Router Table question-Beading on a concave shape

larry merlau

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for Carol or anyone else that has done it:) take a 36" wide and 4" high piece of stock and give me a concave curve with a bead not applied.. cut from the same stock..concave apron.jpg also not with a scratch stock.. i was told it was possible this wknd but dont see how..
 
Ooooh! Good one, Larry. One of the challenges is the grain chain from end of the arc to other. Doing it by hand with a scratch block is out of the question? Probably the quickest way from start to finish. But if think you want to use a power tool, then a bit of jigging is order. Got a thought, but first I have to look to see if there is router bit for the task. Later.
 
i have seen a set up carol where they used a hand held and a small pivot point to use as the follower.. i have done it with a scratch stock and you do need to go both directions to achieve it.. the only bit i have found, only does a double curve carol not the square grove step
 
OK, some research later. I cannot envision how any router bit can make that cut. If you divide a cut in half, you will see. The inner round-over on the bead with its facing straight side with a small flat bottom shows the difficulty. A router bit makes a mirrored cut on either side a center line, in this case the centerline running through the flat bottom of the cut. No bit can cut a round-over on one face and leave the opposite face straight.

The arced board is either presented to the cutter face down or on edge. On edge doesn't work at all. On its face is can work but not produce the flat surface facing the bead.

This cut would appear to be a mark of handwork. Good marketing point, when you think about it.

So two ways I can think of. One is the hand scratch block. The other would be to laminate and bend the beaded part.. Round it over on each edge and then glue it to the arc. Again the hand scratch block is easier and faster.

Is what it is, folks.
 
Ok i aint tried this but is there any reason why one could not cut a corresponding half moon shape out an secure it to the base of a router in such a manner as to have its edge run along the edge of the arc and guide a bit.
Say one were to take a 1/2 piece of ply and cut a dado just to the side of center of the base. Attach it to the base of the router. Then slide into the dado a half round piece cut to match the arc. However prior to inserting, run the piece through the bit mounted in a router table so that its kind of zero clearance sides. This way the router bit would be guided on two surfaces. The arc and the face with the bit to make the bead sticking through. :dunno:
 
well rob if i have this right,, you need to look at the fact that the router bit would need to be extended way out to get the corresponding curved base to work. you need to miss the edges of the router base to get the swing..
 
Larry, I think Rob and Jeb's ideas are looking at using a bit similar to this one...

http://www.grizzly.com/products/Beading-Roundover-Panel-Boring-Bit-1-4-Shank-3-8-Dia-/C1318

I've got one that is smaller that almost comes to a point (1/16" flat area) having a 1/4" round-over.

possibly darren but that bit profile gives you a differnt look than what i have shown and what i saw this wknd..i asked the guy how he did it and he said with a jig and router ??? thats all he would tell me???
 
If I understand it correctly, rob was on the same track I was. I think a horizontal router table approach would be more controllable. You would have to extend the router bit all the way out of the router and the curve would have to be gradual or it would hit the router base on the sides.

Think of a mlcs #5531 mounted horizontal with the top of the bearing flush with the table. The fence would curve back towards the router base on either side. Ive never tried it, but I'm pretty sure it would work if the curve is gentle enough. Might be one of those projects I have to try one day if I ever get some more free time.
 
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OK, maybe I am missing something but why not make in two pieces. Traditional sawing/bandsawing for the large arched piece. Routing the small curved piece with a beading bit (pic attacehd) on a thin strip, sand to final thickness, then glue, bend, clamp, trim to length. Seems doable to me.
 

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OK, maybe I am missing something but why not make in two pieces. Traditional sawing/bandsawing for the large arched piece. Routing the small curved piece with a beading bit (pic attacehd) on a thin strip, sand to final thickness, then glue, bend, clamp, trim to length. Seems doable to me.

Yes, two pieces would be easy enough. I think Larry's quest is to find out if it can be done from a single piece of material. A typical beading bit would foul the vertical wall as it follows the arc (damage varying with bit diameter and arch curvature). It's kind of like a puzzler question ;-) As the router takes the curve, the flat wall will be moved back from the bead since the bit is arcing. If Larry is OK with something a little different than his picture, no prob except a bit of possible tearout.
 
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So I thought I'd give it a shot as per the tutorial I pm'd Larry last night. I did a quick plexi base for my laminate trimmer, and added a depth-stop/guide screw set-up...you can see by the board, that this was my second try:eek: as I couldn't find my beading bit I tried it with a keyhole bit...dummy me, it needs to be a bearing supported bit to keep from digging in{never said I was smart:wave:} Any edge profile bit{w/bearing ;)} should work fine in this type or treatment setting. Sorry for the sad video take, I was using my photo camera in video mode, also forgive the comedic interlude while I plug in the router :doh:

Here's the link I sent Larry and semi followed... http://www.customwooddesign.com/routerbeading.html

& here's a quick hillbilly video take of my test...
http://imageshack.us/clip/my-videos/196/a15u.mp4/
 
I'm late to the table on this, but I'd try it with this kind of bit:
pointro.jpg

I'd make a template using your curve as a guide, attach an edge guide to the router base and hand rout it.

Knowing me, I'd make a mess the first time, but I'd learn! :huh:
 
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