Table Saw Miter Gauge alignment

[William]

I'm new to woodworking and I am looking for a quick way to verify that my miter guage is giving me true 90 degree cuts. I keep getting panels that aren't quit square and I am looking for quick homegrown tricks, tips or techniques to get square cuts.

[Mike W.]

Im no expert. I've only been at it a few years, but the miter guage might be the least of your worries. There are many reasons that you may not be getting the squarest of cuts. Try this site out:

to make sure your saw is setup right. I used it to help align my saw and even though it was pretty good from the factory, I could certainly tell the difference after going through these exercises. If all these things are cool, then I'm 'guessing' people will tell you to get a better mitre guage.

Good Luck.

Mike W.

[Lew Hodgett]

You will never get there with just a miter gauge.

My first choice would be a sled AKA: sliding auxilary table, usually a home made device.

Lots of info out there, but I like Fred Bingham's approach as shown in his book, "Practical Yacht Joinery" available at the library.

Lew

[DJ Delorie]

Obtain a square of plywood about a foot across. Mark the four sides

1, 2, 3, and 4, in sequence, counterclockwise. Put side 1 against the miter gauge and trim side 2 (just enough to give a fresh edge, maybe 1/16 or so). Put the freshly cut side 2 against the miter and cut side 3. Put 3 cut 4, put 4 cut 1. Put side 1 against the miter gauge and compare wide 2 (the first one you cut) with the blade as you move the miter gauge back and forth (don't cut, just pretend). Alternately, check that last corner with a square. If it still lines up, you've created a "perfect" square of plywood, and your miter gauge is square. If there's any deviation in your miter gauge, this test will make it four times more obvious.

[Walt Cheever]

Easy, accurate and quick:

Take a straight scrap about 12'" long, cut it at your best 90 degree setting.

Put the two cut faces together, and rotate one of the two pieces 180 degrees (half a full turn). Push the cut faces together again. If the cut is accurately 90 degrees, the board is still straight. If not, the slope between the pieces is twice the amount of error, and very visible.

Works for getting the blade at 90 degrees to the table too!

Don't know why it took me so many years to see that hint!

Walt C

[PDQ]

Just keeping it to the miter gauge:

1. Turn the gauge upside down
2. Insert it into the miter gauge groove until it meets the table edge.
3. Set the gauge so the two surfaces meet flush.

Now that the gauge is "true", any deviations must be elsewhere.

--=20 PDQ

[Charley]

Now for a quick, less complicated way.

If your saw is running true and you just want to quickly put your miter gauge back on zero after you have used it at another angle setting try this:

1. Remove your miter gauge from the saw and then put it back on upside down with the fence hanging off the front of the saw.
2. Loosen the miter gauge lock and then press the fence forward into the front rail of the saw.
3. Tighten the miter gauge lock. Then remove the miter gauge from the saw, flip it back over and place it back on the table.
4. Your miter gauge is now set back to 90 degrees with reasonable accuracy.

You won't find a much quicker way than that, and you don't need any special fixtures to do it.

[George]

SNIP>

I've got a Delta gage.

I flip the stop down and rotate the arc until the adjustment screw meets the stop - at 90 degrees.

[Doug Miller]

Note that this is impossible on most table saws having full-length front and rear rails.

I believe that I'd put a *lot* more trust in a Starrett or Incra square.

-- Regards, Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?

[Patrick Conroy]

William wrote in news:Xns964BC330FEC45Organdonator@66.250.146.150:

Me too - new that is. Turns out there are a good handful of ways your cuts could be off a true ninety.

Here's what I did:

1) Invest in a decent machinist's square or combo square. One you're willing to trust as accurate. I popped the $70 for a Starrett. 2) Zip over to an Art Supply or Drafting supply store and pick up a Drafting triangle. Most are surprisingly accurate and inexpensive. Pick up a big one - 8" or larger. 3) Using a variety of techniques you can find via google, make sure your miter *slot* is parallel to the blade. There's the combo square "tick a blade tip" technique. I used the drafting triangle. 4) Using one of several methods, make sure your miter gauge is 90* to the slot. If you're dead on with (3) then you could measure it against the blade, but you really want it 90* to the slot. 5) Make some test cuts - and check. Adjust, fine tune, more test cuts. There are several ways to check your cuts. You can test a cut against a reference; cut n' flip and look for the doubled error; or there's the 4 cuts on a square piece. DAGS. 6) Build a cross-cut sled. Take your time. This will become an invaluable addition to your shop. It may take a few tries -- I'm on Sled V3.0 and still have a few modifications planed for V4.0

Then - don't forget to make sure your blade is 90* to the table top too. Align your fence to the blade/slot and I think you've done most of the tuneup work.

[ejb]

Hi William,

I read through all of the replies so far. Hmmm.....

OK. There's lots of folklore and pukey plastic gadgets surrounding this topic and I think most of them have been mentioned so far. I'll start by elaborating on them.

