Thread: Removing riving knife

Id have thought you would really want to be using a riving knife when resawing to prevent kick back

Also wouldnt it be better to resaw on a bandsaw to reduce waste and improve safety?

Originally Posted by mac_man_luke

Id have thought you would really want to be using a riving knife when resawing to prevent kick back

Also wouldnt it be better to resaw on a bandsaw to reduce waste and improve safety?

I am going by the recommended method by Doug Stowe in Fine Woodworking
http://www.taunton.com/finewoodworki....aspx?id=30383

I want to make two cuts each half way through but the riving knife has a part that extends above the line of the saw blade stopping me.

I have tried on the band saw but the blade keeps twisting towards the fence.


C

Not sure about your table saw, so nothing to add there - except that I have reswn timber using 2 cuts like this (actually, mine was too wide for that and I had to finish it with a hand saw). You can deal with a band saw by adjusting the angle of the fence across the table. As long as you keep the tension constant, the twist should be the same for each cut. All you need to do is use a marking guage to mark a line parallel to one edge of a straight board. cut as well as you can be eye down the line. Stop the saw about half way through the cut, and the angle the board is on will be the angle you need to set the fence to. You can adjust the fence, or clamp a strightedge on for a fence, or even make your own fence with adjustable angle.

Peter

A lot of knives don't allow blind cuts. I've never fitted the knife to mine. If you do want a knife for blind cuts and you are prepared to make or already ahve a zero clearance insert have a look at incremental tools at teh micro jig splitter and the other one they sell.

Anyway regarding the nut problem:

A wing nut will be ok as long as it doesn't foul anything, but you need to check through the full range of rise and fall and tilt.

Nuts and bolts fall out mainly due to vibration. It usually take a while. Assuming your not leaving the knife off permanently the fastener should stay in place with a decent nip up until your ready to replace the knife. My saw has the looseness thing and I leave the bolts out but yours may need it to locate or hold something else ? If not leave it off. If it does come adrift while your sawing it could become a missile...

Switching to a bandsaw doesn't necessarily improve safety. If one has a casual attitude because you assume the bandsaw is safe your more likely to injure than if your on a table saw and properly paranoid. You either get hurt or you don't, and that hasa lot more to do with your attitude and thinking through issues than what equipment you choose to use.

2c.

I just watched that video. A couple of things I found interesting:

1. He has a bandsaw but chose to demonstrate resawing on the tablesaw first. This is like going to work on a pogo stick when you own a pushbike.

2. The clumsy way the board is removed from the still spinning blade after making the first cut and generally the whole laid back approach to the job - no feather boards or push sticks or anything. He even laid the board down on the table, putting his hand near the blade before switching the saw off.

3. They edited the most important bit, which is where he manages to remove both boards with the saw still running and still has all his fingers

If you're comfortable around tablesaws, there's no issue with any of that I guess, but there's such a thing as being too comfortable.

However, you might have missed the most important point, and that was that he has added a new insert with a splitter attached. Even he is not game to do that cut without a splitter. If the kerf closes up over the blade, you could be in for all sorts of trouble.

I once had to rip a 90x90 newell post in half. The table saw we had to do the job was not deep enough cut to rip right through, so we had to use this technique. We got halfway through and the kerf closed over the blade. Fortunately, the riving knife was still fitted. There was myself at one end and the tail ender at the other, holding this thing which was jumping around and had started to smoke, so we switched off the saw.

The bandsaw is the perfect machine for this job, and rather than trying to work out how to remove the riving knife, you'd be better off tuning yours. That's my opinion.

If you do need to make this cut on the table saw without a riving knife then you should tap small wedges into the kerf to stop it closing.
This was how it was done before the advent of riving knives

"I am struggling away trying to run a woodwork course at the school I teach at."

My comments are in this context

There was an article in the Australian Wood Review a few years ago re riving knives including the OH&S implications.
I suggest everyone (and especially teachers) read this.
H

Originally Posted by haggismuncher

I am struggling away trying to run a woodwork course at the school I teach at.
I want to use the table saw (Wadkin Bursgreen 10" AGS) to resaw some timber we have been given.

The problem I am having is that I have to remove the riving knife to expose the blade.
[COLOR=black]Any help greatly appreciated

Chris

Geeveston
Tas

CHris,

Leave the riving knife on. If you take it off, you're personally liable for any injury you cause, and it'll be hard to pay any bills without an income.

Your other options.

(a) Bandsaw if it goes high enough to allow you to resaw vertically. Make a resaw fence and ensure you use safe technique

(b) If you have a router table and can do it safely, put a slotting cutter into it and run a slot down both sides of the board. This'll act exactly the same as the saw kerf, but not as deep. ie; it will guide the saw blade when you start hand sawing. USe of a slotting cutter involves a few safety 'musts' - I assume you've been trained.

(c) Speak to a local joinery/cabinet shop and ask them to run the boards through their bandsaw for you. It should be painless for them.

(d) Depending on the number (one or two boards, maybe,) rip by hand. Ripsaws are easy to sharpen.

How wide/thick are we talking about?

CHeers,

eddie

edit; just saw your reply mid-thread

Bandsaw blade drift is because kerf is worn/blade is old or blade tension is too low.

As well, your bandsaw guides are not properly adjusted if it's significant.


Perhaps try resaw with a new blade.




The technique I thought that you were referring to is an old one to resaw a (say) 7" board on a saw.

Run a saw kerf through both edges, with the blade buried in the timber. Turns a 7" board into a 1" board, with two guides for the handsaw so that the resaw goes straight. Skip dress through thicknesser & you're done.

The riving knife doesn't need to be above the blade, usually it is set to be a few mm below the top of the blade. Can you not adjust it down or if not, grind the top of it just below the blade.

Cheers
Michael

make a shorter knife for this procedure
(thats for the wusses and to satisfy oh&s requirements which is important at school)

I've resawn without a knife a few times. As for resawing with a bandsaw - no thanks.

Tightening the nut should be quite ok.

As for resawing with a bandsaw - no thanks.

Why's that? I've come up against this attitude twice now and it mystifies me.

I resaw on mine all the time. I'd be disappointed if it didn't work because that's the only reason I bought it. Thin kerf, one pass, relatively safe. What's the issue?

The making of a short knife is a good idea depending if it is an English or Australian made Wadkin AGS. Can then be left on for trenching etc.
On the origonal English version the riving knife is fixed imediately behind the blade and goes up and down with the rise and fall of the blade.
On the Oz ones the knife is behind the blade but does not go up and down with it.
This means for each adjustment to the depth of cut the knife has to be unbolted and the height adjusted then rebolted.Sounds like this is your problem.
As Eddy suggests the best option may be a inch or deeper cut on each edge with the table saw and then free saw thru on the bandsaw.
This way you can correct for any drift due to damaged teeth on one side of the bandsaw blade.
I certainly wouldn't be using wing nuts, more likely nylocs and a modern ratchet spanner.
If you're ripping without a knife leave the belts a bit loose that way you may stall it before it goes thru your guts or smashes a knuckle.(don't ask we don't want to besmirsh the illustrious dead master)
H

Originally Posted by silentC

3. They edited the most important bit, which is where he manages to remove both boards with the saw still running and still has all his fingers

I asked exactly the question when I watched the DVD last year. What a waste of time that was. I only watched 2 chapters of it but didn't bother to watch the rest.

This is FWW as their best. They can show you some bloke using a tablesaw on youtube as label it as the dangerous ever. They can also show/edit something more dangerous on their on DVD.

FWW my _ _ s _.