Safety Device, Table Saw vs Fingers.

[KC2YOI]

Must be seen to be believed.
I'm using a table & circular saw this morning and will keep this in the back of my head.


http://www.youtube.com/watch?v=E3mzhvMgrLE&NR=1    

[Mike/W8BAC]

Discovery channel has a series called "Time Warp". They use high resolution, very high speed video to study things we can't see in real time.

They had the inventor show how this gizmo works. The inventor even stuck his own finger in it to show how it works. I have just two observations. Your finger (or some part of your body) has to be in contact with the saw table or chassis when the finger touches the blade to close the circuit. Many times the only contact you make is hands, or fingers on the wood guiding the piece to be sawed. Touch the blade and it will still cut you.

The other thing they didn't go into in detail about is bringing the blade, motor and other things like motor fan and key, key ways to an instant stop. They say the safety block is toast as well as possibly the rest of the safety stop device. The blade is done as well but I wonder about the motor. Maybe one of you might have an idea.

Is it worth scraping your saw and saving your fingers? I think so! But will it work if your not in contact with both the table and blade?  

Like other modern safety devices (vehicle airbags, seat belts and ABS braking) it might make the saw operator less cautious thinking "The saw will save me".

Added later: Your link wouldn't work for me so I looked at YouTube and searched "table Saw". I see what looks like video from Time Warp. That might be your link destination, I couldn't tell.

[KC2YOI]

RE:
"Added later: Your link wouldn't work for me so I looked at YouTube and searched "table Saw". I see what looks like video from Time Warp. That might be your link destination, I couldn't tell."

Hmm, the link works consistently for me. If it's a dud for others let me know, I'll change it.

                                                                        D.

[WQ9E]

He has been promoting this device for quite awhile and at one point there was a move to require all new table saws to be equipped with one (sounds very California doesn't it?).  There are a lot of ways to get hurt using a tablesaw and the saw stop does not address most of these (kick backs, knots or other thrown pieces from the work piece, etc.).  It is an interesting bit of engineering but it is no substitute for proper setup, good work habits, and knowledge of what you are doing.  Of course the ultimate safety device is hire someone else to do all of your cutting but that isn't any fun 

I do a lot of woodworking and have a pretty well equipped shop (Delta Unisaw, planer, jointer and  shaper; 24" Centauro Bandsaw, numerous drill presses and portable power tools) and so far the worst I have done in 25 years of woodworking is to pick up a few splinters along the way.  But just like working on HV I don't do it when I am tired and I try to be smart about when to stop.   I spend time on setup and use featherboards and other jigs when needed. 

I spent a couple of hours this morning making sawdust (building the carcasses for a couple of bathroom vanities) and that was a fun way to spend a few hours.  Later I am gluing up panels for the doors and raising the panels on the shaper is something I will do at the start of a session next week when I am not at all fatigued.   Although the shaper is probably no more dangerous than a lot of other shop equipment the sound of a 5.5 inch cutter spinning at 7,000 RPM sure makes it sound dangerous.

[KA0HCP]

The next application is to fit the sensor to a microphone to keep hams from making innapropriate transmissions!   Thwap.   (mic retracted and PTT disconnected)

B.

[K1JJ]

I suppose someone could use a ground strap on one wrist to make the circuit complete.

I have a table saw with a fine toothed blade for Plexiglass. Once in a great while the Plexi will launch across the room. I just cringe when I think of having to use that machine.  I usually go to big extremes to cut Plexi with my band saw. That is much safer, but has limitations.

T

[k4kyv]

And to think I use my Skillsaw with a piece of wire attached to hold the safety guard out of the way when I want to make precision cut. I think the Skillsaw is meant for rough cutting, as when you are building a house or barn, and +/- 1/4" or so is OK.  But on some of my old-house restoration projects when I am trying to retrofit a replacement for rotted out piece, the thickness of the saw blade is far beyond satisfactory tolerance, so I wire the safety guard out of the way, and rely on actual visual observation of the cut, not the gauge built into the saw, to make sure the cut is exactly where I want it to be.  I do use safety goggles because it is very hard to precisely judge a cut while your eyes are being bombarded with sawdust and debris.  What really sold me on safety goggles is the time a strand of EHS guy wire broke off while I was trying to wrap it, and the razor-sharp shard of wire luckily hit my cornea broadside instead of end-fire.

OSHA would have a heyday at my QTH.

