Riving Knives in America...

[Permutation_Jim]

Friends,

As a US expat living in the Cotswolds, I get my share of schtick over American tablesaw practices: from stacked dado blades to, "the guards have been temporarily removed for demonstration purposes."

I ran across a great short video at FineWoodworking dot Com demonstrating the value of riving knives over mounted splitters, and generally showing why kickback is so dangerous.

Less than five minutes in length, you can find it here.

I have two trusty Kity 419 Juniors (one's about to be up for sale ), and I usually use the built-in riving knife. I'll upgrade that to always, once I get one modified to be just below the top of the blade.

BTW, if anyone makes these for the Kity, please let me know.

Thanks, Jim

 

[Ateallthepies]

On this subject, I have been watching a load of Norm on Discovery Shed. Never a riving knife or splitter in sight and no short fence to boot :shock: And this from a guy who constantly goes on about safety :?

Still he has 10 fingers and more experience in wood working than I will ever acquire so must not be bothered or doing something right?

Steve.

 

[jimi43]

I watched a few Norms today...just to see if I changed my mind (I didn't) and I found myself going "NOOOOO!"....quite a few times during only two episodes. At one point he actually leaned over the rotating blade with his arm.... [-X

Anyway...since we know he is hardly a fine example of shop safety...I will move on from that to the case in point.

A riving knife is probably the best aspect of tablesaw safety if it is of the correct thickness and is set correctly. Second that with a short fence and finally with sensible feed practice...push sticks, straight feed etc...the table saw can be as safe as most workshop tools with spinny bits.

You can make a riving knife given a pattern....but you can probably buy spares from NMA for the 419.

Cheers and safe working

Jim

 

[matthewwh]

Hi Jim,

Why would you want a riving knife that is shorter than the blade? They make them taller to hold the blade guard up above the blade so that you can use the full depth of cut. The riving knife is not the only safety feature of a circular saw, the guard is also crucial to safe working practice.

If you want to make trenching cuts then a chop saw, portable saw or router table are all much safer ways of doing it. If you want to rip deeper than the blade depth then it's a bandsaw job.

Don't worry, I'm not having a dig at you personally, at least you are aware of the problem and are making an effort.

By accepting the limitations of the machine and using appropriate alternatives where necessary rather than trying to overcome them you will greatly improve the safety of your working practices.

The other one that Norm is a little tinker for is getting bits of himself behind the timber in line with the feed direction. If a saw kicks back the timber generally flies backwards (opposite to the feed direction) with astonishing force. Most people who lose fingers in tablesaw accidents have had them ripped off by the timber rather than cut off by the blade. Using adequate infeed support, standing to one side and using push pads should negate the need to do this.

 

[tomatwark]

I have been woodworking for over 25 years.

I have timber kick back from a saw , it missed me but went through a full bag of wood shavings that was behiind me about 10 feet away. The saw did have a riving knife, proving that it can still happen BUT that does mean you should not use one, I always have and will.

At a firm I used to work for someone was grooving a piece of 4" wood when the blade nipped and threw the wood up in the air over his head and down the workshop, this is one major reason that you should use a spindle moulder or router table when grooving and either a router, radial arm saw or sliding mitre saw when trenching.

Norm makes some interesting things BUT some of the working practices are just dangerous.

The other offender for this is the Great British Workshop and the HSE should look at him as he is breaking the Law as he is susposed to be in this country.

Matthew I think you meant to say push stick and not push pad.

Tom

 

[Permutation_Jim]

Folks,

Great commentary all around!

As to the short fence, Norm often uses a secondary fence on top of his Biesemeyer, one that stops short of the blade. So, effectively, he uses a short fence, though mainly for lining up cross-cuts using the miter gauge.

For longer ripping, I use the full length fence with "Board Buddies" attached to the top (bought in the States... think Rutlands Dakota have same or a knock-off version). They pull the stock slightly to the right, keeping even pressure against the fence and only roll one way, reducing the chances of kick back, at least for stock on the right side of the blade :wink: !

