Project w/ Pics Trim week at our new house

[creasman]

This week I took a break from making cabinets for our new house in order to install the trim. The first part of the week was spent trimming out several elliptical arched openings throughout the house. I began working on the casing and jambs for these last November as soon as we had finalized the plans. In addition to these openings the front door is round at the top and two of the windows have arcs. The job required a fair amount of custom trim to match all the curves. Add to this the several hundred feet of straight casing required and you see why I started last year.

We're pleased with how it all came together. I used poplar for the casing since they will be painted. The technique used to form the curves is bent lamination using 1/8" thick strips and lots of glue. This method was used for both jambs and casing wherever a curve was required. There are other ways to make this sort of trim -- CNC, specialized moulding machines, urethane trim, etc. I chose the method that fit my budget and didn't require purchasing any specialized equipment.

Below are a few pictures. I'll add more posts to this thread explaining the design and process I followed.

There are eight elliptical arches -- three 60" wide and five 36" wide.

The front door has a semi-circular arch at the top.

Lastly, two of the windows have circular arcs at the top.

 

[Wilsoncb]

Looks great, you definitely didn’t take the easy route!

 

[ptt49er]

Beautiful!

I'm not even sure I can call myself a woodworker anymore...

 

[Graywolf]

Great looking work!

 

[mattfrit]

The arched doorway trim looks awesome. Can you walk through yhe process? My house has two arched entry ways in the living room that have never been trimmed.

 

[Hjanes]

Really elegant; another level of "sweat equity".

 

[Roger45]

This is a whole different level of workmanship quality being done on your home that has been lost in most woodworking today.

 

[Melinapex]

Jim, that is a whole other level of craftsmanship! Truly impressive….

 

[Gboot]

Jim, great work. I can’t imagine the amount of time you spent doing this. Legacy for generations.

 

[drw]

Jim, very beautifully done!!

 

[ACWoodworking]

That’s incredible workmanship. Just wow!

 

[creasman]

Design

I mentioned in my initial post that I would document the process for making these here. This is the first of several updates I will be adding. In this post I'll focus on the design thought and education leading up to making the arches.

The plans for our house include a number of cased openings. Early in the planning we decided these would be cased arch openings. The house has nine foot ceilings. We could have went with a circular arch for the 36" openings. However, for the 60" openings a circular arch would not fit. I chose to use an ellipse whose minor axis is 24" inches (12" height for the elliptical arch above side jambs). This is true of both widths of arches and defined the basic geometry.

The next question was whether to buy or make these. The cost could easily have exceeded $1000 per opening and I knew I could make them for much less. I found a four-part video series by Gary Striegler on curved trim work made using bent lamination. His method seemed straight forward, especially the form he used to shape the curves.

The only remaining challenge was to create the moulding required for the casing. Gary's approach is to use a Shop Fox planer/moulder to cut the shape. That was not going to fit in my world. Instead, I decided to use the router bits I already had and build the casing in layers -- tedious but doable.

I went through my bits and designed 10-12 different profiles I could make. Each had anywhere from 3-4 layers as shown in these diagrams. I went as far to make a 12" sample of them so my wife could see the real shape. I had to be able to make each layer on the router table in both straight and curved form. In the end we chose a casing composed of four layers -- a round, ogee, flat and bead.

By the time I was done I'd made around 600' of casing, including both straight and curved sections as well as the curved and straight jambs required. In upcoming posts I'll dive into the details of each.

 

[ptt49er]

I'm sure you made more than a few chips making that 600'!

Thanks for the pictures of your sketches, I look forward to learning more about the process of making them!

 

[JNCarr]

Great work!

 

[creasman]

Materials

These are the materials used in making the curved sections. The wood used is poplar. It's relatively inexpensive, is flexible and makes a smooth surface when painted.

Poplar. Bent lamination required making a lot of 1/8" thick strips. For accuracy I ran each through the planer after ripping the material to ensure a consistent thickness. For example each 3-1/2" wide curved casing requires 28 strips of poplar. I experimented with thicker strips, but the tight radii needed for the ellipses just didn't work well for anything thicker than 1/8". For the arc over the window I was able to use 3/16" thick strips. This is a more gradual curve.

Melamine. I chose to make the base of the form from a sheet of melamine. It's stable, flat and glue doesn't stick to it. The white surface also makes it easy to see the outline of the curve. That's important when mounting the brackets used for clamping.

