Read this if you made an A+ in geometry class

[Bill Bryant]

I'm starting this new thread on the topic of my table saw's blade alignment problem now that I've done everything the Delta service people told me to do along with reading several Sawmill Creek posts very carefully and lying awake thinking this thing through from every angle I can conceive.

1. This is a Delta contractor's saw.

2. The trunnion rods are now solidly in the same plane.

3. The trunnion brackets snugly hold the trunnions with no play.

4. With the saw set at exactly 90 degrees, I put a dot on the blade about 3/16 from a tooth and used PALS to align the blade so that this dot is inside .001" when measured as far forward as possible and as far to the rear as possible.

5. I took these measurements using a modified A-Line-It tool in the right miter slot. The modification is a small perpendicular bar that screws on to business end of the dial indicator and has the test point screwed into the other end so that I can take measurements right at the plane of the table with the ZCI removed.

6. After being totally certain that the 90-degree saw blade was exactly parallel to the miter slot (inside .001") I lowered the saw blade and took new readings of the dot on the blade. The result is clear. Lowering (NOT TILTING) the blade makes it move out of the original plane and move both closer to the fence (.010") and slightly heeled in toward the fence.

7. When cutting a ZCI I end up with a slot that is slightly but visibly curved--the middle of the slot bows toward the fence, the front of the slot bows away from the fence.

8. It seems to me that the only thing that could be causing this problem is a non-parallel relationship between the axis of the blade arbor and the axis of the height adjustment pivot. If this is indeed the case, it is a machining error that can't be fixed, and the issue becomes one of looking up manufacturing tolerances and perhaps going through the hassle of trying to get the saw replaced. I've already discussed all of this with Delta service, and I've been told that the problem has to be a trunnion alignment issue. I've questioned that with them and been told it isn't possible that it could be anything else.



I need the best geometry experts on the forum to think this through with me and tell me if I'm missing something here.

Much thanks in advance to the top brains on this forum.

Bill

[Cliff Rohrabacher]

When you tuned the table and blade up did you take care to mark the spot on the blade where the indicator would register and then rotate the blade to make that same spot register to the indicator when you checked at the other side of the blade?

All blades have some error in them. Failure to rotate the blade allows that error to become part of your set up deceiving you into thinking you have a good tune up when in fact you don't. Then when you spin up the blade the error manifests in a blade arbor that is not 90-Deg to the miter slot.

[Chuck Wintle]

First what is a ZCI? And after you lowered the blade how were you able to measure the dot on the blade? Is it possible that something needs to be shimmed or adjusted?

[Bill Bryant]

I measured runout at the arbor earlier and it's too small to register--under .0005 at least.

The blade is a Ridge Carbide TS2000. I measured runout off this blade on the arbor and it's under .001 all the way around at 3/16 from the teeth. I can leave a dial indicator point on the blade as I rotate the blade with the motor pully and the indicator wiggles less than .001 all the way around.

A ZCI is a zero clearance insert.

After lowering the blade I measured the dot at 12 o'clock using the same dial indicator set up, this time in the middle instead of at the back or in front.

When a blade is raised and lowered, it should stay in the same plane. Clearly mine does not.

[Jim Chilenski]

Bill,

If I understand what you have stated then I would have to agree that the blade is moving out of alinement with the 'Y' axis as its center changes its position on the 'Z' axis. Sort of like this.

Blade at lowest height | (When looked straight down upon from above the table)

Blade at highest position / (When looked straight down upon from above the table)

If this is what is happening, then "Yes, it has to be a machining error".
But how to prove this? The only thing that I can think to do is to get a perfectly flat, if there really is such a thing, 1/4" steel plate that is 10" x 6" with a 5/8" arbor hole drilled close to one of the 10" sides. Mount this plate on the arbor and using your dial indicator measure the movement of the plate as you raise and lower the height of the plate.

This may prove the error in the height adjustment.

Jim

[David Epperson]

I'm thinking that the fence end of the pivot is higher (closer to the table top) than the other end, and not so much but also a bit out of square with the fence/miter slot. Now this does pose the issue as to whether or not the trunnion is parallel with the blade arbor and also whether or not that misalignment can be fixed or not. But not being able to personally examine a saw exactly like yours I can't tell. I'd bet that there is a tweak that could correct it though.

