Festool TS-55 blade platen thickness ?

[NuggyBuggy]

I've been working with Lee Styron to have a Shark Guard made up for my Inca 259 table saw.  What a great guy to work with.

We're at the point where we're talking about riving knife thickness.  While I do have a selection of about 10 old German and Swiss blades (Inca and Schumacher & Sohn), some of them are a bit rusty and I am thinking about mounting TS-55 blades as they also share a 20mm bore. So I'd like to make sure the knife thicknesses we make up would make sense for the TS-55 blades.

Does anyone know what the platen/blade thickness is of the various blades ? 

Are the thicknesses constant across the line as I understand the kerf thicknesses now are ? 

Unfortunately I have a TS-75 so I can't measure my own blades.

thanks - terry

 

[Alan m]

i dont know why you want to use a ts55 blade in the table saw. if it was a ts75 it would be different as you would be able to use one while the other is shapened. you could get away with 3 blades instead of 4 ( 2 different ones for each saw).
i know the fewtool blades are good but you could get coparable quality blades from other scources.

by platen thickness i presume you mean the thickness of the plate the tct is brazed to . the kerf of a ts55 blade is 2.2mm.
you riving knife should be the same as the kerf or you will get marks from the teeth as they come back up in front of the riving knife. kickback could also be an issue.

 

[MarkF]

Festool TS55 blades work great on the small Inca Tablesaws.  Lee makes quality products.  I use his Shorty Spliter on my Uni. 

Festool 2011 Catalog for newer blades

Festool 2009 Catalog for older blades

 

[Spike]

Terry,
Inca 259 is a great saw, I owned one years ago, sorry I sold it.

The TS55 blade Item#491952 which is a Z=48 ATB configuration has a plate thickness of 1.62mm / .0640". The kerf measures 2.2mm. I also feel that would be a good blade with exception of the diameter which will not allow for the cutting of very thick material on the Inca 259.

I've been working with Lee Styron to have a Shark Guard made up for my Inca 259 table saw.  What a great guy to work with.

We're at the point where we're talking about riving knife thickness.  While I do have a selection of about 10 old German and Swiss blades (Inca and Schumacher & Sohn), some of them are a bit rusty and I am thinking about mounting TS-55 blades as they also share a 20mm bore. So I'd like to make sure the knife thicknesses we make up would make sense for the TS-55 blades.

Does anyone know what the platen/blade thickness is of the various blades ? 

Are the thicknesses constant across the line as I understand the kerf thicknesses now are ? 

Unfortunately I have a TS-75 so I can't measure my own blades.

thanks - terry

 

[NuggyBuggy]

i dont know why you want to use a ts55 blade in the table saw. if it was a ts75 it would be different as you would be able to use one while the other is shapened. you could get away with 3 blades instead of 4 ( 2 different ones for each saw).

I'm only a hobbyist and only get a little time each weekend to work, so I don't really need to keep extra blades around.  The TS75 blades will not fit as the bore is different.  Having said that, I have considered buying a TS-55 as well.

i know the fewtool blades are good but you could get coparable quality blades from other scources.

To be sure, but I was hoping to avoid the hassle of having to have standard blades bored out.  I do know Forrest makes their WWII in 20mm bore.

you riving knife should be the same as the kerf or you will get marks from the teeth as they come back up in front of the riving knife. kickback could also be an issue.

Lee told me that the knife should be somewhere between the thickness of the kerf and the plate.  He  suggested that the chance of binding increases the closer the kerf size is to the thickness of the knife. 

MarkF, thanks for the link.  I did understand that all TS-55 blades were supposed to produce 2.2mm kerf.  But the catalog you linked to seems to show a few different kerf sizes.  Did they never complete the transition to all-2.2mm kerfs, or is the catalog in error ?

Taos - thanks for the dimensions.  My 259 has become a bit of an obsession for me.

 

[ccarrolladams]

Nuggy,
The North America 2011-2012 Festool catalog is shot full of errors and typos. This is especially true of the TS55 blade page 62.

All current Festool TS55 blades have a 2.2mm kerf.

The riving knives I use on my saws needing then are all the thickness of the kerf of the blade in use at the moment. I have been using riving knives for close to 50 years. My experience is that using a riving knife thinner than the kerf defeats the purpose. Every expert I have consulted shares my belief about this.

 

[MarkF]

Sorry for the wild goose chase!  I switched to the Tenyru blades to avoid the kerf issues prior to the Festool change.  I didn't realize there were catalog issues.   

 

[NuggyBuggy]

The riving knives I use on my saws needing then are all the thickness of the kerf of the blade in use at the moment. I have been using riving knives for close to 50 years. My experience is that using a riving knife thinner than the kerf defeats the purpose. Every expert I have consulted shares my belief about this.

ccarolladams, thanks.  Do you have a reference for this ? I ask because every opinion I have found suggests the opposite.  But these are opinions from forums like this one, where members' bona fides are unknown to me.  And if this was true, I'd wonder how people would get knives to be the right thickness, and expect makers to standardize.  I'd love to see a definitive or authoritative analysis of the issue because I am basically in the position to get riving knives of any thickness I want.

Festool has standardized on kerf size (at least for the -55, not sure about the bigger saw), but the rationale I had always seen regarded the zero-clearance strip and not equivalence to riving knife thickness.