The reason for the lower topped riving knife is primarily for the tenoning jig, though I need to get a spare Kity miter gauge bar, such that it will work with my table (one of the reviewers did the same thing).

I take the point about using a router table for trenching, and hope to replace the metal extension inserts on my Kity 419 with a linoleum topped router table. I should be able to then use the existing saw fence with a router, and still use it as a saw extension (having lowered the router bit below the table).

On the router part, I'm planning to forgo Kity's extremely functional, yet bizarrely sized, miter slot for an industry standard 3/4 inch slot.

-Jim

 

[mtt.tr]

I think you should always use a riving knife and guard when you can though sometimes you have to remove it for certain jobs

 

[woodbloke]

I think you should always use a riving knife and guard when you can though sometimes you have to remove it for certain jobs

Which are, please? - Rob

 

[Ateallthepies]

If I can answer Rob,

I have seen people do tenons on the table saw and also make rabbits and dado's (can you tell I have been watching Norm ?)

These would need the guard removed but not the knife? Can't see any reason to remove the knife?


Steve

 

[Permutation_Jim]

If the knife height was below the top of the blade (which is what I want), it would never need to be removed. The stock knife with the Kity 419, however, is about an inch and a half above the top of the blade. At the moment, I need to remove it for tenonning.

-Jim

 

[misterfish]

The other offender for this is the Great British Workshop and the HSE should look at him as he is breaking the Law as he is susposed to be in this country.

Which law is he breaking?

Would it be his use of dado blades - if so he (David Free) discusses this and the HSE rules on his web site http://www.greatbritishwoodshop.co.uk/T ... fault.aspx

Misterfish

 

[tomatwark]

I stand corrected.

While it is true that HSE regs are to protect employees, it should not encourage TV shows to teach bad working practices to the guys and girls who do this as a hobby.

The guard is there for a reason and to use a dado needs to removed making the machine unsafe, I have never seen on any of these shows how you are susposed to guard the machine, Norm some times puts pressures on when rebating, but most of the time they just put a disclaimer on saying the guards have been removed for filming purposes.

It would be interesting for one of the US members on here to tell use what the accident levels are in the States when using dado heads in saws.

Still bringing this back to topic a riving knife is a must especially when ripping solid wood which can nip the blade without any warning.

Tom

 

[mtt.tr]

I think you should always use a riving knife and guard when you can though sometimes you have to remove it for certain jobs

Which are, please? - Rob

Well i have cut tennons on a table saw

 

[Permutation_Jim]

Statistics on dado related kickback are a bit hard to compile, especially from the States. The only folks who've seriously attempted to (that I know of) are manufacturers of additional safety equipment. While I suppose they trust their number (otherwise, why bother making and selling this equipment), I'm a little sceptical, given the profit incentive to inflate those numbers. Add to that, individual States are tasked with some levels of accident statistic collection, rather than one federal body, and you get a leaking bag of day-old worms #-o .

From my own experience, if you really WANT to cause kickback, your best two options are:

• -Fail to properly feed/hold down your stock
  -Over drive a bench saw, when you really need the weight and power of a "to the floor" table saw with a full cast iron top

The latter often applies in accidents I've seen. Those little Bosch 4000 portable bench saws are great, but I've seen one with a "wobble" dado set. When it ran, the unit literally danced on it's stand. Stock would have kicked back, even if you used a machine feeder.

While I'm not suggesting dados are safe/unsafe, improper feeding/hold downs and using the wrong grade machine for the wrong job can often result in "digital reduction."

For my part, I grew up with a classic Sears Craftsman radial arm saw, and I still preferred multiple trench cuts to the dado. If nothing else, it seemed to take an age to set-up, tune and remove the stupid thing, and the cuts still weren't brilliant. But that's just me.

