Dial Indicator Jig for Table Alignment ?

pennview · Post by **pennview** » Fri Mar 23, 2012 11:12 am

Just something to think about when you're making these adjustments to blade and fence is that you want the fence to be PARALLEL TO THE BLADE , OR to have the fence a few thousands further away at the back of the blade than it is at the front of the blade. This ensures that you aren't pinching your stock between the blade and fence, which could result in a kickback.

So when adjusting the fence if you use a dial indicator mounted to the miter gauge slot, realize that you're measuring the relationship of the fence to the miter slot and not the relationship between the blade and fence. So, you need to take into account which the directions the blade and fence are heading in relation to one another and also which side of the blade you place the fence. The angles change if you move the fence to the opposite side of the blade unless everything is in PERFECT alignment (which is near impossible).

Even though these are tiny measurements, you don't want the blade and fence converging at the back of the blade because you're simply increasing the possibility of a kickback.

dusty · Post by **dusty** » Fri Mar 23, 2012 1:08 pm

mountainbreeze wrote:I got lucky I think. With the bolts loose, I aligned the table to the blade to about .003". After tightening the bolts it landed at .002".

As for the fence, no adjustment was necessary. On the left side of the fence, the dial indicator wavers ever so slightly +/- .002". On the right side, it's a different story - much wider variations as I move along the fence with the far end .004" different from the near end.

I think this all falls within acceptable tolerances.

You're not lucky, you're good.

Hope it works for you that way every time. However, speaking of that, you will not need to do this alignment very frequently. The table assembly is really quit solid and does not come out of alignment all that much.

About half of the time that I do a complete alignment it is because I have done something out of the ordinary to make a point.

If it is not out of alignment - don't tweak it!

JPG · Post by **JPG** » Fri Mar 23, 2012 1:53 pm

pennview wrote:Just something to think about when you're making these adjustments to blade and fence is that you want the fence to be PARALLEL TO THE BLADE , OR to have the fence a few thousands further away at the back of the blade than it is at the front of the blade. This ensures that you aren't pinching your stock between the blade and fence, which could result in a kickback.

So when adjusting the fence if you use a dial indicator mounted to the miter gauge slot, realize that you're measuring the relationship of the fence to the miter slot and not the relationship between the blade and fence. So, you need to take into account which the directions the blade and fence are heading in relation to one another and also which side of the blade you place the fence. The angles change if you move the fence to the opposite side of the blade unless everything is in PERFECT alignment (which is near impossible).

Even though these are tiny measurements, you don't want the blade and fence converging at the back of the blade because you're simply increasing the possibility of a kickback.

Point of 'Order'!

Alignment of the fence to the slots is not done until the slots have been aligned to the blade.

The two slots may vary, but there is nothing we can due except recognize and adapt to that.

Likewise the fence sides may not be parallel. Same course of action as the varying slots.

Now common(read elsewhere) thinking is if the rip fence is 0.020 more open at the rear, then all is good. Edited to remove incorrect misleading statements1

So all this nit picking measuring will reveal all the stuff mentioned above and cause much consternation if attempting perfection.

So IMHO by adhering to proper sequence of adjustments that are within Dusty's self inflicted 0.005 limit, the worst you will be off is half that 0.020.

That assumes reasonable parallelness of the two slots and the sides of the fence.

In any event, the rip fence to slot adjustment should be done to the side of the fence most commonly used.

If ya persnickety enough, you can shoot for canceling out of parallel 'error' of the blade and fence to slot.

P.S. I do NOT recommend intentional skewing of the fence to increase back clearance. That guarantees a pinch if the fence is moved to the other side of the blade.

dusty · Post by **dusty** » Fri Mar 23, 2012 2:00 pm

pennview wrote:Just something to think about when you're making these adjustments to blade and fence is that you want the fence to be PARALLEL TO THE BLADE , OR to have the fence a few thousands further away at the back of the blade than it is at the front of the blade. This ensures that you aren't pinching your stock between the blade and fence, which could result in a kickback.

So when adjusting the fence if you use a dial indicator mounted to the miter gauge slot, realize that you're measuring the relationship of the fence to the miter slot and not the relationship between the blade and fence. So, you need to take into account which the directions the blade and fence are heading in relation to one another and also which side of the blade you place the fence. The angles change if you move the fence to the opposite side of the blade unless everything is in PERFECT alignment (which is near impossible).

Even though these are tiny measurements, you don't want the blade and fence converging at the back of the blade because you're simply increasing the possibility of a kickback.

I do not subscribe to the offset theory. I attempt to adjust the fence and blade to be parallel to one another.

charlese · Post by **charlese** » Fri Mar 23, 2012 8:20 pm

dusty wrote:I do not subscribe to the offset theory. I attempt to adjust the fence and blade to be parallel to one another.

So do I, BUT-- if there is a variance I prefer to have it as pennview suggested. I was about to post saying I fully agree with pennview. If you read his post again you will probably not have anything to un-subscribe to.

