So..after A 1x8 Attacked Me

jeffaah

I finally put a riving knife on my DW745 table saw. I've been meaning to do this for a while, never got around to it. Well, I finally had it yesterday when a board pinched the back of the blade and then wanted to go in reverse....at me.

Today, I dug out the useless blade guard and butchered it to get my riving knife. It starts about 1/4' below the blade and follows the blades travel. I noticed a HUGE difference in the saws cut performance after the knife was installed. I was mostly ripping ply today so I assume results will be even better with dimensional stock. If you are using a TS without a riving knife.....GET ONE....I highly recommend them.

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Jason Whipple

Nice job Jeff.

My older Delta 10" got the same treatment about two months ago. My Forman told me he almost caught his wrist on the blade from a pinch of the blade and I remembered that little trick from one of Gary's shows.

It really does work like a charm. I do believe that I'm getting a lot more life out of my blades too.

Don't think OSHA would like to see it though

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jeffaah

Well....nothing but a full blade guard on the saw, wearing chain mail suite while in a Lexan bubble would satisfy OSHA.

IMO proper use of a push stick and a riving knife adds a tremendous amount of safety. I will admit a full guard is optimal...just not practical

house bldr

Was ripping some thin strips of oak for facing melamine shelves the other day without a riving knife,had a peice pinch and kick back,went through both sides of my plastic trash barrel through my osb wall sheathing and put a dent in my steel sidingjust glad I wasn't directly behind it,that woulda left a mark!

HitchC&L

What are the advantages of those. I have seen them around but never paid too much attention to them.

Basically what is their job?

dkillianjr

I am no expert, but I believe they spread the board as you cut to prevent it from binding on the blade. I know I have ripped stuff with my circular saw and had to put a screw driver in the cut to keep it from binding real bad.


Dave

Sportbilly

They prevent pinching, and also they prevent the stock from moving away from the fence at the end of the cut as your leverage on the stock changes.

When the stock edges away from the fence, it rides up on the back side of the blade, causing even more binding, end result, flying wood.

neolitic

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Greg Di

I think I threw out my 745 blade guard about two weeks ago because I just kept moving it around my trailer. It was still in the plastic bag.

Why didn't you figure this out two weeks ago, Jeff?

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DecksEtc

My guard is still in the plastic somewhere too

Dumb question as this is a great idea!

Do I just take apart the guard to get the piece I need to do this?

Sounds like something to do since it looks like I'll be rained out for the next 4 days!

stp57

Actually Jeff,
I believe that you attacked the 1x8 & the board just retaliated.
Steve

Tom R

Wood will often have internal stresses that will 'react' when your blade cuts into them. If those stresses make your two rips 'come back together' they will bind into the (back) sides of the blade and cause (possibly a severe) kickback.

The riving knife will keep the necessary separation in the kerf near the back of your blade.

When the pieces start squeezing the blade, - - it causes more friction and heat, - - which then creates a wobble and increases those chances of kickback even more.

Another way to avoid that kickback is, - - once you realize you're binding, - - bring the wood back towards you and re-cut (another kerf-width off)the scrap-rip as you go. You may have to do this several times as you proceed through the cut.

(Don't try this at home) . . .

A more powerful saw (like a cabinet saw) will lessen the problem considerably.

Always play (what if??) safe and don't stand directly behind the cut . . .

Tom R

Dave, Dave, Dave, - - if anything ever happens to you, - -how will we possibly know if it was your wife or your saw that stabbed you??

jeffaah

Hmmmm....you make an excellent point. But I will get the last laugh