[Chuck Wintle]

I would insist Delta do something to correct the problem. They should either replace the saw or replace the defective parts. Which model of saw do you have? :D

[Bill Bryant]

I would insist Delta do something to correct the problem. They should either replace the saw or replace the defective parts. Which model of saw do you have? :D

Delta 36-982

[Lee Schierer]

7. When cutting a ZCI I end up with a slot that is slightly but visibly curved--the middle of the slot bows toward the fence, the front of the slot bows away from the fence.


Bill it seems to me that even though your blade is parallel to the miter slot the blade is not 90 degrees to the table. Check to see if the blade is tilted to the left. I normally use a drafting triangle to check to insure the blade is 90 degrees to the table before starting any other alignment. Most saws have stops that will get you close to 90, but a little sawdust will affect their accuracy, so I always check.

[Bill Bryant]

Bill it seems to me that even though your blade is parallel to the miter slot the blade is not 90 degrees to the table.

I set the 90 degrees with a Starrett square. I took 20 minutes doing this, using a light source behind the blade and confirming my setting by measuring on both sides of the blade. The stop is backed way out--you can go to 93 degrees if you like.

[Richard Dragin]

I just went and looked at my Delta contractor saw. It seems to do the same thing if I am understanding your procedure and duplicating it. I have an A-line-it and a Wixey digital gauge so I know I am at 90. I notice that when I turn the wheel the blade moves out more than when it is static.

So I guess the question becomes, besides the ZCI, how does the saw cut? Does this .010 differance effect the use of your fence measurment and if you make two cuts without moving the fence but at differant blade heights how far off do they differ?

Now my saw is 20 years old and I understand you wanting your new saw to be perfect but is it really off? The measurement you are describing is new to me as most folks are happy to be lined up with the miter slot at 90 and 45 and don't look beyond that.

[Bill Bryant]

most folks are happy to be lined up with the miter slot at 90 and 45 and don't look beyond that.

I want to be able to change my mind about saw blade height during a cutting run and not have some of the parts come out .01 wider than others. I also want to the blade not to go out of parallel with the fence as I lower it. What good does it do to set up the blade within .001 of parallel up at 3" if I do most of my cutting with it down around 1" or 2" where the blade is no longer parallel and burns the wood?

[Chuck Wintle]

Bill,
Just looking at the exploded parts diagram for your saw and was wondering if the weight of the motor could be affecting the blade arbor somehow? :)

[Ken Fitzgerald]

Bill,

The curve in the ZCI tells you that your blade or the trunnion is NOT lowering in a perfectly perpendicular plane with respect to the table top or the blade is bent.

Raise the blade to a height where the gullets are just clear of the table top and you can measure at that surface just below the gullet. Manually rotate the blade and check the run out on the blade. If you don't see a remarkable runout on the blade, then I'd bet your trunnion isn't lowering perpendicular to the surface of the table top.

[Mike Marcade]

Is it possible the axis of your blade arbor is not perpendicular to the axis of the blade raising mechanism. Then when you set your blade square to the table the raising mechanism would be a little bit off from straight up and down.

In particular I am talking about the axis of the bearing recesses in part #207 in your exploded parts diagram.

Maybe you could try angling the blade slightly like 1 or 2 degrees and see if the distance the blade travels (the .015" you talked about) changes?

[Bill Bryant]

Bill,

The curve in the ZCI tells you that your blade or the trunnion is NOT lowering in a perfectly perpendicular plane with respect to the table top or the blade is bent.

Raise the blade to a height where the gullets are just clear of the table top and you can measure at that surface just below the gullet. Manually rotate the blade and check the run out on the blade. If you don't see a remarkable runout on the blade, then I'd bet your trunnion isn't lowering perpendicular to the surface of the table top.

The blade isn't bent. Or, at least, if it is, it's still inside .001 runout 3/16 from the teeth. I measured this by puting a dial indicator on it and slowly rotating the blade using the motor pulley. The indicator dial hardly twitches all the way around. Flattest blade I've ever seen. Ridge Carbide.

All comments continue to convince me that the axis of the blade arbor is not parallel to the axis of the height adjustment pivot. This is a can't fix it situation. It's a big piece of cast iron that's supposed to have had two perfectly parallel holes bored through it. But I'm pretty sure they're a few thousanths off parallel.

