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Dips in a rabbet using a router table (for a picture frame)

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Forum topic by LotsToLearn posted 63 days ago 442 views 0 times favorited 12 replies Add to Favorites Watch
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LotsToLearn

3 posts in 63 days


63 days ago

Topic tags/keywords: rabbet router dips problems pine router table technique beginner picture frame bit straight bit

I’m fairly new to using the router and hoping that someone can explain the error of my ways. In photo below, you’ll see the problems I had routing a rabbet in the side of my pine picture frame. (I cut the miters after routing because it seemed easier to push the piece through on the router table with square ends).

For the artwork being framed, I needed a 3/4” wide, 1/2” deep rabbet. I didn’t have a rabbet bit, but I had a 3/4” straight bit. So, what I tried to do was to put the frame side on its edge and make multiple passes on the router table, deepening the rabbet by moving the fence out with each pass until it had the 1/2” depth.

I had twelve pieces that I worked this way. What you’ll see in the photo is one piece where the result is not clean. I had eight or so fairly clean pieces. I think the bad work is what the author of:

Rabbet Joints with a Router

calls “wobbles and dips”.

Any thoughts on what might be causing the dips in the piece? I used one push stick on the end and one on the side of each piece as I moved it through the router bit.

I appreciate the help.


12 replies so far

View NiteWalker's profile

NiteWalker

2709 posts in 1211 days


#1 posted 62 days ago

Looks like the router bit is chattering, usually indicative of too big a bite. The fence could also be slipping.

-- He who dies with the most tools... dies with the emptiest wallet.

View Mas's profile

Mas

10 posts in 897 days


#2 posted 62 days ago

Since you were using a push stick to keep it up against the fence, it looks to me that you may have been pushing harder at times causing the board or fence to flex.
if you can use a feather board to keep consistent pressure and that may help get rid of most of the dips

View bondogaposis's profile

bondogaposis

2495 posts in 985 days


#3 posted 62 days ago

I agree w/ the above posts, another thing to consider is that a 1/2” shank bit is going to give you better stability than than 1/4” shank bit pictured.

-- Bondo Gaposis

View LotsToLearn's profile

LotsToLearn

3 posts in 63 days


#4 posted 62 days ago

I wouldn’t doubt that I applied uneven pressure with the push stick that pressed the piece against the fence. I’ll look into the feather board, especially as I plan to be doing a lot more of this in the future.

I’m using a homemade router table (cabinet) so I’ll look at good ways to attach the feather board.

I appreciate the comments.

View Iwud4u's profile

Iwud4u

326 posts in 163 days


#5 posted 62 days ago

It’s easier, in my opinion, to cut them out with the table saw.
I think your board was moving in and out every time you stopped the cut while you were pushing it through.
Notice that most of the bumps are towards the end after the material was removed making your pc more unstable against the fence as you pushed through. (letting your pc rock)
You need a feather board as tall as the frame to keep the pc parallel as your pushing through.
EXAMPLE:

-- It's far better to be criticized by a wise person than applauded by a fool --

View cabmaker's profile

cabmaker

1309 posts in 1443 days


#6 posted 62 days ago

Appears that your setup may not be evacuating chips quick enough to keep the way slick and smooth

As stated, table saw would be a more efficient method

JB

View Pezking7p's profile

Pezking7p

1118 posts in 285 days


#7 posted 62 days ago

I disagree with what most above posted. In order for your router bit to cut deeper, it must move further into the wood. Therefore it is not failure to evacuate chips, or uneven pressure.

It is unlikely that your fence or router bit are flexing the 32nd – 1/16th shown in your pic. I think something in your router table is loose, and when the bit get a little harder bite it pulls your router up out of its mount and into the wood. My router, for instance, just sits in an insert in my tables saw extension and there is nothing to stop it from pulling up out of the table. If this were happening on my router, I would start by bolting my insert to the table saw extension instead of just letting it sit inside the inset.

Check your router/lift/insert/fixed base for any movement or wobbles, secure everything. I bet that solves it.

-- -Dan

View Pezking7p's profile

Pezking7p

1118 posts in 285 days


#8 posted 62 days ago

Ok I changed my mind after looking closer at your pic. It looked like at those points the bottom of your piece was pressed into the router bit. Solve by applying pressure to only the part that is not being cut.

-- -Dan

View Iwud4u's profile

Iwud4u

326 posts in 163 days


#9 posted 62 days ago



Ok I changed my mind after looking closer at your pic. It looked like at those points the bottom of your piece was pressed into the router bit. Solve by applying pressure to only the part that is not being cut.

- Pezking7p

Exactly, the spacer block behind the bit will help keep that from happening

-- It's far better to be criticized by a wise person than applauded by a fool --

View NiteWalker's profile

NiteWalker

2709 posts in 1211 days


#10 posted 62 days ago

I just noticed you did the cuts on edge; doing them face down would result in a more even cut.

-- He who dies with the most tools... dies with the emptiest wallet.

View Rutager's profile

Rutager

27 posts in 938 days


#11 posted 62 days ago

Routing the rabbet with the board on the edge is giving you so little support, that it will be almost impossible to keep it stable, I would instead rout it flat and move the fence over a couple times to get the width. The other benefit will be that the bit doesn’t have to stick up as high, giving less flex and making it safer. Use a push block to give downward pressure and to keep your hands away from the bit.

View LotsToLearn's profile

LotsToLearn

3 posts in 63 days


#12 posted 62 days ago

great advice – thanks again!

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