Deviation of cut on table saw

kurtwp

New User
Kurt
Refer to the 60 marks on the ruler.

The two pictures attached depict a small deviation over 24 inches from a rip cut The picture with the word TOP
was fed into the TS blade first and the second picture is of the end of the board. The ruler is being placed about
1/2 inch in from the ends of the board.

Would the deviation illustrated in the two pictures be a concern over a longer rip cut such as 5 feet?
Would this be a concern for sleds?

Thanks

Kurt
cut2bottom.jpg
cut2top.jpg
 

TENdriver

New User
TENdriver
Between the parallax and my “mature” eyes, I am guessing you see a 1/64” difference.

Is that correct?
 

Gotcha6

Dennis
Staff member
Corporate Member
I'd say you are in need of a table saw tuneup, making sure that (1) the blade trunnion is parallel to the miter slots, and (2) the rip fence is parallel to the blade. A simple, but sometimes time consuming process. Look in our archives for several pictorials on doing it. A feather board may be in order too if you aren't using one.
 

kurtwp

New User
Kurt
With my current ability and depending on which tooth of the blade I measure from, the back of the blade is in between the 0 and 1 marks on my dial gauge. The furthest I measured was between the 1 and 2 marks on the dial gauge using the same blade. The back of the blade is moving away from the right miter slot. Maybe I have to bring the fence in toward the miter slot as the fence does veer away about 6 marks at the back of the fence.

I did not use a feather board when I made the cut that is being seen is this post.
 

bowman

Board of Directors, Webmaster
Neal
Staff member
Corporate Member
put a mark on 1 tooth of your blade and use that as a common measure point from the mitre slot. This will tell if your blade is parallel. Once you have that corrected, then you can concentrate on your fence.
 

kurtwp

New User
Kurt
That is exactly what I did. Set my dial gauge to 0 on the tooth. Rotate blade back and measure the same tooth. The smallest value was between the 0 and 1 marks on the dial gauge. Just for its and giggles I did the same measurement but using different teeth. Out of the four or five different teeth I measured, the largest was between the 1 and 2 marks the smallest was between the 0 and 1 marks on the dial gauge.
 

bowman

Board of Directors, Webmaster
Neal
Staff member
Corporate Member
Thanks for the details, wasn't sure from your original post. Is your fence straight?
 

Jeff

New User
Jeff
That is exactly what I did. Set my dial gauge to 0 on the tooth. Rotate blade back and measure the same tooth. The smallest value was between the 0 and 1 marks on the dial gauge. Just for its and giggles I did the same measurement but using different teeth. Out of the four or five different teeth I measured, the largest was between the 1 and 2 marks the smallest was between the 0 and 1 marks on the dial gauge.

That doesn't sound like much and you stated "about less than a 1/64" deviation over 24" in your rip cut example. Do the trigonometry to find out how much.

tangent x = 1/64/24, x = the angle of deviation and x = 0.0373 degrees.

Is this the first time that you've noticed this or the first time that you've attempted to measure it?
 
Last edited:

kurtwp

New User
Kurt
Yes, I noticed it before and measured my blade which was about 3 marks out at the back from the same tooth I used to measure when I tried to adjust the blade again. I have not re-adjusted my fence after this last attempt to get the blade to zero. My fence veers away at the back by 6 marks. I did this as the fence has a wave in it. The wave moves toward the blade near the front of the blade. To compensate for the wave, I adjusted the fence to veer away from the blade by 6 marks. The back of the fence is 6 marks out. Suggestions?
 

mgreene93

Mark
Corporate Member
Yes, I noticed it before and measured my blade which was about 3 marks out at the back from the same tooth I used to measure when I tried to adjust the blade again. I have not re-adjusted my fence after this last attempt to get the blade to zero. My fence veers away at the back by 6 marks. I did this as the fence has a wave in it. The wave moves toward the blade near the front of the blade. To compensate for the wave, I adjusted the fence to veer away from the blade by 6 marks. The back of the fence is 6 marks out. Suggestions?
Time for a new fence?
 

Mike Davis

Mike
Corporate Member
Is the cut consistently off by 1/64 over 24 inches?

Is that evenly distributed or does it jump out at some point?

What rip guide do you have? Is it aluminum, HDPE, or particle board on the face? Does it flex or move when you push against the edge?

Are you jointing the board to be sure it is straight before you cut it?
 

kurtwp

New User
Kurt
The fence is a SS Pro T-glide and if I push hard enough I can move the back of the fence a bit maybe one or two marks on the dial gauge. The front won't budge once locked in. The board is not jointed.
 

Ed Fasano

Ed
Senior User
I doubt that exercises in deviation measurements will have useful meaning If the test board is not well jointed, i.e. a clean straight edge again the rip fence. So... you may or may not have a table saw tuning and/or fence flex issue, but I wouldn't recommend wasting time on those things unless the test cuts are made with a trued board. A feather board would also promote more consistency testing. Remember too that we are woodworkers not machinists.
 

Jeff

New User
Jeff
Remember too that we are woodworkers not machinists.

Good point. I wonder sometimes if we're overthinking the accuracy needed and applying machinists standards.


The fence is a SS Pro T-glide and if I push hard enough I can move the back of the fence a bit maybe one or two marks on the dial gauge. The front won't budge once locked in. The board is not jointed.

That's a Saw Stop fence that looks pretty darn sturdy so I'd expect that it doesn't deviate very much.
 

Rwe2156

DrBob
Senior User
Even a small error like this will multply, especially in a project like cabinets.

Even the best fences will give a little I doubt that's the issue. That said there shouldn't ever be that much lateral pressure on a fence during ripping.

I suggest you re-verify your fence/blade alignment. The outfeed side of blade should be .003-005" wider than infeed.
 

kurtwp

New User
Kurt
Added a feather board and used a jointer to true up the edge the best I could. This did help to reduce the deviation. My jointer technique still needs some work as there was some flex in the board when I placed on the wing of the table saw. Maybe I did not run it through the jointer enough as it was a scape piece of 2x4.
------------------------------
With my current ability and depending on which tooth of the blade I measure from, the back of the blade is in between the 0 and 1 marks on my dial gauge. The furthest I measured was between the 1 and 2 marks on the dial gauge using the same blade. The back of the blade is moving away from the right miter slot. Maybe I have to bring the fence in toward the miter slot as the fence does veer away about 6 marks at the back of the fence.

-----------------------------------
My fence veers away at the back by 6 marks. I did this as the fence has a wave in it. The wave moves toward the blade near the front of the blade. To compensate for the wave, I adjusted the fence to veer away from the blade by 6 marks. The back of the fence is 6 marks out.
 

JimD

Jim
Senior User
Kurt,

I think your fence needs to not have a "wave". Can you shim behind the fence faces or something to make it flat? I had to shim my home made router table fence over the weekend to avoid a feeding issue and one business card behind the split fence on the infeed side solved my issue. Masking tape can also be used to shim things like this. My SS fence is not perfectly perpendicular to the table surface on both sides but is straight. I made the fence perpendicular on the left side, the side I normally use, but that makes it out a little on the right side. So in the rare event I put the fence to the left of the blade I will have to readjust.

Anyway, I think you need to get rid of the wave in the fence. Any lack of straightness in the fence will result in dimensional issues in the work.

Jim
 

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