Router and Flush Cutting Bit Disaster

[Dennis Putnam]

I had a major disaster with with my flush cutting bit last night. I needed to trim my face frame edges so I used a brand spanking new flush cutting bit. As I started trimming, the wood (birch) began not just tearing out but splitting out. I have one spot where a huge chunk (maybe 1/8" deep x 1") was torn out (I have no idea how I'm going to fix that). I tried slowing my feed rate, speeding it up, nothing seemed to help.

What did I do wrong? I've done flush trimming before with no problem but this is the first time I tried to trim anything this wide (3/4") but at thickest part I was trimming <1/8" at most. The only thing I can think of is the bit diameter was too small. Is there a rule of thumb for the bit diameter vs. the width of the material to be trimmed? It seemed the larger the diameter the shorter the blades was the way the case was stocked at the store. The bit I used was 3/8" because it was the only one that was 1" long.

[Cliff Rohrabacher]

brand spanking new flush cutting bit.
What make? Was it actually sharpened at the factory? Errors do occur.

Was that Birch solid wood or Ply??


splitting out. I have one spot where a huge chunk (maybe 1/8" deep x 1") was torn out (I have no idea how I'm going to fix that) Piece it in. Use a chisel and cut the chip out to some geometry you can cut a patch for. I like to taper the ends to little points: helps hide the repair.



What did I do wrong?[...](3/4") Prolly nuthin. 3/4" ain't much neither.


The only thing I can think of is the bit diameter was too small.Doubt it.

Is there a rule of thumb for the bit diameter vs. the width of the material to be trimmed?Not to my knowledge. It's all about sharp edges when routing unless you have a feed rate that is so aggressive that the cutter can't clear the chip (a CNC issue not hand routing).

Get yourself as Whiteside cutter and lose that nickel plated sissy pistol.

The only thing I can think of is that the bit is defective.

[Chuck Saunders]

Probably just a grain direction issue. Unfortunately unlike a hand plane, you can't work in both directions equally. You will get better results going the opposite direction but you will be climb cutting and the router will have a tendency to run away, firm grip and light cuts will be the name of the game.

Hope this helps
Chuck

[Dennis Putnam]

Thanks for the repair tip. Not sure I have the skills (I don't seem to have the patience for a chisel and wind up gouging too deep) to do that but it sure has to be better then wood filler. Fortunately the chip doesn't go all the way to the edge so from the front it won't be noticeable.

The bit was a Ryobi. My normal router bit store is closed by the time I can get there week days and I didn't want to wait until Saturday where I usually get Freud or Vermont American. Guess I should have waited as I'll be doing something other then making the doors, as it turns out anyway. :-(

[Dennis Putnam]

Probably just a grain direction issue. Unfortunately unlike a hand plane, you can't work in both directions equally. You will get better results going the opposite direction but you will be climb cutting and the router will have a tendency to run away, firm grip and light cuts will be the name of the game.

Hope this helps
Chuck
I tried going the opposite way but I guess I'm too weak. I just couldn't control it (unlike Norm I don't have a drawer full of routers where I might have gotten a smaller one). Maybe I should have taken the wimp's way out and sanded it down but that takes a lot of time and patience, neither of which is very plentiful. Does that mean I'm pursuing the wrong hobby? :confused:

[Jules Dominguez]

I'd think grain direction. I've had experiences with flush cutting bits really grabbing the wood. I've learned never to start a cut in end grain, but ease into it. When I make my rough cut before routing, I try to leave as little wood as possible to trim, generally no more than 1/16. It's safer sometimes to climb cut bad sections.

[Matt Day]

I would think grain direction is the culprit, as mentioned above. I would do my best to take as little material off as possible, especially considering you're off 1/8" of material with a 3/8" bit. In my experience (which is amost zero compared to some people here!), splitting in large chunks occurs most when you try to take too much material off.

[Rich Torino]

Would a spiral flush trim bit have prevented the tear out due to grain direction??? Just a thought..

[frank shic]

dennis, were you trying to flush the outside edges of the face frame to the case?

[Dennis Putnam]

dennis, were you trying to flush the outside edges of the face frame to the case?
Yes. Sorry for not being clear.

