I am (soon to be “was”—selling to a friend) an owner of an HKC 55 and I now own a TSC 55 KEB, which I bought relatively recently. The 160mm diameter / 1.8mm kerf blades are compatible and I own quite a few — for various materials and cut-types.

I see that the TS60 uses a 168mm diameter / 1.8mm kerf blade and I get why Festool want to go that little bit further with depth.

I just splurged on a CSC SYS 50 and I have mixed feelings about the saw blades being 168mm. It’s great that the tablesaw will go that little bit further, but I have several 160mm blades I would like to use in it.

I see no reason why I shouldn’t use the 160mm blades in the CSC SYS 50 — with the caveat that I might want to add 4mm to measurements, rather than calibrating to the new blade size (because otherwise the machine might(?) try to raise itself too high (though I’m sure it’s cleverer than that)).

But the manual says:

Only use saw blades with the following dimensions:
– Saw blades according to EN 847-1
– Saw blade diameter 168 mm
– Cutting width 1.8 mm
– Locating bore 20 mm
– Standard blade thickness 1.2 mm
– Suitable for speeds of up to 9500  rpm

so I thought I’d bounce it around here first.

The main point is that I really want to be able to use the same blades in both the TSC55K and the CSC SYS 50 wherever possible, as it’s costly having 2 of everything.

Any advice?

I'll stop buying rip and universal blades for my TS55 when the CSC comes in.  I might keep a cheap 3rd party oshlun for the rare occasional rip.  Hence I'm not concerned about having 2 of each blades.  The only overlap would be the crosscut blades - but thats fine.  General advice is not to minmax consumables.  If you're in the situation of job-work that'll occasionally leave you with only one of the two tools onsite, then min-maxing blades will leave you at risk of having the required blade 'in the other tool'.

Below is a universal advice/statement. Not Festool-specific.
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The safety aspect is, that a blade which is heavier (thicker disc), wider or has a bigger diameter, or, in general, was not tested with the saw, may: *)
- damage the saw
- create a safety hazard

This means, as far as the pure mechanical load on the saw goes, anything which is same or lower diameter and has same or lower (disc) thickness and the disc thickness is supported by the blade securing mechanism and has same or lower kerf and has same arbor and is rated to same or higher speed is generally considered safe to use in a rotating tool like a saw.

This is why most professional tools do not limit the user to specific blade diameters but have "up to" stated in documentation. The trick there is those are professional tools which only qualified professionals (are allowed to) use. These professionals are required/expected to be trained/qualified to not use an incompatible/unsafe blade-tool combination. In those case the tool maker is *not* obliged to tell the user how to use the tool - the user is supposed to have formal qualifications for that already in place.

Aand here comes the "issue":
Festool (Makita, Bosch..) sells to BOTH the professional and the consumer markets. Thus *all* their documentation must meet the stricter "consumer market" standards where the tool is expected to be used by a non-trained or at most semi-qualified person. Thus the documentation cannot leave such safety-critical decisions to the user.
Of course, the user may override/ignore the documentation, BUT then Festool cannot be held liable for any consequences. Be they tool damage, or, critically, an injury.

To reiterate. Above is not Festool-specific. This is how *all* the tool makers which span both the consumer and the professional markets are forced to operate. And that is also why Festool cannot allow users on this semi-official forum to propagate non-approved/tested tool use. Such advice being tolerated here could be construed as "being encouraged by them" in common law .. with all the legal consequences.

For my own: I use all kinds of blades in my TSC 55 and other saws, following the physics limitations mentioned above. BUT, I am a physicist by degree ... so lets say I fall into the "qualified" group on this able to make my own decisions, on my sole responsibility.

Hope helps.

*)Even 0.0001% probability of such meets that "may" and is a no-go for the tool maker vis-a-vis the consumer-focused documentation.

EDIT: Added the that a thinner (disc) blade is not safe also when the blade securing mechanism does not support such thin blades.

Thank @mino and @woodferret for helping me come to the conclusion that the 160 blades are probably OK in the CSC SYS 50.

However, I've just seen the circular saw blade FAQ on this page, which says:

Can the 160 mm saw blades also be used on the TS 60 K?
No, the TS 60 K is designed exclusively for the 168 mm diameter saw blades.

This tells me that they will almost certainly say the same thing for the CSC.

So I've decided life is too short to mess around recalibrating etc. I'll just buy new -- not minmaxing my consumables, as @woodferret suggests.

Thanks for all the replies.