I do know that Lee's credentials are well-established to my satisfaction.

This has me curious, though.  If I were at my shop I would measure the thickness of my TS-75 blade kerfs and its riving knife. I wonder if they are equal.  I know that Sawstop RKs are narrower than most blades.  Inca made several thicknesses of RKs but I can't find any recommendations as to when to use what.

terry

p.s. A few months ago I had a dream that I drove by your shop and that it was in Culver City. I used to live in Los Angeles and recall it fondly, but I thought it was odd that I was dreaming of a FOG member's shop, when I've never dreamed of Festools.  I'm sure some here have, though.

 

[Ken Nagrod]

Terry,

A riving knife should be thicker than the blade kerf thickness by about a couple of thousands of an inch in order to keep the cut section of the material being passed thru the saw blade from closing up on the blade.  That's why the riving knife shouldn't be the same thickness or thinner than the blade's kerf.  Companies do making interchangeable riving knives for use with different blade kerfs.  I believe the Bosch portable table saw is just such a model or has information about this in the user's manual.

 

[NuggyBuggy]

Well, now, this is getting confusing.  Ken advocates a knife thicker than the kerf, ccarolladams recommends one the same thickness as the kerf, and Lee recommends one narrower than the kerf but wider than saw blade.

 

[Ken Nagrod]

Terry,

Buy one of each flavor and do the test yourself with some really crooked wood while standing off to the side as you're feeding it.  By the way, the Bosch saw I was just using as a low cost example.

The only point of a riving knife is to prevent wood that's already passed the blade from pinching it.  If it's the same thickness as the blade and the wood closes up on the knife...it's also closing up on a rotating blade --- kickback!

EDIT:  My response was for a specific type of cut, but my response should have actually stated that the riving knife needs to be almost the same thickness as the blade kerf (just a wisp under) while using the rip fence so as to prevent the two halves of material from binding on the riving knife as they pass thru.  So take the previous post for safe crosscut operation and this update for ripping or just stick with the ripping info for all operations.

 

[ccarrolladams]

Nuggy,
If it will be easy for you to buy as many riving knives as you want for your saw, perhaps you should try various thicknesses. Then you can see the results for yourself.

One major advantage to our pressure beam saw is that the beams are on both sides of the blade. They serve as ultimate splinter guards reducing tear-out. The second advantage is that they prevent the cut closing in, so no riving knife is needed. The pressure beams enclose the cut, for excellent duct extraction and safety.

Our Felder sliding table saw uses riving knives. These are separately designed to be appropriate for the kerf of each blade and also the diameter. The Felder Kappa550 E-Motion stores in memory the kerf of every blade for accuracy setting the fences. We have only owned this sliding table saw since August of 2010, so none of the blades for it have needed a third sharpening yet. Part of our deal with our sharpening contractor is to provide a kerf measurement with every sharpening, which is input to the Kappa database. That software will provide a prompt if a particular blade's kerf is thinner than when new so that we can decide to change riving knives. So far none of those blades have needed enough grinding their kerf is thinner, but we will be paying close attention following their third and subsequent sharpenings.

 

[Ken Nagrod]

Note correction in above post.

 

[NuggyBuggy]

Thanks for the replies guys.  Thanks Ken for the clarification - if you had simply edited your post I would have missed it.

I am going to be reading up more on this issue.  That Felder sounds like one heck of saw.  But I guess that's a "duh" if ever there was one.

So does anyone want to put a caliper on a post-standard-kerf-size  TS-55 riving knife ?

 

[tiralie]

I agree that a thicker riving knife is an advantage for preventing kick back it does introduce some other problems. I have a Bosch 4000 and the riving knife is slightly wider just double checked, it's the same width  of the Freud thin kerf blade that I sometimes use. I have slightly beveled the leading edge of the knife so stock passes past the riving knife without catching the edge while still maintaining a maximum opening behind the blade.
A thicker riving knife is of particular advantage when cutting stock that starts to bow as a result of internal stresses in the stock. The stock will bind up on the riving knife long before it does so on the blade allowing you to avoid burning or seriously maiming yourself.
I have my fence set in a neutral or parallel to the blade so as to get the smoothest cut but because the riving knife is a bit thicker than the blade some additional friction (particularly in thicker stock) occurs. Some folks recommend that the fence should toe out slightly  to avoid binding on the side of the fence but this often gives a much rougher cut than I prefer.
Tim

 

[Ken Nagrod]

The TS55 has a riving knife thickness of 1.80mm and the TS75 has a thickness of 2.00mm.

 

[JeromeM]

Well, now, this is getting confusing.  Ken advocates a knife thicker than the kerf, ccarolladams recommends one the same thickness as the kerf, and Lee recommends one narrower than the kerf but wider than saw blade.

Lee is correct. If you have a knife that is kerf width or wider you are asking for the work to bind on the knife.

The HSE (Health and Safety Executive) have codified best practice in the UK. You will find the information http://www.hse.gov.uk/pubns/wis16.pdf here.

The US is finally getting riving knives at least 50 years after they were common on UK saws.

I don't know if you have the 10second or under stoping time on table saws yet? If not then in time you will.

The HSE is often maligned but for the most part they advocate sensible practice.