how do i make this cut safely?

[David Zaret]

i made a bunch of curved mouldings, all of which requires a rabbet on the back. you can see my setup in the picture... but i'm struggling with the best/safest approach to hold and guide the material through the cut. i have to keep some pressure on the front "slope" to keep it flat to the shaper surface, and that, combined with the fact that the meat of the material is right at the cutter is making it difficult to see how to safely guide the material through this cut.

i have lots of Aigner stuff... just curious if any experts can visualize this and educate me on the appropriate way to consider the setup. thanks.

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[Jared Sankovich]

i made a bunch of curved mouldings, all of which requires a rabbet on the back. you can see my setup in the picture... but i'm struggling with the best/safest approach to hold and guide the material through the cut. i have to keep some pressure on the front "slope" to keep it flat to the shaper surface, and that, combined with the fact that the meat of the material is right at the cutter is making it difficult to see how to safely guide the material through this cut.

i have lots of Aigner stuff... just curious if any experts can visualize this and educate me on the appropriate way to consider the setup. thanks.

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Are all the same radius? and all rebates on the outside of the curve?

[Russell Hayes]

I'm thinking on a router table, with a rabbet bit, and use a support pin.

[David Zaret]

Are all the same radius? and all rebates on the outside of the curve?

no, four different radii, inside and outside. i could use the router table, and i could make templates... maybe my question should be "how do i make this cut safely ON THE SHAPER."

[brent stanley]

i made a bunch of curved mouldings, all of which requires a rabbet on the back. you can see my setup in the picture... but i'm struggling with the best/safest approach to hold and guide the material through the cut. i have to keep some pressure on the front "slope" to keep it flat to the shaper surface, and that, combined with the fact that the meat of the material is right at the cutter is making it difficult to see how to safely guide the material through this cut.

i have lots of Aigner stuff... just curious if any experts can visualize this and educate me on the appropriate way to consider the setup. thanks.

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Do you have any extra length on the ends you can sacrifice to use for fastening to a jig or similar?

B

[Kevin Jenness]

I would set up a curved outfeed fence that matches the rabbet's radius and height and feed the stock with one wheel on the powerfeed, bearing down on the bead just before or after the cutter. Maybe a curved infeed fence as well or at least a starting pin. Presumably there is extra length on the blanks.

[David Zaret]

I would set up a curved outfeed fence that matches the rabbet's radius and height and feed the stock with one wheel on the powerfeed, bearing down on the bead just before or after the cutter. Maybe a curved infeed fence as well or at least a starting pin. Presumably there is extra length on the blanks.

kevin, yeah, this matches my original thinking. i was hoping to avoid it, but i agree it's a safe approach. thanks.

[Warren Lake]

how big is the rabbet?

split collar ball bearing head, knife extended out what you need. Part longer than finished length and a steady block for a lead in when you start. Or maybe one fence from the shaper fence for the lead in.

[David Zaret]

rabbet is 12mm x 12mm. the aigner attachment you see solves the lead-in issue. i can safely bring the piece into the cut.

[Joe Calhoon]

Outside radius rebates are easy. Use one wheel of the feeder centered about 20mm on the infeed side of the cutter. Pictures show using the fence fingers same as you would the Bowmould.

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[Kevin Jenness]

kevin, yeah, this matches my original thinking. i was hoping to avoid it, but i agree it's a safe approach. thanks.

I have done this successfully on narrow curved glazing bars. The key is getting the outfeed height to exactly match the rabbet. A short ramp at the start of the outfeed will help. On second thought, the feeder wheel should be just before the cut. If the uncut material will feed without rolling, an accurate outfeed support will keep it upright when rabbeting. If that approach doesn't work then maybe you need to attach the parts to a sled with double stick tape or something but that seems more complicated.

[Lee Schierer]

That is a very heavy cut to make in one pass on a small piece of trim. I would not attempt this with a hand held router, nor with a shaper.

Here's what I would do. Use a bearing piloted rabbeting bit in a router table. Attach each piece of trim to some scrap 1/4" plywood with double sided tape along the full length of the molding piece. Trim the plywood so it is close to the profile of the curved trim piece. Use the replaceable bearings on the rabbeting bit to take light cuts (1/16" max), starting with a flush trim bearing. Since your pieces are curved you may need to climb cut certain areas to prevent the bit from grabbing the grain and breaking your piece.

Here's a link for making router (shaper) cuts on curved pieces of wood. Bear in mind that the directions in the article are for a hand held router, they will be mirror image for a table mounted router.