Riving Knives and Saw Blades.

[JimTaylor]

Hello my new TS1800 table saw has these markings on the Riving Knife and understanding what they mean.

254 x 2.8 x 1.8
45 HRC +- 3HRC
t : 2.3

My guess on the first line is a maximum 254mm blade diameter with a minimum kerf of 2.8mm and minimum saw blade disc thickness of 1.8mm
Not sure about "45 HRC" or "t : 2.3"

This is in relation to replacement Saw Blades for the table saw and a warning in the manual about the riving knife thickness and blade kerf thickness.
I email Axminster Tool reference 16mm bore blades for a saw with a 5/8" arbor.
Axminster advised not to use 16mm blades with a 5/8" arbor, but buy specific blades with a 5/8" bore.
You can get 30mm to 16mm reducers and 30mm to 5/8" reducers.
I wonder what the specification on the tolerance of blade bore holes is, as 5/8" is 15.875mm
30mm bore blades are a third of the cost, even adding in bore reducers.

I don't want to damage the arbor or motor due to my lack of experience and knowledge.
If the blade is not centred correctly running at 4200 rpm what vibration would that cause.

 

[ola c]

HRC is the hardness, probably for the saw blade. Wouldn't care too much about that, I never purchased a saw blade based on it's HRC.

t=2.3 would be the riving knife thickness. The riving knife should be slightly thinner than the blade so for a 2.8 kerf blade a 2.3 riving knife is suitable. I would say 2.8 is not minimum kerf for that knife, it's the correct one. Going with a thicker blade than that you should, if you follow all the rules, also have a thicker riving knife.

I run all my blades with reducers and never had any problems, but you should have the correct reducer with 5/8" bore, not 16mm.

 

[JimTaylor]

Thank you for your help

 

[Fergie 307]

Likewise no problem using reducers. And I would agree with Ola c, if you can get a 5/8 then that's what you ought to use. The difference may seem trivial, and you might get away with a 16mm. On the other hand it might be enough to make it run slightly out of balance so I wouldn't do it. In engineering terms 0.125mm clearance on something that size is a yawning casm

 

[johnnyb]

hardness rockwell c is the hardness of the riving knife( nice and soft as its next to a fast spinning thing) 2.3 is the thickness of the knife. accounting for .5mm clearance.

 

[JimTaylor]

Thank you for clearing this up, some threads had conflicting advice on using 16mm bore blades with 5/8" arbors.
I will stick with a 2.8mm kerf blade and 5/8" bore or reducers