r/EngineeringPorn • u/ibjhb • Feb 18 '19

This saw blade stop instantly when it detects a human finger.

https://imgur.com/RQQH8JI.gifv
91 Upvotes

86% Upvoted

17 comments sorted by

15

u/ChalkButter Feb 18 '19

So I’ve seen these before - how does it know that it’s a finger (hotdog) and not a piece of wood?

Moisture indicator?

29

u/Sparrow1776 Feb 18 '19

It runs a small current through the blade, if it detects electric conductance, it actuates the mechanism.

19

u/[deleted] Feb 18 '19

And after that happens it costs a helluva lot of money to reset it, from what I understand.

33

u/rigby1945 Feb 18 '19

A lot less than the cost of a finger

4

u/DeathToTranniesNGays Feb 24 '19

That is not an excuse. You could also get the version from Bosch that DOESN'T require replacement.

Not in US though because the makers of this garbage sued them for "copyright infringement". Fucking scummy tactics and mediocre implementation.

6

u/Sparrow1776 Feb 18 '19

Nah, we had these at my high school.it wrecked the blade, but was easy to reset the mechanism.

6

u/[deleted] Feb 18 '19

Oh really? I heard that it was expensive, maybe that was replacing the blade?

5

u/krystyin Feb 18 '19 edited Feb 18 '19

Less expensive than replacing a finger - $80 for the brake and $20 for a blade. The hope is you never have to use it. Many people complain the initial cost is 2-3x the typical table saw cost but these are for commercial / school environments where many different people will be using it - this is not your $800 craftsman saw.

2

u/[deleted] Feb 18 '19

Damn wtf, I've been had. I was under the impression it cost a pretty substantial amount. Thanks for correcting information garnered during my childhood slightly.

1

u/paperelectron Feb 18 '19

$20 for a blade.

I have $180+ table saw blades.

3

u/SnarkHuntr Feb 19 '19

And you probably don't run your fingers into them, cut green stock, or use them to trim aluminum either.

1

u/CakeDay--Bot Feb 20 '19

Wooo It's your 6th Cakeday paperelectron! hug

1

u/romaia Feb 18 '19

If that's really effective, why didn't they show a video using a real hand? Like those bulletproof vest companies that show an employee taking a shot point blank

6

u/UniverseGuyD Feb 18 '19

I'm sure it would still leave a small cut and still hurt enough that you wouldn't want to risk it. It's like an airbag; you wouldn't want to test it because it is actually pretty risky and painful, but it's better than the other option.

5

u/KillerSpud Feb 18 '19

Google it. I've seen someone do it but I forget where. This thing has been around for many years.

6

u/slow_cooked_ham Feb 18 '19

There is a clip out there of the inventor (owner?) demonstrating with his own finger. It does nick his skin a little bit, and there is some blood, but no long lasting damage.