It just doesn't feel good to have the saw make more noise (cutting action) on the back of the blade. Maybe .004" is O.K., but I don't favor the back of the fence being closer than the front. This is probably why all my rips are on the right side of the blade.

JPG · Post by **JPG** » Fri Mar 23, 2012 8:34 pm

charlese wrote:So do I, BUT-- if there is a variance I prefer to have it as pennview suggested. I was about to post saying I fully agree with pennview. If you read his post again you will probably not have anything to un-subscribe to.

It just doesn't feel good to have the saw make more noise (cutting action) on the back of the blade. Maybe .004" is O.K., but I don't favor the back of the fence being closer than the front. This is probably why all my rips are on the right side of the blade.

+.005 - 0 and use it ONLY on that side!

FWIW I am not sure the fence reference at the table front is all that exact anyway. The clearance probably changes with distance from the blade!;)

pennview · Post by **pennview** » Fri Mar 23, 2012 8:51 pm

JPG, I don't mean to be offensive, but you are sadly mistaken in your believe that the fence can be .020" closer at the rear of the blade than at the front. YOU AND ANYONE WHO FOLLOWS THIS ADVISE IS ASKING TO GET HURT. YOU NEED TO CHECK YOUR FACTS BEFORE PASSING OUT ADVISE LIKE THIS. Many, many blades have less that .020 side clearance between the carbide tips and the plate of the blade. When you rip a board that doesn't fit between the plate of the saw and the fence, you are asking for a kickback.

The fence should be parallel to the blade, period. Barring that, the fence should be a few thousands of an inch away at the back than at the front. If you set up your saw with the fence closer at the back than the front, you are inviting trouble.

If you're using a dial indicator to align the blade to the miter slot and also set the fence, you need to take the above into account if you can't get the blade parallel to the slot.

JPG · Post by **JPG** » Fri Mar 23, 2012 9:09 pm

pennview wrote:JPG, I don't mean to be offensive, but you are sadly mistaken in your believe that the fence can be .020" closer at the rear of the blade than at the front. YOU AND ANYONE WHO FOLLOWS THIS ADVISE IS ASKING TO GET HURT. YOU NEED TO CHECK YOUR FACTS BEFORE PASSING OUT ADVISE LIKE THIS. Many, many blades have less that .020 side clearance between the carbide tips and the plate of the blade. When you rip a board that doesn't fit between the plate of the saw and the fence, you are asking for a kickback.

The fence should be parallel to the blade, period. Barring that, the fence should be a few thousands of an inch away at the back than at the front. If you set up your saw with the fence closer at the back than the front, you are inviting trouble.

If you're using a dial indicator to align the blade to the miter slot and also set the fence, you need to take the above into account if you can't get the blade parallel to the slot.

I did not say "I", but referred to seeing that elsewhere. I also referred to doing something else.

Those other place 'experts'(manufacturers and sharpeners of saw blades) were referring to a 0.020 greater clearance at the back.

I went back and looked at my post, and there is <> confusion. I will correct that. I recall them mentioning set depth, but now do not recall why - I was misleading above for sure.

P.S. No 'offense' taken. I deserved that!

pennview · Post by **pennview** » Fri Mar 23, 2012 9:30 pm

I disagree. If you cite something, you're endorsing those statements unless you clearly distance yourself from what was said by saying something to the contrary. That wasn't the case.

I'll only add that someone can get seriously hurt following such blatantly false set-up instructions about setting up a tablesaw.

JPG · Post by **JPG** » Fri Mar 23, 2012 10:09 pm

pennview wrote:I disagree. If you cite something, you're endorsing those statements unless you clearly distance yourself from what was said by saying something to the contrary. That wasn't the case.

I'll only add that someone can get seriously hurt following such blatantly false set-up instructions about setting up a tablesaw.

Go back and re read what is now there. I have corrected the <> misstatement that implied rear closer to the blade was ok.

Nowhere did I say(originally) to intentionally set the fence closer at the rear. Closest I came to that was the compensatory adjustment.

My point was that although your assertion of blade to fence is what really matters(absolutely correct in and of itself), we should have already assured slot to blade parallelism. To set the fence to the blade without first setting the table/slots to the blade is folly and will have to be done again once the table is aligned. If the table is not aligned to the blade other gremlins appear.

Lastly I doubt anyone who does not have a dial indicator will get anywhere as close as that 0.005 limit. I am sure that there are many setups out there that do have closer at the rear alignment. Perhaps they are a contributing factor to all these kickbacks that have occurred(elsewhere!;)).

I do not disagree with the do not give out bad instructions admonition. I already admitted to deserving your critique because of my confusing misstatement when 'quoting'. I did not however give instructions for creating rear pinching.

I disagree with intentionally increasing rear spacing unless you NEVER use the fence on the opposite side of the blade.