Sawstop: Amazing Slo-mo

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Yaakov

Joined Jan 27, 2019
3,609
Sawstop has been around for a while and you may well have seen some demos, but it's evolved and the Jonathan Katz-Moses YouTube Channel posted some high speed video with a high quality modern camera.

It's very, very impressive. The Sawstop puts a 500KHz sine wave on the blade and the MCU monitors the amplitude. If meat (finger, hot dog, etc.) contacts the blade, the signal is capacitively coupled to it and the amplitude drops activating a brake which was originally polycarbonate but is now aluminum.

The results are amazing.

https://www.youtube.com/channel/UCXBNF-A7QlYT3tT-B9N4ElA

Edit by moderator: Direct link:
 
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atferrari

Joined Jan 6, 2004
4,445
Sawstop has been around for a while and you may well have seen some demos, but it's evolved and the Jonathan Katz-Moses YouTube Channel posted some high speed video with a high quality modern camera.

It's very, very impressive. The Sawstop puts a 500KHz sine wave on the blade and the MCU monitors the amplitude. If meat (finger, hot dog, etc.) contacts the blade, the signal is capacitively coupled to it and the amplitude drops activating a brake which was originally polycarbonate but is now aluminum.

The results are amazing.

https://www.youtube.com/channel/UCXBNF-A7QlYT3tT-B9N4ElA

Edit by moderator: Direct link:
Impressive slow motion. Thanks Yaakov.

Pity he is not speaking a little bit slower so I could understand the speech better.

Two questions: the brutal stoppage, does it mean any damage to the saw / motor set?

The sparks originate where?
 
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MrChips

Joined Oct 2, 2009
24,458
A mechanical brake is released that grabs the blade, stops it from rotating and retracts the blade.
The brake mechanism is destroyed and has to be replaced. The blade is not damaged.

The sparks are from blowing the mechanical fusible latch that releases the spring holding the brake.

 

MrChips

Joined Oct 2, 2009
24,458
You are correct.
In the video at 1:01 he says "put a new blade on".

At 0:53 when he said "without damaging the saw" I thought that included the blade.
 

MrSalts

Joined Apr 2, 2020
655
I'd definitely put a new blade on after jamming a block of aluminum against carbide teeth to stop it. Those teeth are only held in by a laser melting a few grains of iron dust between the carbide and blade blank.
 
Each mistake, I think will cost you about $100.00. Wet lumber can also cause the brake to engage. I think there is a test/disable button. The shaft on the saw is massive. Maybe an inch or 1-5" in diameter. The saw is impressive. I have seen one up close at the local Woodcraft, but not in operation. Impressive saw.
 

shortbus

Joined Sep 30, 2009
8,886
Those teeth are only held in by a laser melting a few grains of iron dust between the carbide and blade blank.
Is that a new way I 'm not aware of? All my carbide blades both for woodworking and my homemade dry saw for steel have the carbide teeth brazed on. The videos of them doing the brazing show it being done with induction heater coils.
 

atferrari

Joined Jan 6, 2004
4,445
A mechanical brake is released that grabs the blade, stops it from rotating and retracts the blade.
The brake mechanism is destroyed and has to be replaced. The blade is not damaged.

The sparks are from blowing the mechanical fusible latch that releases the spring holding the brake.

I find extremely hard to go step by step in my mobile but around 0:53 it seems there is a tooth starts flying across the screen.
 
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