Cutting slot using router table

Page 1 of 3  
I know this is going to sound stupid, but my knowledge of a router is mostly limited to putting a fancy edge on plaques.
I want to take a 30" length of 4" wide board and put a slot all the way through the board about 4" long. the centerline of the slot will be 3/4 of and inch from the edge of the board. Where do I put the fence? Do I hold the board above the router and slowly lower it in position, or do I drill my 5/16 hole first into the board and fit the router bit into the hole, bringing my fence up to the board? Will I get a true straight clean slot this way, with no wobble? Thanks for any and all answers! Paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
sam wrote:

I have a pic of my set up at
http://www.handleys.us/router.jpg
Thanks, Paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I'd probably use the second method, of making a hole then setting the fence. However, if you need the groove to be exactly the same size the entire width, you'll have to either make multiple passes with a smaller bit or perform a plunge cut. Be extremely careful with plunge cuts, as you cannot see the bit until it emerges from the board. (They're best done on a hand-held router, but you've gotta use the tools you've got.)
Puckdropper
--
On Usenet, no one can hear you laugh. That's a good thing, though, as
some writers are incorrigible.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I understand you said router table, but my first choice for routing this operation, work size permitting, would be an edge guided plunge router.
But, going with the router table, I think either way would work, but unless you predrill, be sure the router bit is one suitable for plunging - has a cutting edge that extends completely across the end of the bit.
If the size of the work permits, I'd recommend stop blocks positioned to limit the movement of the work so that the ends of the slot are determined by the stop blocks.
If there is no router lift installed on your table, I think I'd go with the predrilled hole, position the work, then position the fence, the turn on the router. If you do have a router lift, position the fence 3/4" from the edge of the work, position the work against the fence, and raise the bit through the work.
My last choice would be to lower the work onto a spinning bit and then only if stop blocks can be used to locate and restrain the work. I've done it, but have never been comfortable with that technique.
Tom Veatch Wichita, KS USA
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
If you use the correct bit you can plunge down to get started.
Set the fence with a pencil mark of where you wnat to start and a stop block for the finish if you need real precise.
You will get a little bit of shake because the bit is cutting in two directions. It would be nice to have some hold downs but a little difficult when you are plunging, but make some sort of feather board, springs of even just a second fence to help keep it from jumping.
a 5/16 slot should be able to cut in one pass in most woods pretty easy but play with feed speed. Also, clogging can be an issue where the chips don't evacuate but a full through slot should make this not to problematic and strong down suction dust removal will be a big help.
Another option is to place the piece on top of a sacrificial piece of ply and construct a jig over the top with a few boards and do it free hand. In this case I would take multiple succesivly deeper passes and you can control super precise start and stop locations.
Or even just use a base guide on the router and do it free hand.
Lots o options
You will get a little shake because the bit is cutting in two directions when it is in

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

Thanks for all the answers! I'm a little leary of lowering the board onto the table with a spinning router. I have ten fingers and I want to keep them! I think I will just drill the hole and experiment with scrap wood. My problem is I want it to look like it came from a professional shop. Thanks, Paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Are you trying to make a stopped slot - where the slot does not come all the way to the edges of the board? I'm not clear from your description - it almost sounds like you're just trying to figure out how to set the fence and take into consideration the width of the cutter. If that's the case, there is no need to do a plunge cut, just add 1/2 the bit diameter to your 3/4 inch center line and you should have it.
Like I said though, I might not be clear on what you are trying to accomplish...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I would be fearful of starting up a router bit in an existing hole. If it touches any where when you start the router it is going to grab and slap the board. Better to have the bit spinning before it comes in contact with the board.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 19 Mar 2009 11:48:07 +0000, Leon wrote

