Problems using Router Table as a Jointer

[BobMcCormick]

After watching a video on the subject, I thought I'd try jointing some 3/4" thick white oak boards on my router table. The boards were about 30" long x 6" wide. What I got when I butted two jointed boards together was a gap in the center that was about 1/32" to 1/16" wide. It did this to all four boards I jointed, plus a couple of shorter boards. The gap was just not as pronounced on the shorter boards. I reviewed my set up over and over, making sure the bearing on my bit was flush with the shimmed out outfeed fence. I even took my fence apart and made sure the "L" shaped metal fence mount was straight and true, and the fence boards themselves were same. The bit I'm using is a 1" bearing guided flush trim bit with 1/4" shank. Could the problem be the 1/4" bit is flexing and I need a 1/2" shank bit? I know the ultimate solution to my problem is to buy a real jointer, but that could be a long way down the road. :confused:

[hewood]

How flat are the boards Bob? If they're uneven, the edge won't be a consistent 90° to the face.

[BobMcCormick]

How flat are the boards Bob? If they're uneven, the edge won't be a consistent 90° to the face.

The boards were already finished 3 sides from the lumber yard. I should have let well enough alone, but I wanted to experiment with the router idea. The already jointed edge may have been just fine.

In any case, it wasn't so much an out of square situation with the face. The edge was fine for the first few inches, then got gradually deeper as it neared the middle of the board. It then got shallower as it worked toward the other end, until it was back to cutting correctly at the last few inches.

[hewood]

Is the outfeed side of your router fence shimmed or offset by the same amount that you're taking off with the router bit? If not, that may be the culprit...it needs to be.

Using the router table as a jointer (http://images.google.com/imgres?imgurl=http://images.rockler.com/rockler/images/27328-01-200.jpg&imgrefurl=http://www.rockler.com/blog/index.cfm%3FcommentID%3D64&usg=__wpxxERtWbgAYkWrZWRIZyUbtQsY=&h=200&w=200&sz=37&hl=en&start=54&tbnid=RytUa3iU3_61KM:&tbnh=104&tbnw=104&prev=/images%3Fq%3Dusing%2Ba%2Brouter%2Bas%2Ba%2Bjointer %26start%3D40%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa fe%3Doff%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN)

[BobMcCormick]

Is the outfeed side of your router fence shimmed or offset by the same amount that you're taking off with the router bit? If not, that may be the culprit...it needs to be.

Using the router table as a jointer (http://images.google.com/imgres?imgurl=http://images.rockler.com/rockler/images/27328-01-200.jpg&imgrefurl=http://www.rockler.com/blog/index.cfm%3FcommentID%3D64&usg=__wpxxERtWbgAYkWrZWRIZyUbtQsY=&h=200&w=200&sz=37&hl=en&start=54&tbnid=RytUa3iU3_61KM:&tbnh=104&tbnw=104&prev=/images%3Fq%3Dusing%2Ba%2Brouter%2Bas%2Ba%2Bjointer %26start%3D40%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa fe%3Doff%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN)

Yes, I shimmed out the outfeed fence with .030" plastic shim stock. I then laid a straght edge against the outfeed fence and the bearing on the bit, making sure they were flush to each other. I made my cut, insuring the front edge of the board did not catch on the outfeed fence edge and no snipe occured at the end of the cut. I feed the stock with pressure against the infeed table at first, then shift pressure to the outfeed fence once enough stock has passed the bit to do so, just as you would on a jointer

My thought about this at present is the 1/4" bit shaft may be flexing ever so slightly as I make the cut. The white oak takes more force to feed than soft wood, which I initially used to test the set up. That flex might be undetectable at first, but as more and more of the board is pushed through, it multiplies itself. It's just a theory, but seems feasable. I just can't account for why it goes the opposite way once I feed the last half of the board. I may pick up a 1/2 shaft bit this week and test my theory.

The other thought I had was the router insert plate itself may be flexing and not the bit shaft. I bought the table and insert plate from Rockler. The insert is just 1/4" thick. I notice they have gone to a thicker plate on the newest models they are selling. Just another thought, but I'm looking at every angle.

