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Router Table question what am I doing wrong

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Forum topic by Eric_S posted 06-07-2010 02:06 PM 2184 views 0 times favorited 36 replies Add to Favorites Watch
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Eric_S

1521 posts in 1883 days


06-07-2010 02:06 PM

Using a router table is still pretty new to me so maybe you can shed some light on what I’m doing wrong. While still new to one, I have done many cuts on the router table and never had issues. I’m not sure if I had issues this time because of grain direction or what but here is the situation.

I messed up some grooves on the nightstand aprons(they were offcenter from the tenons which they shouldn’t be). I glued a piece back in to the groove so that I could reroute them correctly in line this time with the tenons. I wasn’t paying attention to the grain direction of the reglued piece in relation to the apron though other than it being an edge face. I let the glue dry for a day before rerouting.

As I was recutting the grooves on the edge faces, taking two passes, first 1/4” depth off, then second pass to final depth of 3/8”, a few of the boards seems to want to shoot out the other side.

Most were ok, but a few as I slid it from the right over the router bit, would jerk to the left, some very forcibly. I am using a 1/2” collet 3/8” straight bit by the way. The very first time it happened I was not expecting it and it jumped out of my fingers causing a good sized chunk to chip off the edge. Luckilly I can have it facing inward so the drawers will cover up those mistakes. One piece actually escaped my fingers and shot into the wall. Luckilly the wood wasn’t damaged and neither was the wall or myself. But I dont know why it was doing this. There wasn’t any crazy grain directions going on, but it was the edge face. Can anyone shed light on my mistake? Is it because the reglued piece grain might be opposite of the aprons? Or is it something completely seperate?

Thanks for the help.

-- - Eric Indianapolis, IN


36 replies so far

View rance's profile

rance

4142 posts in 1849 days


#1 posted 06-07-2010 02:27 PM

I’m not sure about you saying you used the table with a ‘collet’. Collets are normally used when routing by hand with templates. Could you elaborate?

Boards shooting across the room indicates you may have moved the fence between the 1/4” cut and the 3/8” cut. This could also be inadvertantly done when you raised the bit on the 2nd pass if your router is real sloppy in the base. Your problem is that your wood is being trapped between the bit and the fence. You need to fix that.

I can’t see the grain direction making that much of a difference.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View CharlieM1958's profile

CharlieM1958

15706 posts in 2906 days


#2 posted 06-07-2010 02:38 PM

Also, what you’re describing could happen if you allowed the workpiece to move even slightly away from the fence as you slide it through. What’s occurring is the trailing edge of the bit (farthest away from you) is grabbing the piece. Are you using featherboards to keep the piece tight against the fence? That is one possible solution.

-- Charlie M. "Woodworking - patience = firewood"

View Chiefk's profile

Chiefk

163 posts in 2459 days


#3 posted 06-07-2010 02:39 PM

If the board wants to shoot out the other side, perhaps you are cutting in the same direction the bit is moving. For example, If you are making your cut with the stock between the fence and the bit, you need to feed the stock into the bit from left to right. pkennedy

-- P Kennedy Crossville, TN

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Howie

2656 posts in 1611 days


#4 posted 06-07-2010 02:42 PM

Also check your router speed.

-- Life is good.

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Eric_S

1521 posts in 1883 days


#5 posted 06-07-2010 02:49 PM

Rance I think you are thinking of guide bushings not the collet. By collet I am referring to the router’s collet that the bit sits in. They come in 1/4 and 1/2” diameter.

The fence hasn’t moved at all, and the boards grabbing is occuring more on the first pass than after I adjust the depth. The router is not sloppy in the base either, its very sturdy. When you say wood is being trapped between the bit and the fence can you elaborate? The apron is whats between the bit and the fence as this is a groove being cut in the middle of the bottom edge face.

here is picture to help explain what I’m cutting.

-- - Eric Indianapolis, IN

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Eric_S

1521 posts in 1883 days


#6 posted 06-07-2010 02:51 PM

What should the router speed be set at? I thought the high speed is what it should be for the smaller bits. Its not a wide bit, just a 3/8” straight bit. What rpm should I use for 3/8 straight bit?

