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Table Saw Technique Problems

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Forum topic by harriw posted 12-12-2012 05:36 AM 980 views 0 times favorited 13 replies Add to Favorites Watch
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harriw

92 posts in 931 days


12-12-2012 05:36 AM

Hey folks,

I was cleaning up some lumber tonight in preparation for a pair of cutting boards, and noticed a problem in my Table Saw “Technique” that I could use some help with. I don’t think I see this problem when using the miter gauge, but when I use the fence.

Basically what’s happening is as the very end of the board passes by the blade completely, the back side of the blade is shaving a tiny bit more from the board’s edge, on the lower half of the board. Makes it look almost like you hit the bottom rear corner with your sander for a second or two.

Has anyone run into this before and know what I’m doing wrong to cause it? My saw is a Ridgid TS3612, and it doesn’t seem to make much difference if I’m using a push block, hands, etc. I was using the stock splitter, with the anti-kickback pawls attached. Blade is a Freud Premier Fusion Think kerf (P410T I think it is), brand spanking new – but I’ve noticed this problem with other blades as well.

I think I’m over (or under) compensating somehow towards the end of the cut as I run out of fence and lose the ability to help control the board from in front of the blade. But I’m not sure exactly what I’m doing to cause this.

Today I was using a roller-stand (with ball-bearing type rollers, not a single roller on one axis) as an outfeed, and had it set about 1/4” lower than the table. So the board would raise a tiny bit at the tail end if I wasn’t careful, but I don’t know if that’s having an effect or not.

Anyway, I’m being nit-picky about these cutting boards and trying to get everything just right, and wanted to see if anyone has seen this happen before. Any suggestions would be appreciated. Thanks very much!

-- Bill - Western NY


13 replies so far

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harriw

92 posts in 931 days


#1 posted 12-12-2012 05:49 AM

Just thought of something else….

I’m using a home-made Zero-clearance insert made from .mdf and shimmed with blue painter’s tape. The rear end was too high with 5 pieces, too low with 4, so I kept it slightly high so that the workpiece wouldn’t stub on the back side of the insert.

When the board end reaches the back side of the insert, it will tend to drop to the right as it leaves the ZCI area, which might explain what I’m seeing. But the center of gravity of the board would have passed that point long before.

Maybe if I’m keeping enough pressure on the backside of the board with my pushblock (a 2×4 on its edge with a heel piece glued on the back), it isn’t dipping down to the right until the end of the board gets there?

Just thinking out loud… I’ll let wiser ones tell me what I’m doing wrong now :) Thanks!

-- Bill - Western NY

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a1Jim

112538 posts in 2300 days


#2 posted 12-12-2012 06:06 AM

It sounds like maybe your fence is out of square and does not line up with your saw blade.

-- http://artisticwoodstudio.com Custom furniture

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Jorge G.

1526 posts in 1198 days


#3 posted 12-12-2012 06:19 AM

I agree with Jim, you might want to check that as it is also a cause for kick back.

-- To surrender a dream leaves life as it is — and not as it could be.

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harriw

92 posts in 931 days


#4 posted 12-12-2012 01:17 PM

Thanks guys, I’ll check the fence tonight. When I set it up I had it splayed out by .003” in the back, but it’s been a while since I checked it. Thanks!

-- Bill - Western NY

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Monte Pittman

15139 posts in 1061 days


#5 posted 12-12-2012 01:22 PM

With the blade at it’s full height, check distance from front and back of the blade to the fence. I am becoming paranoid and I trust nothing is square.

-- Mother Nature created it, I just assemble it.

View Cosmicsniper's profile

Cosmicsniper

2199 posts in 1882 days


#6 posted 12-12-2012 01:45 PM

I get this sometimes. It’s a technique issue, methinks. For me, I think it occurs as I transition to a push stick. So, it typically happens on the more narrow cuts. I even get it if I retain pressure against the fence with the left hand. In fact, I think I might over-push in the fence to compensate.

