allen wrenches). All holes were properly placed and accurately tapped. All hardware was of good quality and bolt locations were well deburred. I didn't have any problem with connections creeping as I tightened them. Below are the basic steps required:

• Bolt on the left extension wing. Take care to get it dead level to the main table casting.
• Screw the speed handle onto the tilt adjustment wheel.
• Snap the ferrite filter onto the communication wiring that runs to the brake cartridge. This may already be done on saws shipped after mine. The filter reduces line noise that could interfere with proper system operation in extremely noisy power conditions.
• Install the blade and adjust the brake cartridge to be the proper distance from the blade. The riving knife and guard plates are designed to work with either thin or full kerf blades.
• Bolt on the fence rails. Vertical adjustment on the main table casting is not required and not possible. Crank in five countersunk Allen head bolts and you're done. Use a good straightedge and spreader bar clamp (pressing between the floor and underside of the wings to microadjust the wings) and bolt on the extension wings dead level with the main table casting.
• Bolt on the fence tube. The attachment holes are slotted. Setting the tube closer to the front rail makes the fence stay fairly parallel to the miter slots as you slide it. Setting the tube further away from the front rail makes it easier to lift the fence off the tube. I went with the close setting.
• Install the plastic laminate extension wing and leg. These were nicely manufactured and fit well.
• Drop in the zero clearance insert and level it with the saw top.
• The saw does not come with a power cord. The manual says to hard wire it to your electrical system. I used a dedicated 230V/20A circuit, three prong twistlock outlet, and good grade 12/3 cord instead (SawStop agreed that those components would be acceptable for instances where the saw has to be mobile—such as mine). Connections in the junction box are crimp-on loop type. I recommend that the owner open the junction box, verify the loop sizes, and get the proper crimp-on connectors from the borg or an electrical supply store such as Radio Shack.

That's all. I puttered at the assembly over a couple evenings. If in a hurry I could have done everything in a couple of hours. Not that it matters, but this is a gorgeous saw. Steel parts are stout, accurately made, and nicely finished with black powdercoat. Castings are thickly ribbed and painted flat black. Machining is appropriate for each part's function—clean everywhere but finer and more precise where needed.

Adjustment

The SawStop Cabinet Saw was designed to be more easily adjusted than conventional cabinet saws. The owner's manual includes detailed instruction for all major adjustment procedures. Critical adjustments on my saw were spot on from the factory. The blade runs dead parallel to the miter slots. This alignment stays good when heeled over to 45°.

The blade/slot relationship is particularly easy to adjust. When the cabinet/top bolts are loosened the main casting pivots around a pin at the cabinet front and is microadjusted by setscrews at the cabinet back. One of the setscrews is visible in the photograph at left.

Most other adjustments and alignments were set acceptably at the factory, but over the next few weeks I ended up tweaking them. I restricted the max height stop to keep the arbor block from touching the underside of the zero clearance insert. The 45° blade tilt stop had to be backed out a tad. The knife/guard holder was a little off angle, but was easy to adjust. I used the adjustable pads to raise the fence a tad higher off the table front. The fence faces were a teeny bit out of parallel; I set the tilt to make the left face closer to perpendicular with the table.

Performance

My previous saw was a well-tuned Delta Contractors Saw. I can't offer an accurate comparison of the SawStop Cabinet Saw relative to a Unisaw, General 350, or PM66, but it is way superior to my old saw. Here are some notes:

• The SawStop runs dead smooth and cuts effortlessly. I haven't attempted to measure arbor runout, but suspect that it is within the factory spec of 0.001".
• The controls have a smooth, accurate, and precise action.
• The blade is approximately centered front-to-back in the saw top. Conventional saws have their blade somewhat toward the back. The SawStop placement is more tolerant of operation without an outfeed table. On the other hand, it leaves a couple inches less cast iron in front of the blade—possibly a problem for people who crosscut wide stock with the miter gauge. The 30" deep top is a nice luxury.
• The assembled top, wings, and extension are much flatter than my previous saw. I don't see light anywhere beneath my 36" Suburban straightedge.
• The fence faces are about 35" long. Stock control seems to be good, but the faces are about 7" shorter than the Commercial Biesemeyer I was using before. The shorter fence is a little easier to slide and lock in position though.
• So far I have ripped, crosscut, mitered, and dadoed with the saw. Each task has gone well.
• Dust capture appears to be pretty good. I don't have an accurate figure, but would guess that more than 90% of the dust that is directed below the top ends up in my collector. Capture is, of course, much worse when taking a partial kerf off the side of a board. A fair amount of sawdust scatters across the cast iron top in those instances. There has been some buildup of extremely fine dust beneath the top and on the parts that are right in front of the blade. I can't tell yet if this will have to be cleaned off periodically or not. I didn't clean the fine dust out of my contractors saw and had no problems.

• So far I am more impressed with the riving knife. It actually helps keep the stock tight to the fence to improve cut quality in addition to reducing kickback risk. The full guard works well, too, but I'm just not used to that sort of thing. I have heard reports of the anti-kickback pawls scratching the workpiece but haven't noticed that myself. This could be altered by changing the spring pressure or cutting with the blade set higher.