[Mike Marcade]

All comments continue to convince me that the axis of the blade arbor is not parallel to the axis of the height adjustment pivot. This is a can't fix it situation. It's a big piece of cast iron that's supposed to have had two perfectly parallel holes bored through it. But I'm pretty sure they're a few thousanths off parallel.

You should be able to confirm this by tilting your blade ever so slightly and see if the distance changes. See post #15.

[Bill Bryant]

Is it possible the axis of your blade arbor is not perpendicular to the axis of the blade raising mechanism.

If you've got access to a parts diagram, this makes communication much easier.

What I believe is that the hole in part #207 (elevating bracket) that part #202 (arbor shaft) goes through is not parallel to the hole in #207 that #205 (shaft) goes through.

[David Epperson]

All comments continue to convince me that the axis of the blade arbor is not parallel to the axis of the height adjustment pivot. This is a can't fix it situation. It's a big piece of cast iron that's supposed to have had two perfectly parallel holes bored through it. But I'm pretty sure they're a few thousandths off parallel.
Well yeah I tend to agree, that's the way it's sounding. It's not really a "Can't fix" situation, but it is one that you shouldn't have to fix. The fix involves some additional machine work on either the casting, the trunnions, or the mount.

[Mike Marcade]

If you've got access to a parts diagram, this makes communication much easier.

What I believe is that the hole in part #207 (elevating bracket) that part #202 (arbor shaft) goes through is not parallel to the hole in #207 that #205 (shaft) goes through.

Agreed. I attached the parts diagram for reference.

[Bill Bryant]

Mike, Thanks for posting the pdf file of the parts diagram. That's a real help.

[Mike Marcade]

Mike, Thanks for posting the pdf file of the parts diagram. That's a real help.

No problem. Best of luck to you getting Delta to fix this. It does make me question their quality control processes though. :(

[Rob Will]

This has nothing to do with the blade being 90 degrees to the table.

This has nothing to do with the blade being paralell to the miter slot.

So let's put the dial indicators aside for a moment.

Were this not a contractor's saw, the saw's top could be completely removed leaving the trunions and blade arm undisturbed.

Let's imagine that the saw's top is not even there.

Now we raise and lower the blade.

If the axis of the blade arm pivot and the arbor axis are paralell, the blade will move in a singe plane......not sideways.

This would hold true if the saw were on it's side, hanging from the ceiling, or in China.

When the blade is tilted one degree it still must move in a single plane.

When the blade is tilted 45 degrees, it still must move in a singe plane.

Again the saw's top (an unrelated plane somewhere in space) has nothing to do with whether or not the blade moves in a single plane.

Bad blade arm.

JMHO:confused::confused:

Rob

[Mike Marcade]

If the axis of the blade arm pivot and the arbor axis are paralell, the blade will move in a singe plane......not sideways.

Keyword here: IF

[Bill Bryant]

OK the saw is back upside down. A possible new twist. (pardon the pun)

Part 251 is a eccentric bushing--the hole through it is not centered. Part 246 goes through 251 and it engages the threads on 207 either tightly or loosely by rotating 251 and locking it with 245.

On my saw 251 was rotated to make the worm gear on 246 very tight against 207.

The curved, "threaded" part of 207 is not a perfect arc in relation to the worm gear on the end of 246, so toward the end that would be "blade down in table" the worm gear pushes hard against 207. This pushing against 207 increases as the saw blade is lowered.

There is enough flex (not play in bearings) in 207 that I can bend it a few thou with two hands gripping hard.

I think it's possible that 251 can be adjusted to free up the worm gear at the end of 246 so as to stop pushing against the threads in the arc on 207--there are shiny worn spots at the bottom of the threads in 207, especially at "blade down," and the peaks of the threads on the worm gear are shiny, but not the slopes.

I'm going to free up this worm gear and see whether it was slightly bending 207 as it moved it to the "down" position.

[Rob Will]

IF flex is occuring for whatever reason then the two axis are no longer paralell.

IF some outside force is creating flex, then I retract the "bad blade arm" comment. (Assuming it will spring back to the correct shape when the outside force is removed.)

I think you're getting close.
Good luck!:)

Rob

[Art Walker]

Part 251 is a eccentric bushing--the hole through it is not centered. Part 246 goes through 251 and it engages the threads on 207 either tightly or loosely by rotating 251 and locking it with 245.

