Table Saw Setup Question

[DaveP]

I have an older Jet 10” contractor’s table saw and I have been experiencing what I believe to be a slight misalignment between the blade, fence and miter gauge slots. So, I got a dial indicator setup and checked the blade to miter gauge slots. And, I see the blade is about 0.003 out of dead parallel. Unfortunately, this saw has no built-in adjustment for this alignment. So, I am considering whether to live with it, or, purchase an alignment kit which could get me to dead-on parallelism.

Am I asking too much? Is 0.003 acceptable? Should I try for better?

And, how do I set the fence? Parallel to the blade? Or, parallel to the miter slots? Or, as I’ve seen some have their fence slightly open on the backside of the blade?

Thanks for whatever input you have!

 

[Henry W]

Dave:
NOT an expert, and no direct experience with this, as my saw was setup when I purchased it (used).

I would be surprised if there was 'no built-in adjustment for the alignment'. Most contractor saws are aligned using I think 4 bolts that mount the trunnions to the table top. As I understand it is a finicky and frustrating process to accomplish this alignment, as the in the process of tightening the bolts, the relative positions can shift. Searching archives here might provide some perspectives on this.

Also as you state the fence should be 'open' towards the back, relative to the blade, and never 'closed'.
Seems to me the miter slots should be as close to parallel as possible. I can't comment on whether 3 thousandths is close enough.

So how's that for a non-answer?

 

[Jack A.]

It might help to explain why you think you have misalignment. Describing the symptoms should help narrow down the cause.

 

[DaveP]

Dave:
NOT an expert, and no direct experience with this, as my saw was setup when I purchased it (used).

I would be surprised if there was 'no built-in adjustment for the alignment'. Most contractor saws are aligned using I think 4 bolts that mount the trunnions to the table top. As I understand it is a finicky and frustrating process to accomplish this alignment, as the in the process of tightening the bolts, the relative positions can shift. Searching archives here might provide some perspectives on this.

Also as you state the fence should be 'open' towards the back, relative to the blade, and never 'closed'.
Seems to me the miter slots should be as close to parallel as possible. I can't comment on whether 3 thousandths is close enough.

So how's that for a non-answer?

Great non-answer! LOL!

Yes, there are four bolts that secure the saw mechanism to the table. There is no adjustment built-in, but there is a kit available to do just that. That kit has screw adjustment for left-right at one end of the mechanism. It is not expensive, but I can see installing it and using it to get "perfect" would be a pain in the duppa. But, then it would be right.

And, I understand the fence should be "out" at the backside to avoid pinching. So, I'm good there.

 

[Mike Davis]

This 'misalignment' is causing what kind of problem in using the saw?
.003 is very small.

 

[DaveP]

It might help to explain why you think you have misalignment. Describing the symptoms should help narrow down the cause.

To start, I could sense the blade was not in line with the feed direction as it would "drag" a bit during the outfeed portion of a rip cut. I thought I had the fence parallel to the blade. But, still had that slight drag.

So, I got this dial indicator gizmo to check the blade for square to the miter slots. That test shows the blade slightly out of parallel by 0.003" or so. Not much, but its there. Is that OK? Or should I go for better? That is where my post was headed.

The fence gets adjusted last.

 

[DaveP]

This 'misalignment' is causing what kind of problem in using the saw?
.003 is very small.

The workpiece drags a bit on the feed side of the blade as it goes out the other side. In other words, the workpiece is being fed through the saw at a very slight angle. I can easily adjust the fence, but not the blade alignment.

Yes, 0.003" is quite small, but that is over a distance of about 8". Maybe that is OK, I don't know. Could I make it better? Maybe, but is it worth the time/expense?

 

[pop-pop]

The mitre slots are not involved in rip cuts. Fence to blade parallelism is what counts.

 

[Gofor]

For cuts using the fence, align your fence with the blade. For these cuts, the work will then slide through true to the blade. The blade being out of alignment with the miter slot will then only affect cuts using a miter gauge or sled.

When doing miter cuts, be aware that the work piece will be moving slightly diagonally across the blade. Although you may be able to minimize the effect of this on the cut being square by adjusting the gauge, there will still be some risk of kickback on the side the back of the blade is canted to, so use appropriate protection, especially to prevent the back of the blade from lifting the work piece on that side. Raising the blade so only about three teeth are above the work piece will also minimize the risk of kick back (teeth coming more forward as opposed to straight up on the back of the cut). The wider the piece, more the pronounced any cut deviation will be. Using your figures, a 4" wide piece will move sideways in relation to the blade .0015", but a 12" wide piece will move .0045". Keeping the blade lower may slightly affect the squareness of the cut vertically due to the radius on the blade. Probably not noticeable in a 3/4" thick piece.