Myths debunked:

1. Having a dial indicator will make the task extremely easy and accurate, but buying a "SuperBar" and a "MasterPlate" won't help in the least. Only the last photo on the Woodshop Demos page addresses the miter gauge. However, the technique demonstrated doesn't really require either of the products. In addition, the technique (which is widely accepted as accurate) isn't guaranteed to provide good miter gauge alignment (see Myth #3).

1. There is no guarantee that the miter slots are square to either the front or rear edge of the table. So there is no guarantee that butting the face of your miter gauge against them will result in accurate alignment. If it isn't a square, and it didn't come with a squareness specification, then don't trust it for machinery setup.

2. Using a square between the blade (or blade replacement plate like "MasterPlate") and miter gauge face does not guarantee square cuts. The angle of the cut is defined by the orientation of the board relative to it's motion, not relative to the surface of the blade. Motion of the wood in this case is defined by the travel of the miter gauge in the miter slot. Squaring the miter gauge up with the blade surface might work if the blade is really flat and carefully aligned to be parallel with the miter slot. These two dependencies make the practice dubious at best. You really don't want to have to check blade alignment and flatness every time you square up your miter gauge.

1. Cutting up a bunch of stock to check squareness is (in my opinion) wasteful of time and money. Two methods were proposed (the "cut and flip", and the "four consequetive cuts"). Yes, they work. I just can't bring myself to doing it. I'm sure that people with a lot of free time and wood who would disagree with me. I don't think they fall into your qualification of being "quick".

2. Having a sled doesn't guarantee that it produces square cuts. It needs alignment too. I've done some amazingly accurate cuts using my miter gauge and it's the stock POS that came with the saw. Still have it, still use it, haven't seen the need to buy a fancy one.

1. I don't trust stops. First, they have to be properly set up so you don't get away from the whole alignment issue. Second, they flex and are prone to error from a number of sources (sawdust, etc.). They are really handy for general, low accuracy work, but it sounds like you are looking for something more precise.

So, what is a quick and accurate way to ensure square cuts with a miter gauge? All it takes is an accurate square and a measurement device. I prefer a dial indicator because it's cheap, easy, accurate, and quick. However, you can use anything you like - including a subjective "feel the rub" or "hear the scrape" measurement technique (if you happen to be proficient at it). It's a whole lot easier to show a picture (or demo) than to describe:

Open the TS-Aligner Jr. User Guide at

and go to p.27.

- or -

Watch the "Table Saw" video at

at about 10:57 into the clip.

This method is independent of all other saw adjustments and absolutely as accurate as your square. It's not completely foolproof but pretty darn close. Let me know if you have any questions.

Thanks, Ed Bennett [e-mail]

of the TS-Aligner

[Patrick Conroy]

[e-mail] wrote in news:1115242581.857598.58650 @g14g2000cwa.googlegroups.com:

As long as we're sharing opinions, I'd venture an uneducated guess that you could make quite a few test cuts on scraps before you'd equal the expense of a quality instrument.

And, unless you already have the instrument, you could get hopping on making test cuts tonight. As opposed to waiting for UPS.

And, I'd venture another guess that "cutting a bunch of stock to check squareness" is a subject that's easier to teach.

That said - once they cross the gray line from "newbie" to "serious" - I'd venture that they consider spending money on good instrumentation. A tool like the TS Aligner would be an investment I'd value as much as my investment in a Starret combo square.

Amen!

[Doug Miller]

Probably true... but time has some value, also, and the TS-Aligner is certainly a time-saver. Plus, it's useful for other things besides table saws. For example, I find it a *lot* easier to align jointer knives with the TS-Aligner than with the see-how-far-the-stick-moves method, and get better results.

-- Regards, Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?

[CW]

[ejb]

I suppose it depends on the instrument you use. As I said, if your skills at subjective "feel the rub" or "hear the scrape" methods are good, then the expense would be minimal. I'm no good at these methods so I prefer using a dial indicator. I think that it wouldn't take too many test cuts before you burn through the $20 (or less) for a reasonable instrument.

And, of course, you would need to ignore the value of your time. The alternative (which I've seen all too often) is to regret spending so much time getting the miter gauge squared up that it's versatility is abandoned. It ends up becoming nothing more than a "cross cut" gauge.

Very true. I think it would be very educational to learn the test cuts methods. It gives added appreciation for more precise methods. One can always get started doing test cuts. The question is, when do you get started on the real project at hand?

Maybe. Certainly the concept is easier to grasp and may seem less intimidating to those with a dial indicator phobia. But, when it comes down to obtaining accurate results, the situation might be reversed. Trial and error always has an element of frustration, especially for those who encounter excessive errors (with the excessivly requisite trials). It might well be easier to teach the test cuts process but much more difficult to teach someone to obtain accurate results using a test cuts method.

instrumentation. A

Indeed, both are nice to have.

Ed Bennett [e-mail]

of the TS-Aligner