V3.26 - Table Saw: Blade Alignment

Ok, let’s see if, after a couple of trips to never-never land, we can get back on track this week.

One of the most common adjustments on table saws is that of making sure the blade is properly aligned within the saw. There are several indicators that let one know that the blade is not in proper alignment. The operator could see some burning on the side of the stock. There could be some excessive roughness on the sides of the cut. There might be a tendency for the stock to lift at the back of the cut or even kickback at the operator. This isn’t a complete list, just those that are the most common. When those conditions are showing up in your work, it’s time to do a bit of blade alignment checking. It’s not difficult when done the right way.

First, choose an accurate ruler with which to measure. Personally, for this task, I use a combination square because it can be locked to a length and you can hang the angle-finder inside the miter slot. Raise the blade to maximum height and pick one blade tooth and mark it. Rotate the blade so as to put the chosen tooth at the front of the saw. Measure the distance from that tooth to the miter slot in the table and write it down. (This is where the combination square comes in handy- it can be locked into that distance and you know it stays accurate) Then rotate the blade backwards which puts the chosen tooth at the rear of the saw. Measure the distance from that tooth to the miter slot. These two measurements must be the same.

The reason for using one particular tooth is to eliminate any possibility of the blade being warped and that causing your measurement to be inaccurate.

Once it has been determined that the measurements are not the same, it’s time to get the blade properly aligned. In my experience all table saws, no matter their size, have the means to align the blade to the miter slot. What needs to be done is to determine exactly how this is accomplished on the particular saw that is being checked. Start by looking at the undercarriage of the saw and see how the saw arbor is hanging from the table. That should tell you where you need to loosen to be able to shift the saw arbor to properly align the blade. Most Contractor-style saws have 4 bolts that hang the undercarriage to the bottom of the table. Most larger saws have an independent table and the undercarriage hangs from the cabinet. On those saws, simply loosening the table to cabinet bolts allows for the alignment adjustment.

Send your questions or comments to:
Toolsmartz@bellsouth.net and we’ll see what we can do to help you.

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V3.25 - Static Electricity wakes you up

What with summer upon us and its sometimes, drier air, it’s time to re-visit a column from a couple of years ago.

This week let’s talk about static electricity in your woodshop. I’m sure we’ve all experienced it when using our belt sanders, but it can show up on all rotating equipment and especially in your dust collector ducts.

Static electricity in a wood shop is mainly caused by two things. First is low humidity in the air. Static is especially troublesome in winter when the outside temperatures are low. A rule of thumb is the colder it is outside, the lower the humidity is inside a heated shop. As a result, static charge builds up easily and causes shocks when the electricity discharges through contact. The problem is even worse if a shop’s dust collection system exhausts its air outside the building. This builds an additional requirement for fresh air coming in and the fresh, cold air will have low humidity once it has been heated indoors.

The second thing that causes the static electricity problem is motion between two things. In the case of a belt sander, it is the motion between the belt, platen and pulleys that causes the build-up of electricity. In the case of the dust collector or Shop-Vac, it is the motion of the particles through the hose. There are two places where the charge can build up. One is in the machine the dust collector is attached to and the other is on the person who is operating it. Fortunately, grounding the frame of the machine will eliminate the buildup of the static charge. All fixed machinery, such as a table saw, jointer, planer etc., should have its frame grounded to a water pipe or at the very least, to the ground conductor or conduit sheath of the machine’s electrical wiring. Sometimes this is not possible, especially if the machine is electrically double insulated, as is the Shop-Vac.

Beyond grounding the machine, the best cure for static problems is to try to keep the humidity in the shop from getting too low. This can be done by using bag-type dust collectors that re-circulate the same air within the shop after the dust has been removed. These collectors will also reduce your heating bill. Other ways of adding moisture to the air, such as using humidifiers, are worth considering. Another thing you can do is wear shoes that bleed off the static charge rather than allowing it to build up.

Send your questions or comments to:
Toolsmartz@bellsouth.net and we’ll see what we can do to help you.