Agreed.
assuming a router bit of the correct width... I'd lower the wood onto the spinning bit, some way into the length of the slot - pressing firmly into the fence - and climb cut (move the piece to the right) to the origin of the slot, then "properly" - right to left- for the rest, against a stop block.
Frankly it would be easier with a hand-held router and a side fence.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You don't want to do a climb cut moving the work from left to right. The bit will pull the work away from the fence. If you let one end of the work set on the table top against a stop and lower the other end onto the spinning bit you have good control.
I have performed this procedure probably 1500 times. I used to make mouth blocks for Steve Knight. Each mouth block was made out of Ipe and had 2, 1.5" long parallel slots in blanks that were about 2" wide and 3.5" long and .375" thick I plunged the small piece of wood down on to the bit on the router table and against the fence. I did make a jig for hand held use but that took too much time and did not yield as accurate of results for me. Using a hand held resulted in having probably 30% more rejects than using the router table method.
Each situation changes the method of attack.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You are absolutely right of course. I was merely advocating a climb cut _just_ to get the bit completely vertical at the extreme end of the slot but ONLY if the bit is the final slot width so it's cutting on both sides of the slot at the same time, definitely not for widening the not_against_the_fence side of a slot.
I do, however, bow to your deeper knowledge of slots and I agree that climb cutting is generally a Very Bad Thing.
On Sun, 22 Mar 2009 14:15:02 +0000, Leon wrote

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

Your thinking makes a good case however if the bit is the final width of the slot the bit is really only cutting in "1" place in the slot. It is not cutting on eigher the fence or far side of the slot, it is cutting on the leading side of the bit back to tangent with either the sides of the slot, It is the direction of rotation on that leading side of the bit that will determine which way the work will be pulled by the bit. If pushing the stock from right to left the leading edge of the bit is on the right end of the slot, turning away from you towards the fence. If you are feeding left to right the leading side of the bit is on the left end of the slot, turning towards you and away from the fence.

Don't bow to me, I am the one that mentioned in an earlier post that I probably cut 1500 of these type slots in Ipe. Just last week when making a DP fence with a similar slot I forgot that you absolutely need to as close to the extreme left end of the slot as possible. I plunged the slot starting it near where I wanted it to begin and went left to right 1/2" to establish that end of the slot. The bit immediately pulled the work away from the router table fence a bit and I ended up with a slight bit of wobble in the slot. When I was cutting the many slots in Ipe I was always using stops for both ends of the work. "Beginning against the right end stop" and pushing towards the left end stop insured that I did not go in both directions to make the slot.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bored Borg wrote:

That's a pretty broad brush you're using there (especially with the capitalization)!
Climb cutting isn't a bad thing - not having adequate control of a power tool is the Very Bad Thing.
All of the routed stuff in the photos at
http://www.iedu.com/DeSoto/Projects/Bevel /
was climb-cut, with both the workpieces /and/ the router adequately controlled - without any hint of a problem.
--
Morris Dovey
DeSoto Solar
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Just picked up this thread again. I thought it was dead but it bit my ankles when I was weeding stuff out.
On Thu, 26 Mar 2009 14:47:24 +0100, Morris Dovey wrote

Hi Morris. My broad brush was rather sweeping... er.., I was particularly being general. :-)
I climb cut on most pieces, somewhere. Often to stop end grain blowing out and if I'm going round a curve, freehand, with a bearing I find that a final backwards nibble smooths out any forward-cut roughness.
I'd be wary of whacking straight into a deep cut going back'ard though, just as I'd be wary of starting a deep cut straight into the corner of a board and going for'ard. As you say, it's all about control. If you think about how the cutter is addressing the stock geometry everything should be reasonably obvious and all you have to do then is factor in how the wood grain lies and you're sorted.
I was replying to being told off because I advocated climb cutting a slot, remember? ... and in the face of chastisement agreed that willy-nilly use of the technique as THE general method is a Bad Thing . My whimsy probably obscured communicative precision, damn you and your eagle-eyed powers of observation !!!! :-)
Now I'm getting it in the neck from both sides. I never expected the....
Our threeeeee main weapons are: -Loyal and unquestioning devotion to The Pope -Surprise -Routing so the leading edge of the bit pulls you into the work, not throws you out of it is generally safer, particularly if you're taking off a lot of stock in a pass and conversely, taking off very little stock lessons any risk.
That's four, isn't it?
Our FOUR main weapons are: -Loyal and unquestioning devotion to The Pope -Surprise -Routing so the leading edge of the bit pulls you into the work, not throws you out of it is generally safer, particularly if you're taking off a lot of stock in a pass. -Taking off very little stock probably means you have better control of the set-up so you can go in whatever direction gives the best finish. -Never draw to an inside straight or top post a long reply to a short thread in a newsgroup
Our FIVE main weapons are....
Oh Bugger!!
Love what you've done with the protractor, btw.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bored Borg wrote:

