Edge Tearout Using a Router

[Jim Foster]

Hi,

I'm wrking some Q-Sawn White Oak, on a router table (PC's big router) and I'm getting some edge tearout. The bit I'm using is a whiteside bit that reduces the edge thickness of a panel so that the panel will fit into a groove. My fist cut removed about .05-.06 in thickness and about 1/2" in width, at about 25,000 RPM. The panels are running across the table flat. I'm using a finge holddown and when the grain is right, it's not a problem, but on the pieces where the grain is running is a bad direction I can't seem to avoid this. Fortunately the edge will be covered by he groove, but I'd like to do better.

Any ideas?

Also, would a shaper with a significantly larger cutter diameter solve this issue?

Thanks for any advice

[Heather Thompson]

Jim,

If I understand you correctly, the cuts that go with the long grain turn out fine, it is the end grain that is giving you grief. I would suggest to do the end grain cuts first, then go back and make the two passes with the long grain, this should clean up any blow out that you are getting. When I was learning to hand plane panels and about to pull the last hair from my head, this is what my instuctors told me to do. Hope this helps and I am understanding the issue correctly.

Heather

[Jim Foster]

Sorry for the incomplete description. The endgrain is coming out very good, and there is no "blowout" at the end of a cut along the end grain. It's the cuts along the grain that the edges are having a problerm. So on a panel that is 42" long and 10" wide, the 10" wide sides (end grain) are coming out fine and usually one long side is OK, but the other is getting some edge tearout along the cut.



Jim,

If I understand you correctly, the cuts that go with the long grain turn out fine, it is the end grain that is giving you grief. I would suggest to do the end grain cuts first, then go back and make the two passes with the long grain, this should clean up any blow out that you are getting. When I was learning to hand plane panels and about to pull the last hair from my head, this is what my instuctors told me to do. Hope this helps and I am understanding the issue correctly.

Heather

[Jim Rimmer]

Sounds like you are using a large panel cutting bit so it probably needs to be slowed down to about 10-11K RPMs. Don't know it this will solve the tear out but it should run slower than 25K.

[Heather Thompson]

Jim,

I am no router pro, but Pat Warner is and he is a member of SMC, you might want to PM him and see if he can provide some insight. Pat does follow the router threads here on the Creek and my jump in at any time, this is the link to his web site and you may find some good info there, best of luck. http://patwarner.com/ Another thought would be to contact WhiteSide to verify proper RPM as Jim mentioned.

Heather

[Jim Foster]

I initially had it pretty slow. The bit is not that big and it's doing a very nice/clean job on everything except the edge, which is closest to the center of the bit.

Tomorrow I'll try a run at a much slower speed and see what happens.

Thanks


Sounds like you are using a large panel cutting bit so it probably needs to be slowed down to about 10-11K RPMs. Don't know it this will solve the tear out but it should run slower than 25K.

[Jim Foster]

Thanks Heather.


Jim,

I am no router pro, but Pat Warner is and he is a member of SMC, you might want to PM him and see if he can provide some insight. Pat does follow the router threads here on the Creek and my jump in at any time, this is the link to his web site and you may find some good info there, best of luck. http://patwarner.com/ Another thought would be to contact WhiteSide to verify proper RPM as Jim mentioned.

Heather

[Andy Bardowell]

Just a guess based on your description Jim but it may be the way the grain is oriented to the bit and being open as Oak is doesn’t help either. We pay attention to this when milling four-square but you may be running into this on the router table.

Is your cutter going with or against the grain, if it’s against then you’ll have tear out; can you mill one side then flip the fence around and mill the other?

I got these drawings for illustration from //commons.wikimedia.org/

[Jim Foster]

Andy,

I think your right. It's pretty easy to see where the grain is going to catch before a panel is routed, but I am hoping with a good bit, and the right speed & feed it would be mitigated. This is the first time I've used Q-Sawn White Oak for a project that required this much milling and it seems to be more prone to tearout like this than other things I've done.

As far as changing the direction of cut, the only thing I could do is climb cut and I am a little hesitant to do that.

Thanks for the help.


Just a guess based on your description Jim but it may be the way the grain is oriented to the bit and being open as Oak is doesn’t help either. We pay attention to this when milling four-square but you may be running into this on the router table.

Is your cutter going with or against the grain, if it’s against then you’ll have tear out; can you mill one side then flip the fence around and mill the other?