V3.23 - Table Saws: Pick a Fence

I know we kind of got sidetracked (remember, I call them detours) because of our discussion about Sawstop and Flesh-Sensing Brake Technology, but this week, we’re going back to our previous world of Table Saw fences. The table Saw fence is basically just a guide for the stock as you move it thru the blade and cut it. There are really only a couple of time-tested designs of fences. One is called the Jet-Lock fence. This name is not intended to be connected to any brand, but it was what old Delta called their basic fence system, starting back in the 1940’s. Many other saw makers have used the same basic design and they call it other things. I won’t go into the ‘name-calling’ here, but the way to tell what it is, is this: This type of fence does require a rear fence rail because it clamps on both the front AND rear rail. There are usually several adjustments that allow the operator to make it perform correctly. The usual problem with this type fence is that, when the operator pushes down on the front clamp handle (this handle is supposed to clamp the fence tightly against the front rail AND align the fence parallel to the sawblade) the fence clamps fine, but it does not align parallel to the sawblade. This is a most frustrating situation. Well, here’s the ‘trick’ solution: The front of the fence should clamp to the front rail BEFORE the back clamp locks the fence to the rear rail. The way this fence was designed, the very act of clamping to the front rail MAKES the fence align to the sawblade. As you can probably guess, if the back end clamps up first, then the front cannot make it align properly. At its most basic, if one adjusts the fence clamping sequence properly, and has taken the time to adjust the alignment of the fence so that it aligns when the front clamp engages, then this fence locks in and will be one of the best guides for your work. The other fence style is the T-square fence. One of the most famous of those fences systems is the Biesemeyer brand. There are many other manufacturers that make a t-square style fence, but I think that Biesemeyer is sort of like the grandfather of them all… or maybe he was just the best for a many years. Either way, it is an excellent fence system. The working difference between the T-square fence and the jet-lock style is that the T-square has a much wider front clamp AND does not use a rear rail. It is usually much more heavy-duty and is so stable that it does not need to clamp at the rear. The T-Square fence is much easier to square up to the blade and because it does not have that rear rail, there is no premature clamping on the rear to interfere with fence alignment as it locks down. Till next time….

V3.22 - Table Saws: What’s Kick-Back?

So where does all the talk about FSBT leave us? Right back where we were…simply saying that new technology is good ; however, if one will USE the guards that have been part of table saw equipment since the 1930’s, one will avoid injury. Just as a side note, one of the other things that the engineers noticed with the Sawstop FSBT feature was that they felt it would encourage users to leave their standard guard off the saw. ‘After all, you now have this great flesh-sensing safety device that stops you from cutting your finger off’. Well, it’s my understanding that Sawstop still furnishes a standard guard with its saws AND they intend for you to USE it. Even THEY will acknowledge that use of a standard blade guard will prevent contact with the blade. Amazing how that works isn’t it? Truthfully, the FSBT safety device is merely another layer to help prevent injury. Sort of like seat belts AND airbags. Seat belts DO save lives, if one will USE them. Add airbags to them and you have another layer of safety. But ask yourself, would a car maker sell you a car that ONLY had airbags… and if they did, would you drive it? I’m thinking… not. Bottom line: USE the guards and safety devices that are supplied with your unit. Life will go well with you. Ok, so back we go to our discussion of table saw fences. Some fences have a ‘micro-set’ adjustment knob that allows very small, controlled adjustments. In all cases, it is very important that the fence does not pinch the workpiece between itself and the blade. If that happens, the subject of ‘kick-back’ could become very familiar to you. But since we’re on that subject, we might as well define it. “Kick-back” is a condition wherein the workpiece is grabbed by the blade and shot forward –TOWARD THE OPERATER- at tremendous speed. When kick-back happens, it not something you can dodge…well, not unless you are The Flash and are used to moving at supersonic speeds. I knew an engineer in Jackson, TN who did some very in depth studying of kick-back – even to the point of doing some hi-speed video of what happens as the blade grabs the stock and flings it back toward the operator. It was really incredible to see. The stock usually came flying out in a circular motion which produced an arced gouge in the surface of the piece. The blade deflected so far that you would have thought it would shatter, but it didn’t. Kick-back is not something to want to see. I’ve seen many a cinder block wall get some wood imbedded into it by kick-back. It isn’t pretty. Just guess how bad it hurts to be hit by it. Till next time…. Send your questions or comments to: Toolsmartz@bellsouth.net and we’ll see what we can do to help you.