Saw stop technology on bandsaw?

[Robin Frierson]

I'm sure some of you have seen the videos on the meat cutting bandsaw's that have the saw stop technology. Are there any wood cutting bandsaw's that incorporate that technology. I'm a little surprised I haven't seen some. Is there just no demand for that safety feature on the wood cutting bandsaw since its supposedly a "safer" machine?

[Robin Frierson]

https://m.youtube.com/watch?v=NiRegdech_E

[Van Huskey]

I think there are two major roadblocks, the market and physics. Bandsaws are all but dead in commercial and industrial settings being replaced by CNC and in the hobby market the number of people who buy $2k+ bandsaws is very small. Physics wise a medium or large bandsaw has a huge amount of kinetic energy when running FAR more than a small 10" tablesaw blade and there is nowhere to "hide" the blade like under the table of a TS. Further to implement SS tech directly to a BS one has to overcome the insulating properties of the tires. I think the biggest issue is the momentum presented by the BS, shaper, jointer and the like but at least the shaper and jointer have tables to retract behind. IIRC there was some talk about shearing the BS band. I think in the end the juice is not worth the squeeze.

[Eduard Nemirovsky]

No doubt for me that bandsaw even more dangerous than tablesaw.
This meatsaw technology little bit different than SS, all of the users working in blue gloves - I think it is a key. But I could be easily wrong:confused:
Ed.

[Steve Demuth]

The original Bladestop technology is very similar to Sawstop, in that it actually detects the operator's flesh contact electrically. It's different in that rather than detecting the capacitance change as Sawstop does, it relies on the operator being electrically bonded to the sensing circuit via a belt worn by the operator, so the operator becomes the "switch" that completes a circuit when the blade is contacted. This permits the saw to cut meat without tripping as a Sawstop obviously would. Clearly, insulating gloves are required for this to work.

There is a second technology that senses the moving blue gloves in front of the blade. That can often stop the blade before any contact at all.

Clearly neither approach would work unmodified for a wood cutting bandsaw.

[Steve Demuth]

The Bladestop meatsaw technology show that the physics isn't an issue - they get large saws stopped cold in 8 - 15ms

[Scott Brandstetter]

I am and have been in the packaging business for most of my life, way too long. Every year there is a packaging show that is way too long and it goes from McCormick in Chicago to the Las Vegas Convention Center every other year. This past November the show was in Chicago and it just so happens that our booth was next door the the Band Saw People with this new Patent. I spent a lot of time talking with their developers, understanding how their technology works, and came away amazed. They have essentially two safety systems built into one...and I don't remember exactly but one was the saw looked for a color and the other I believe was a fiber in the glove.

My point to this response is that I said to them, and i felt stupid for saying it after I did, "you guys could control the market on tools like bandsaws, routers, planers, jointers, etc". They laughed and said they realized that but had so much business in the meat business they havent had time to go to any other markets. I asked them if they thought about licensing the technology and they responded with, "why" we have the patent....kind of a young bull, old bull scenario. Anyhow, I have no doubt that this technology will make it into our woodworking business but it may be a while.

[Mike Henderson]

I had looked at the meat saw stop technology a while back. I don't remember a lot of it, but the blue glove was a camera detection mechanism. The operator didn't have to come in contact with the blade. It his/her hand got close enough, the saw brake engaged. At least that's what I remember.

Mike

[Van Huskey]

The Bladestop meatsaw technology show that the physics isn't an issue - they get large saws stopped cold in 8 - 15ms

Meatsaws tend to have very low rotational mass, using light weight aluminum wheels, wood bandsaws tend to have high weight drivetrains in order to carry a lot of momentum. It is less of an issue with larger saws since they already tend to use steel wheels with less proportional rotational mass. In the end the market size is likely the big issue, meatsaws are still a staple of industrial meat production there are almost no vertical bandsaws left in constant use in US industry those jobs are mostly done via CNC now and bandmills have almost zero chance of moving band to body contact.

[Tai Fu]

Just an idea...

But couldn't the same sensing technology be used in bandsaws but instead of physically stopping bandsaw wheels (which for larger bandsaw is quite massive and all that rotational energy is hard to stop) the brake mechanism could be a guillotine above or below where the saw is exposed to the operator, and when the system trips, it basically physically BREAKS the blade.

Basically once the blade on a bandsaw is broken, you only have the momentum of the blade itself which is very low, in fact too low to do more than scratch you once it breaks and therefore no longer driven by the wheels... So basically if it detects it's cutting fingers it breaks the blade and maybe somehow jam that one section so it stops in 1/1000th of a second. Also if the blade is broken just below the table then the tension would cause the blade to move UP instead of down, and so it wouldn't cut the user anymore. Perhaps to be able to do it fast enough it would use blank cartridges similar to what is being used for powder actuated nailgun, so it would have enough force to break any bandsaw blades immediately.

just an idea.

[Bert McMahan]

Just an idea...

But couldn't the same sensing technology be used in bandsaws but instead of physically stopping bandsaw wheels (which for larger bandsaw is quite massive and all that rotational energy is hard to stop) the brake mechanism could be a guillotine above or below where the saw is exposed to the operator, and when the system trips, it basically physically BREAKS the blade.

