Can someone help?

[Jeff Cord]

I just completed a number of raised panels and had an odd result. Using sandpaper I was able to fix the problems but I would like to avoid this in the future.
First of all my router is mounted in the extension table of my table saw. The table and the router plate are adjusted and level. I also checked the router bit and it is vertical.
I also used feather boards to hold the panels tight to the table.
Here is a picture of the end result:
54709
I labeled the edges 1, 2, and 3 to indicate the order in which I routed. I also colored the edge of the panel blue since it makes it a bit easier to see.
The problem is the corners where the edges meet (I have circled them).
It's easiest to see at the corner where 2 and 3 meet. The 2 edge is thinner than the 3 side. Although it's harder to see at the other cornder but the 1 side is thinner than the 2 side.
It appears that the router is planing "downhill" where it's thinner at one end than the other. :mad:
With a flat router table what's happening???
thanks,
Jeff

[Chris McDowell]

Jeff did you use any featherboards to hold the stock tight to the fence. I would guess that would be the most likely cause. I have never been a big fan of vertical panel bits, too many potential problems running a panel through on edge. I use a horizontal cutter in a shaper and a power feeder for that very reason.
Good luck

[Ken Fitzgerald]

Jeff.......a question....maybe a dumb one.....the panel bit you're using.....is it a horizontal bit? I wonder if the panel is just ever so slightly warped?......I used a horizontal bit on the panels for my wifes oak sideboard. I had similar results as you did. I found the panels were just ever so slightly warped and that was what caused my problem.

[Bill Arnold]

Jeff,

I have run into a similar issue using my router mounted in the tablesaw extension. The problem turned out to be the particle board extension top has warped very slightly. To complete a project a while back, I used a straightedge to level the router plate to the edges of the table, which improved the cuts.

Long term, I'm building new benches as part of my shop addition and upgrade. I plan to use a torsion box design for the router table to reduce any warping.

[Dan Gill]

Another thing to check is whether the bit moved in the chuck. I've had this happen.

[Jeff Cord]

To answer the questions and clarify.

It is a horizontal bit so the panel was lying on the table with feather boards holding the panel to the table.

The panels are all MDF and all 7 panels had the exact same problem at every corner.

My table is particle-board but I wedged a leg under the table to provide extra support and to be sure the table was flat.

Finally, I cannot imagine the bit moved since the doors showed the same exact "sloped" cut on all 28 edges (7 doors, 4 edges per door) which would mean that the bit would have to raise up before each cut and then drop during each cut.

Jeff

[Jerry Olexa]

Do your panels before routing have a slight cup or warp in them? Also are you holding them down firmly in contact with the table as you cut? This is esp important in the 3-4" as it approches the spinning router bit...This has happened to me but is corrected when I run them through again paying special attn to the above...

[Dave Diana]

You don’t by chance have a Rousseau router plate do you? I ask this because I had one and had the same problem. The Rousseau plate is made with a slight crown which caused a lot of problems for me. I recently changed to a Jointech Smart Lift and the problem went away. Another cause may be that your router plate has slight sag. Try putting a straight edge on your plate and see if it’s the problem.

[Chris Giles]

Jeff,
This is a very common occurance with this sort of machining. Generally, youre stance places you behind and to the left of the workpiece, and as such your arms have to reach quite far from your body at the beginning of the cut. This means the downward pressure you are able to exert is considerably less at the start of the cut than at the end of it, when you are positioned almost directly over the cutterhead. Even on small panels, you can see this happen. Try taking a hogging cut first, then doing a finish pass with top fence piece screwed to your fence which prevents the panel from rising up even slightly at the beginning of the pass. And make sure you aren't pressing down to hard at the end of the cut because this will make the cut too deep and create the same problem. Good luck.

[John Lucas]

Jeff,
I think it is due to the difficulty of cuttng some grain direction. It is not unusual for the router bit to climb up a wee bit to make the cut easier. Simple to rememdy...make multiple passes. You should be able to hear when the cutter is no longer cutting. If your cuter isnt very sharp and/or if your stock is real difficult, this can happen. The way I prevent it is to plan to make the final pass removing no more than 1/16th...but I also will make a couple of passes at the final setting if the corners are perfect.

[Alan Greene]

Jeff,
I will qualify this statement by saying that I do not have any experience with these bits. But, I have been doing a lot of research as I start back into my woodworking and one thing I have come across several times is to make sure that you are not building up to much sawdust under your cut as it will raise up your panel some and change the depth of the cut. Is this a possibility? Happy Woodworking

[glenn bradley]

"The table and the router plate are adjusted and level. I also checked the router bit and it is vertical."

OK, so I'm assuming that the table has no sag from this statement. I'm not being a smarty-pants but, check it again. The reason I say this is I had a table that I 'thought' was level but overall there was a sag. I was so focused on the plate edge measurements that I missed the overall table-edge to table-edge measurement which showed sag. The result on my table was just what you show in your pic.

Now if the bit is a vertical bit, I would expect a different problem. Board warpage as mentioned could also be the culprit and you don't want to be trying to muscle the warp out of a board on-the-fly while you are routing . . . dangerous.

As you are not using a curved profile; if all else fails I would try the panels on the table saw. With a flat table, adjusted plate and solidly mounted router and bit, this problem should not be present (like telling you that is going to help). Please let us know what you find out.

[Mike Goetzke]

Where on the fence are the feather boards attached (i.e. front/back/center of bit)?

[JayStPeter]

I've had that problem. I had the previously mentioned Rousseau plate which was crowned. It was almost impossible to prevent until I made my new router table very flat (with a new insert of course).

[glenn bradley]

From your second post I can only imagine a sag in the table which would set the panel angled down into the bit, flattening as the 'starting' and 'ending' edges of the panel straddle the sag and then the 'ending' edge dipping as it enters the "sag zone".

I'll be interested to hear the fix. Don't give up. Sometimes advice is given on what we think we understand. Once the fix is found or "the light comes on" for myself or others, the problem and the fix are more obvious.

[Greg Funk]

Jeff,

You should measure the flatness of the table with the panel (or a piece of wood) under the featherboard. It would be useful if you had a picture of your setup but it is quite possible that the featherboard is distorting your table enough to cause the uneven routing you have shown.

Greg

[Jeff Cord]

I'll post a picture next time I have my saw out (hopefully this weekend) to show the setup along with the feature boards.
Maybe that will help.

[Jeff Cord]

Here's a picture of my setup.
55726
You can see I have a feather-board on both sides of the bit and the table top is perfectly level.
And please, I realize I don't have a bit in the router, I just set this up to take pictures. :cool:
Here's a picture with a piece of wood (OK, actually MDF) as it would move across.
55727
Thanks again.
Jeff

[Alan Greene]

It is hard to tell from the pictures, but the question that entered my mind on looking at your setup is:
What is holding the fence down to the table vertically?

Maybe some clamps on either end would stop it from raising up slightly. I am assuming that you are clamping your jig to a fence that is behind it. If so, that could be putting some upward pressure on your jig.

Just my .02 Hope this helps:)

[Jeff Cord]

Alan, good question.
I have the fence clamped to my RIP fence but not clamped down to the table.
I'll have to check out if the fence is raising up during the cut.
Jeff