I was very interested in the table saw safety thread. Particularly since I’ve had a few kickbacks in my short time as a woodworker ( not proud of that fact!). I decided that I’d better get it right if I wanted to pursue this as a serious hobby and possible second career. At any rate, I’ve just purchased the Excalibur splitter as part of my new safety ethic. I made the decision that now was the time to do a full tune up on the saw, a Delta Contractor with a 30″ Unifence. When I checked the blade for parallel with the miter slots I found it was off by 0.012″. This is consistent when measured from either slot (at least the slots are parallel)
My question is this; what is an acceptable tolerance? I don’t want to chase perfection to the point of irrelevance (My feeler gauges go down to 0.002).
Replies
Another question I have is when you have the blade parallel to the miter slots how much do you kick out the back of a fence?
My miter slot is 28" long. How much you kick it out over what distance?
.012 is less than a 64th. Nothing wring with that. If you can get a bit better you would be OK but you are talking woodworking not metalworking. As far as the fence goes I prefer to keep it parallel so I can move it on either side of the blade plus with the modern retro fences there isn't a need like the old jet lock fences to do that.
I'm with Rick on keeping the fence parallel to the slot and blade (not kicked out). Especially if the Unifence design is such that you might be tempted to move it to the other side of the blade occasionally. If you're using your splitter religiously, there's really no need, IMHO, to kick the fence out.
I would feel tempted to try and get just a big better alignment between the blade and the miter slots, but with a contractor's saw and it's "hammer and 2x4" approach, it's debatable whether the effort is worth it.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Hi, my daughter Rose wants to try this.:-) :-0 :-(:- ~:-(
For safety and for the smoothest cut, the blade should be within .002-.004 of parallel to the miter slot.
Here is the low tech, low cost way to align a tablesaw that I learned maybe forty years ago and teach to my students now.
Make 3/4 x 3/4 x 12" hardwood stick. Drill a hole somewhat centered in one end and insert a brass #8 x 1" round head wood screw about half way. UNPLUG THE SAW. Raise the blade completely up. Clamp this board in your miter gauge (if you determine that there is some slop in your slot to miter gauge, use a playing card to take up the slop) so the screw head just about touches the blade at the front. Now rotate the blade by hand and determine which tooth is the closest. Adjust the screw in or out until it just touches this tooth. Mark this tooth. Rotate the blade so the tooth is now at the back of the table and move the miter gauge/stick assembly to the back and see if it touches the marked tooth to the same extent. If it doesn't, adjust the trunnion (if a contractor saw) or the tabletop (if a cabinet saw) until it does.
For a contractor saw, first use a small c-clamp on the rear trunnion and cradle to keep the assembly from moving. Then loosen the two rear trunnion bolts and use a stick to tap the trunnion until the blade and screw lightly touch. The blade does not move directly around the center so you will need to repeatedly go back to the front of the blade, readjust the screw, and then again measure the back. Be sure to check after tightening the trunnion as the trunnion frequently moves when being tightened.
The same adjustment gauge can be used to set the fence parallel to the miter slot. Slide the miter gauge to the front of the table and move the fence over to the screw head and insert a playing card between the screw head and the fence just so you can move the card as it touches both the fence and the screw head. Now move the miter gauge to the back of the table and see if you have the same feel when you insert the card. I like my fence absolutely parallel--if you want to have a slight opening to the fence, you can easily estimate the opening by adding a thickness of paper to the card.
I always show my students with a dial gauge that their adjustments are within .001 - .002.
You can also use the same gauge to measure blade runout by using a $5.00 feeler gauge.
Finally, after you are satisfied with the above adjustments, check the position of the splitter to make sure it is exactly in line with the blade.
Bottom line, there is no need to spend more than the $0.05 for the brass screw.
RE: "....Finally, after you are satisfied with the [blade-fence-slot] adjustments, check the position of the splitter to make sure it is exactly in line with the blade."
"In-line" with the blade is somewhat elusive (center line of blade and cl of splitter). Width of the splitter can present an unforeseen but potential danger. (Worse is the distance gap from splitter-to-blade which we rarely can control).
Howie, you present excellent points of wisdom, and well taught to your students. Keep up the good work.
A technical point: I believe the side of the splitter nearest the fence should be even (flush) with the right cutting edge of the blade, i.e., to prevent any rotational movement of the wood into the back spinning teeth. Whereas, on the opposite side of the splitter (away from the fence), a "too-skinny" splitter doesn't have to keep wood away from the back teeth, per se. The objective is to prevent wood jamming between back teeth and fence. A splitter flush with the right cutting edge of the blade is a step in the right direction.
(Regardless, round the leading edge of the splitter, on both sides to prevent a "bump-stop")
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