-- - Eric Indianapolis, IN

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Eric_S

1521 posts in 1883 days


#7 posted 06-07-2010 02:53 PM

Chiefk, based on that picture I’m guessing you may be correct. I am moving from right to left, but since i have wood between fence and bit I should go from left to right? I thought hand held I should always do left to right and router table always right to left? No?

Charlie, no I did not use a featherboard although I meant to. It was sitting right next to me the entire time lol.

-- - Eric Indianapolis, IN

View handi's profile

handi

118 posts in 3128 days


#8 posted 06-07-2010 03:00 PM

The direction of the bit is likely your issue. If I am reading the drawing correctly, you are trapping the part between the fence and the bit, and on the fence side, the bit is turning with the feed direction, not away from it, so it wants to grab.

When cutting a profile where the bit is buried in the fence, the cutting action wants to push the part left to right, and you are working against that by feeding right to left. The tension between the two gives you control. In your drawing, the back side of the bit wants to move the part right to left, and you are puching that way, so the parts will tend to accellerate rather than offering the expected resistance.

I would set a stop block on the fence to keep you from going too far, and take no more than 1/8” deep cuts at a time. More lighter cuts means better control.

Hope this helps,

Ralph

-- www.consultingwoodworker.com

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Eric_S

1521 posts in 1883 days


#9 posted 06-07-2010 03:03 PM

Thanks ralph, I actually want the groove to go all the way across the rail as a panel will be seated in it so not sure about stop block. But lighter passes would help probably. You are correct about the drawing though, the part is trapped between fence and bit.

Do I want to go left to right when doing a cut where wood is trapped between bit and fence or just shallower passes?

-- - Eric Indianapolis, IN

View Mary Anne's profile

Mary Anne

1057 posts in 1897 days


#10 posted 06-07-2010 03:18 PM

I’m no expert by any means, but you should be be pushing from the right side of your router table toward the left. Like Charlie says, this can happen if you pull even slightly away from the fence. Try using a featherboard or flat push block to ensure your piece is held flat against the fence.

View CharlieM1958's profile

CharlieM1958

15706 posts in 2906 days


#11 posted 06-07-2010 03:36 PM

Eric, whenever you cut a groove, this always tends to be an issue. Feeding from the opposite direction won’t help because then the front of the bit will tend to pull the workpiece to the right. The key is shallow passes and keeping tight against the fence.

-- Charlie M. "Woodworking - patience = firewood"

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Eric_S

1521 posts in 1883 days


#12 posted 06-07-2010 03:40 PM

Thanks Charlie and Mary, I thought I was correct in direction of feed.

I’ll have to rememberr to use my featherboard that is sitting right next to my router table lol next time and take lighter passes then. I appreciate the help guys thanks.

-- - Eric Indianapolis, IN

View rance's profile

rance

4142 posts in 1849 days


#13 posted 06-07-2010 03:41 PM

Eric, doooooh on me, yes you are correct. I was thinking of bushings.

If cutting a dado or groove in the center of board somewhere, then pushing right to left is correct. The bit pushes and pulls with leading and trailing contact, but more importantly it also tries to push your work toward the fence when the cutting edge is perpendicular to the push direction.

When cutting a profile on the EDGE of a board, then you’ll bury the bit behind the fence and STILL push right to left. If you had the fence way back in this configuration trying to profile the edge facing you against the fence, then you would push from left to right, however, THIS IS A BAD IDEA. :)

And as has been mentioned, a feather board may fix all your problems. An lighter passes would help too. Is your bit sharp & clean?

I’ll look at your pic later but it is blocked where I am now.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View gizmodyne's profile

gizmodyne

1763 posts in 2778 days


#14 posted 06-07-2010 03:43 PM

Take shallow passes.

Why don’t you consider doing this cut on the table saw? Or use a slot cutting bit. You would have more control.

-- -John "Do I have to keep typing a smiley? Just assume it's a joke." www.flickr.com/photos/gizmodyne

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Eric_S

1521 posts in 1883 days


#15 posted 06-07-2010 03:43 PM

Rance, thanks. I’m so glad that my new place of work doesn’t block photos from photobucket and a few other places like my old place of work did :)

-- - Eric Indianapolis, IN

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