Cutting mitersin curved moulding

I am confused as to the best way to figure out the best miter with curved moulding. I have 3 windows with elliptical tops. I have thought that maybe I could somehow mount the moulding on some kind of base so that I can keep a consistant line against the fence.

Here is a picture of the windows.

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thoughts?

Thanks

Danh

Reply to
danh
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Dan explain a little better what your looking for How to cut the miter or what would the angle be

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> Any thoughts?

Reply to
George M. Kazaka

Well, there are two problems

  1. How to figure the correct angle. It would be easy with 2 straight pieces, but with one curved it will be tougher. I plan to make some templates from scrap MDF to get the angle just right

  1. How to hold a curved piece of moulding against a straight fence of say, my SCMS so that I am assured of the proper angle for each cut

Dan

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Reply to
danh

Lets see if I can explain this that is easy to understand, if not I will have to resort to a drawing. what you do is layout the curve piece and trace it on a large paper or cheap wood whatever. Say the moulding is 2-1/2" wide, now draw the up and down lines that represent the up & down moulding drawer these two line which is also 2-1/2" wide past the curved lines Now draw a line across the outer point to the inner point and that gives you the angles Use an angle gauge to transfer the straight moulding angle to your miter saw.

to cut the mitre on the curved molding get the angled line you have drawn transferred to the mould cut this line a 1/4" big any way you want and set the inner arch against the miter box fence and adjust the angle to the line with your eye once set all the angle will be the same as long as the arch is a section of a radius.

If my explanation is not clear enough let me know and I'll do a sketch or two so it will be

Good Luck, George

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Reply to
George M. Kazaka

I remember an eliptical face-plate lathe for making mirror frames at the old Schwamb Mill in Arlington, MA. I am sure it isn't the only one, but even if it is the priciple is there.

The faceplate had a track on it with a sliding frame on which the work was fixed. A crank on the end of the fixed axle connected to the sliding member with a connecting rod. The lathe was belt-driven and the oscillation determined the eccentricity of the ellipse.

An ellipse jig could move a router around a wood frame clamped to the bench with similar results.

In either case, you could join up the wood with approximate miter angles and cut the ends to fit after the molding is done.

I hope this makes sense in words. I don't have a web site to put a sketch on.

Rodney Myrvaagnes J36 Gjo/a

Does one child rape really change Strom Thurmond's lifetime record? For better or worse?

Reply to
Rodney Myrvaagnes

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> Any thoughts?

Windows like this are often trimmed with rosette blocks at the corners. That said, if you want to miter the moulding (and assuming only a couple of windows), hold up the overlong pieces and mark inner and outer intersections on the wall and jambs. Then position the head casing and transfer the marks and cut. I do these with a SCMS and don't use a full contact fence - just the one point of contact. A sharp blade and gentle touch will get you through it without having it snatched away. Cut the side casings overlong and plane the miter for final fit. Fit the bottom last if picture framed

Reply to
Eric Ryder

Yes the moulding was manufactured curved

danh

Reply to
danh

Lets see if I can explain this that is easy to understand, if not I will have to resort to a drawing. what you do is layout the curve piece and trace it on a large paper or cheap wood whatever. Say the moulding is 2-1/2" wide, now draw the up and down lines that represent the up & down moulding drawer these two line which is also 2-1/2" wide past the curved lines Now draw a line across the outer point to the inner point and that gives you the angles Use an angle gauge to transfer the straight moulding angle to your miter saw.

to cut the mitre on the curved molding get the angled line you have drawn transferred to the mould cut this line a 1/4" big any way you want and set the inner arch against the miter box fence and adjust the angle to the line with your eye once set all the angle will be the same as long as the arch is a section of a radius.

If my explanation is not clear enough let me know and I'll do a sketch or two so it will be

Good Luck,

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Reply to
George M. Kazaka

Lay one profile over the other in the configuration that it will have when complete and cut on a line from the outside intersection to the inside intersection.

Thomas J. Watson - Cabinetmaker (ret.) (Real Email is tjwatson1ATcomcastDOTnet)

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Reply to
Tom Watson

Tom you are right but I think going a little bit further. .... Place the vertical moulding on the wall up through the area of intersection and trace down a real fin pencil line.. Then place the curved moulding in place and mark the two "cut points" on each side of the moulding.

John

Tom Wats>>

Reply to
Eddie Munster

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