Tablesaw blade trunnion adjustment question

Excuse me if this is a repost of my request. I tried to post it previously and it did not show up in my sent folder, so I posted it again.

I have a Grizzly G0444Z TS. The back of my blade when I rip a board is almost a quarter of an inch closer to the fence than the front of my blade and causes gunk to build up on the right side of the saw blade, and causes the board to bind up and I have to force it through. .I used ovenoff to clean the blade. My sawblade is not bent. According to my saw manual it says to loosen the trunnion bolts and move the assembly to the right or left and retighten the bolts. I did this I cannot get the blade dead-on. The assembly will not move any farther. It is off by a 1/16th of an inch. Is this an acceptable tolerance or do any of you have any suggestions as to how I can get it perfect? Thank you all for your suggestions.

Reply to
Tom
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To get it dead-on perfect get one of these: (TS-Aligner Jr.) You can't go wrong with having one in the shop.

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the instruction video for table saw on his website.

Read my review here:

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Reply to
Stoutman

  1. First you need to get your blade parallel to the miter slots in the table. I had a Grizzly saw that wouldn't adjust far enough to get parallel to the slots. I had to take the trunnion sector block (the part that bolts to the bottom of the table) off and egg the holes out with a round file to get it in the right place. To check if the blade is parallel to the slot, get a pointy piece of wood and put on the miter gage as if to cut it. Instead, check to see if the point just scrapes the blade on the front AND back as it slides by. If it only scrapes one or the other, you still have adjustments to make.
  2. After you have your blade parallel to the miter slots, you need to adjust the FENCE so that it locks down parallel to the blade. There are bolts on the fence that allow you to adjust the angle at which it locks down. Unless Grizzly has improved their fence a lot since I had mine, your fence may not always lock down in the same relationship to the blade. It may heel in one time and out another depending on which direction you last moved it. If that is the case, you need to measure from the fence to the front and back of the blade with a tape to be sure it locks down parallel. After a little practice, you may learn to always make the last movement in whichever direction that causes it to lock down correctly every time.
  3. DO NOT continue to operate the saw with the back of the fence closer to the blade than the front. It is a recipe for nasty kickback, in addition to overheating your blade and burning your wood. It is best to have the fence absolutely parallel to the blade, but if you can't consistently accomplish that, then it is better to have the back of the fence slightly (1/32 or so) farther away from the blade than the front.

Good Luck and Be Careful!

DonkeyHody "Even if you're on the right track, you'll get run over if you just sit there." - Will Rogers

Reply to
DonkeyHody

I have the TS-Aligner Jr. too, and I highly recommend it if you can spare the $130 or so for admission. But you can get from the unsafe condition you have now to a much safer condition without one. Just DON'T keep going with the fence closer to the blade in the back. It will bite you!

DonkeyHody "We can't all be heroes because someone has to sit at the curb and clap as they go by." - Will Rogers

Reply to
DonkeyHody

Tom do you have a problem when cross cutting? If not, you trunion alignment is probably OK or was OK. If you are only having the problem with rips, you fence needs to be adjusted parallel to the blade.

Typically the blade should first be made parallel to the "miter slot" by adjusting the trunion and then the fence made parallel to the miter slot or blade. Do not adjust the trunion to be parallel to the fence, only adjust the trunion to be parallel to the miter slot and then the fence to the miter slot or blade.

Reply to
Leon

Folks I'm sorry for all the reposts. The only way I could receive you answers is by getting them on my laptop PC. Outlook Express is all screwed up on my desktop pc.I installed OE 7 and then went back to OE 6. I will get the problem fixed soon. Thank you all very much for your suggestions and have a very Merry Christmas!!!!

. .

Reply to
Tom

It's best if you align both the fence and the blade so that they are parallel to the miter slot. You don't want to use a short thing (like the blade) as the alignment reference for a long thing (like the fence). Small variations in the blade (which is rarely very flat) will result in larger misalignments in the fence.

Ed Bennett snipped-for-privacy@ts-aligner.com

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Reply to
ejb

Thanks for the recommendation DH! Actually, the "price for admission" is much lower (about $76). And, if all you want to do is basic tablesaw alignment, you can put together a "dial indicator on a stick" for less than $15:

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Bennett snipped-for-privacy@ts-aligner.com
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Reply to
ejb

While I understand what you are saying here Ed, you seem to contradict your first sentence with your second sentence. You mention that you do not want to use a short thing like the blade as the alignment reference for a long thing like the fence. How is that not OK, when it is OK to use a short thing like the blade as the alignment reference to align a long thing like the miter slot? I under stand the concept you are referencing here, it is easier to align long parallel lines than a short and long one. The problem here is that the short one was used to align the long reference that you want to align the fence with. Am I missing something here? It seems to me if it is acceptable to align the slot to the blade, doing the same to align the fence is not much different since the original reference point for the whole process of aligning the fence was the blade.

