# Riving Knife Along With Feather Board



## Jerry Bowen (Jun 25, 2011)

In another thread a discussion about spiitters and/or riving knives has been interesting. In all of the discussion about the safety issue of preventing kick backs, nothing has been said about the value of the magnetic feather board. I have been using that item and have felt that it is doing a pretty good job of keeping the workpiece solidly down on the table on the out feed or far end of the blade. I have experienced a couple of kick backs and they were the reason that I purchased the magnetic feather board. I'm wanting to add a splitter or a riving knife now after reading the thread about the subject. I am not able to install the blade guard due to the fact that I the reils for the Incra LS fence prevent the guard and splitter to be installed. After talking to Mark at Incra he told me to split the back rail which then will result in two rear rails creating a space for the installation of of the guard. I would prefer a riving knife to a splitter but csn't seem to find one for my saw. I will probably will end up with a splitter installed in the face of a home made insert. I am just wondering what members of the forum have to say about the magnetic feather board. It seems to me that as long the work piece can't raise up from the table and is 
held in place that the blade will cut through the area that is pinched if the pinch occurs that would lead to a kick back. Comments on the matter will be appreciated.


Here is a link to the website for the Grip Tite Magnetic Feather Board if you are not familiar with it. If you go to the website click on Videos to see how the system works.


http://www.rockler.com/product.cfm?page=2356







Jerry Bowen
Colorado City, TX


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## Heilander (Sep 29, 2012)

Microjig splitters in a shopmade ,zero clearance plate?


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## Phil P (Jul 25, 2010)

Jerry Bowen said:


> I am just wondering what members of the forum have to say about the magnetic feather board. It seems to me that as long the work piece can't raise up from the table and is held in place that the blade will cut through the area that is pinched if the pinch occurs that would lead to a kick back. Comments on the matter will be appreciated.


Hi Jerry

Firstly I've never needed a feather board on a table saw, nor ever seen one used in a trade shop, with the sole exception of when using trenching or dado heads (and then more as a form of guard than anything). Sunk cuts, where you are ripping a groove and the blade does not come all the way through would come into that category, too, and for those I will concede that a featherboard might boe of use. To be honest, though, that isn't such a common cut to make

Secondly there are a couple of points about riving knives and blades which haven't been touched on:-

There are two styles of riving knife - one which carries a crown guard on top of it and which therefore extends above the top of the blade - a second style which looks like a new moon in side view and stops slightly sort of the top of the blade

In an OEM installation and where the crown guard does not mount on the riving knife (new moon style) the riving knife is generally set to be about 2 or 3mm (1/8in) below the top of the blade and a 3 to 5 millimetres behind it with the front edge bevelled or V-shaped (see drawings below from the UK HSE file), the blade is normally set to protrude no more than half to a full tooth height above the surface of the board when through ripping.


















This style of knife permits "deeping" or saw blade grooving

With this type of riving knife were you to lift a board upwards from the infeed end of the machine the riving knife alone will pretty much stop the board from contacting the rear teeth of the blade which at least partly negates the need for a featherboard. Such set-ups benefit from the use of a "floating" or independently mounted crown guard

In the main we over here tend to use a crown guard mounted on the top of the riving knife, at least for through cuts (where the blade pierces the board). This is ostensibly to prevent the operator from placing their hand directly over the blade. but can and does serve as a secondary dust extraction device (when connected to a vacuum/dust extractor) but more importantly to my mind it can and does restrict the movement of the board in the event that a kickback occurs. With a riving knife and short position rip fence kickbacks are much less likely, but if/when they do occur the crown guard (if there is one) can and does absorb a lot of the force of the kickback. I've had guards pulled clean off the top of riving knives on industrial saws before now, although the material didn't actually go that far afterwards (3in thick badly kilned walnut boards about 12 in wide x 16 feet long - and absolutely full of tension). The crown guard retaining bolts fit into inverted slots and the crown guard is actually "pinched" in place so that this can happen - you can just make out the inverted U-slots in the riving knife on the Hammer below (note crown guard removed for illustration purposes and fence plate not necessarily in the best place):










Another common cause of saw bench accidents is failure to adequately support materials on the outfeed side of the saw. If the material isn't supported, either by an outfeed table, roller stand or helper it can drop, twist in so doing or when it hits the floor and then catch the rising teeth and be launched towards the rear of the saw at the operator. I've made that mistake a couple of times on site and lived to tell the tale!

