I was told a regular rip fence (in its regular position) is unsafe for large boards

[John Northowl]

Hello, I was told today that when ripping large boards having the fence in its normal position was unsafe. The explanation being that wood tension could cause the board to be pushed by the fence into the back of the blade. The recommendation therefore, was to pull the fence back so the far end is in line with the blade (and not extended past like in its normal position). I looked up the manual for the saw and it too mentioned this fence position as recommended. I believe it said no more proud of a 45 degree angle from the front of the blade.

I am slightly confused why having the fence in its normal position and using a riving knife if unsafe?

Sorry if this is unclear.

[Lee Schierer]

I would question whomever told you that their basis for determining that; i.e what is their source? How large it too large?

If you have the old style Unisaw fence, they could be adjusted in the manner described, but the majority of fences cannot be shortened easily.

[Andrew Hughes]

That’s mostly true if your trying to rip Rough sawn 8/4 hardmaple .
If it’s rough sawn 8/4 western red cedar it’s not going to be as true.
I calculate 1.7 million variables
I use my bandsaw to rip thick timbers
Good Luck

[Marc Fenneuff]

What was your source? It's common practice in Europe for the rip fence to stop at the end of the blade.

[brent stanley]

What was your source? It's common practice in Europe for the rip fence to stop at the end of the blade.

Exactly, this is common, ordinary and in fact required for ripping in some jurisdictions in Europe I believe. Without a fence there, the wood is free to expand into the space where the fence would normally occupy.

[Philip Glover]

I am slightly confused why having the fence in its normal position and using a riving knife if unsafe?

When ripping a long board sometimes the board pinches in, sometimes it splays out.
The riving knife helps when the board pinches in. It does nothing when the board splays out.
Pulling the rip fence back helps to prevent serious problems when the board splays out and pushes out against the fence and forces the board back into the blade.

PCG

[Rod Sheridan]

Hello, I was told today that when ripping large boards having the fence in its normal position was unsafe. The explanation being that wood tension could cause the board to be pushed by the fence into the back of the blade. The recommendation therefore, was to pull the fence back so the far end is in line with the blade (and not extended past like in its normal position). I looked up the manual for the saw and it too mentioned this fence position as recommended. I believe it said no more proud of a 45 degree angle from the front of the blade.

I am slightly confused why having the fence in its normal position and using a riving knife if unsafe?

Sorry if this is unclear.

That’s true, however it’s not related to width, it’s related to material.

1) for stable material such as sheet goods the rip fence can protrude past the start of the blade however I normally pull mine back so it ends at the arbour, this gives me more infeed guidance

2) for unstable material such as solid wood the fence should end at the start of the blade. This prevents wood movement from internal stress binding against the fence. It also increases infeed guidance.

The riving knife is prevent wood from contacting the rear of the blade, causing a kickback. This is due to wood rotating into the blade.

The crown guard (guard on top of the blade) prevents kickback by preventing the wood from contacting the top of the blade.

These are common safety practices, the riving knife, crown guard and short fence are over a century old.

The Delta Unifence is an example of such a fence, so are the fences on European saws…….Regards, Rod

[Jared Sankovich]

That doesn't work well in the US since
1. Most american fences can't be moved forward or back (just left and right)
2. Most US table saws are missing the riving knife/splitter/guard

[Jim Becker]

One of the things that folks with Euro machines as well as the UniFence and similar appreciate is the ability to position the rear end of the fence appropriately for various kinds of cuts. When I'm using the rip fence on my slider for anything other than very narrow, long rips, the back of the fence ends just before the rear of the blade. That does provide relief for any "outward" tension release while the riving knife deals with "inward" (pinching) behind the blade. Obviously, if you're using a typical "tee-square" type fence like the Biesemeyer or copies, you can't do this so you have to pay attention for sure, particularly with lumber that is exhibiting tension. If you detect that, do the initial rip with the bandsaw and then clean it up after jointing one edge and going back to the table saw.

This has nothing to do with the size of the board. It's about the characteristics of the individual board.

