Passing timber diagonally over saw blade to create curve ?

[flanajb]

I was just flicking through Fine woodworking magazine and was amazed to see a guy passing a piece of timber diagonally over the top of a saw blade (riveing knife removed) to create an internal curve.

My initial thoughts were one of :shock:

Is this a widely practiced method of creating an internal curve along the length of a piece of timber?

 

[Dodge]

NO it is not!

There was a link on here recently to a pootube video of this being done.

I have seen it done in real life and it is highly dangerous procedure and personally i would never recommend it is done!

No guards/no riving knife and using the side of the teeth of the blade to cut against their design - an accident waiting to happen

Obviously this is my humble opinion but I still have all my fingers and it is over 30 years since i sold my first piece of furniture!

 

[Steve Maskery]

It's widely shown as a technique, and I suspect it is done quite regularly in the USA, but it is not a wise thing to do, for all the reasons Dodge cites. The saw just isn't designed to cut like that and even if you use a blade that you can sacrifice if it all goes horribly wrong, the difficulties of guarding it make it very risky indeed

I have actually done it myself, before I knew better, and it didn't feel right even then. Now I shudder at the thought. It's not as if the result is very good, it's not, there is a very large amount of sanding to do.

Don't go there. Instead, hog out the waste with a series of straight cuts. You'll need to lower your riving knife and use an overhead guard like the ones I show in my films. Then you can shape a cabinet scraper to suit and finish by hand. If you have a hollow plane, then even better.

Cheers
Steve

 

[jimi43]

If it's a widely accepted technique...I think you are very brave to try it!

I would like to shake your hand...you can post it to me at....... :mrgreen: :mrgreen: :mrgreen:

Jim

 

[woodbloke]

Then you can shape a cabinet scraper to suit and finish by hand. If you have a hollow plane, then even better.

Cheers
Steve

A highly dangerous practice and as Dodge and Steve have rightly said...not recommended. That said, this:

...is the way I went about shaping a hollow stool seat. Get hold of a standard woodie jack plane, put a curve on the sole, re-grind the cutter to the appropriate profile and away you go. That curve took about 15mins to do and was finished off with a card scraper and sandpaper - Rob

 

[flanajb]

I was horrified when I saw the picture in the magazine. To push a piece of timber across a spinning saw blade is just wrong. Surely, the blade was never designed for such a process.

 

[Den Dezyn]

Norm abram demonstrated this on the NYW cant remember which show

 

[Dodge]

Norm abram demonstrated this on the NYW cant remember which show

Well that sums it up in my opinion - i wonder how many people have ended up in A&E after trying to copy Norm - personally I cannot stand the guy and so many of his methods are just plain dangerous!

 

[Jamesc]

I have a book lurking somewhere on radial arm saws, it recomens this technique except reversed for forming coves. This would enough to scare the life out of me but they then went on to suggest using a dado head to get a better finish :shock: and that using a sencondary fence you could raise panels by only cutting half a cove.
Neadless to say I have not tried this technique, the thought of a dado head hurtling around above the workpiece restrained only by the slide lock on the overarm was too much for me even in my braver days :roll:

James

 

[Steve Maskery]

Crikey
That would be even worse on a RAS than on a TS!
S

 

[Jamesc]

I must admit I do wonder that there are any American woodworkers left. The practices that they advocate seem to suggest that they should all be missing so many digits/appendages that they can no longer work.

James

 

[woodbloke]

I have actually heard of a technique (probably colonial again) where a router ordinarie with a cove cutter is suspended from a pendulum affair fixed to the 'shop roof an gradually lowered for each pass across the timber...sort of a 'pit and the pendulum' but a different slant on Edgar Allen :lol: - Rob

 

[Dodge]

Sounds more like the Medieval torture of Death by a thousand cuts where the swinging knife slowly lowered onto the victim :shock:

 

[Chems]

I've done it, was fine:
















Very slight bites was the key. It didn't feel wrong I quite liked it. But then I am a man not a mouse, once you've used hydraulic cutting kit that'll take apart a car or water lance that'll cut through 1 inch steel, anything to do with a little TS blade feels fine! <<<This is in jest just incase H&S squad lynch me!

 

[andersonec]

As with any other machining task, it is as safe as you make it and cove cutting on the table saw can be made as safe as any other table saw cut. Just to reiterate on what Chems posted, this cut is not made in one go, the blade is brought up 2mm each time and the cove is made with many passes over the saw, and as long as the workpiece is supported on both sides with clamped fences, the work cannot go left or right, the saw blade cuts with the tips and not the sides. There is no reason why a strip of wood cannot be screwed to one of the fences to secure the work down as in this jig sold by Rockler, http://www.rockler.com/articles/cutting ... -saw-1.cfm it is completely safe. yes I know, another American company, but they do seem to be able to supply some stuff you just cannot get in this country.

 

[woodbloke]

...it is completely safe.

Wrong, end of. The tablesaur is an inherently UNsafe machine and any machining operation that entails the removal of the crown guard and riving knife only makes it more so, which is why this sort of thing is a complete 'no go' area in any professional 'shop in the UK. What the 'murricans get up to, with a rather more cavalier approach to elfn'safety, is to me at least, beyond belief. One of the main reasons why I never look at FWW 'cos if I did, it wouldn't do the old BP any good - Rob

 

[9fingers]

For those who want to use this method, here is a calculator for the set up.
http://woodgears.ca/cove/calculate.html

Bob

 

[jimi43]

Norm abram demonstrated this on the NYW cant remember which show

Well that sums it up in my opinion - i wonder how many people have ended up in A&E after trying to copy Norm - personally I cannot stand the guy and so many of his methods are just plain dangerous!

Hey Dodge...around here that's fightin' talk! :mrgreen: :mrgreen:

Couldn't agree with you more mate...can't stand the guy either!

You watch the front door...I'll cover the back! :mrgreen:

Jim

 

[Digit]

I'm with Chems!

Roy.

 

[oakfield]

Well, i may be in the minority, but i have also done this in the past week.

As has been said before, i think it is safe enough for a competent person to do if they are sensible about it.
ie. clamp fences both sides of the work piece, a bridge between them over the blade and take very small cuts feeding the wood slowly.

the riving knife isn't an issue as you aren't cutting a kerf that can close on the blade.