I think the eccentric is there to allow the long-time owner to compensate for wear on the gear and screw surfaces to keep backlash low. Waiting on bated breath for the impact on your problem of reducing the bending moment on the elevation shaft. Seems to me a little backlash would be a small penalty to keep the blade from translating as its elevation is changed.

Art

[Bill Bryant]

Well, rats! It didn't help. Not one bit. I eased the worm gear eccentric bushing and put enough slop in there to make totally sure nothing was binding, and it didn't help.

My conclusion tonight as I wash the grease off my hands and get ready for bed:

I think part 207 is made of cheap cast iron that wasn't seasoned properly before machining and is probably slightly warped. This makes more sense than it having been bored poorly. I don't know though. It's late, I've given nine hours to this investigation today, and I'm ready for some shut eye.

[David Epperson]

Well, rats! It didn't help. Not one bit. I eased the worm gear eccentric bushing and put enough slop in there to make totally sure nothing was binding, and it didn't help.

My conclusion tonight as I wash the grease off my hands and get ready for bed:

I think part 207 is made of cheap cast iron that wasn't seasoned properly befor machining and is probably slightly warped. This makes more sense that it having been bored poorly. I don't know though. It's late, I've given nine hours to this investigation today, and I'm ready for some shut eye.
Right now, as I look at the parts diagram, I tend to agree with you. Will Delta not send you a new Part 207 at least? I would think that they would do more (or should), but that's another matter. To really check you could take 207 out of the saw, install the arbor bearings and some dead straight witness shafts, and check parallel between the arbor axis and the pivot axis. Micrometers, center to center both sides and plate glass and gage blocks across the top. Again the "fix" will be either a new 207 or rebore and bush at least one set of the holes. Not a job for a dremel tool either.

[Chuck Wintle]

One thing that occurred to me was if the fit between part 207 and part 250 was loose because part 205(pin) was undersized. This could allow part 207 to slop from side to side causing the problem being observed. :D

[David Epperson]

One thing that occurred to me was if the fit between part 207 and part 250 was loose because part 205(pin) was undersized. This could allow part 207 to slop from side to side causing the problem being observed. :DThat's what I'm thinking. Either there is play between 207 and 205 in the bored hole(s) or the bored holes in 207 are not parallel to the holes bored for the arbor bearings. either situation can be remedied by bushing and reboring the holes for 205 though. 205 should be held solid in part 250 by a setscrew (part 248). But slop here would not give the repeatable results reported. Reboring 207 to use a slightly oversize pin in the place of 205 will also work, but 207 will probably also need to be relieved/reamed/rebored to allow that. The precision on 207 is not as critical since it does not affect parallelism between 205 and 202.

[Chuck Wintle]

Perhaps another shim is needed between part 207 and part 250. One shim is already there though but maybe another will help. :)

[David Epperson]

Perhaps another shim is needed between part 207 and part 250. One shim is already there though but maybe another will help. :)
Possible, but I wouldn't think so. Any slop here would show up as looseness and not misalignment since this fit does not change the parallelism between 205 and 202, which seems to be the major problem. Also slop would show up as a jerky change from one position to the next instead of the smooth change described. 205 could be bent though.

[Bill Bryant]

To really check you could take 207 out of the saw, install the arbor bearings and some dead straight witness shafts, and check parallel between the arbor axis and the pivot axis. Micrometers, center to center both sides and plate glass and gage blocks across the top. Again the "fix" will be either a new 207 or rebore and bush at least one set of the holes. Not a job for a dremel tool either.

Not worth doing on a $450 saw. At least not worth it to me.

[David Epperson]

Not worth doing on a $450 saw. At least not worth it to me.
One would think that it would be worth it to Delta though.

[Wilbur Pan]

I want to be able to change my mind about saw blade height during a cutting run and not have some of the parts come out .01 wider than others. I also want to the blade not to go out of parallel with the fence as I lower it. What good does it do to set up the blade within .001 of parallel up at 3" if I do most of my cutting with it down around 1" or 2" where the blade is no longer parallel and burns the wood?

Two thoughts:

1. If you do most of your cutting at 1-2", why not calibrate your blade in that position? It won't solve your problem completely, but it will help to minimize the error.