ROFL :-D
--
Morris Dovey
DeSoto Solar
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"sam" wrote:

What you want to do is the functional equivalent of cutting a mortise using a router and a straight bit.
IMHO, it is not possible to safely accomplish this operation using a fixed base router, router table with a fence.
You need a plunge router and jigs that duplicate the functional equivalent of cutting a mortise.
Do a Google for "mortise jig" to get and idea of an approach to solving your problem safely.
Lew
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Better yet, look up "Multi-router" ala David Marks. Not only is this setup safe, accurate and easy - it's about the coolest router accessory I've ever seen. Might be a bit expensive, but it sure would be nice to have in the shop!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Better yet, look up "Multi-router" ala David Marks. Not only is this setup safe, accurate and easy - it's about the coolest router accessory I've ever seen. Might be a bit expensive, but it sure would be nice to have in the shop!
The Multirouter being a $3,000.00 router accessory it would be cheaper for the OP to simply pay a pro to do the "slot".
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Yes, super cool. I hope to have one soon. However, they only have an 8" throw so if you are doing a longer slot it will be a little less perfect for the job. Even though they are dead accurate, unclamping and moving the stock to continue a cut is never perfect. Probably more than perfect enough though.
Interesting side note (to some): Many of the folks who I know that are using this unit to do furniture are often (or exclusively) using it like a domino with floating tenons when doing M&T. Even though it does mortise and tenon, the tenons are more setup and less consistent. I also see that most of these folks do not pin both sides of the joint, so in my opinion, they are not building furniture that will last forever. A true pinned M&T has a mechanical lock in addition to the glue and the glue will fail someday.

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

The biggest source or error in this case would be the accuracy of the dimensioning of the stock to begin with. IOW, with the M-R, the cut will be as accurate as using the most accurate of fences on any other type of tool ... for you would clamp the stock to the table, and move the table, which is, in effect, the "fence" in this type of operation.
An added benefit, that is not usually available when passing the stock over the cutting device, instead of vice versa, is that clamping pressure to the M-R's table can mitigate error in the flatness of the stock.
Granted, as you say, we're talking a case of "perfect enough".

Yabbut, forever is a long time and the "pin" is also glued in, and, as you say, glue will fail someday ... and, it is arguable that the wood itself will not last "forever" in any event. :)
It would be interesting to see some test results bearing out your contention. Like you, my gut feeling is that pinning would certainly add some mechanical strength to any joint, but how much, or whether it is necessary, is highly subjective.
IME, it is not remotely necessary to pin a properly done "floating tenon" joint.
AAMOF, in all the test results I've seen of the relative strengths of this type joint compared with various others, I've yet to see a test which "pinned" the floating tenon as one of its parameters.
What is interesting in these tests is that the "rounded" floating tenons performed slightly better than squared ones.
(Fine Woodworking, Nov 2006)
And, while I've been known to do it myself, I would certainly NOT want to leave the impression with anyone that pinning their properly done floating tenon joinery is necessary to it's practical longevity.
--
www.e-woodshop.net
Last update: 10/22/08
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    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.