[frank shic]

dennis, spare yourself the hassle in the future and just leave the reveal. once the cabinets are joined together, no one will be able to tell if you flush trimmed them or not. even on exposed ends, a small reveal around 1/16" is acceptable since the wood is going to expand and contract anyways. a hand plane is a great alternative if you know how to sharpen one. look on the bright side: at least you didn't hurt yourself!

[Peter Pedisich]

Dennis,

I've had the same thing happen to me with an inexpensive flush trim bits.
The problem was lessened greatly, but not completely, by getting a higher quality bit (Amana in this case).

I have had good luck getting smooth, chatter free cuts with Amana bits.

The grain direction was the problem with mine too.

Good Luck,

Pete

[Cliff Rohrabacher]

Maybe I should have taken the wimp's way out and sanded it down but that takes a lot of time and patience, neither of which is very plentiful. Does that mean I'm pursuing the wrong hobby?

No it means you need to spend more money on more expensive tools. Lots and lots more.

[Dennis Putnam]

dennis, spare yourself the hassle in the future and just leave the reveal. once the cabinets are joined together, no one will be able to tell if you flush trimmed them or not. even on exposed ends, a small reveal around 1/16" is acceptable since the wood is going to expand and contract anyways. a hand plane is a great alternative if you know how to sharpen one. look on the bright side: at least you didn't hurt yourself!
In this case it is a home theater equipment cabinet so it needs to be furniture quality (euphemistically :-)). Also, this is my first real project (obligatory beginner bird houses don't count) so there are some flaws that made the "reveal" (I call it mistake) irregular so the trimming was necessary. I though of a plane but since the carcass is plywood I was afraid it would be gouged. Next time I won't have as much "reveal" to deal with (hopefully) so sanding will be sufficient.

I am going to put solid wood around the edge of my plywood top and shelves so I will be more careful about thickness there (along with challenging my poor mitering skills). I'll use the shelves for practice since I only need to do one edge on them.

[Dennis Putnam]

No it means you need to spend more money on more expensive tools. Lots and lots more.
Then maybe I really am in the wrong hobby. The problem is, it is a long time between adding expensive tools and I can't just let the one's I have sit until I get the whole shop outfitted. Do you have any idea how many honey-dos are needed to buy just a jointer, which is what I want next?

[Charles McCracken]

I think you need a bit like this 50-509 so you can cut part of the piece in one direction, then flip it over and cut the rest in the other direction to reduce grabbing and tearout:

[glenn bradley]

I have had similar experiences where suddenly I'll just blow a chunk out. Once (or maybe every time) it was my fault for misreading the grain. Another time I had the experience with two pieces from the same batch of wood but no trouble with the other (again reading the grain to the best of my limited ability). I got spiral bits for this type of work and have not (yet) had the problem again, so they seem to help. I do wish I could find a bearing guided spiral larger than 1/4" diameter though.

[Rod Sheridan]

Hi Dennis, welcome to the fun of woodworking.

In your post you mentioned trying to feed the work in the opposite direction, this is called climb cutting, and is extremely dangerous. Never attempt to do this when feeding material by hand.

The double bearing trim bit, as suggested by another member is a good idea for some items, assuming you can flip the work over to cut in the correct direction.

Shapers have reversible spindle rotation for exactly the reason you've discovered, you can flip the cutter, reverse spindle rotation and cut the other grain direction.

I would simply use a hand plane to get the trim close, then sand to final size.

regards, Rod.

[Doug Shepard]

Dont throw those big splinters away - even if you have to crawl around your shop floor to find them. Put a tiny bit of glue on them and seat them back into the jagged hole they came from. If you have multiple splinters, you may have to do this in layers but you'll never find a better fitting or color/grain matched patch. Blue tape is about all you need to cinch them down while the glue dries. I've done this more times than I care to admit and it's usually a real chore to find the patch afterward. At most the glue line ends up appearing like a slightly different color grain line or spalt line.

[Dan Forman]

Then maybe I really am in the wrong hobby. The problem is, it is a long time between adding expensive tools and I can't just let the one's I have sit until I get the whole shop outfitted. Do you have any idea how many honey-dos are needed to buy just a jointer, which is what I want next?