Basically once the blade on a bandsaw is broken, you only have the momentum of the blade itself which is very low, in fact too low to do more than scratch you once it breaks and therefore no longer driven by the wheels... So basically if it detects it's cutting fingers it breaks the blade and maybe somehow jam that one section so it stops in 1/1000th of a second. Also if the blade is broken just below the table then the tension would cause the blade to move UP instead of down, and so it wouldn't cut the user anymore. Perhaps to be able to do it fast enough it would use blank cartridges similar to what is being used for powder actuated nailgun, so it would have enough force to break any bandsaw blades immediately.

just an idea.


I think it would be simpler to just de-tension the bandsaw and apply a brake to the blade itself.

[Erik Loza]

Here's the thing: Bandsaws are about the simplest and most basic machine in the woodworking industry and the vast majority are offered for <$2K. Being in the industry, I can tell you that there is not a lot of motivation to "advance bandsaw design", if that makes sense.

Erik

[johnny means]

Occam's Razor dictates that they don't make them because people don't need them. Bandsaws just aren't causing the life changing injuries that table saws do.

[Bill Dufour]

I have had a few bandsaw blades break. When they do break they tend to stay pretty much in place but often 6-8 inches shoot up outside the guard. So a power gulitene might just allow the blade to escape the safety zone and do more damage.
Bill D

[Bob Falk]

Just an idea...

But couldn't the same sensing technology be used in bandsaws but instead of physically stopping bandsaw wheels (which for larger bandsaw is quite massive and all that rotational energy is hard to stop) the brake mechanism could be a guillotine above or below where the saw is exposed to the operator, and when the system trips, it basically physically BREAKS the blade.

Basically once the blade on a bandsaw is broken, you only have the momentum of the blade itself which is very low, in fact too low to do more than scratch you once it breaks and therefore no longer driven by the wheels... So basically if it detects it's cutting fingers it breaks the blade and maybe somehow jam that one section so it stops in 1/1000th of a second. Also if the blade is broken just below the table then the tension would cause the blade to move UP instead of down, and so it wouldn't cut the user anymore. Perhaps to be able to do it fast enough it would use blank cartridges similar to what is being used for powder actuated nailgun, so it would have enough force to break any bandsaw blades immediately.

just an idea.


Perhaps the trigger would loosen the blade rather than breaking it. Would make it much easier to stop.

[Tai Fu]

The problem with loosening tension is, it's a LOT to do in 1/1000th of a second, and also in order to loosen tension you must actually drop the upper wheel in 1/1000th of a second. That may not be possible at all within that time frame. Perhaps someone with a high speed camera can tell me, how long it would take for say a 26 inch bandsaw upper wheel to fall enough to kill the blade tension. I feel that breaking the blade physically is much faster than trying to drop a bandsaw wheel down (not to mention this may damage the saw).

As for the actual breaking of the blade itself, not sure if a powered guillotine will be fast enough... But if it could be made small enough, perhaps one can be placed above and below both guides, so the blade is broken in two places.

May be more useful for larger bandsaws as used in sawmills.

[Charlie Jones]

How about dropping a close fitting blade shroud that pushes your fingers away. Then the blade wouldn’t have to be broken or stopped.

[Zachary Hoyt]

We have a bandsaw mill that runs the blade on trailer wheels with 4.80 12" tires. Every now and then a blade will break, once it's been resharpened a few times. I have seen it throw the broken end a few feet, once it even hit the wall against which the sawdust piles up. Every couple of years on average the broken blade will cut the sidewalls of a tire, if it gets in behind one of them. Operator position makes blade breakage pretty safe since I'm behind the machine, but I would not like to have a thing that broke the blade intentionally on a shop bandsaw.

[Tai Fu]

A little off topic, but why 12 inch tires? Why not something larger as using a larger tire wouldn't expend anymore effort in building a sawmill but it would dramatically reduce blade breakage...

[Zachary Hoyt]

These are tires on 12" rims, so the overall wheel diameter is probably 22" or so at a guess.

[Tai Fu]

I feel though vehicle tires like this is probably not the best platform for bandsaw blades. It seems like unless the tire is inflated to insane pressure it has a bit of a give in it, and that give will cause the blade to have to bend more each turn, similar to what a three wheel bandsaw does to blades. I imagine the air must be used as a means to tension the blade but it just makes me think this can cause the blade to flex.

After all I never seen air filled tires in commercial bandsaw at all. The one I just got does not even have tires at all and is not crowned. The wheel is flat.

[johnny means]

The problem with loosening tension is, it's a LOT to do in 1/1000th of a second, and also in order to loosen tension you must actually drop the upper wheel in 1/1000th of a second. That may not be possible at all within that time frame. Perhaps someone with a high speed camera can tell me, how long it would take for say a 26 inch bandsaw upper wheel to fall enough to kill the blade tension. I feel that breaking the blade physically is much faster than trying to drop a bandsaw wheel down (not to mention this may damage the saw).

As for the actual breaking of the blade itself, not sure if a powered guillotine will be fast enough... But if it could be made small enough, perhaps one can be placed above and below both guides, so the blade is broken in two places.

May be more useful for larger bandsaws as used in sawmills.
Sawstops drop the entire trunnion mechanism far enough to bury 3 inches of blade below the table in that time frame. Loosening the tension on a bandsaw seems like a relatively minor movement to make in comparison.

[Zachary Hoyt]

The tires work pretty well aside from getting cut occasionally. What I was getting at was just that the blade can have enough kinetic energy to do cut through a tire sidewall after it breaks, and that would be more than enough to seriously injure a user's hand.

[Warren Lake]

if you need this on a bandsaw time to change hobbies.

[Tim Janssen]

https://m.youtube.com/watch?v=NiRegdech_E
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