Regards

Phil


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## Jerry Bowen (Jun 25, 2011)

Phil,
After reading your post and seeing that you are not familiar with the magnetic feather board, I added a link to the product. If you should elect to have a look, I suggest that you click on Videos. The video will give you a better idea of how it works.

Jerry


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## Phil P (Jul 25, 2010)

Jerry Bowen said:


> After reading your post and seeing that you are not familiar with the magnetic feather board, I added a link to the product. If you should elect to have a look, I suggest that you click on Videos. The video will give you a better idea of how it works.


Hi Jerry

My comments about the useability or otherwise of featherboards on table saws still stand. These devices look to be OK if you are sawing fairly consistent and straight timber on a table saw, however they won't work in several important situations, e.g. straight edging waney edge stock which requires the rip fence to be drawn back out of the way and a rip cut is then guided by sight against something like a chalk line the remove it (this is a dangerous operation and really only suitable for experienced machinists, removing the waney edge with a hand power rip saw and straight edge is preferable for the less confident), ripping non-straight stock (i.e. bowed across the width) to get a straight edge before going to the jointer or straight-lining timber in wind. In fact the onkly place I can see a use for them is in "deeping" (edge ripping from both edges to reduce the thickness of a board too deep to rip in a single pass, a very hazardous technique) which is much better done on a bandsaw. They don't in any way reduce the need for a crown guard and the side featherboard requires the use of a through rip fence to attach to the main rip fence which needs to be a through (Biesmeyer-type) fence. They are a source of danger (of kickback) if you ever centre rip wide reaction timber, i.e. stuff which diverges from the blade or pinches back onto it. My experience of wood machining makes me feel that it is hard not to dismiss them as anything other than "sticking plaster solutions" which have little or not place if primary safety considerations are met first

Regards

Phil


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## Jerry Bowen (Jun 25, 2011)

Phil, 
I certainly do agree with you. Fortunately I generally am able to work pretty straight stock that I get from a distributor near Lubbock, TX. I would not like to work with the type of wood that you have described as not be such that it would with a feather board like the one that I am talking about, by the way, did you watch the video that I ssuggested?

Jerry


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## Phil P (Jul 25, 2010)

Jerry Bowen said:


> by the way, did you watch the video that I ssuggested?


Yes I did, Jerry. That's why I'm dismissive of the steel rip fence face plate. It won't work with the type of hi-lo type rip fence I'm familiar with at least not in the low position (and I won't work with the guard off if at all possible). It also requires a through type rip fence which has it's own safety implications and I can't see it being much use for larger size sheet ripping, either. So scratch the steel fence plate/hold down position

I'll concede that the side position where the unit is gripped directly on the table has it's uses _for straight-line ripping of ready machined stock_ - although I find it more economical to rough to size then plane/joint/thickness dead to the required size. Part of the problem with getting extra long rips right is that users (especially hobbyists) often don't appreciate the need to have adequate infeed and outfeed support on long rips for both accuracy and safety, not to mention quality of cut. Saying that clean-up is minimal is all very well, but ripping without scorching generally requires a coarse square tip rip blade for speed, especially on a low-power contractor-type saw and making a single pass with a sharp block plane (or a sanding board for MDF) to clean up the edge afterwards is no great hardship to me. By the time you've swapped over onto a glue-line rip blade, I'd be long done and off doing something else. I still think that the amount of time taken to set-up these units rules them out for one-off cuts and that after a while they'd tend to fall into disuse. So only useable in _some_ instances IMHO. 

Before you comment about commercial usage I've used rip saws retro-fitted with power feeders which can do the same sort of thing as these two items combined as well as power feed at the same time. They need a long fence position as well, are generally only suitable if you are removing small sections (slivers) of stock from the material, i.e. where there is little or no liklihood of stress movement and consequent risk of trapping between the blade and the fence because that will bend your blade, and they generally take an inordinate amount of time to set-up and so people just don't use them on one-off cuts

And I'm still concermed that yet another firm hasn't taken on board some of the fundamentals about saw safety, like using guards and the rip fence position.

Regards

Phil


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## MAFoElffen (Jun 8, 2012)

Wait- really?