• Replacement of the brake cartridge, switching between the riving knife and full guard, and blade changes are easily accomplished through the unusually large throat plate. The dust shroud beneath has a pivot and a couple magnets that allow it to be pushed out of the way for this work and then snapped back before the throat plate is put back.

Maintenance

So far I haven't had to perform any maintenance. The following thoughts come from the owner's manual and speculation based on what I've seen so far.

• Non-hardening grease should be applied to the tilt and elevation gears and linear bearings from time to time.
• Seals or tight fitting parts around the linear bearings and acme thread rod seem to keep dust from accumulating in those parts and causing wear. I see dust on the parts beyond their travel limits but the wearing surfaces look good.
• The brake cartridge is sealed, but not hermetically. It is supposed to be inspected every ten operating hours to see that excessive dust has not accumulated.
• Whenever installing a particular blade for the first time you should check the clearance between the blade and the brake pawl. It should be between 1/16" and 1/8". Rotate the blade to make sure it doesn't touch the pawl. Too far away and the brake may not activate as quickly and the saw may not run at all since there is a blade proximity sensor. You won't be able to run 7 1/4" circular saw blades on this machine.
• The cartridge may, on rare occasion, refuse to let the saw fire up. This hasn't happened to me—I'm just using general logic on this point. The saw runs a self-diagnostic routine every time it is initially powered up. It would seem that after extensive use the capacitor may not take a charge properly or there may be some other electronic aging problem. Replace the cartridge with a new one and you're back in business.

• The condition of the drive belts should be checked periodically. Tension in the belt that runs from the motor to the arbor block pivot can be adjusted by pivoting the motor. The belt that runs from the arbor block pivot to the arbor cannot be adjusted—it must be replaced when loose.

Additional Points

• I got the 3hp 230V single phase motor. The saw is also available in 5hp 230V single phase, 3hp 208V three phase, 5hp 208V three phase, or 5hp 460V three phase. The junction box on my saw is labeled 13 amps. The motor is a capacitor start and capacitor run TEFC unit tagged for 12.8 amps.
• I did not perform dial indicator measurements on the saw. I have an indicator but do not consider myself qualified to perform those measurements according to uniformly accepted procedures. My results might have unjustly made the saw look better or worse than it is. You might want to download the brochure from the SawStop website. They are bold enough to publish manufactured accuracy/precision figures for many key saw measurements such as the ones you mention. Although I haven't measured my saw, I suspect that it complies with their specifications based on its performance.
• Accessories! The basic saw comes with a miter gauge, zero clearance insert, full guard, riving knife, 10" brake cartridge, blade wrenches, Bypass Mode keys, a well-written and fairly comprehensive manual, and Allen wrenches that are required for assembly and maintenance. A fence is not included, which leaves you to refit your own, buy theirs separately, or go aftermarket. Other additional cost accessories include more 10" cartridges, the 8" dado cartridge, the dado insert, and extension tables.
• The miter gauge is the best OEM one I've seen. The bar has adjustable spring loaded balls to fine tune the miter slot fit. Mine was perfect right out of the box. The gauge has adjustable stops at 0° and the 45°s. I'll add a wood fence and use this gauge for a while.
• The blade that came with the saw looks suspiciously like a relabeled Tenryu RS-25560. That's a reasonably good blade for general purpose cabinetmaking—60 10° ATB teeth, 0.118" kerf, finished to 400 grit. Its runout is looser than premium blades, as evidenced by scratch marks on some of my cuts. These marks appear to be the fault of the blade instead of the saw because ones left by the front of the blade are exactly matched by the back of the blade. I'll use the blade for a while and see how it goes. In any event, I wouldn't call it a premium blade.
• I didn't make comparison cuts between my old contractors saw and the SawStop before passing the Delta on to Habitat. I don't think the Delta would have fared well though. It vibrated more than the SawStop, the arbor deflected under motor load, it spun at 3000 RPM instead of 4000, the saw's lighter weight would sometimes shift under feed forces, and the bearings had quite a few turns on them. The SawStop cuts like a laser beam compared to my recollection of the Delta.
• So far all I've done with the saw is work on its mobile base, build a base for an architectural model, and perform some test cuts. This work has involved most basic table saw cuts. The saw has performed well.
• I plan to post anything of note that comes up during continued use of this saw, and prepare a long term test report at some point.

Summary

So far the saw has impressed me. I recommend that SawStop be added to the classic Delta/General/Powermatic debate. I particularly recommend this saw for schools and commercial shops, but think that dedicated private woodworkers might enjoy working with it as well. Best of luck to SawStop—I hope that their patents and this strong saw design will give them enough of a head start to make it in this competitive market

Final Point

I've had my saw for less than a month at the time this article was originally posted. Wear and maintenance issues that may eventually be noteworthy just have not had time to surface. While I feel there is enough information here to make calculated judgements regarding fit and finish, performance, engineering, and costs, longevity has yet to be determined.

Addendum

A number of SawStop owners have complained about the goofy large blade wrenches. Nothin' that a Sawzall, file, drill press, and some dip coat can't solve.

NB: the wrench is hardened—don't forget to use a torch on the cut/drill spots first to anneal the steel, or you won't be able to cut/drill.

Regards,