Table Saw Calibration from WoodCentral
The original poster in this thread wondered if the small measurement by which his table saw is out of alignment truly mattered in the end. - Editor
"I've got this new Unisaw that I'm tinkering with. Arbor runout is 0.002" at most. That's near the end of the arbor. I guess that's OK. Using a Freud 10" reference blade (no teeth) and measuring first from the miter slot to the front of the blade, and then rotating the blade so that the measuring spot is at the rear, and then measuring from the miter slot to the blade at the rear, I get a difference of 0.01". Therefore, over a distance of almost 10" the blade is out of parallel with the miter slot by 1/100". On the one hand, that seems like a lot (~1/32" over 30"). On the other, adjusting it to the better will take a while. Am I obsessing and in need of a slap?" - Ron
He received some suggestions on how to calibrate his saw. - Editor
"If it were me, I'd crank the blade over to 45 and check it. If you get something close to what you have at 90, call it good. If it is way out, then I'd work on getting something better than .010 after shimming the trunnions." - Robin C.
"I think I would try to get the saw closer to zero if it were mine. .01 misalignment in 6-8" that the blade sticks above the table will give you burn marks when you cut wider boards and leave noticeable teeth marks. It will also make ripping more difficult." - Lee M.
"Thought cabinet saw alignment was a matter of loosening 3 of the 4 bolts holding the top to the cabinet and tapping with a dead-blow hammer to bring the slot parallel with the blade. My miter slot (JET cab) is dead-nuts parallel with the blade. Not that it means much since I've never used a miter gauge anyway (use sleds instead). My fence, however, is deliberately set .02 wide at the rear of the blade to help prevent kickback and binding." - Mark M.
And a few -- somewhat philosophical -- questions about whether his calibration measurement really mattered. - Editor
"I typically wait until I have to start fixing the results of this kind of thing in the finished product. While 0.01" may seem like a lot, when is the last time you cut a piece larger than about 8-10" using the miter slot? I doubt you'll even notice it when cutting a bunch of 2-3" rails. Another way to look at it, that 0.01" is probably already closer than the 90 degree detent on the average chopsaw. Just the mechanics of those spring in notch detents means if you set it, cut, then change the setting and go back to the original setting, you are likely to be off by more than 0.01" over 10". Just sayin', don't sweat it." - John
"My uncle taught me many years ago how he set up his table saw and kept it aligned. Now grant it, his shop was in his barn, but he made some of the finest cabinets and furniture that I ever laid eyes on. He would get it close with a 'story stick' and then he'd check to see how the saw cut ... rip with the fence and then, when he was happy with how it cut with the fence, he would check how it cut with the miter. Typically, that's all he ever did and his stuff was awesome! Sometimes, I think we have strong tendencies to 'over engineer' or overthink our setups and pieces we make. After all, wood moves a LOT more than our tool tolerances from season to season and the truth comes out in how the machine cuts the wood for you. In short, if it cuts good and performs like you expect? It's all good." - Dennis P.
"This perceived problem of requiring the blade to be perfectly parallel to the miter slots is drastically overblown. Contrary to initial intuition, it does not impact the squareness of your crosscuts. Even if they are drastically non-parallel, the crosscuts will still be square, assuming your miter gauge is square. You could literally have your miter slots and blade be several degrees out of parallel, and although you will have a very rough cut, it will still be square to the fence of the miter gauge. Even in terms of cut quality, you have to be drastically out of whack before they become noticeable. If the workpiece touches the blade plate, it is probably because the plate is wobbling, not because the workpiece is traveling skew to the blade." - Rick C.
How about you? What's your personal tolerance for blade calibration? - Editor
Veneering in the Third World from WoodWeb
Woodworkers may be used to coming up with creative solutions, but what do they do when they need to "make do" in the absence of common materials? That's the experience this poster is having. - Editor
"I am a better than average 'DIY'er underway on a project replacing a few panels on a sailboat in Guatemala. The original 1/2" ribbon mahogany plywood had suffered dry rot over the years (the leaks causing the dry rot have since been repaired). Mahogany plywood is currently nonexistent in Guatemala, so I thought to import some WOW ribbon mahogany veneer and apply it to the 1/2" plywood panels being replaced. The largest panel is approx 3' X 4' in size. Adhesive selection here is limited. It might be possible to find some over-the-counter 3M spray on adhesive, but other than that it would be limited to water-based 'wood glue' types. I originally intended to use contact cement, but after reading the pros' advice not to use, it I'm really hesitant to proceed. Now I'm considering a 2-part polyester 'epoxy' resin with plywood sheets as a press weighted with dead weight. Any advice on increasing the chance of success on this 'in the field' job?" - Westsailor
He heard one proposed solution. - Editor
"As a sailor, I would say the only hope you have is epoxy. Contact adhesive in the sun will not hold for long. 3M 4200 or 5200 are really not for large surfaces. Try to get a WOW 3-ply that is 3/32; it holds its own flatness and should work good with epoxy. Borrow all the clamps and cauls you can and put something over the veneer at least 3/4" thick to spread the pressure. Remember that with epoxy, too much pressure is not good." - Mike
And then reminded participants, more specifically this time, of his limited supplies. - Editor
"Re: vacuum system. I could probably get my hands on the brass fittings, but that's about it. I have the following adhesives available:
Grade 'B' contact cement; 3M '77' all-purpose spray adhesive; PVA wood glue; polyester resin (two-part). I'm looking for a long-term adhesion. Indoor but 'high' (80-90 percent) humidity environment. My plan is to apply the veneer using a block of wood to smooth (middle to edges). Then sandwich the veneer/substrate (plywood) between two sheets of plywood with dead weight distributed evenly over the surface for, oh, 24 hrs. Advice? Suggestions?" - Westsailor
Suggestions came in for using some things not traditionally thought of as shop tools (solar shower bags and beach sand, anyone?). And it seems they just might work. - Editor
"As a Guatemalan cruising sailor, I don't think you need to make a 'federales' case out of this. I suspect (given your latitude) that epoxy and vacuum bagging might be a bit expensive or impractical? So what would Practical Sailor advise? I think I would just roll-on the Titebond® II or III and lay on the veneer. I'd stack my panels between plywood culls and and shovel a foot of dry beach sand over the whole thing and call it a day. (Solar shower bags also make great water-weights and provide added heat.) I'll bet you have at least a pair somewhere? I do.) Unless you're planning to anchor over a submerged, active volcano and submerse your Westsail into boiling sea water, the Titebond should be adequate. You can also press and smooth your Titebond-ed veneer into position with an electric clothes iron (provided you have electricity). If you're still not sure, you can always use powdered plastic resin. (Mix well with an old eggbeater for no lumps.)" - Jim B.
"Well, there is a lot of options here. I would go epoxy. No matter, if you have a shop vac available, you can use that as a vac pump. My shop foreman did it as an experiment and it worked. Just hook up the vac end hose to a bag or, in your case, lay a piece of plastic/vinyl over your work and duct tape it in place around the outside edges. That will seal it. Once the air is out, you will have 15psi." - Charles
"Hmmm... now there is a thought. I have a small (2-1/2hp) shop vac and plenty access to plastic/vinyl sheeting. It certainly sounds easy/cheap enough to at least experiment. Thanks for the idea. Two-part polyester resin is readily available and relatively cheap ($30/gal). True epoxy resin is available and not so cheap ($100/gal). I would estimate I would need no more than a quart." - Westsailor
Have you ever had to make a "make-do" attempt at a project? How about incorporating something that you wouldn't normally think of as a "tool"? Email us at email@example.com to be included in next issue's Feedback section. - Editor