Need to cut a dado channel in a curved rail

[Mike OMelia]

So the dado blade is out and I realize the router table is the way to go. But I cannot think of the bit name. and it needs a bearing to control depth. If there are aother ways to do this, please let me know. This is a top rail for the back of a seat on a blanket chest (serves as a seat as well). This panel is curved, so therefore is the rail.

Thanks!

Mike

[Bill Huber]

How about a slot cutter with a bearing.

http://www.eagleamerica.com/product/v146-0130/ea_-_slot_cutters

http://www.eagleamerica.com/product/196-0022/ea_-_slot_cutters

[Mike OMelia]

Bill, that will work. Think I will get two of the 1/4" and one of the 3/16". Permutating those provides just under 3/4", just under 1/2", in addtion to 3/16", 1/4", and 1/2"! Thanks. (I needed just under 3/4")

Mike

[Sam Murdoch]

Here are some rabbeting bits which will give you a wider groove with one pass - the depth is controlled by the size of the bearing but I think most of these will give you at most a 7/16" depth http://www.rockler.com/product.cfm?page=2116

Of course there are other sources - Freud, for example...

[Mike OMelia]

Well, Sam, those are nice too. A bit cheaper setup as well (not cheap as in shoddy! just less $$). I actually was thinking about these, when Bill reminded me of the the slotting bit (which I had forgotten about). A nice feature is the included depth bearing kit! and considering I only have 3 ft of slot to cut, this might be the better, overall option. I will have to make two passes to get shy of .75", but that's no issue.

Thanks! Gonna have to think a bit on this.

Mike

[Jerrimy Snook]

My concern about the rabbet bits is the shear angle. The angle helps create a smooth cut on the bearing side of the bit but may cause tear out on the collet side in a grooving application. You might try a Whiteside 1924 which is a 3/4" slotting bit. Bearing kits or replacements are available for various cutting depths.

Jerrimy

[Mike OMelia]

Is this because rabbeting bits are not really meant for cutting channels?

[Mike OMelia]

I'm glad u pointed that out. I used an old bit for binding guitars the last time I tried this. The bit was very similar to a rabbeting bit and I had that exact same problem! I guess this confirms the right bit is a slotting bit. Thanks!

Mike

[Sam Murdoch]

Well the Whitesides from Woodcraft aren't that expensive http://www.woodcraft.com/product/2008059/6392/whiteside-1924-slotting-and-rabbeting-router-bit-12-sh-114-d-x-34-cl-x-38-cd-212-ol.aspx though the shear angle appears much the same as that of the Freuds. I see Jerrimy's point, though I haven't observed this to be a problem in my work. Perhaps the wood species and/or grain orientation is a factor (very likely). I do prefer to take my cuts in shallow passes and will not hesitate to change out the bearings to creep up on the full depth. Also, and more importantly, I DO NOT start at one end and rout full tilt, but rather start near the end of my cut and work in 2" or 3" increments, always passing into a previously routed surface. Tear out is never an issue even in curved parts where the grain orientation changes. But Mike, you've got the big picture now. Happy and successful slotting :).

Sam

[Mike OMelia]

Thanks Sam. Feel like I have a better grasp of it. I googled the term "rabbet" and Wikipedia (of course!) described it as a two sided cut, not three which is (of course!) a dado. :) So, best as I can tell, a rabbeting bit is not really designed for dado or channel cutting. Though as you and I have discovered, with sneak moves, it can be done. I cut enough channels to justify the three slot cutter investment. And I'll have quite a bit of flexibility with that.

Thanks,

Mike

[Jerrimy Snook]

Mike,

Some slotting cutters will not stack easily and may be damaged when the nut is tightened. I found this Timberline (http://www.toolstoday.com/p-6039-multi-3-wing-slot-cutter-router-bit-set.aspx?variantids=10683,0&) set that may be what you are looking for. It has the cutters, spacers, and bearing assortment.

Good luck,

Jerrimy

[Mike OMelia]

Jerrimy, very nice! Thanks! And it comes with the shank and a carry case!

Mike