[hewood]

If the bit were flexing it'd probably present itself as scalloping on the cut edge. The insert flexing is very possible too. Sorry I have no other suggestions for you.

[erngum]

I tried and tried on my Benchdog promax and it never came up right (I used 1/2 inch shank straight bits). I resorted to a table saw jointing jig (http://www.woodworkingtips.com/etips/2005/01/28/wb/) and it works very well. I used it with success until I bought my jointer.

Ern

[BobMcCormick]

I tried and tried on my Benchdog promax and it never came up right (I used 1/2 inch shank straight bits). I resorted to a table saw jointing jig (http://www.woodworkingtips.com/etips/2005/01/28/wb/) and it works very well. I used it with success until I bought my jointer.

Ern

I think I'll try that table saw jig and dump the idea of jointing on the router table, at least for hard woods. Ironically, I resorted to just running the boards through the table saw twice. Once with the badly jointed edge against the fence to cut off the unfinished edge, and then flipped it over and made the second pass. I spend a lot of time insuring my fence and blade are parallel, and I have a good Freud blade installed. The end result looks good enoug to go ahead with the glue up.

[harrison2119]

I have been using the router table method and have bee successful with mahogany, white oak, pine, and others.
I have had problems with snipe if the opening on each side of the bit is not cloose enough to the bit.
If I am not careful when aligning the out feed side with the bit and keep the infeed side straight and not have an angle to the fence.
I use a 1/4 straight bit with no bearing.
I have done 3/4 oak 36 inches long with no problem. I usually have to run it through twice to get it right and be careful when reaching the end of the board that it stays straight and true. If the ends aren't fed in a tight against the fence manner it will leave high spots on the front and end.

[BobMcCormick]

I have been using the router table method and have bee successful with mahogany, white oak, pine, and others.
I have had problems with snipe if the opening on each side of the bit is not cloose enough to the bit.
If I am not careful when aligning the out feed side with the bit and keep the infeed side straight and not have an angle to the fence.
I use a 1/4 straight bit with no bearing.
I have done 3/4 oak 36 inches long with no problem. I usually have to run it through twice to get it right and be careful when reaching the end of the board that it stays straight and true. If the ends aren't fed in a tight against the fence manner it will leave high spots on the front and end.

I think my problem has been solved. I posted the same question on another forum, and got a reply suggesting I check the fences with a long straight edge. I had not done so earlier, but had checked the aluminum extrusion on which the fences mount. When I did this I found a .030" gap on the far right side of the infeed fence. Apparently the MDF fence material isn't consistant. That explains why the bit was climbing into the board rather than cutting straight.:rolleyes:

[Handidad]

An easier method of jointing with a router is to put the board between the fence and the bit. The fence needs to be twice as long as the board. There is no need of an offset. First joint the convex side of the board, so that it will stay firm against the fence.
Also reverse the direction of feed since the bit will help to push the board against the fence.
I use the largest dia bit possible.

[Joe Lyddon]

Very GOOD!

Now you need a Jointer to fix your router fence! :) :)

I good Featherboard just behind the bit to keep the board firmly against the fence would also help. (I think)...

I use a steel straight edge taped to the workpiece for the bearing to ride on... don't use the fence at all! :)

[Handidad]

Joe,
The advantage of your approach is that the straight edge only has to be as long as the board.
The disadvantage is that it would require very precise measurements and placement of the straight edge to keep the 2 edges of the board parallel.

Any reference straight edge that is twice as long as the board could be clamped to a router table and used as a fence.

[LONGHAIR]

Part of this can come from the length of the fence itself. You really can't joint a piece that is much longer than the infeed side of the fence. That is the whole point of "long bed" jointers.

[Handidad]

But with a router there is no need of a fence that is a part of the table. Simply use any straight edge and clamp it to the table. THe straight edge can be as long as you want.

i.e. there is no need to keep the fence parallel to anything, because the router bit is round. A fence for a router is much easier than for a table saw.

[Handidad]

A much clearer eplanation of jointing between a fence and the router bit is in a post by Niki.
http://www.ridgidforum.com/forum/showthread.php?t=15782

[mike gager]

i dont think you are supposed to use a bit that has a bearing. try using just a regular straight bit


when the wood hits the bearing its going to track along it and the wood will come off the fence