Rabbeting on a Router Table?

[Mark W Pugh]

So, I've successfully rabbeted ply on a router table. However, every time I attempt to rabbet hardwood/cherry, I get a lot of tear out on the inside edge/corner against the fence. I've used a straight bit, fluted bit, took multiple pass, results the same.

Is it just me?

[pat warner]

Take a 5% climb cut first, then take the rest in anti-climb. Test on scrap, see if that helps.

[Gerry Grzadzinski]

Or use a fence with a zero clearance insert.

Rabbeting on a router table is a difficult operation, and there's little you can do to avoid the tearout.

[Malcolm McLeod]

I have had luck making a light climb cut at the correct height, but only 1/16 or so wide. Reset fence to correct width and finish the cut normally.
I have had very limited success using blue tape covering the cut.
Also have read that a scribe line will stop a lot of it (just never had the confidence or need to try it).

Edit - Assume this is on the end-grain edge... Is the end-grain against the fence or against the table? Put it against the fence.

[glenn bradley]

A couple things come to mind. Your bit needs to be sharp obviously. the fact that you get the same result with multiple passes makes me lean this way. If you have a known sharp bit I would check the alignment of the router in the table. If the bit is not perpendicular/parallel to the feed path you will get fraying/tearout as the geometry is blown. How are the bearing on the arbor? Everything super smooth and wiggle-free?

[Chris Hachet]

I use a porter cable 690, certainly not a high end router, and a spiral bit. I have zero issues and have had for years. My guess is a worn bearing in the router....but I have cut tons of rabbits with never an issue. Actually, I prefer to cut them this way or with a skew rabbit plane by hand. I very rarely cut them on the table saw. The time to set up the table saw is much greater, and I actually get better results on the Router table.

My router is in the wing of my table saw, so I am using a good fence and the work piece is always well supported. I suppose one could look at how well supported the work is in your situation. But I would look at bit sharpness and bearing trueness first and foremost.

But before I gave it to my son my 25 year old dogmeat craftsman router cut perfect rabbits, so unless your router has been damaged....odd....

[Chris Hachet]

I would also check to make sure the bit is clean. If you cut Pine or Teak or some wood that will put sap or oil on the bit, I have had DIRTY but sharp bits produce issues.

Would note that you will also get a much smoother cut with a 1/2 Shank bit. I typically bury a 3?4 inch bit into a sacrificial fence, as the greater mass of the alrger bit seems to make a smoother cut. YMMV.

[lowell holmes]

If the routerman to try a 5% climb cut, I will take a 5% climb cut.:)

[Art Mann]

I have made rabbet cuts on my router table more times than I can count and I have never had any trouble. If the dimensions are large, I will make 2 or even 3 passes. I use a 3/4 inch straight bit. I don't know that it is just you because some other people have also had the problem but I doubt it is a router problem. You already know whether your bit is sharp. I do have a problem with cherry burning every once in a while.

[Chris Hachet]

I have made rabbet cuts on my router table more times than I can count and I have never had any trouble. If the dimensions are large, I will make 2 or even 3 passes. I use a 3/4 inch straight bit. I don't know that it is just you because some other people have also had the problem but I doubt it is a router problem. You already know whether your bit is sharp. I do have a problem with cherry burning every once in a while.

the feed rate with Cherry is a bit of an art form.....which is why I prefer to sue hand tools with Cherry.

[al heitz]

I'm assuming your tear out is coming at the end of your pass. I was taught one way to avoid the tear out is to make about a 1/2" cut (or at least equal to the diameter of your bit) the into the "wrong" end of the piece, then make your entire run from the correct feed direction. That little "notch" at the end of your cut will prevent blowing out the end when you get there. Otherwise even a brand new sharp bit can blow out the end.

[Lee Schierer]

If you learn to read the grain where you intend to make your router cuts you will get where you can predict where tear out would occur and there by avoid it by starting out with a climb cut for the first pass or two.

When routing cherry, you never want the wood to stop moving during a cut. If you stop or even hesitate, you can get burn marks. You also want to use a quality bit that has some relief behind the cutting edge. Freud, Whiteside, and Amana make good bits. Woodtek, Viper and some other house brands have given me poor results so I don't buy them any more. Yes you pay a bit more for them, but the quality of cut is worth the price.