I watched the video. (theory vs. application)

Let's see if I got that right... You end up about $200 deep into their system (2 magnetic hold downs and a fence extension) that you have to remove the crown guard to use... because it is in the way to use it. Then it's in the way to do work safely.

Did you notice the convenient video fade-outs when they start to use a push stick to push the work through past the blade? (There is a functional reason they faded out at that point. There is a flaw there.) Before each fade-out- Did you see the hold-down on the fence and it's handle? Did you see the path of the push stick? Not going to happen as planned.

So you end up with a system that you're going to come up with work-rounds to make work, that you have remove safety features... Hmmm. I'm thinking something is wrong there, don't you?


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## del schisler (Feb 2, 2006)

i watch the video and he used a push stick when you get to the feather board how do you get the wood all the way through the blade?? Do you reach over the blade and pull the wood thro the reast of the way through. Unless i am missing something the push stick is stop at the feather board? If you are reaching over that isn't a good thing to do?? let me know thanks del


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## del schisler (Feb 2, 2006)

thanks for posting, read my post, i couldn't see it working at all,, now at first when you start the cut, but not all the way through the cut, I thank they are dreaming about selling something that isn't thought all the way through thanks for your post del


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## MAFoElffen (Jun 8, 2012)

del schisler said:


> i watch the video and he used a push stick when you get to the feather board how do you get the wood all the way through the blade?? Do you reach over the blade and pull the wood thro the reast of the way through. Unless i am missing something the push stick is stop at the feather board? If you are reaching over that isn't a good thing to do?? let me know thanks del


+1 with del schiser-
That's what I see.


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## DaninVan (Jan 1, 2012)

Ooh! Good point! 
I can certainly go along with some form of vertical restraint when ripping strips of laminate, but that's the only reason that comes to mind...I'm sticking with my splitter, guard, and pawls. 
It just occurred to me; the lack of a splitter may well have some bearing on why radial arm saws are so prone to kick backs while ripping. The The blade guard on my old Dewalt has a spring finger device which makes contact with the material on the infeed side while the drop-down rod with pawls catches the outfeed side.

On both the TS and RAS using featherboards _on the table itself_, to guide the material into the fence, is common practice for me. Bit of a p.i.t.a. time wise but sure worth the effort on narrow material.
Magnetic devices would obviously work only on steel/cast iron.
Another reason for querying the granite choice.


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## Jerry Bowen (Jun 25, 2011)

Well, it is obvious that for the most part the magnetic feather board is not seen as being of much value. I have used it for about a year and really like it, couldn't ask it to work better. I suspect that my lack of experience has allowing me to be snookered. I buy rough cut lumber and with the jointer and thickness planer to get it close to final size. As to when the stock has passed all the way through the blade there has been no problem. I place the magnetic hold down far enough past the far edge of the blade so that the work piece is held in place when the cut is completee.

For the time being I will continue to use the system but do want to add a splitter.

Jerry


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## Phil P (Jul 25, 2010)

DaninVan said:


> Ooh! Good point!
> I can certainly go along with some form of vertical restraint when ripping strips of laminate, but that's the only reason that comes to mind...I'm sticking with my splitter, guard, and pawls.


Me too, Dan. One of the shop fitters I work for from time to time has a piece of plywood with a small aluminium profile (U-section) screwed along the bottom edge for just that purpose. Clamps onto the rip fence. Good for those jobe where you need to cut a dozen or more identical strips and _prevents the laminate from submarining under the fence_, too



DaninVan said:


> It just occurred to me; the lack of a splitter may well have some bearing on why radial arm saws are so prone to kick backs while ripping.


I can only agree with you there, too

Regards

Phil


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## J. Leigh (Jul 15, 2012)

Featherboards do NOT prevent kickback. That is not their job. Featherboards, when used on a tablesaw, are mounted in FRONT of the blade and help to hold the stock against the fence to improve cut accuracy. If you are mounting a featherboard beyond the blade (after the cut), you are using it incorrectly and are creating a dangerous situation. Featherboards are no substitute for a riving knife.


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## Jerry Bowen (Jun 25, 2011)

J. Leigh said:


> Featherboards do NOT prevent kickback. That is not their job. Featherboards, when used on a tablesaw, are mounted in FRONT of the blade and help to hold the stock against the fence to improve cut accuracy. If you are mounting a featherboard beyond the blade (after the cut), you are using it incorrectly and are creating a dangerous situation. Featherboards are no substitute for a riving knife.[/QUOTE
> 
> 
> Joe,
> ...