I think that the point Cliff is trying to make is that in the absence of patience, you will need to pony up some bucks. Even so, you will still need at least a little patience. The good news is that patience can be developed, and will serve you well in your non-woodworking life as well. In fact, aquiring patience is easier than becoming wealthy enough to afford all of the high-tech (and high dollar) new tools that allow you to work with less skill. Lest that sound harsh, I don't mean to imply that all users of time saving tools are unskilled!

Let's consider the Domino. This is NOT an anti-Domino comment, so please don't take it as such!!! For a considerable outlay, I can buy a Domino and go right to making very precise mortise and tennon joints, (so long as I can cut a square board) without having to learn the skills necessary to make these joints by hand. I not only save time and effort in making the joint in the here and now, but also all of the time that would have been consumed by the learning process.

As to whether you have chosen "the wrong hobby", that's for you to decide. You have certainly chosen a hobbly in which patience is a virtue. It is also one which will provide many opportunities to cultivate that patience. Money can enable you to buy tools which allow you to be more efficent with your time, and require a shorter learning curve. However, impatience in life has it's own costs as well.

Dan

[frank shic]

dennis, you may want to consider investing in a pocket hole jig in the future so that you can quickly remove the face frame from the carcase, take apart the face frame and then rebuild it. don't be too discouraged by the initial "investment" that you make in woodworking. after all, you can always sell off the tools that you don't need on either ebay or craigslist like i'm doing right now!

[David Dundas]

In your post you mentioned trying to feed the work in the opposite direction, this is called climb cutting, and is extremely dangerous. Never attempt to do this when feeding material by hand.



Rod,

It is misleading to say that climb-cutting is extremely dangerous. In some situations climb-cutting is the only feasible way of doing the job effectively. For instance, when I was routing the profile on the edge of this coffee table, I used climb-cutting on the two quadrants of the edge where, if I had fed in the nornal fashion, I would have been routing against the grain. By climb-cutting these quadrants I achieve perfect results with no tear-out. So long as you take care to control the router, avoid taking excessive bites, and clamp the workpiece properly, there should be no danger. But it would be wise to do some climb-cutting on scrap wood, to gain some practice in the technique, before risking a prized project.

David

David Dundas

[Alan Tolchinsky]

although I was able to repair it using a hand plane. Boy the tear out was major on a walnut cabinet I was building. What I learned from this is:

1. Don't try to take off too much at one time. I'm talking 1/32" at a time to play it safe.

2. I think the rotation of the bit should be perpendicular to the grain direction and not parallel to it

3. Use a sharp hand plane for this

4. As suggested just leave the extra reveal and don't worry about it. This is the best way to go IMHO

[Dave Falkenstein]

There is another way to trim edge pieces flat to the panel to which they are attached. I have a jig I built from a plan in the book, "Router Magic" by Bill Hylton that does the trick. Pat Warner offers a similar base here:

http://www.patwarner.com/vertical_trim_subbase.html

With Bill Hylton's jig or Pat's base you can easily trim hardwood edging up to 3/4" or more to be flat to the adjoining surface. The cutting is done with a bottom cutting straight bit. I have not experienced any chipout using this method. I like it so well, I have dedicated an older Porter Cable trim router and bit to the jig. Setting the bit up initially requires precision trial and error, but once set it can be used for a long time without the need to change the bit. Here's a photo of my version of Hylton's jig:

[Bruce Wrenn]

I feel for you. Last winter I made two high chairs out of birch- my first and my last! When triming edges for tray, same thing happened. Never again will I use birch, except for ply.

[Scott Taylor]

I'm just trying to think outside of the box here, but...

What is the moisture content of the wood you're using? I have not had this particular experience with a router, but I do remember having this problem when I first got into woodworking when I was trying to plane "moist" wood. I didn't know any better at the time, but now I'd like to think that all the reading has paid off.

My problem, then, was tear out no matter has shallow of plane cut I was making. The only thing I could not rule out was moisture content. And the wood was pretty fresh.

[Al Willits]

Dennis, another newbie here, don't get frustrated, just remember there's a lot to learn and it takes time.
I found the less I take with a router, the better it works, slow and steady.
Also it seems there's several ways to do things in woodworking and it takes time to find which way works best for you.

Keep at it, and realize your gonna make mistakes, the trick is hiding them...:)
Also I don't know where your from, but there may be a Creeker close enough to help maybe?
Might ask....
Good luck.

Al