Angle iron brackets. A length of 4"x6" angle iron was cut into 1-1/2" sections to make clamping brackets. This was salvaged from a house I demolished on the property. That saved me some money, but I still paid about $200 to get it cut into 30 pieces. I drilled two holes into each 6" side to mount these onto the melamine base. Once mounted the 4" side made a rigid clamping surface.

Steel bar. To shape the curves I purchased two 10' lengths of 1/8" x 2" flat bar steel. One length is used to wrap around the inside of the curve and the other wraps the outside with the wooden strips sandwiched in between. The steel bends smoothly and doesn't let the brackets dig into the wood.

Glue. Most any wood glue would work, but I recommend Titebond Extend. The "extend" refers to a longer tack time. With this glue you have about 20-25 minutes before it begins to set. You will need this time to get all the clamps in place and bind the wood to the curved form. All together I used at least three gallons of glue.

Applicator. Spreading this much glue by squeezing a bottle would not be practical. Instead, I used this inexpensive glue applicator I ordered from Amazon. It works very well. I even think it would earn @pop-pop's coveted "worth a ****" award.

Clamps. I used anywhere from 25-30 C-clamps during each glue-up. A few hand-release bar clamps are useful as extra hands while you're bending the wood.

Stretch wrap. This is the stuff often found in packaging. It's a great way to manage a stack of strips once the glue is applied.

I'm sure you're wondering how all this goes together. Stay tuned...

 

[JD52M]

Outstanding craftsmanship!

 

[creasman]

Layout and Setup

The focus in this post is on laying out the arches and then setting up the clamping system. I used the same setup for both jambs and casing. The only change is the curvature increases by 1/4" for the casing to allow for the offset.

The first task is to draw the curve on the melamine. For circles and arcs this is trivial. Ellipses require a bit more planning. A similar shape can be formed by blending arcs from two small circles and one large one. However, this is not a true ellipse in the mathematical sense.

My goto method for drawing an ellipse is to use a square and trammel stick. The trammel stick is made by fixing a pencil at one end. Then, from the pencil point measure back half the length of the minor axis. Fix a blunt nail at this point so that it extends slightly. Affix another nail at half the length of the major axis from the pencil. For both arches the length of the minor axis was 24". This keeps the arch height and jamb length the same. The major axis is the width of the arched openings -- 36" and 60" in my case.

Begin by laying out the major and minor axes. These are just two straight lines intersecting at a right angle. I was careful to locate these with the minor axis centered on the melamine and the major axis a few inches from the edge. The goal is to have enough space to extend the strips past the halfway point. This gives you extra material to trim and ensures a smooth curved when joined to the straight section.

Using clamps or double-sided tape align the square with the axes. Carefully move the trammel stick so that the nail ends slide along the square. This will trace one quarter of the ellipse. Move the square and repeat the process until you have as much of the ellipse as necessary.

Once the arch curve is drawn the next step is to place each clamping bracket. These should be about 4"-6" apart, depending on how tight a curve you want. I used dividers to step out equal spaces along the curve. From each point I drew a line perpendicular to the tangent at the curve. This was by eye since it doesn't need to be exact. The purpose of these lines is to align the brackets since you want the clamping surface of each bracket to follow the curvature.

With the lines drawn I made a simple jig that I could use with my plunge router. The goal is to make a 1/4" wide slit along each line that is used to bolt a bracket in place and provide some adjustment. Double-sided tape was used to hold the template in place for each slot.

The last step is to bolt the brackets around the curve. The slots allow you to adjust each as necessary. Initially, these need to be placed to make the jambs. For the casing each bracket is shifted further out by 1/4". Note, you want the two corners of each bracket to align with the curve (not the middle) and you want to allow for the thickness of the steel band. This meant shifting each bracket inside the curve by 1/8". I used a scrap piece of brass bar stock when aligning each before tightening the bolts.

At the end of all this all the brackets are in place and you're ready to begin gluing the strips around the form. This will be the topic of my next post. This is the same setup used for all the curves -- circular, elliptical and arc.

 

[Danny Batchelor]

Fantastic! Why does the clamping extend below the horizontal?

 

[pop-pop]

Jim’s work is a great example of why you should pay attention in geometry and trigonometry classes and do your homework sans AI help!

 

[creasman]

Why does the clamping extend below the horizontal?

Good question. You get better results if you have extra material extending past the point you actually need. When I post pictures of the gluing process you will see the ends are pretty ragged. The layers shift and the outer layers don't extend as far. It would be almost impossible to get these to line up where you want at the end. It's much easier to extend the layers and clamp around the curve. When it's all dry you then trim off the excess. I'll post pictures of the jig I made to trim these.