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## DaninVan (Jan 1, 2012)

I'd be very surprised, Jerry, if a full-on kickback wouldn't just rip the magnetic feather-board right off the fence and throw it as well as the stock.
Remember that the force being applied, in the event of a kickback, is across the face of the fence, not outwards from it. Nothing to stop the magnets from sliding(?)...


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## DaninVan (Jan 1, 2012)

I wouldn't be at all surprised, Jerry, if a full-on kickback simply ripped the magnetic feather-board right off the fence and threw it as well as the stock. The force being applied (by the kickback) is parallel to the fence, not outwards from it; the magnets will simply slide. We're talking about a lot of energy over a very short period of time.
The sense of security is likely unwarranted, sort of like a condom with a hole in it...


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## J. Leigh (Jul 15, 2012)

Jerry,
Sorry if that came across as argumentative, that certainly wasn't my intention. There are a lot of misconceptions out there concerning kickback and what causes it. 
To answer your question, no, kickback does not start off with the wood raising up from the table. Kickback starts off with the wood making contact with the back, or rising teeth of the blade as it passes through the cut. Making contact with the rising blade is what lifts the wood from the table. Not the other way around. Trying to press the wood down to the table does NOT prevent it from contacting the rising teeth. Only a properly installed and adjusted riving knife can do that. 
Hope that helps clarify things a bit.


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## Jerry Bowen (Jun 25, 2011)

J. Leigh said:


> Jerry,
> Sorry if that came across as argumentative, that certainly wasn't my intention. There are a lot of misconceptions out there concerning kickback and what causes it.
> To answer your question, no, kickback does not start off with the wood raising up from the table. Kickback starts off with the wood making contact with the back, or rising teeth of the blade as it passes through the cut. Making contact with the rising blade is what lifts the wood from the table. Not the other way around. Trying to press the wood down to the table does NOT prevent it from contacting the rising teeth. Only a properly installed and adjusted riving knife can do that.
> Hope that helps clarify things a bit.



Joe,
You were not arguementive, I just didn't want you to think that I was being so. We are on the same page so to speak on the reason for the kick back. Let me explain my thinking a little further. First of all, I do realize that the raising teeth of the blade contacting the board and grabing it is what causing the kick back and the first thing that happens is that the teeth lift the board from the table. Now here id what I am thinking. If the feather board can hold the board down so that the teeth just cut through the board where it is pinched relieving the tention, then there would not be a kick back. I do understand that this is only my thinking, not something that I have experienced and I sure do reserve the right to be wroing. What is wrong with the concept, even if it doesn't work in the real world. I still plan to make a home made insert and installing a splitter in it. Would rather install a riving knife but don't see how I can do it on my saw with the Incra LS system installed on it.

Jerry


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## Dmeadows (Jun 28, 2011)

Jerry, what model saw do you have? A simple riving knife shouldn't interfere with the Incra. A full blade guard may indeed. I can get just the riving knife for my Grizzly G1023 for about 36 dollars(gonna do that soon!). Be happy to see if one is available for your saw!


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## Jerry Bowen (Jun 25, 2011)

Dmeadows said:


> Jerry, what model saw do you have? A simple riving knife shouldn't interfere with the Incra. A full blade guard may indeed. I can get just the riving knife for my Grizzly G1023 for about 36 dollars(gonna do that soon!). Be happy to see if one is available for your saw!




Duane, 
Thanks for the offer to help me on this matter. The model number on the manual is 
351-221140. However, when I needed to get a replacement insert for the saw, I was asked to change the Model number to 152-221140. I do not see this saw any longer on Sears Web Site, They show one that is similar except that it has sheet metal wings instead of the heavy cast iron wings that my saw has. I purchased the saw three years ago and was told by Mark Mueler, the tech for Incra, that the waw was designed and/or built by an ex employee of Delta and marketed through Sears. When I needed to buy an insert through Rockler I had to buy one for a Delta Saw. Due to the presence of the rails that are part of the Incra LS system I have not attempted to install the blade guard which has a splitter as part of the assembly. I would really like to install a riving knive but will settle for a splitter if there is no option for a knife.