Reply to
Leon

Hi Leon,

No contradiction. It's not just a "length makes measurements easier" thing either. It really deals with using a procedure which provides the best possible information so that good decisions can be made and correct action can be taken.

What I recommend is to use the miter slot as the alignment reference for a table saw. The blade is aligned parallel to the slot, not the slot to the blade. The fence is aligned parallel to the slot, not to the blade. I know it seems like the same thing and under ideal conditions you will accomplish the same results. But, the parts of a table saw are far from ideal. When you choose a reference, you don't want that reference to introduce error into the measurement process. When the reference introduces error, then uncertainty creeps into the measurement process. Uncertainty leads to bad decisions. Bad decisions cause incorrect actions. Blades and fences often have considerable surface variations. These variations introduce error into the measurement process. However, the miter slot is a machined feature with some substantial material behind it so it is most likely to be accurate (straight).

An example might help clarify. In this particular case, the OP was measuring between the fence and the blade. He observed variation and assumed that the blade alignment was to blame. He was assuming that his fence was straight and properly aligned. Therefore, his choice of reference was the fence. So he attempted to adjust the alignment of the blade to match that of the fence. But, that didn't solve the problem. Bad reference, bad decision, incorrect action.

Suppose he chooses the blade as his reference and adjusts the fence. This might not resolve the problem either. Variations in reading between the two surfaces could be due to misalignment or they could be due to variations in either surface. The small segment in the middle of the fence (where distance to the blade can be measured) might not represent its actual shape. More instrumentation will be required. He could verify the accuracy of the fence by checking it with a straight edge. But, he still can't be certain if the variation is due to blade warp (or some other runout problem) or misalignment. So, more tests are needed to confirm the accuracy of the blade (his reference). Some people choose to purchase a flat blade replacement plate at this point. While this might eliminate warp in the blade plate, it doesn't eliminate other sources of runout (arbor, flange, bearings,...) and cannot guarantee good results.

When he's done eliminating all the various possibilities, he will still need to concern himself with miter slot alignment if he wants to use his miter gauge. Moving the blade/slot alignment at this point will disrupt the blade/fence alignment. So, now order becomes important because the accuracy of one alignment influences the accuracy of another - all because of the choice of reference.

Suppose he chooses the miter slot as his reference. Now the blade/slot and fence/slot alignments are completely independent. The miter slot is far less likely to be warped or deformed so it can be used to judge the quality of the other surfaces (just like a straight edge). It's long enough to fully characterize the fence (not just a small portion in the middle). Variations in reading can be attributed to the fence or the blade with fairly good confidence. There is little or no uncertainty. Decisions are more likely to be good and lead to correct actions. Even on a cabinet saw, where you literally move the slot (because it's part of the table) you are still using it as your reference because it is being used as the standard to independently judge the condition and alignment of the other surfaces.

I know it's l> While I understand what you are saying here Ed, you seem to contradict your

Reply to
ejb

Being somewhat anal myself, and an engineer to boot, I assumed I knew what to do. My reasoning was, that since the blade-to-fence distance is most critical, I'd rather take that measurement directly instead of taking two measurments, with the chance that the errors in measurements or inconsistency of construction of both blade and fence may stack up. After reading your explanation, I can accept that your way is indeed better. You have obviously spent a great deal of time thinking over these matters. I wouldn't have thought the issue important enough to argue with you about, but I would have just kept doing it my way without your very articulate explanation.

DonkeyHody "We are all ignorant, just about different things." - Will Rogers

Reply to
DonkeyHody

This I will agree with.

Understood, Sorry If I lead you to think that using the blade slot was to be used in the mix.

The fence is aligned parallel to the slot, not to

Correct and the point I was trying to make. My point was that I see no difference except in ease of aligning the miter slot and the fence to the blade. Theoreticaly if you use a reference that was aligned to the blade as the reference to align the fence you could be introducing an incorrect setting or compounding a setting problem. For example if you use a length of wood to mark boards to be cut to a given length you get more consistant results than if you use the last cut piece each time to reference the next mark. Esentually, if you align the miter slots and the fence in the correct order both have used the blade as the starting reference point. It seems to me that adding another reference point/miter slot into the mix increases the chance for erreor.

If you are simply saying that referencing the fence to the miter slot vs. the blade is easier and there fore may decreased the chance for procedure error, I totally agree.

IMHO if you use the blade as a reference to align both the miter slot and the fence you will get closer results than if you use the blade to align the miter slot and then use the miter slit to align the fence. Since nothing is perfect, adding the miter slot into the mix of another alignment procedure would introduce the potential for more error. I like to keep the common denominator as simple as possible.