[Joe Calhoon]

Below is a picture from a German safety manual. The fence pretty much ends at the start of the blade then as the material gets wider the fence goes out at 45 degrees. This is what is taught in the German, Austrian Italian schools. It is not the law there. Now in real life in shops there is this practiced? Not really, many differences of opinion about this and some like the support of the fence further out.

I roughly follow this because it is easier on the blade. Takes a little getting used to without much support at the end of the cut. I’m never taking a finish rip on the table saw either. My preferred method of ripping on the slider is using a basic F&F with soft edges and using the fence pulled back all the way. To me this is the safest on a slider.

The UK is a little behind Continental Europe on safety but getting better. Some of the shops we visited there had rip saws with large blades all the way up with the fence ending just short of the blade. Very scary. Most have phased these out especially with employees.
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[Patrick Kane]

Below is a picture from a German safety manual. The fence pretty much ends at the start of the blade then as the material gets wider the fence goes out at 45 degrees. This is what is taught in the German, Austrian Italian schools. It is not the law there. Now in real life in shops there is this practiced? Not really, many differences of opinion about this and some like the support of the fence further out.

I roughly follow this because it is easier on the blade. Takes a little getting used to without much support at the end of the cut. I’m never taking a finish rip on the table saw either. My preferred method of ripping on the slider is using a basic F&F with soft edges and using the fence pulled back all the way. To me this is the safest on a slider.

The UK is a little behind Continental Europe on safety but getting better. Some of the shops we visited there had rip saws with large blades all the way up with the fence ending just short of the blade. Very scary. Most have phased these out especially with employees.


Ha, the Wadkin SR Rip saw comes to mind. Absolutely enormous 20"+ blade with the shortest fence. I suppose i understand the theory, but ive never had a safety issue with a board expanding into the fence. Ive seen it happen with the offcut banana out and away from the blade, but that was more an issue of wasted lumber and not a safety issue. The opposite happening is a little more concerning. Ive stalled 5hp saws many times with tension in lumber, and i always have a splitter/riving knife on my machines. It is incredible the force that will clamp down on the blade and splitter. The few times ive had my fence pulled back on my slider and performed a conventional rip, the absence of a reference surface(fence) past the blade made for mild inaccuracies. I found it easy for the majority of the board to stray out of parallel to the blade, in my experience.

[Michael Burnside]

If it isn't dry and could easily move when cutting, I'd use my track saw. Generally I only rip 8/4 and thinner dried lumber on my TS. Anything rough or thicker and I get out the bandsaw or track saw. Ripping to final dimension with very little waste seems fine to me if the blade height can accommodate.

Dimensionally stable sheet goods? Nah, I don't buy it, never had an issue at all.

[brent stanley]

Ha, the Wadkin SR Rip saw comes to mind. Absolutely enormous 20"+ blade with the shortest fence. I suppose i understand the theory, but ive never had a safety issue with a board expanding into the fence. Ive seen it happen with the offcut banana out and away from the blade, but that was more an issue of wasted lumber and not a safety issue. The opposite happening is a little more concerning. Ive stalled 5hp saws many times with tension in lumber, and i always have a splitter/riving knife on my machines. It is incredible the force that will clamp down on the blade and splitter. The few times ive had my fence pulled back on my slider and performed a conventional rip, the absence of a reference surface(fence) past the blade made for mild inaccuracies. I found it easy for the majority of the board to stray out of parallel to the blade, in my experience.

Yes, that's a beast but probably a 70 year old saw now, at least the design. But even back then they had short fences and riving knives that could be adjusted properly and moved with the blade, unlike some more modern NA cabinet saws though there are exceptions of course. The HSE authority in the UK requires commercial shops to use a short fence with the positioning being from the gullet bottom to 18mm back as the acceptable range. Unless your outfeed and back of the bench are perfect and your wood behaves well, it can be more challenging to get the last bit of your stock perfect for the reasons you state. I don't rip solid wood on the bench saw anymore if I can avoid it, I just rip it close on the bandsaw and bring stock to final width on the shaper with an outboard fence. Cleaner results and safer than a cabinet saw IMO.

[Curt Harms]

I would question whomever told you that their basis for determining that; i.e what is their source? How large it too large?

If you have the old style Unisaw fence, they could be adjusted in the manner described, but the majority of fences cannot be shortened easily.