So far, the magnetic feather board idea has worked pretty well by keeping the board being ripped pressed tight against the table so that it can't come up when and/or pinched, but as you can tell from my thread that this concept may not be as good as I have believed it to be. 

Thanks again for the offer to help.

Jerry


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## MAFoElffen (Jun 8, 2012)

Jerry Bowen said:


> Duane,
> Thanks for the offer to help me on this matter. The model number on the manual is
> 351-221140. However, when I needed to get a replacement insert for the saw, I was asked to change the Model number to 152-221140. I do not see this saw any longer on Sears Web Site, They show one that is similar except that it has sheet metal wings instead of the heavy cast iron wings that my saw has. I purchased the saw three years ago and was told by Mark Mueler, the tech for Incra, that the waw was designed and/or built by an ex employee of Delta and marketed through Sears. When I needed to buy an insert through Rockler I had to buy one for a Delta Saw. Due to the presence of the rails that are part of the Incra LS system I have not attempted to install the blade guard which has a splitter as part of the assembly. I would really like to install a riving knive but will settle for a splitter if there is no option for a knife.
> 
> ...


Jerry-

The concept and principle of holding the work down is sound and safer. For instance, board buddies do the same. Heck, I have roller skate wheels that I use to do the same. If fact I was wondering if I could find one-way bearing-clutches in a size for those wheels to act as a hold-down / feeding mechanism... Like a pawl, but not as aggressive.

What was said was not against that using it. Holding work down to a table is safer for control of the work piece. IMHO, any time you can add "control" to your work, help steady it and feed it, adds to your safety. It also adds to accuracy. 

Rather, it was said that in the product video that the hold down (that's what I'll call it) had a handle that stuck out obtrusively and prevented the push stick from being able to push the work pasted the blade. If a wider piece of work was being cut than the one displayed, it would have made it past it. That model shown just has limitations on narrow work. Of course with narrow work, that is when it is important to be able to use a push stick.

Example of another DIY hold-down / anti-kickback device I use, is a 3/4" x 1-1/2" board with spring pawls. I make the pawls out of banding strapping material. I have a hole drilled in the end, that I screw to the board. There is another screw under the strap to give it tension away from the board.The pawls face towards the rear. Work fed under it are pushed towards the table and feed from front to rear. If work tries to move towards the front, it catches on the ends of the pawls.

I also use a small, thin board clamped to me fence above some pieces of work.

Having said all that., I rarely use those on a table saw. Some "special" instances. Jig work. Thinking out-of-the box kind of work on a table saw. I do use most of those kinds of appliances more for router tables, shapers and jointer work.


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## Sawdust Don (Nov 1, 2012)

I watched the Grip Tight video, noticed also the fade out before finishing the cut.
Certainly the cut the cut could not be finished with the push device the fumbling demonstrator was using.
It looks to me, the Board Buddies do the same thing, but take up less room, and perhaps a bit more clearance to push the board past the back of the blade-"though its still a problem with the Board Buddies on narrow work."

In that video, it was shown a clamping device for attaching other work boards to a Biesmeyer style fence.
The Board Buddy base clamps can be used for that purpose, however the attachments for doing that have to be fabricated. Quite simple to make as in this photo.
This is quick to use for various purposes, and very solid.


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## Jerry Bowen (Jun 25, 2011)

Seems to me that the bottom line in regard to the use of the feather board is that if and I will stress the word IF, the work piece can indeed be held solidly against the table when ripping, a kick back would be impossible. This all depends on wether ir not the device holding the work piece down is sturdy enough to hold the work piece in place and if it is not capable of doing that, then the whole concept can be thrown out and is not practical. A splitter, or riving knife on other hand is much closer to being fool proof. At least that is my condlusion on the matter and if anybody disagrees with this observation, I hope they will say so as this is an important issue in my ipinion.

Jerry


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## Dmeadows (Jun 28, 2011)

Jerry Bowen said:


> Seems to me that the bottom line in regard to the use of the feather board is that if and I will stress the word IF, the work piece can indeed be held solidly against the table when ripping, a kick back would be impossible. This all depends on wether ir not the device holding the work piece down is sturdy enough to hold the work piece in place and if it is not capable of doing that, then the whole concept can be thrown out and is not practical. A splitter, or riving knife on other hand is much closer to being fool proof. At least that is my condlusion on the matter and if anybody disagrees with this observation, I hope they will say so as this is an important issue in my ipinion.
> 
> Jerry


 The riving knife will help _prevent_the cause of kickback, the hold down will try to _stop_ the kick back. Not that much difference most of the time. But when you have a reaction board that twists when cut, I'd rather have the riving knife and a hold down device. The main problem with the magnetic device is the are not strong enough to hold in that situation.

