Jointing boards with a router

I have a router setup similar to that from the Router Workshop with the infeed side of the fence 3 mm less the outfeed. I aligned the cutting edge of the bit with the outfeed side of the fence so each pass should take off 3 mm along the entire length of the board. This should give a sound edge- to-edge join boards. The boards I am using are already dressed and simply need some edge work to enable a sound glue joint to form.
I keep pressure against the infeed side of the fence until the last 25 mm or 1" of the board and then move the pressure to the outfeed side of the fence. The boards are about 400 mm or 17" long. Each of the boards that I have jointed in this fashion end up with a banana shape in the middle, it somehow seems that I am taking off more material in the middle of the boards than at the ends. What am I doing wrong?
Thanks for the help in advance.
--
Garry Collins
Remove the spamno from my eamill address.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Consider applying pressure to the out feed side as soon as there is enough wood in that location to be supported by the fence. Also insure that the cutting edge of the bit is "precisely" on the same plane as the out feed side of the fence. To check this adjustment, carefully feed a straight edged piece of stock from the out feed side towards the bit and adjust the fence until the blade just kisses the wood.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Garry Collins wrote:

As soon as you have enough material in contact with the outfeed fence to do so, move pressure there--keeping pressure on the infeed fence just traces the shape of the board.
Also, if you can, try setting for a lighter cut--3mm is pretty heavy--you're going to waste a lot of wood that way.
--
--John
Reply to jclarke at ae tee tee global dot net
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I agree with the earlier post about keeping pressure on the outfeed side as soon as possible. Also, check that your infeed and outfeed fences are parallel. It not, and you try to keep the leading edge against the outfeed fence then that could cause your concave cut.
Garry Collins wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sounds (reads) backward. Transfer pressure to the outfeed side as soon as there's enough stock there to hold. The no pressure on infeed side - outfeed only.
My joints have improved as I lightened up on the pressure too. I take *many* light cuts - 1/32nd" and use light pressure.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Pressure on the outfeed side is important, especially when you have a few inches over there to generate an alignment, BUT it's also important for your infeed fence to be longer than your board, to keep the same support points as the cut progresses. Also, put the bow convex side out. Then you will have support at the outfeed fence and at the tail end of the board throughout the cut, until the tail hits the bit. Think about it. If the poard is convex side out you realy have alignment only until the high point of the curve gets to the bit. At that point you have alignment only on the outfeed side, which may or may not be long enough to keep you straight.
If the infeed fence is shorter than the board you have to work convex side to the fence and the high point of the curve must be on the fence before the cut starts or you'll pull away from the bit when the high point gets to the fence. Same thing if the board is convex side out and the fence is short. The tail will be behind the fence at startup and the board will be lifted away from the bit as the high tail rides up the end of the fence.
With your short workpieces it should be no prob to get an 18" infeed fence set up.
Wilson

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 09 Aug 2004 13:48:14 GMT, Garry Collins

are your fences straight? if so, retract the bit by a hair.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Summary, pix and text on router table jointing at the http://www.patwarner.com/routertable_jointing.html link. ********************

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Garry Collins wrote:

Garry, You have received many good replies. Using the router table for jointing does work but takes some "technique" and practice. The shape you describe does happen if the input "table" and outfeed "table" are not exactly parallel. Adjust your fences accordingly. I used to use business cards for shim stock to exactly that. And the other thing I would highly recommend, you mentioned taking 3mm cuts. I would certainly try thinner cuts! Try 1 millimeter (or less even) and I think you will see some difference.
Philski
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.