I was able to have my cake and eat it too. My TS fence has T slots on the sides. I took a piece of 6/4 Poplar (I think) and planed it to exactly 1". Drill and counter bored holes so I could attach the Poplar piece using T nuts. Now I can move the Poplar piece wherever I want. The 1" is just to make the fence tape easily usable, I just have to make sure to add 1". I learned the value of a short fence when ripping some 2 X 4s. As soon as it was cut thru it wanted to form a Y and bound the blade. Luckily it was a low powered saw so it didn't take much to stop the blade.

[Jeff Bartley]

Yes, that's a beast but probably a 70 year old saw now, at least the design. But even back then they had short fences and riving knives that could be adjusted properly and moved with the blade, unlike some more modern NA cabinet saws though there are exceptions of course. The HSE authority in the UK requires commercial shops to use a short fence with the positioning being from the gullet bottom to 18mm back as the acceptable range. Unless your outfeed and back of the bench are perfect and your wood behaves well, it can be more challenging to get the last bit of your stock perfect for the reasons you state. I don't rip solid wood on the bench saw anymore if I can avoid it, I just rip it close on the bandsaw and bring stock to final width on the shaper with an outboard fence. Cleaner results and safer than a cabinet saw IMO.

Brent, how well does a back fence work with thin stock? I usually try to rip on the BS and then thickness with the planer.

To the OP, ripping on the BS and thicknessing with the planer works much better for me, but it’s not always practical. I do pull the fence back when possible on the TS.

For those with non-movable fences: you can always add a sub-fence and position it at the end of the blade. When I only had a Jet TS with a Biesemeyer fence I made a sub-fence that I could clamp on for cutting rabbets (burying a dado stack in the fence), you could easily clamp a fence like that at the end of the blade.

[brent stanley]

Brent, how well does a back fence work with thin stock? I usually try to rip on the BS and then thickness with the planer.

To the OP, ripping on the BS and thicknessing with the planer works much better for me, but it’s not always practical. I do pull the fence back when possible on the TS.

For those with non-movable fences: you can always add a sub-fence and position it at the end of the blade. When I only had a Jet TS with a Biesemeyer fence I made a sub-fence that I could clamp on for cutting rabbets (burying a dado stack in the fence), you could easily clamp a fence like that at the end of the blade.

It wouldn't be the choice for thin stock of course, but everything else it works very well for and is safe with good clean results if you know how to set it up properly. Not all planers like edge planning unfortunately, and for thin stock some of them don't behave well either without some jigs etc. A lot of folks also have perpetual losing battles with planer snipe too which can lead to unsatisfactory results I bought my Wadkin RK specifically because it will plane 8"+ timberframe brace blanks on edge for me, but I've been using the shaper for this till I get something sorted out with the RK. For very thin stock, jigs can be made the deflect the thin bit away from the blade. I believe the sub fence attached to the Biesemeyer style is what Curt mentioned above, and can be helpful if well executed.

[Jim Dwight]

I think the best way to deal with material that wants to warp is to cut it to rough length prior to ripping it to width. The longer the piece is the more it will want to move and the more you will have to cut away to make it straight. I routinely use my track saw to get a straight edge on longer boards. Much easier for me than trying to use my admittedly small jointer. It is also necessary to leave some extra width to have the material necessary for straightening cut or cuts.

I don't like cutting wood that wants to warp significantly on my PCS, I look for other ways. I guess I could add a short add on fence but that isn't going to help eliminate the warping. Track saw is safe and straightens the board.

[Bryan Hall]

"Unsafe" is in the eye of the beholder. There are folks who will tell you that it's unsafe to use any table saw that isn't a sawstop, so understanding what they specifically think is unsafe and why and in what specific circumstances is important.

I use a sliding table saw now. I suppose I could argue that cabinet saws are unsafe, but that's not true, they just have different strenths/weaknesses.

There will be pros/cons to moving the fence into various locations for rips, crosscuts, large pieces, small pieces, etc. I don't think there is a hard and fast rule. If there was, then why would the manufacturer give you the option to move the fence forward and back?

[Warren Lake]

had a regular fence from the start.