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7K views 6 replies 3 participants last post by  Patternguy 
#1 ·
There is an inside, and an outside, to everything.

Master patterns and production tooling belonged to whoever paid the invoice. On the other hand, whatever was used to build the pattern, things like jigs, fixtures, molds, negatives, or plugs, was recycled in the shop, or was dis-guarded.

Stuff like that usually got thrown into the scrap barrel. The objects that are the focus of this story escaped that fate and ended up on a shelf in my garage. I think they have a story worth telling.

Patterns often required unique shapes that had to be "developed". Development jobs involved a bit of thought into how to accurately create the shape. Some shapes are just plain "cool", as well as being descriptive.

This is a picture story about one of those jobs that was nothing but a compilation of unique shapes.

Wood Table Tableware Flooring Room
 

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#2 ·
The flower is defined by its wire frame

First I'll clarify what this pattern will actually make…

The casting is a "Cooperstown Flower". It's a piece of architectural iron that got its name from a restoration project done in 1985 in Cooperstown NY. Unfortunately, I don't have any pictures of the casting and will have to rely on a model I put together for illustration.

Petal Serveware Art Kitchen utensil Tableware


I have a video too, but I have to figure out how to post it.

Now that we know what we are making, hopefully, the next couple of images will explain where the wire frame fits into the story…

Slope Rectangle Parallel Sky Wire

Wire frame exists in three dimensional space, but the output it defines will always be two dimensional, at least when it is viewed from a single plane…think of a piece of paper.

Table Rectangle Kitchen appliance Gas Major appliance

This is the output for one axis of the wire-frame ( shown in 3D for illustration)

Peripheral Input device Automotive design Mouse Font

This is the output for the the other two axis's of the wire-frame.
(It is a little more complicated than that, but I leave it there unless someone is interested)

Clothing Plant Headgear Automotive design Rectangle

Here are both wire-frame outputs.

Plant Input device Automotive design Font Peripheral

When you combine what is common to both outputs, the result is this.

Tree Plant Tints and shades Ceiling Circle

Put eight shapes together and you get this!
 

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#3 ·
The flower is defined by its wire frame

First I'll clarify what this pattern will actually make…

The casting is a "Cooperstown Flower". It's a piece of architectural iron that got its name from a restoration project done in 1985 in Cooperstown NY. Unfortunately, I don't have any pictures of the casting and will have to rely on a model I put together for illustration.

Petal Serveware Art Kitchen utensil Tableware


I have a video too, but I have to figure out how to post it.

Now that we know what we are making, hopefully, the next couple of images will explain where the wire frame fits into the story…

Slope Rectangle Parallel Sky Wire

Wire frame exists in three dimensional space, but the output it defines will always be two dimensional, at least when it is viewed from a single plane…think of a piece of paper.

Table Rectangle Kitchen appliance Gas Major appliance

This is the output for one axis of the wire-frame ( shown in 3D for illustration)

Peripheral Input device Automotive design Mouse Font

This is the output for the the other two axis's of the wire-frame.
(It is a little more complicated than that, but I leave it there unless someone is interested)

Clothing Plant Headgear Automotive design Rectangle

Here are both wire-frame outputs.

Plant Input device Automotive design Font Peripheral

When you combine what is common to both outputs, the result is this.

Tree Plant Tints and shades Ceiling Circle

Put eight shapes together and you get this!
Interesting thread….
 

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#4 ·
Subtracting the inside from the outside yields a flower with just the right wall thickness

That is of course,
Brown Plant Orange Petal Wood


if your wire-frames layouts are accurate.

Here are some closer looks at the plugs.

Helmet Cutting mat Tableware Dishware Wood


Helmet Sports gear Sports equipment Nerve Wood


Wood Petal Flooring Table Plant


Brown Wood Petal Flooring Floor


Brown Wood Petal Flooring Floor


Hair Brown Amber Petal Wood


Notice the direction of the grain on the two pieces???
I could not decide which direction would be the easiest to work, so I tried both ways.
(It's been so long that I can't remember which one was the better choice)

Anyway,
The individual "petals" were roughed to shape on the disc sander.

They were finished with a spoke sheave and templates.
The template edges were rubbed with a stick made of bees wax and lampblack.
It was the best transfer media to use on wood.
 

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#5 ·
Subtracting the inside from the outside yields a flower with just the right wall thickness

That is of course,
Brown Plant Orange Petal Wood


if your wire-frames layouts are accurate.

Here are some closer looks at the plugs.

Helmet Cutting mat Tableware Dishware Wood


Helmet Sports gear Sports equipment Nerve Wood


Wood Petal Flooring Table Plant


Brown Wood Petal Flooring Floor


Brown Wood Petal Flooring Floor


Hair Brown Amber Petal Wood


Notice the direction of the grain on the two pieces???
I could not decide which direction would be the easiest to work, so I tried both ways.
(It's been so long that I can't remember which one was the better choice)

Anyway,
The individual "petals" were roughed to shape on the disc sander.

They were finished with a spoke sheave and templates.
The template edges were rubbed with a stick made of bees wax and lampblack.
It was the best transfer media to use on wood.
Interesting stuff
 

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#7 ·
What remains, is what you want.

Corny title…but it pretty much sums it up.

The wood pieces in the previous posts are what's known as "plugs". The red plug represents what the inside of the flower casting will look like. The mahogany plug represents the outside of the flower.

1. Two pieces of plywood are drilled and pinned together. Center-lines are transferred from one to the other.

2. The mahogany plug is mounted on one piece of plywood using the center-lines to locate it.

3. A wood frame is placed around the plug and clamped to the plywood.

4. Two-part urethane epoxy is mixed and poured into the frame.

5. When cured, the plug is removed from the mold. The mold is called a "negative".

6. The red plug is mounted to the 2nd piece of plywood (on centers). We'll call this the "male" half.

7. A 3rd piece of plywood, which will become the "match board", is laid out to what ever flask size the foundry will use to mold the casting.

8. The match board gets a step routed on both sides and the center of the board is chopped out with a forstner bit.

Wood Bag Rectangle Beige Font


9. A 3/4" hole to drilled thru one side of the board.

10. The negative is clamped to one side of the match board, and the male half is clamped to the other.

Human body Rectangle Wood Table Automotive exterior


Rectangle Wood Font Slope Roof


Rectangle Building House Font Roof


11. The entire arrangement is stood up on one side and clamped in a vise.

12. Urethane is poured through the 3/4" hole until full.

13. The negative and the male are removed.

Wood Rectangle Hardwood Font Cylinder


Here is a cross-section of the match board.
(The colors are not accurate but you get the point)

Brown Wood Gesture Rectangle Tree


Bag Gesture Rectangle Wood Wrist


The pattern for a Cooperstown Flower. Perhaps one day I'll get there and see one of them.
 

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