[ka3zlr]

Table Saws are nice in certain areas, I've never put one in I like the
Portable Rechargeable hand saws an there is a great many to choose
from for different jobs.

73

Jack.
 

[k4kyv]

A friend of mine showed me a table saw that he made using a skill saw.  It is basically an unwarped  piece of 1" plywood mounted horizontally on a wood frame made of 2 X 4s, with a slot cut in the plywood to accommodate the blade, and he fabricated a JS bracket to firmly attach his skill saw to the underneath side.  Using a pair of C-clamps and a piece of 1" X 2" as a guide, he can cut a piece of wood as precisely as anyone I have ever seen using a real professional grade table saw.

[Opcom]

original post gave link for ful screen pop-up. This is regular:

http://www.youtube.com/watch?v=E3mzhvMgrLE&NR=1

[KC2YOI]

original post gave link for ful screen pop-up. This is regular:

Thanks, I put your better link at the top.
                                                           D.

[WQ9E]

I have a table saw with a fine toothed blade for Plexiglass. Once in a great while the Plexi will launch across the room. I just cringe when I think of having to use that machine.  I usually go to big extremes to cut Plexi with my band saw. That is much safer, but has limitations.

T

Cutting Plexi on a table saw certainly has potential for mayhem as the plastic material melts and then solidifies it is the perfect setup for kickback.  The pawls designed to stop this with wood probably aren't very effective with plexiglass.  If you have to do this I would suggest raising the blade a little higher above the material than usual and use a fairly fast feed rate.

The bandsaw is certainly safer but even with larger saws you run out of size capacity pretty quickly.  Given the behavior of plexi when it is cut/drilled I would think using a jig saw and guide would be preferable to having a piece launched by a table saw.  With the material properly secured, this is one of the cases where a radial arm saw would be safer than the table saw.

[ka3zlr]

With the right Equipment and the Right Speed and Feed anything can be cut Safely
I have a Machinists manual that describes the correct procedure for Plexiglas.

73

Jack.

 

[k4kyv]

The biggest frustration I have with sawing plexiglass is that the melted saw dust re-solidifies after the saw blade passes and the two cut pieces weld back together, and I end up with little more than a mark across the sheet of plexiglass, which remains one solid piece.

Maybe a jig could be contrived that would continuously squirt a small stream of water right where the blade contacts the plastic, and cool down the sawdust as soon as the blade makes the cut so that the saw is not spewing out melted plastic as it goes.

[K1JJ]

The biggest frustration I have with sawing plexiglass is that the melted saw dust re-solidifies after the saw blade passes and the two cut pieces weld back together, and I end up with little more than a mark across the sheet of plexiglass, which remains one solid piece.

Maybe a jig could be contrived that would continuously squirt a small stream of water right where the blade contacts the plastic, and cool down the sawdust as soon as the blade makes the cut so that the saw is not spewing out melted plastic as it goes.

Don,

The melting and fusing only occurs with a small blade heatsink, like a tiny hand saber saw blade. When using a bigger table saw round blade or bandsaw, the Plexi cuts cleanly without melting. The bigger blade never really gets hot. It's just a matter of degree.

T

[W1VD]

Some info on blade selection for cutting various plastics:

http://www.plasticsmag.com/features.asp?fIssue=Mar/Apr-01

   

[ka3zlr]

With the right Machine an then it's speed an feed, add a shop-vac and your there.


73

Jack.

[W3SLK]

A bandsaw works deluxe on acrylics like Plexiglas®

[flintstone mop]

About 20 yrs ago the sign of a carpenter was to have at least one finger missing

Fred

[Ed/KB1HYS]

That sort of safety device is probably worse than no safety at all.  You'd get complacent around tables saws (maybe not if you have to by a new module every time) and one time you'd be running an OT saw and WHAP now your a lefty.

safety is designed in to a point (lots of people remove guards and such though) and Learning. If your smart you learn from someone else. If not, well you've got nine more chances to figure it out...


I did run my thumb just over the top of a table saw blade when I was 17 and new everything.  It was a light touch but it took out a 1/8th inch swath of skin and meat to make a shallow trench across the ball of my thumb.  healed up good, but I use a push stick and feather blocks etc when needed now.  Set up, plan the cut. Plan AFTER the cut (where's that scrap going to go?) and have the Kill switch where I can hit it with my leg/knee to stop the saw without taking my eyes off of the work surface (it does NO good for safety stop, takes too long).