CMT 235.160.20H

[stefano]

Hi guys,
have someone of you heard of this quite expensive blade?
Does it make any sense to spent so much money to but it?

Thanks

 

[mino]

Hi guys,
have someone of you heard of this quite expensive blade?
Does it make any sense to spent so much money to but it?

Thanks

Yes it does .. if you have a panel saw cutting melamine all day out.

It is a diamond-tipped blade, will last about 20-100x as much as a normal carbide one, cannot be re-sharpeneed though, so in realisty it lasts about 15-20x as much as a carbide one resharpened 3 times.

The big saving is in the labor - this one willl just keep chugging while you have to replace the carbide one 60 times and send it to resharpen 40 times from that. That adds up fast on labor costs and downtime that come with them.

For a normal one-man-shop, who resharpens like 3-4 times a year at the absolute most, not sensible so much as this could last a person his whole work life and still be sharp ... also these are really for the big melamine shops. A one-man-shop is more likely be higher in the value chain, no moving much melamine to begin.

IMO in hobby/small shop world, diamond does make sense in the Festool variety with 4-8 teeth just for the special cases. But not much beyond that.

My 2c.

 

[luvmytoolz]

[member=61254]mino[/member] As I understand it from the Lamello Zeta point of view, the diamond coated is really more suited to man made materials than natural timber, and the carbide apart from being able to resharpen, will hold a sharper edge?

 

[stefano]

so it just a question of durability than really performance, isn't it?

or should I image that for HPL and solid surface materials and Plastics in general it works better?

 

[mino]

[member=61254]mino[/member] As I understand it from the Lamello Zeta point of view, the diamond coated is really more suited to man made materials than natural timber, and the carbide apart from being able to resharpen, will hold a sharper edge?

Yes, diamond (infused) blades shine in abrasion - i.e. cutting of the engineered materials.

When new, it would work fine, but the problem twofold: diamond itself is not very tough - unlike steel or even carbide - meaning that a sharp angle diamond edge will break off well before it gets abraded. Secondly, it is not actual single-crystal-diamond but a diamond-infused carbide. meanign the edge itself is actually weaker than the carbide is. With abrasion this is fine, as the "sticking" pieces of diamond is what does the abrasion. With cutting, this gets bad fast.
All this makes sharp-angle diamond-infused materials not last very long.

But a blade cutting wood must be as sharp an angle as possible to cut the fibers, not abrade them .. hence the unsuitability in general cases for wood. There are way to mitigate this - e.g in a CNC the blade is more of an abrasion-action, if the blade is big-enough and can have negative rake, then it may work even with wood. But the point is "may work" is different to "is optimal". Then the thing is that a quality carbide blade for wood will last way longer than a blade made from same carbide cutting melamine ..
So even assuming diamond blade would not shatter the edge, it still lasts only about as long as two carbide wood blades that were sharpened 3-4 times. For a big shop, it can still make sense as one's saving on labor and downtime can make up for it. But the big advantage present with melamine cutting is no longer there.

so it just a question of durability than really performance, isn't it?

or should I image that for HPL and solid surface materials and Plastics in general it works better?

Yes and no. When a (quality) blade is new/sharp, it will cut as good as concentric it is. Basically how precisely it is made. As the blade dulls, the cut quality falls down. Especially with melamine and such, the blade is still cutting (abrading really) while it already does not make a perfect cut due to it being dull.

So over a lifetime of the diamond blade - courtesy of it lasting way longer - it generally will provide better *average* cut quality.

In practice, people solve this by having 3-4 blades in a re-sharpening cycle and using a fresh blade for the cuts that must be perfect while satisfying themselves with not-perfect cut edges where it is not necessary. So the "issue" become way less of an "issue" than may seem. One could even argue that having multiple carbide blades around instead of a single expensive diamond one is preferable for this reason - one may easily keep a fresh blade around for the cases where it is required. Once into a "big shop" territory, the optimum changes ..

 

[stefano]

Thank you so much mino for your detailed explanation. I'm more than a thank to you.

 

[Cheese]

I wonder how they resharpen it if it's just diamond dust attached to carbide inserts?

 

[Peter Kelly]

I don't think the process for sharpening PCD teeth is exactly the same as a conventional carbide-tipped blade as they're super brittle and get chipped easily. That CMT (Leuco?) blade shown above also has hollow ground teeth, not sure if every shop is able to sharpen this geometry either.

PCD blades are just crazy expensive, I can't see the advantage to using one over a slider / beam / vertical saw that has scoring. 

 

[Crazyraceguy]

In practice, people solve this by having 3-4 blades in a re-sharpening cycle and using a fresh blade for the cuts that must be perfect while satisfying themselves with not-perfect cut edges where it is not necessary. So the "issue" become way less of an "issue" than may seem. One could even argue that having multiple carbide blades around instead of a single expensive diamond one is preferable for this reason - one may easily keep a fresh blade around for the cases where it is required. Once into a "big shop" territory, the optimum changes ..

That's how we do it. Each type/size of blade has a specific slot a in cabinet, built for the propose, since we have so many different saws.
It has taken us a while to get this well organized, but it seems like we have a much better grasp of the inventory.
Diamond tooling is reserved for the CNC machines. The cut quality over time is way above the usual carbide alternatives.

 

[jimbo51]

It appears that the blade has a warning not to play music.