2. If you are worried about trimming off 0.01", two words: hand planes. ;)

[Color chosen in memory of the brief life of the SMC theme revision.]

[Rob Will]

[quote=Bill Bryant;696865]Well, rats! It didn't help. Not one bit. quote]

Who are you calling RATS ??

:D

Rob

[Bill Bryant]

[quote=Bill Bryant;696865]Well, rats! It didn't help. Not one bit. quote]

Who are you calling RATS ??

:D

Rob

I used to call him something else, but now that I'm a baptized Christian I don't use his other name.

[Bill Bryant]

I spent some more time with my problem this afternoon, and I devised a simple (you veterans will say obvious) way to easily show anyone what's wrong without using a dial indicator or any other sophisticated tool.

I lowered the saw blade to about 1/2" and put the blade of a combination square against the saw blade with the head referenced to a miter slot.

Then I raised the saw blade to full height while keeping the combination square's blade in the exact same spot.

An easily visible crack came into view between the saw blade and the end of the square's blade.

My wife took one look and said, "Take it back. You can't make furniture with that."

News Flash: I just found the name of a Delta service center here in Rapid City. I think I'll cart the saw over there and see what they say.

[Mike Marcade]

My wife took one look and said, "Take it back. You can't make furniture with that."

Why didn't you show that to your wife before you did all of this work. :D

[Danny Thompson]

Maybe I missed some of your facts, but, can you answer the following:

Is there any "play" as you raise the blade? On my much cheaper table saw, cranking the wheel causes the blade to slighly rock back and forth.

Is the width of the kerf greater in the center than at the ends of your freshly made ZCI?

Assuming no, have you measured the flatness of your blade in both the up and down positions? Is it possibly cupped in one or both?

[Bill Bryant]

Maybe I missed some of your facts, but, can you answer the following:

Is there any "play" as you raise the blade? On my much cheaper table saw, cranking the wheel causes the blade to slighly rock back and forth.

Is the width of the kerf greater in the center than at the ends of your freshly made ZCI?

Assuming no, have you measured the flatness of your blade in both the up and down positions? Is it possibly cupped in one or both?

There is no "play" as I raise the blade. Everything seems very tight.

The kerf is the same end to end of a ZCI. But it arcs.

The blade is not cupped. It's the flattest blade I've ever run across. A Ridge Carbide TS2000.

[Bill Bryant]

UPDATE:

I found a Delta warranty station in my area and went there yesterday to talk to them about my problem.

After being told two different things I knew to be factually untrue--(1) Delta contractor saws are never used by furniture makers; everybody knows you can't expect them to be made to tight tolerances, and (2) the Powermatic 66 has been discontinued, replaced by the 2000--it was hard for me then to accept the answer to the issue that brought me to their shop:

Delta won't replace my saw. They MIGHT repair it IF it's really out of tolerance (not likely, though, since this is only a contractor's saw which everybody knows means poor quality), they can't talk to me about it further next week because they will be doing inventory, and after inventory it will be at least six weeks before they can look at it.

:mad::eek::mad::eek:

:confused::confused::confused::confused:

[Mike Marcade]

I would make it known to them that you will never ever buy another Delta, Porter Cable, or Dewalt power tool ever again and that you will tell 9 of your closest friends, and so will they ... etc ... etc.

See what they say about that.

[Chuck Wintle]

UPDATE:

I found a Delta warranty station in my area and went there yesterday to talk to them about my problem.

After being told two different things I knew to be factually untrue--(1) Delta contractor saws are never used by furniture makers; everybody knows you can't expect them to be made to tight tolerances, and (2) the Powermatic 66 has been discontinued, replaced by the 2000--it was hard for me then to accept the answer to the issue that brought me to their shop:

Delta won't replace my saw. They MIGHT repair it IF it's really out of tolerance (not likely, though, since this is only a contractor's saw which everybody knows means poor quality), they can't talk to me about it further next week because they will be doing inventory, and after inventory it will be at least six weeks before they can look at it.