By the way I was not able to find one for you saw, Jerry.


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## J. Leigh (Jul 15, 2012)

A riving knife cures the disease.
A hold down ATTEMPTS to cure the symptom.


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## Jerry Bowen (Jun 25, 2011)

J. Leigh said:


> A riving knife cures the disease.
> A hold down ATTEMPTS to cure the symptom.


The truth of the statement above is why I will stay with the magnetic feather board and install a splitter on the table insert. I would prefer a riving knife but since there is not one available for my saw the splitter will have to do. By the way, the magnets are pretty darn strong. I have never had a serious kick back on the table saw, but the RAS is another story, boy a kick back on that saw is powerful, sure glad that it kicks away from me and not in my direction. I have learned to only use the RAS for cutting rough cut lumber into into shorter pieces before taking the shorter peices to the TS. 

Jerry


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## DaninVan (Jan 1, 2012)

From the 'SharkGuard' site...

"If you don't see a Shark Guard for your particular saw and are interested in one, please contact us. We would be interested in working with you to develop a splitter design that would make the Shark Guard work on your saw. We are currently working on splitters or riving knives for some saws not listed here.
We may already have a pattern that is not listed yet. We do make models that will cover up to a 14" blade for some saws. I haven't listed many of those models yet, but if you need a larger one, we may have a solution for you."
Leeway Workshop, LLC

Can't hurt, eh?


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## Phil P (Jul 25, 2010)

Jerry Bowen said:


> Seems to me that the bottom line in regard to the use of the feather board is that if and I will stress the word IF, the work piece can indeed be held solidly against the table when ripping, a kick back would be impossible.


I have the feeling that you've never ripped a reaction board, Jerry. Perhaps I should explain a little; a _true_ rip cut is actually something like a middle cut down a wide board, say 12 in wide with 6in of timber either side of the blade, a "dust cut" on the other hand is a trimming rip cut where you are removing only a small amount of timber from one edge of a board, say 3mm (1/8in). BTW Apologies for not making a distincton before. In the latter case there will be little or no stress relieved in the timber by the cut, it's highly likely that the timber will twist or move and a so a long or "through" fence can be used relatively safely. For those cuts the featherboard could be used, also a hold down - providing that neither interferes with the crown guard or the push stick being used to propel the timber. In the case of the former type of cut, a _true_ rip cut, the short rip fence should be the order of the day. Some timbers, such as walnut, can have an amazing amount of stress in them and will part dramatically away from the blade, or worse still _towards_ it as they exit the blade - in fact I've had 2in thick black walnut grip the riving knife so tightly in the middle of a cut that it required hardwood wedges to be driven in every 2 or 3 inches to allow the cut to continue at all with small kickback events all through the cut. Where the material diverges as it exits the blade anything with restricts the outwards movement of the material, such as a long or through rip fence inevitably results in the blade being pinched between it and the blade. To be effective the hold down requires that downwards pressure is maintained on the timber at the point where the rising teeth of the blade exit the table - and is precisely where you don't want or need a long fence to trap the timber. That is why I have no faith in them - that and the fact tjhat I consider that they will be an obstruction to pushing timber through the saw with the push stick

In either case the purpose of the splitter or riving knife is to minimise the propensity of the rising teeth at the back of the blade to catch and propel the board back towards the operator so they are always a good idea



Dmeadows said:


> The riving knife will help _prevent_the cause of kickback, the hold down will try to _stop_ the kick back. Not that much difference most of the time. But when you have a reaction board that twists when cut, I'd rather have the riving knife and a hold down device. The main problem with the magnetic device is the are not strong enough to hold in that situation.


That's the point of having a crown guard on the saw. It not only acts as a stop should a piece be kicked back (it should ideally be adjusted to be no more than 25mm (1in) above the material, but it also actrs as a visual and physical deterrent to you plonking your hand on the blade in the event that anything goes wrong and you lose your balance. This does happen from time to time as accident stats show

Regards

Phil


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