Rebbating Problems

[Nuggett]

Can any one help me, when cutting a rebate using a 16mm straight bit speed lowest appox 1000rpm on a Router? Why is it that I continually get tear out along the work piece?
Also can any one tell me what speed to set my Router at? Is there different speed for different wood types, and bit sizes? Mine is variable from 1-6 (1000- 22000 rpm)
Thanks Nuggett

[Kev Y.]

Nugget, one thing that could help ( if your not already doing it) is to make the rebate in a series of small bites. make each pass about 5mm in depth.

Another thing that MAY give you tear out is the direction of the grain in the timber, I have not mastered the art of telling which way the grain is running down the work piece, but I believe that when you go against the grain you are more likely to experience tearout than if you cut with the grain.

Having said that, it is not always possable to orientate the work piece to cut with the grain.

hope this helps.

Kev.

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IF at first you don't succeed, relax your normal.

[zathras]

Now I know the following will probably scare the s&%t out of some, but I have often used "climbing mode" when I *know* I will get tearout - Red Gum especially.
By this I mean I move the router with the rotation of the cutter, not against it as recommended.

Mind you I always make sure I am pushing the router away so if it does decide to run, it moves away from my body.

I find this is not as bad in practise, expecially if you have a nice heavy router (more static inertia), use a firm grip, and most importantly TAKE IT SLOWLY.

Note: I only ever do this with the router hand-held.
NEVER EVER DO THIS ON A ROUTER TABLE. A piece of timber can grab and be whipped out of your hands quicker than the blink of an eye, and a very high possibilty of your hand following past the cutter.

This is all assuming you are using a bearing guided cutter. All other bets are off.

Cheers Ray

[ubeaut]

Try using a sharp cutter. This will help and give a very clean edge.

Just out of interest tungsten tipped blades usualy aren't all that sharp. Try slicing a piece of paper with the cutter's leading edge if it won't do it easily with little or no pressure, it needs sharpening.

Get it sharpened by someone who knows what they are doing. High speed steel is easier to sharpen, will take a sharper edge and cut cleaner than tungsten. Unfortunately it won't do it for very long before it has to sharpened again.

Hope this is of some help.

Cheers - Neil

PS A blunt cutter will cut even worse at slow speeds so run the router flat out and see the difference. Oh yeah, and by the way. Unless you are really proficient don't use the climbing cut. You may get away with it for a while but sooner or later it will get away with you and the consequences may not be very pretty.

[ken yates]

I have found hard woods require low speeds and soft woods require high speeds to be the rule of thumb so to speak.

[derekcohen]

Nugget

With a 16mm bit you should be running your router at its fastest speed (22000). As others have suggested, do several shallow cuts at a time (say, 1/8"). I was routing Western Red Cedar doors a few weekends ago with a 19mm bit in my Elu and had to resort to a climb cut to avoid splintering the wood.

Derek

[Nuggett]

Thanks to all for replying.
Tried all tips and all worked, but I'll leave the climbing cut alone as the wood was shot out of the router at high speed & dented my tinnie !!
I did some rebates on a triton table saw, which worked well.
I have my router mounted on a triton router table.I've never used mine hand held as it weighs a ton and is very powerful at 3hp!! So I am a little nervous about it stuffing my work up!!
All the bits I use are made by Triton & CMT so I don't know whether they are tungston or H.S.S??
Any suggestions?? Who does the sharpening?

[soundman]

You may find diferent results taking your small bites from the side or the face (adjusting the height or the fence ) depending on the timber grain & character. one other tip may be to scribe the edge or the rebate with a marking knife or in some cases to scribe the edge of the rebate with the table saw first then use the router to trim out the waste.
p.s. dont be a wuss grab two fists full of you router & set your self up properly & the weight wont be a problem. I love my big porter cable because it is heavy, you plonk it down on the work and it stays there.