:mad::eek::mad::eek:

:confused::confused::confused::confused:
Bill,
Is there any way you can return this saw and get your money back? It sounds like this shop is passing the buck and hoping that you just fade away. I would try complaining directly to Delta and let them know the problem and how you were treated by this shop. If its only a poorly machined part that will correct the problem then it should be repaired promptly. By the way I wonder if any Delta reps read this board? Can't be too good for their reputation if customers are being sold junk and then telling said customer to get lost. :confused::mad:

[Ed Blough]

Bill
In your first post you said two things that caught my eye.
First the trunion rods are solidly in the same plane. How do you know and did you change them at all?

Secondly I used PALS to adjust. Don't PALS require you to completely remove the trunion bolts? Is there any possibility that some crude got under one?

There was also something you didn't say, you clearly stated that when the blade was up it was 90 degrees to the table. What angle is it when it is lowered? I'm guessing it is off.

The fact that the ZCP is cut in a bow tells you the blade is moving in an arc rather than perfectly vertical up and down. If the slot simply got wider then you would know the blade was moving laterally. The arc, or bow as you called it, tells us the blade is moving in an arc right to left as it is being raised. This would happen if the height piviot part 205 was not parallel to the table. I suspect the side opposite the bevel crank side is slightly (read very slightly) lower than the end closest to the bevel crank side.

Going back to the trunion rods. Have you measured them to insure they are exactly the same distance from the table top (bottom)? If one of these are torqued it would do exactly what your describing.

Play detective. Insure part 207 is exactly 90 degrees to the table and see if it changes as you crank the blade up and down. I will wager it is also moving in an arc.

If so check part 250 if it isn't exactly 90 or changes then check the two rods and see if they move. If they don't move and are exactly even then check parts 267 and 214.

My guess is one of these parts is not square to the table and/or one of the trunions rods are torqued.

I'm guessing the side of 214 or 267 (most likely 214) that points away from the bevel crank is higher off the table than the other end.

In any case I would think a shim placed on the bevel crank side of one or both of these parts will solve your problem.
Hope this helps
Ed

[Ed Blough]

Bill
One last question why are you even messing with Delta at this point? Why aren't you talking to the dealer you bought the saw from?
I would think any reliable dealer would make this right in an instant. They should be the mediator between you and the Delta. In fact I would expect them to be your advocate!

Ed

[Bill Bryant]

I set the trunnion rods exactly planar, and exactly parallel to the table top.

I set the blade at 3", exactly 90 degrees to the table top and exactly parallel to a miter slot.

But this is irrelevant. I could set the blade in any other plane and I would still get the same problem, and it has nothing to do with problem of setting a blade parallel to the miter slot at both 90 degrees and 45 degrees. I know all about that now and can set that up easily.

Please understand that the problem has NOTHING TO DO WITH TILTING THE BLADE AND GOING OUT OF PARALLEL WITH THE MITER SLOT.

You can have your trunnion rods twisted like a pretzel. You can have them totally out of parallel with the table top. But none of that affects what makes a blade change planes when lowered or raised.

I know that the guys at Delta have said otherwise, some in a rather patronizing tone.

But they need to examine their design a bit better. Nothing, but nothing affects a blade staying in the same plane when being raised or lowered (not tilted!) except for whether the blade arbor pivot and the height adjustment pivot are parallel.

[Chris Parks]

Bill, is the table perfectly flat? It has been a while since I looked at a contractor saw but the one I had the table was not flat and maybe that could be an issue in alignment.

[Bill Bryant]

Bill, is the table perfectly flat? It has been a while since I looked at a contractor saw but the one I had the table was not flat and maybe that could be an issue in alignment.

The part of the table I'm measuring from is flat enough for it not to matter.

[Ed Blough]

I set the trunnion rods exactly planar, and exactly parallel to the table top.

I set the blade at 3", exactly 90 degrees to the table top and exactly parallel to a miter slot.

But this is irrelevant. I could set the blade in any other plane and I would still get the same problem, and it has nothing to do with problem of setting a blade parallel to the miter slot at both 90 degrees and 45 degrees. I know all about that now and can set that up easily.

Please understand that the problem has NOTHING TO DO WITH TILTING THE BLADE AND GOING OUT OF PARALLEL WITH THE MITER SLOT.

You can have your trunnion rods twisted like a pretzel. You can have them totally out of parallel with the table top. But none of that affects what makes a blade change planes when lowered or raised.

I know that the guys at Delta have said otherwise, some in a rather patronizing tone.