 

[DaveP]

The mitre slots are not involved in rip cuts. Fence to blade parallelism is what counts.

Yes, I understand... But, I also have a sled and good miter gauge. My thinking is that, if I can get the saw set up properly, then all this falls into place.

 

[DaveP]

For cuts using the fence, align your fence with the blade. For these cuts, the work will then slide through true to the blade. The blade being out of alignment with the miter slot will then only affect cuts using a miter gauge or sled.

When doing miter cuts, be aware that the work piece will be moving slightly diagonally across the blade. Although you may be able to minimize the effect of this on the cut being square by adjusting the gauge, there will still be some risk of kickback on the side the back of the blade is canted to, so use appropriate protection, especially to prevent the back of the blade from lifting the work piece on that side. Raising the blade so only about three teeth are above the work piece will also minimize the risk of kick back (teeth coming more forward as opposed to straight up on the back of the cut). The wider the piece, more the pronounced any cut deviation will be. Using your figures, a 4" wide piece will move sideways in relation to the blade .0015", but a 12" wide piece will move .0045". Keeping the blade lower may slightly affect the squareness of the cut vertically due to the radius on the blade. Probably not noticeable in a 3/4" thick piece.

Yes... I understand. And, I do have a sled and a good miter gauge. Just trying to get things better, as I know "perfect" is not realistic. Maybe I'm good where I'm at... that is really the basis for my question. Am I good? Or, do I need to work a bit more at this?

 

[Gofor]

IMHO, that depends on you. To put it into perspective, a cheap miter gauge probably has more than .003" slop between the slot and the runner. You have already eliminated this by making a sled and upgrading your miter gauge. Have you checked the other miter slot? It may be truer to the blade.

I would say its acceptable until it is not. That can only be determined by using it and if it is not producing the quality of cuts you need to be happy with your work, or causing you extra work to dress up the cuts, then its time to fix it.

Realize that If you "toe out" your 24" long fence by .003", you are introducing 1/3rd of the same problem you have now. If you toe it out 1/64", you have introduced more deviation in 8" (.005"+) than the blade is causing now.

What you have is definitely more accurate than a hand saw, which was used for centuries. However, there is the old saying "measuring with a micrometer, then cutting with a chain saw" which highlights the futility of trying to apply metal machinist accuracy when working with wood.

Personally, I would use it as is until it started to frustrate me. I would then either fix it or buy another saw.

One other observation: I have experienced "drag" at the end of a long rip cut. The problem was not the saw, but my outfeed table. It was not in the same plane as the saw table, so was causing the end of the board to slide sideways as I got further into the cut. May want to check that.

 

[DaveP]

IMHO, that depends on you. To put it into perspective, a cheap miter gauge probably has more than .003" slop between the slot and the runner. You have already eliminated this by making a sled and upgrading your miter gauge. Have you checked the other miter slot? It may be truer to the blade.

I would say its acceptable until it is not. That can only be determined by using it and if it is not producing the quality of cuts you need to be happy with your work, or causing you extra work to dress up the cuts, then its time to fix it.

Realize that If you "toe out" your 24" long fence by .003", you are introducing 1/3rd of the same problem you have now. If you toe it out 1/64", you have introduced more deviation in 8" (.005"+) than the blade is causing now.

What you have is definitely more accurate than a hand saw, which was used for centuries. However, there is the old saying "measuring with a micrometer, then cutting with a chain saw" which highlights the futility of trying to apply metal machinist accuracy when working with wood.

Personally, I would use it as is until it started to frustrate me. I would then either fix it or buy another saw.

One other observation: I have experienced "drag" at the end of a long rip cut. The problem was not the saw, but my outfeed table. It was not in the same plane as the saw table, so was causing the end of the board to slide sideways as I got further into the cut. May want to check that.

Great info! Thanks for the explanation and reinforcing my thinking that “I’m good” no need in obsessing over this. Coming from a mechanical engineering background, I know my tolerance there were much tighter than I can get with woodworking. Thanks for reminding me!

 

[Mark Fogleman]

Mark's comment about precision measurements on WW'ing machines rings true, but I've met Jerry Cole (Inline Industries, now closed and products sold by Peachtree) and his 70s Craftsman contractor's saw was precise after he made a few changes. Whatever you do, don't attempt to loosen the table mounting bolts for .003" as the slop in the threads as you tighten them will pull the table in every direction you don't want it to go.