Be careful when climb cutting to insure you have the ability to hold on to the piece being cut as it will tend to self feed.

[Mark W Pugh]

If the routerman to try a 5% climb cut, I will take a 5% climb cut.:)

Definitely try this next time.

[Mark W Pugh]

I'm assuming your tear out is coming at the end of your pass. I was taught one way to avoid the tear out is to make about a 1/2" cut (or at least equal to the diameter of your bit) the into the "wrong" end of the piece, then make your entire run from the correct feed direction. That little "notch" at the end of your cut will prevent blowing out the end when you get there. Otherwise even a brand new sharp bit can blow out the end.

Actually, the tear out is occurring along the entire cut, with either bit.

Thanks for all the replies.

[Greg Hines, MD]

I would use a rabbeting bit for a rabbeting job.

Doc

[Art Mann]

A rabbeting bit has a bearing and is used for free hand routing. I don't see how it would be any better than a straight or spiral bit in a router table if you are cutting straight against a fence.

[pat warner]

Doc's right, rabbet bit, of radial design, is the most efficient cutter to cut a rabbet.
Moreover, it will yield the best result. Plenty stiff, + will not deflect like a straight bit.

[Mel Fulks]

I use the small climb cut first method,too. And single flute bits cut really fast.

[Art Mann]

Doc's right, rabbet bit, of radial design, is the most efficient cutter to cut a rabbet.
Moreover, it will yield the best result. Plenty stiff, + will not deflect like a straight bit.

If someone is deflecting a straight bit while cutting a rabbit, then they are pushing waaaay too hard. That would certainly explain why they are getting poor results. I don't understand this thread. People cut rabbits with a straight bit on a router table all the time. I am not the only one who doesn't have problems doing this. There si some other explanation than "wrong bit".

[Mark W Pugh]

Doc's right, rabbet bit, of radial design, is the most efficient cutter to cut a rabbet.
Moreover, it will yield the best result. Plenty stiff, + will not deflect like a straight bit.

Any recommendations on which product to buy? I'm looking at Whiteside 1955 or 1960 set, or both. Any comments?

[Jerry Miner]

Bit diameter can matter also--- a larger diameter bit will tear-out less than a smaller diameter one(all other things being equal). Rabbeting bits tend to be larger diameter, with a cutter geometry that is better for rabbets than a straight bit.

p.s. Don't know what you mean by "fluted bit." The flute is the area where the cutting happens. Some bits are single-flute, some are 2-flute, some 3-, and Freud makes some bits in a "Quadra-cut" form. Flutes can be straight or other shapes, but "fluted bit" doesn't communicate much.

[pat warner]

" Any recommendations on which product to buy?"
************************************************** *************
I'd get something that will cut 3/8 -1/2 x maybe 3/4" in Y.
On the table, a cutter of that size, without its bearing, will cut from 0,0 - 3/8+ x 3/4. One cutter to do all that and do it well, awesome.

[Art Mann]

Heaven forbid having to route a 1/4" X 1/4" groove instead of a rabbit. Does that mean it is impossible to eliminate splintering?

[Greg Hines, MD]

Any recommendations on which product to buy? I'm looking at Whiteside 1955 or 1960 set, or both. Any comments?

Something similar to this is what I would use:

http://www.woodcraft.com/product/129688/woodriver-rabbet-router-bit-set-12-sh.aspx


(http://www.woodcraft.com/product/129688/woodriver-rabbet-router-bit-set-12-sh.aspx)

[pat warner]

" Heaven forbid having to route a 1/4" X 1/4" groove instead"
************************************************** ************************
A slot with a straight bit is one of the most rigorous cuts for a router and its cutter.
A 1/4 x 1/4 slot, if done in one shot will measure >.250" wide.
The cutter is slamming into both sides of the path way and dragging along the bottom. No room for the chip; it fouls the foot way. It's web is often <.125"; not a lot of steel or carbide to resist deflection.
A 1/4 x 1/4 slot = .250" is possible, however, and in a single pass if you must.
A 3/16 CD cutter, cut down the center of the path way will wiggle, twist and deflect. However, as it wastes the remaining 1/32"/side there is very little deflection and a near perfect slot is possible.
Notwithstanding, if the slot were close to the edge I'd use a radial 3-wing slotter, cuts like a saw blade.