An interesting note on Festool TS55 blades

[jcrowe1950]

Hi Folks,

    I was doing some TS55 blade measurements for an upcoming review an in the process discovered something that I hope somebody can explain. In the picture annotated below, I discovered that on Festool blades, the gullet size is consistent but the size of the metal between the carbide side of the gullet and the "front" of the gullet varies into three sizes. The distribution on the blade seems random to me. Any ideas from any of you geniuses?

[attachimg=1]

 

[Svar]

This is to prevent resonance and decrease vibration. Randomly spaced teeth hit the material at random time intervals.

 

[jcrowe1950]

This is to avoid resonance and decrease vibration. Randomly spaced teeth hit the material at random time intervals.

  I thought that's what the anti-vibration laser cutouts were for.....that's what other vendors use...the variable sized "tooth supports?", seem counterintuitive as an anti resonance mechanism, but I'm not that type of engineer so school me....

 

[Svar]

Laser cuts are expansion slots to prevent warping and vibration when blade heats up. Slots and teeth spacing are complementary and work in different ways.
PS. Sometime slots are enclosed (don't reach the edge). Those too dampen vibrations. There is more than one way to address this issue.

 

[Cheese]

As Svar said...similar to a variable tooth band saw blade. Reduction of resonance gives a smoother cut.

 

[jcrowe1950]

As Svar said...similar to a variable tooth band saw blade. Reduction of resonance gives a smoother cut.

  Thanks so much to Cheese and Svar for the information. I did some searching but could not find the information using the usual sources.

 

[escapegoat]

This is to avoid resonance and decrease vibration. Randomly spaced teeth hit the material at random time intervals.

  I thought that's what the anti-vibration laser cutouts were for.....that's what other vendors use...the variable sized "tooth supports?", seem counterintuitive as an anti resonance mechanism, but I'm not that type of engineer so school me....

I think the anti-vibration laser cutouts reduce the vibration of the blade. There is also the workpiece+workbench and TS55 to consider. Each time a blade tip engages the workpiece it's going to apply a force to the workpiece and an opposing force to the TS55. If the impacts occur at a rate near a resonant frequency of the workpiece or TS55, vibrational energy will build up.

 

[peter halle]

Leitz - who I believe manufacturers the blades - is a leading world class manufacturer.  The items you mentioned along with variable spacing in some blades leads to re sharpening issues with some vendors.  For instance, for a period of time Forrest would not sharpen Kapex blades.  That may have changed on their front now.

Peter

 

[Cheese]

FWIW...the laser slots that start at the edge of the blade and extend an inch or two into the plate are for thermal expansion. They usually take the form of a “J” or an upside down “?”. They are used to prevent the blade from warping and vibrating as it becomes hot.

On some newer blades there is also a series of laser cut “squiggles” that are cut further into the plate. Those are for sound damping.

On older blades there were sometimes 3/16” diameter brass or copper plugs pressed into holes, those were again for sound damping.

I’ve noticed that recently some 6”-7” Hilti framing blades have some fairly large cut-outs towards the middle of the plate. Those are for cooling.

Reducing the noise and reducing the heat all leads to a smoother cutting blade with a longer life.

 

[sancho57]

Oh heck I dont know,

I just put the blade in my saw and so far they all been working great

 

[Martin Johnson]

This is correct...one of our companies does reliability testing, and resonance is one of the factors that causes product failure...I've seen simulations of rocket launches in the lab that completely destroyed welded enclosures due to this effect.  Silly German's think of everything.

This is to prevent resonance and decrease vibration. Randomly spaced teeth hit the material at random time intervals.