But, the parts of a

Another reason that I have brought this up, it is also important to use the same miter slot to align the fence as the one that you aligned to the blade. While we hope that the miter slot is a precision cut feature of a saw there have been instances where the 2 miter slots are not parallel to each other. Granted they are supose to be but again not all equipment is perfect or created equally.

Exactly.

Correct, Might not, but certainly possible.

Snip

I understand but still, ;~) and I know that you are going to crenge. I set my Jet cabinet saw up then I first bought it 6 years ago. It was and still is equiped with Forrest blades. I did use a dial indicator to check arbor run out and the blade to miter slot and found both to be better than needed and or expected straight out of the box. I used the miter slot to align the fence and got good results but not quite what I was looking for. My cross cuts were producing clean and burnished results but signs of tooth marks were evident on the riped pieces. Several times I rechecked the fence being parallel to the miter slot. Finally I simply looked at the results and simply adjusted the fence using no reference at all other than the results. I made 1 or 2 minute adjustments to one of the adjusting set screws and I achieved and continue to achieve a ripped surface that shows no sign of tooth marks and the surface on hard woods will reflect objects. Basically I can see glare on the cut surface. Because my and most fences are long and only fixed at one end deflection is possible. An individuals feed technique can and does in many cases add yet another factor to how/where a fence should be aligned that a dial indicator may be able to duplicate but not achieve to begin with. While a dial indicator does permit near perfect alignment of a TS it cannot predict an individuals technique that may cause less than perfect results.

Thanks ED.

Reply to
Leon

Hi DH,

Sorry about not expla> Ed,

Reply to
ejb

No, I knew you were talking about the miter slot. I just wanted to make sure everyone else did too.

I'm not sure what you mean by "ease". I can't imagine a more difficult task that to use the blade as a reference - unless, of course, you ignore the potential for error that can influence the outcome.

This sounds just like BLeeds! The bottom line is this: I have to recommend a procedure which works best for everyone under all circumstances. I can't recommend a procedure that works only under ideal conditions. It's better to align two unknown surfaces to a known surface than to try to align them directly to each other. The known surface reveals the errors in the unknown surfaces. Aligning two unknown surfaces to each other allows the errors to remain hidden, lead to incorrect actions, and influence the accuracy of the results. Sorry Leon, I've really agonized about how to explain this in such a way that you could understand it. Perhaps someone else can do a better job.

This is a good example of the use of a length standard (or reference). But, it's not quite analogous to this situation. Think of it this way: suppose you need two 36" pieces of wood. Instead of using a reference for 36" (like a tape measure), you pick a piece of wood that looks like it's about 36". You use this as your reference and cut another piece of equal length. Yes, you end up with two pieces of wood that are the same length, but you don't really know if they are 36" long. You don't introduce more error by using known standard (the tape measure) - you ensure that both pieces of wood have less error because they conform to a known standard.

It's just bad practice to use a procedure that makes the accuracy of one adjustment dependent on the accuracy of a previous adjustment. Sometimes it's unavoidable. In this case it's not.

It's not "adding another reference"; it's "choosing the best reference". You actually decrease the chance of error because the reference you choose is superior to the items you are aligning - allowing you to characterize otherwise unknown surfaces.

Nope. It's not a matter of ease. BLeeds used to say that he formulated his blade/fence alignment idea because he found it difficult to achieve accurate travel in the miter slot.

Of course, you are welcome to do (and think) whatever you like. BLeeds said the exact same thing (practically word for word). I seem to recall that you used to recommend aligning the blade and the fence to the miter slot. Did you change your mind recently?

It's true that nothing is perfect, but the miter slot is a lot closer to perfection than the blade or the fence. And, it's long enough to characterize both. It's just a much better choice.

I would say that this is a good practice. I personally haven't ever encountered a saw where the two miter slots weren't parallel but it "can" happen (the table shifts in the fixturing during machining). I'd call it defective.

You must have changed your position on this just recently. I found a number of messages where you talk about the fence and blade needing to be absolutely parallel to the miter slot (with no toe-out) and that this is how you get "shinny smooth" cuts:

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when you were recommending that people align their blade and fence parallel to the miter slot, were the cuts "shinny smooth" or showing "signs of tooth marks"? I guess I'm trying to reconcile your previous statements with the ones you are making today.

Here's one where you say it both ways (parallel to the blade and parallel to the slot):

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'm confused.

In other words, a perfectly aligned saw can produce bad results if the operator doesn't have good technique. And, it is possible that alignment can be used to compensate for poor technique. I can see how that might be true.

Ed Bennett snipped-for-privacy@ts-aligner.com

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Reply to
ejb

YES, ;~) I still do recomend the miter slot as it is pretty easy to use as a reference. I do however believe that the blade can be used also. IMHO one no better than the other but one is easier.

By something I said???? ;~) I can be confusing.

Yeah.

Thanks for the clarification.

Reply to
Leon

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