-Jim

 

[woodbloke]

I think you should always use a riving knife and guard when you can though sometimes you have to remove it for certain jobs

Which are, please? - Rob

Well i have cut tennons on a table saw

The only safe way to do this sort of thing is to use a jig like Steve M's (which I've seen in action) where the exposed blade is totally covered and fingers remain a long way from the it. I personally don't use any jigs on the table saw, but cut all my tenons on the bandsaw (for which Steve also has an excellent jig) which is an inherently safer way of doing the job.
Any device or process though, used in industry in this country that entails the removal of the guard and riving knife is illegal and has been for decades, but apparently not so in the good 'ol US of A, which probably accounts for their much greater incidence of 'accidents'. Norms woeful machining practices of course don't help the statistics...who is this Norm guy anyway :lol: - Rob

 

[tomatwark]

I suspect what will happen in the end is someone who is doing this as a hobby will have a really nasty accident and then try to sue the makers of the progams.

Having worked in the industry all my working life, I think some of the HSE rules that have been brought in over the last few years are daft, but this sort of regulation is not as there are lots of safer ways to do these operations.

Tom

 

[Finial]

Having worked in the industry all my working life, I think some of the HSE rules that have been brought in over the last few years are daft, but this sort of regulation is not as there are lots of safer ways to do these operations.

Tom, there are probably people who will say 'this sort of regulation' is daft too. I really wish people who condemn the health and safety legislation would say exactly what is wrong with it because it seems OK to me. Can you give an example of these daft new rules?

 

[mtt.tr]

my personal view is allways use a riving knife but if you do remove it then you have to understand you are responsble for what you are doing.

I think more accidents involve hands tools though and because people dont concentrate in the same way

 

[Steve Maskery]

The only safe way to do this sort of thing is to use a jig like Steve M's (which I've seen in action) where the exposed blade is totally covered and fingers remain a long way from the it. I personally don't use any jigs on the table saw, but cut all my tenons on the bandsaw (for which Steve also has an excellent jig) which is an inherently safer way of doing the job.

Rob
Thanks for the plug, much appreciated.
I have been following this with interest and it's been hard not to poke my nose in. You've saved me from doing it!

The jig to which the OP refers is dreadful. It requires the removal of the guard, whatever mealy-mouthed caveats they may put in the product description:

Warning: This jig should only be used with suitable tablesaws. Please refer to your table saw's manual for further information. All tablesaw safety features and guards must be kept in place and in good working order during the use of this jig.

It simply cannot be used with the normal machine guards in place. Furthermore, it it very slow to operate, requiring two separate cuts for the cheeks. If the workpieces vary at all, so will the fit of the tenons. And the tenon is always dead central, which may or may not be what you want. If you are making face-frames, they need to be flush, so the tenon needs to be in the same place as the mortice. if the mortice is 1mm off-centre, so must the tenon be, or else there is an awful lot of hand-planing to do. It, and its many look-alikes, are a very poor design indeed.

I cannot think of a single sawing operation on a TS where the riving knife has to be removed. Not one. Adjusted correctly, yes. The rip guard removed, yes, but then only because something more suitable is being used in its place. My normal guard is a SUVA-style affair which is independent of the RK, but sometimes I remove it for some jigs or bevelling operations. In that case I use a guard that is an integral part of the jig, like on my Ultimate Tablesaw Tenon Jig, or use a magnetic stand-alone jig. Several of my YouTube vids show it clearly.

There is NEVER a need to use a TS without both RK and a guard in place. They just might not be the ones that came with the machine.

S

 

[SBJ]

The idea that an experienced woodworker/machinist couldn't use a saw safely without a crown guard is ridiculous. The rules that are in place are to protect employees from unscrupulous employees forcing staff to do things for which they aren't trained for and as such have to be a catch all for all processes.

Cutting shoulders on tenons is one example where you might do it if you don't have a tenoner.