But they need to examine their design a bit better. Nothing, but nothing affects a blade staying in the same plane when being raised or lowered (not tilted!) except for whether the blade arbor pivot and the height adjustment pivot are parallel.

Bill
I think you dismissed my answer without fully reading what I said. I never said a thing about tilting the blade or setting it as 90 and 45 degrees. Please reconsider what I said.

If the slot in your ZCP just got wider it would mean the blade is moving in a laterally plane as well as up or down plane. But the bow in the ZCP says it is moving in an arc.

here is how it is happening. As you raise the blade the top of the blade passes through the zcp the blade is closer (but parallel to the mitre slot) to the right, then as the blade comes up the sides of the blade in the arc are moving way from the mitre slot as the blade reaches the top of height adjustment the sides are further to the left (but still perfectly parallel and set at 90 degrees). The result is a bow in zcp.

Since the piviot point is left to right that means the lateral axis of the piviot is either tilted or is moving. We can discuss this all day but there is no other way for a flat blade to cut an arc just adjusting the height.

You hit on it when you said "Nothing, but nothing affects a blade staying in the same plane when being raised or lowered (not tilted!) except for whether the blade arbor pivot and the height adjustment pivot are parallel." You are nearly one hundred percent correct. The height adjustment pivot (the pivot where the blade arbor piviots as the blade moves up and down) has to be parallel to the table. If not the blade when moved up and down will move in such a manner that it will in effect cut an arc in the ZCP. Is the piviot parallel? We both know it is not.
Whether it was bored wrong or the tubes and trunion that attach it to the table are not holding it parallel, it is easily fixed by making it parallel. Either by shiming the trunions or if there is crud under them removing it.

I'm not patronizing you, nor am I trying to be stupid. Before you dismiss me as being another idiot think about your symptoms. The arc is key. Reset your focus (trees and forest) Stop thinking about what you have proved can't be wrong and think of the only way a bow would be cut in the ZCP.

Sorry if I offended you in any way.

[Bill Bryant]

If I may be so bold to say, stop thinking what you have proved can't be wrong and start thinking about how a flat blade could cut an arc.
Sorry if I offended you in any way.

Relax, I'm not offended at all. We're big boys here.

I've been thinking about how a flat blade could cut an arc for quite some time, Ed.

Trunnion rods out of plane with each other won't do it unless you tilt.

Table not parallel to trunnions won't do it unless you tilt.

The thing that WILL do it is for part #207 to be warped so that #202 isn't parallel with #205. It's that simple.

If 202 and 205 are parallel, you can have the rest of the mechanism they are attached to twisted into a pretzel, and the blade will stay in the same plane when raised and lowered.

If 202 and 205 are NOT parallel, you can have the rest of the mechanism they are attached to lined up to .0000001 and the blade will cut an arc when raised and lowered.

[Ed Blough]

Relax, I'm not offended at all. We're big boys here.

I've been thinking about how a flat blade could cut an arc for quite some time, Ed.

Trunnion rods out of plane with each other won't do it unless you tilt.

Table not parallel to trunnions won't do it unless you tilt.

The thing that WILL do it is for part #207 to be warped so that #202 isn't parallel with #205. It's that simple.

If 202 and 205 are parallel, you can have the rest of the mechanism they are attached to twisted into a pretzel, and the blade will stay in the same plane when raised and lowered.

If 202 and 205 are NOT parallel, you can have the rest of the mechanism they are attached to lined up to .0000001 and the blade will cut an arc when raised and lowered.


Bill
I will concede if 202 and 205 are not in the same plane the blade will cut an arc when raised. However if just 205 is not parallel to the table this will also happen. The thing you need to find out is which is not parallel to the table 202 or 205. If 202 is not parallel but 205 is parallel then you do have a problem the casting is bad.

However it is my guess you will find 205 is not parallel. Check it both at the highest and lowest blade position. I think your going find when the blade at it's lowest point 205 is not parallel to the table.

I really believe you closing in on the problem. Do this and prove me wrong.
Check the blade at the highest setting is it exactly 90 degrees to the table? Now check it at the lowest is it still 90 degrees? Hard to measure and only a fraction of a degree will cause a fairly large .001 arc in the blade. If you say yes then I'm totally wrong and I have misunderstood what you telling me is happening. I understood you to say your cutting a bow like this looking down on the ZCP ")".