I got these drawings for illustration from //commons.wikimedia.org/

[glenn bradley]

I'm going with grain direction also. I flip the material over so I am always routing "downhill". This is true in edging and pattern routing. In pattern routing I use a bit with an upper and lower bearing so I can flip the material and the pattern (which is attached with double stick tape) and just adjust the bit height so the "other" bearing rides the template.

[Chip Lindley]

Hi,

I'm wrking some Q-Sawn White Oak....I'm getting some edge tearout. The bit I'm using is a whiteside bit that reduces the edge thickness of a panel so that the panel will fit into a groove. My fist cut removed about .05-.06 in thickness and about 1/2" in width....

Your vague discription leads me to believe you are cutting rabbets or tongues on the edges of the white oak. Could it be a raised-panel bit? TMI is better than NEI in a photoless thread.

White oak is a very hard wood. Your stock may have been overheated during the drying process, making it even worse. Old white oak timber from salvaged buildings is obscenely hard!

Even speaking normally, Q-sawn is parallel to the ray flecks, and when very dry/brittle, can chip these out. Mostening the oak may prevent such tearout. Instead of water, denatured alcohol or mineral spirits could be used to wet the grain. take shallow passes and *sneak* up on the final profile, taking off a very small amount of stock. Good Luck!

[Myk Rian]

Try a climb cut. Feed it from the other direction, but hold on tight.

[Lee Schierer]

Try a climb cut. Feed it from the other direction, but hold on tight.

I agree with Myk, climb cutting will cure the tear out in the reversed grain areas. Just be sure to take light cuts .020-.03 max and keep a good grip on your wood as it may tend to self feed.

[Chip Lindley]

I hesitate to recommend climb cutting *out-loud* in a public forum. Although it IS done, freehand climb-cutting is inherently dangerous, in the wrong hands. Even with experience, the unspeakable can happen.

IF anyone were to attempt climb-cutting at the router table, sufficient hold-downs or featherboards are absolutely necessary, not an option! As a *rule of thumb* *assuming you still have a thumb, the LARGER the bit, the THICKER the stock, the more dangerous!

[Jim Foster]

I am not going to "Climb Cut" on this project. It's a lot of tongue and groove cuts (a lot) and a lot of relief cuts on the back of flat panels. I've used this technique before (many years ago and do understand the benefits and the risks)

I am thinking the tablesaw might be a much better and way to go for the next phases of this project.

I bought these two bits (Tongue & Groove and Panel "Back Cutter") thinking I would have better control and accuracy. With the router table lift I have, I can easily adjust the height within several thousandths, and I have a pretty good guard on it. But I can also do this on the tablesaw with a dado blade safely as well. Setup may take longer, but I won't have to use multiple passes for each cut



I hesitate to recommend climb cutting *out-loud* in a public forum. Although it IS done, freehand climb-cutting is inherently dangerous, in the wrong hands. Even with experience, the unspeakable can happen.

IF anyone were to attempt climb-cutting at the router table, sufficient hold-downs or featherboards are absolutely necessary, not an option! As a *rule of thumb* *assuming you still have a thumb, the LARGER the bit, the THICKER the stock, the more dangerous!

[Peter Quinn]

So your getting tear out on the router table with the back cutter in QSWO? Not much you can do really. Take light passes, no more than a 1/16" of depth per pass. Make your last pass even lighter. I wouldn't climb cut that one personally. Feather boards will hold the stock to the table, but they are designed to prevent KICKBACK, which is not the problem with climb cutting, its KICK FORWARD! There isn't much you can do that I can think of relative to grain orientation. You pick your best face for the show face, and now you are committed and can't change grain orientation. And chances are you will have some switch backs in WO that you can't avoid anyway. Given it is hidden in the groove, to the back, I would chamfer those rough spots to make assembly easier and move on. Do the best you can, and if it don't show, it ain't broke so don't fix it.

"Would a shaper do better?" I can say maybe, even likely, but no guarantee there either. I have definitely had tear out on the edges of panel tongues with both big panel raisers and back cutters on the shaper. It happens.

You might try setting the cutter to take its full depth of pass and shimming the fence out with a series of 1/8" hardboard shims, starting with three shims or so and removing one with each pass to go deeper into the edge of the stock. Sometimes this can help. Think of it as taking light passes, but advancing from a different direction.