Router Tearout

[twistsol]

I need to mill about 14 feet of crown moulding for my office and I'm having a problem with the birch splintering as I run it through the router table. I've ruined 6 pieces of birch already. I'm taking painfully shallow cuts as in < 1mm per pass, but every time the result is the same. Always in one of the later passes you can hear and feel when the bit grabs and tears a chunk out of the stock. I can't identify what is causing it and can't afford to keep shredding more birch.

I'm thinking of trying to do this as a climb cut but my brain has come up with stupid dangerous ideas before so I don't always trust it. Any rational ideas on how to prevent the tearout would be welcome. At this point I may entertain crazy ideas as well.


Examples of the tearout from a couple of the pieces.





This is the bit I'm using and I'm running the stock through the table on one edge and then flipping it 180 degrees and running it through the other edge. The bit was brand new before I started the process.

[leehljp]

Wet the board before cutting. Get a well dampened wash cloth, not dripping but close. Run it down the board so that it is good and wet on the cutting side. Let it set for 30 seconds to soak in. See if that helps.

If I could make another suggestion: It might work better if the board was sanded a little smoother. I can see the waves from the planer and that "may" be causing some of the "grabbing" and splintering.

[dbhost]

Good useful ideas? I have none. Crazy ideas?

Sorry, brain manfunctioning tonight.

[capncarl]

Have you played with router speeds?

[Black walnut]

I would try climb cuts in very small passes with lots of feather board and push stick controls. That said it could be a function of reading the grain. Can you choose boards with more of a quarter sawn grain and not flat sawn? I f you are shaving with the grain without climb cutting rather than feeding into the grain it might help.

Are you using a zero clearance on the infeed side of your router fence so the board is fully supported before the cut?

Maybe take a diamond hone to the cutter to sharpen it just a bit.

Maybe the birch is the problem? can you match close enough another species, like say ash or hickory that might machine cleaner?

[LCHIEN]

Get a faster router.

(big Grin) sorry couldn't help gloating.
Costing less than my old 12 MBit service.

[twistsol]

I'll try some of the suggestions and see if I can get this to work

As far as the faster router, I've already tried that. In the country, we were never able to get above 2 Mbps and were usually in the 1.1-1.5 range. It's a little different now that we live in civilization and cheaper as well.

[leehljp]

router or router?
Back in the late 1970s while working on a freight dock at night during graduate school, I grabbed a pallet (stacked with something) that was about to tip over, a Forklift driver decided to help from the opposite side at the same time and I had 1/2" of my right thumb ripped off. With surgery and my propensity for using my hands, I recovered, but my right thumb is 1/2" shorter.

Fast forward to the spring of 2010 (I think). Trying to finish a set of book cases for my middle daughter in time to ship it completed - back to the USA from Japan, I got my right thumb too close to a turning router blade that was in a router table. I went to the doctor in Toyota City Hospital. He looked at it and noticed how short it was, and asked about it. I said, "Oh, that is the 2nd time I cut it off!" My wife laughed when she saw the expression on his face when I said "2d time I cut it off."

The doctor worked on it, put some kind of "skin grow" bandage on it, and then asked me how I did that. He had to record the cause of the accident.

Me: "I got it caught on a router". (Japanese pronunciation of router is "rootah") He looked puzzled and then opened a book, studied it for a minute and then asked: "How did this 'rootah' cut your thumb like that?" He showed me a picture of an internet router! He had no idea of what a wood working router was! Life is interesting cross culturally!

[LCHIEN]

I venture to guess than many doctors in the US will also not know what a woodworking router is. You should tell them you did it using a woodworking power tool.

[twistsol]

I finally got back to this and the problem was partly not perfectly straight birch and mostly technique. As I was feeding the the stock through, it wasn't always staying tight to the fence and when I repositioned my hands, I would push harder and take ever so slightly larger a cut and that is when it would splinter. Using some scrap poplar instead of birch, I could cut it two passes with no tearout and much deeper cuts. Lots of featherboards.

When I went to Menards to get a couple of pieces of poplar, premade crown was cheaper than the individual boards. I bailed on cutting my own crown and bought it.