Usually it’s rectified on wider cuts when I use my hand and push through at a constant rate. Ideally, we’d never pause during a cut, but sometimes it’s difficult to make those transitions.

I would also check to see if your fence locks down tight with zero flexure. Even the slightest move will cause these issues with the slightest change of pressure against the fence, even when the pressure, you think, is mostly north and south along the fence. My over-pushing while making the push stick transition is probably making the fence flex a little bit.

-- jay, www.allaboutastro.com

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Cosmicsniper

2199 posts in 1882 days


#7 posted 12-12-2012 01:50 PM

Never mind…I re-read your description and you seem to have a different problem. Though I would certain look to see if fence pressure is an issue. Perhaps you are pushing against the fence too hard during the cut and then relaxing right at the end?

-- jay, www.allaboutastro.com

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SnowyRiver

51450 posts in 2204 days


#8 posted 12-12-2012 02:03 PM

I agree with the fench issue. Thats easy to check. If the fence is square to the blade, then what I do when pushing the wood through is to always push the wood against the fence through the entire cut. It sounds simple and it is, but its easy to let the wood drift away from the fence as you near the end of the cut. When using a push stick, I stand a bit to the left of the blade which makes it a bit easier to keep pressure on the wood against the fence. Also the handle type push stick that has the long front end works best for controlling the wood.

-- Wayne - Plymouth MN

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runswithscissors

1166 posts in 748 days


#9 posted 12-14-2012 07:58 AM

I wonder if your slightly high table insert might be contributing to the problem?

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

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harriw

92 posts in 931 days


#10 posted 12-19-2012 04:50 AM

Hey folks,

Just an update…

I don’t have a dial indicator at the moment (it’s on my Christmas list…), but both the fence and blade look perfect with a combination square. When I set the saw up (~6 months ago) I used the “2-cut method” (same as the 5-cut, but with only 2 cuts since the fence is parallel instead of perpendicular) and measured the cut-off with a micrometer to get the fence to toe-out by 0.003” in the back. So while it might have shifted, it doesn’t look that way.

I do think what I’m seeing is technique-dependant. I’ve been contiously thinking about pushing against the fence towards the end of the cut, and realized I’ve been doing that with the same “forwards and to the right” pressure that I use through the beginning of the cut. Problem is, once the workpiece leaves the blade so that the blade is no longer helping to keep the piece in line, there’s not enough fence left for pressure in that direction to work. Instead, pressure in that direction is making the piece pivot around the back corner of the fence, shoving that stub of a corner into the blade.

So, I need to work on keeping pressure into the fence towards the end of the cut directly to the right, rather than right and forwards. Difficult to do since you also need to push the piece forwards still… But at least I think I understand what my problem was.

A riving knife would probably help this too, but my rear-connected splitter can deflect right-left too easily at that point (directly beyind the blade, which is the splitter’s furthest point from its anchoring).

Thanks all for your help!

-- Bill - Western NY

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patron

13146 posts in 2064 days


#11 posted 12-19-2012 05:02 AM

you could sticky tape a longer fence board
to the fence you have
and see if the short fence is the problem

i always use my right hand to push at a 45 deg.
forwards and sideways too
all the way thru
but i have a besy fence
so it doesn’t deflect
like some saw fences do

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View harriw's profile

harriw

92 posts in 931 days


#12 posted 12-21-2012 01:31 AM

That’s a good idea Patron – my fence actually has t-track on the face so I could easily bolt-on an extension that would reach further back. I don’t think it’s deflecting since it clamps both front and rear, but I think I’m inadvertently rocking the workpiece around the back corner of the fence when it clears the back edge of the blade.

Thanks again everyone!

-- Bill - Western NY

View a1Jim's profile

a1Jim

112538 posts in 2300 days


#13 posted 12-21-2012 01:51 AM

Save yourself from messing with double sided tape get a set of these guys or make a shop made version .

http://www.youtube.com/watch?v=w_eTWiAGLsE

http://www.youtube.com/watch?v=QBnSZ5eqiZ0

-- http://artisticwoodstudio.com Custom furniture

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