[Ed Blough]

Okay I have played this over in my head a hundred times.

I concede if the blade is exactly 90 degrees to the table then part #202 by default would also have to be perfectly parallel to the table.

For the blade to cut an arc in the ZCP would then require part 205 to be out of parallel which could only happen if casting 207 was bored wrong or warped.

However if the blade was anything less than perfectly 90 degrees to the table what is happening would happen. If the blade was 89.5 degrees the blade moving raising or lowering approx 3.25 would produce a bow in the zcp of about the amount your seeing.

So the question becomes is the blade exactly 90 degrees to the zcp?
If so then yes part 207 is bad or at least the culprit causing the problem.

I feel rather bad now accusing you of not being able to see the forest for all the trees when if fact it was me being blinded by the trees. I was totally certain the arbor support tubes were racked.

I guess we all know how well I did in geometry now.
Sorry

[Bill Bryant]

That was big of you, Ed. There was really no need for an apology, but thanks all the same. I appreciate it.

Now do you think you can help me firgure out how to get the guys at Delta to get it? :D

[Don Squire]

Hi

Step 1

Go to the dealer that you purchased the saw from and nicely tell them what the trouble is and what you and others have figured the problem to be and ask them what they can do about it. If they remedy the problem satisfactory them things are OK. If not proceed to step 2.

Step 2

Report your findings on this forum and we can all send an email or make a phone call to Delta and let them know that if this is the way they treat a customer after making a purchase that we will make a point of not making any purchases from Delta, Porter Cable etc. and will be sure to tell everyone that we can about how they only want peoples money and after they get it, tough.

I find that asking in a nice polite manner first, then as necessary becoming more vocal usually gets their attention. If you are standing there complaining about bad service and other potential customers can hear that you are getting the runaround, it makes them think twice before they make a purchase.

My 2 cents worth

Don

[julie Graf]

is the actual frame for the saw square?

i returned a rigid contractor saw because the frame bent, which in turn messed everything up. so all the trunions & inside parts were fine, but the frame was pulling things out of whack - the blade would not stay square and you could not get a 45 when trying to tilt.

[Ed Blough]

That was big of you, Ed. There was really no need for an apology, but thanks all the same. I appreciate it.

Now do you think you can help me firgure out how to get the guys at Delta to get it? :D


Bill
I think to convince Delta will be a huge problem.

First I will guess that part #207 is probably a casting that is has a final machining done by a precision boring machine setup to make perfectly parallel holes for part 202 and 205. So they can/will not think beyond that.

Secondly if the blade is even .2 of a degree out of 90 in reference to the zcp this problem would be seen. The angle the blade is moving is calculated, tangent = Opposite side/adjactent side. As I calculate .01"/3" (tan-1) = aprrox a .19 degree off of 90 degree angle and would cause the error your actually seeing. The numbers I used are, .01" is the amount you said you measured the blade tooth moved toward the fence and I used three inches as the amount of you lowered the blade figuring you have to leave a little above the table to measure. If your lowering the blade less than 3 inches this angle of error would slighly increase. That all said you will have to prove to Delta your are capable of that kind of exactness. First that you set the blade to exactly 90 degree with less than a .2 degree error and that you measured the movement of .01 again without any error.

Thirdly we have no idea what Delta's specs are for part #207 is. This could well be within their range. I will wager many many table saws exhibit this same problem but it has never been discovered by the owners. Further the chance of this really messing up a project is slim to none. That is no excuse, but I think it will effect Delta's view of the severity of the problem.

Fourthly I think your going to have to involve the dealer you bought the saw from. If you can get him on your side I think you have a chance with Delta.
Ed

[Phil Thien]

I think we're all going to have to call Delta Customer Service on his behalf and tell 'em we aren't buying any more Delta products until this fix this for him. Maybe if 100 of call we can get their attention.

[Bill Bryant]

Please, nobody call until I've given them another chance. I'll go back over the problem with them again, and if they are still telling me it's a trunnion alignment issue, I'll hop back on here and let y'all know where we stand.

[Ed Blough]

I think we're all going to have to call Delta Customer Service on his behalf and tell 'em we aren't buying any more Delta products until this fix this for him. Maybe if 100 of call we can get their attention.

Phil
Do you believe your saw is set up at tighter tolerances than this?
Have you ever measured it?
Ed