If you haven't already, I would remove the blade and scrub the arbor flange and nut to bare metal with a green Scotchbrite pad and brake cleaner to ensure a clean reference for the blade. Then measure the runout of the arbor as you turn it. Use a metal file to reduce any high spots, casting gradue, rust, etc, until it runs true. Then mark and mount your blade at 12, 3, 6, and 9 positions to see the best mounting position for that particular blade. If you still aren't satisfied, get the Contractor Saw PALS
(Precision Alignment & Locking System) from Peachtree and dial it in. A-Line-It System ~$30 is worth the serious amount of frustration if you feel the need to adjust the top.

 

[DaveP]

Mark's comment about precision measurements on WW'ing machines rings true, but I've met Jerry Cole (Inline Industries, now closed and products sold by Peachtree) and his 70s Craftsman contractor's saw was precise after he made a few changes. Whatever you do, don't attempt to loosen the table mounting bolts for .003" as the slop in the threads as you tighten them will pull the table in every direction you don't want it to go.

If you haven't already, I would remove the blade and scrub the arbor flange and nut to bare metal with a green Scotchbrite pad and brake cleaner to ensure a clean reference for the blade. Then measure the runout of the arbor as you turn it. Use a metal file to reduce any high spots, casting gradue, rust, etc, until it runs true. Then mark and mount your blade at 12, 3, 6, and 9 positions to see the best mounting position for that particular blade. If you still aren't satisfied, get the Contractor Saw PALS
(Precision Alignment & Locking System) from Peachtree and dial it in. A-Line-It System ~$30 is worth the serious amount of frustration if you feel the need to adjust the top.

Wonderful reply and explanation... thanks! I had been looking at the PALS system and decided I'd better check to see if I had a problem first. (Trying to avoid unnecessary work.) So, got the dial indicator and checked. However, I have not yet thoroughly cleaned all those points of contact. Thanks for the recommendation! I'll do that and recheck it all.

 

[Gofor]

Another thought on the "drag" issue. A misaligned splitter/riving knife will also cause drag, as well as might cause the board to skew. It has to be aligned vertically as well as in parallel to the blade, and not extend beyond the kerf on either side at any point on the splitter/knife. If you have one designed for a full kerf (1/8") blade, and change to a thin kerf blade, it may be too wide.

My old TS3650 Ridgid saw has a notoriously ill-designed splitter that easily gets bent out of alignment. Its width is only a couple thousandths less than a thin kerf blade and its adjustment features are horrible. Reasons why most people remove them. I use alternative anti-kickback methods the majority of the time.

 

[DaveP]

Another thought on the "drag" issue. A misaligned splitter/riving knife will also cause drag, as well as might cause the board to skew. It has to be aligned vertically as well as in parallel to the blade, and not extend beyond the kerf on either side at any point on the splitter/knife. If you have one designed for a full kerf (1/8") blade, and change to a thin kerf blade, it may be too wide.

My old TS3650 Ridgid saw has a notoriously ill-designed splitter that easily gets bent out of alignment. Its width is only a couple thousandths less than a thin kerf blade and its adjustment features are horrible. Reasons why most people remove them. I use alternative anti-kickback methods the majority of the time.

Agreed... I removed my splitter long ago. It was not a good attachment and was, I think, for 1/8" blades. I use the Woodworker II Thin Kerf (3/32"?) blades because the motor is only 1.5hp. I also added a blade-stabilizer to support the blade.

My throat plate needs replacing. And, when I do that, I plan to add the MicroJig thin kerf splitter to match the blade. Get some safety back into the equation.

 

[ErinJ]

0.003" is actually pretty good for an older contractor saw, and most people would consider that well within acceptable tolerance. You’ll likely never notice it in normal cuts. I wouldn’t start chasing adjustments unless you’re seeing burn marks or kickback issues. As for the fence, set it parallel to the miter slots first, that’s your main reference. From there, many people leave the fence dead parallel to the blade or open it up just a hair (maybe 0.002–0.003") at the back to help reduce pinching. Honestly, with only 0.003" at the blade now, I’d probably just run the saw and not worry too much about it.

 

[DaveP]

0.003" is actually pretty good for an older contractor saw, and most people would consider that well within acceptable tolerance. You’ll likely never notice it in normal cuts. I wouldn’t start chasing adjustments unless you’re seeing burn marks or kickback issues. As for the fence, set it parallel to the miter slots first, that’s your main reference. From there, many people leave the fence dead parallel to the blade or open it up just a hair (maybe 0.002–0.003") at the back to help reduce pinching. Honestly, with only 0.003" at the blade now, I’d probably just run the saw and not worry too much about it.

Agreed... I am probably chasing perfection, which is impossible. Thanks!

 

[Mike Davis]

In rereading all this I don’t see any mention of the quality and condition of the blade.

How long since it was cleaned? Sharpened? Replaced?