THE LAMP CLAMP
Designer Edition
Wedgies Wedgie Jr's Pro-Boxer Octahex Lamp Wedgie Home
This is a photo of the inside of a "clamped" lampshade. Each of the green alignment guides was set to the exact angle between the panels prior to beginning assembly.
This lampshade can be picked up easily without distorting anything. Then it can be soldered starting with the outside seams.
Scroll down to learn more.
Every now and then we get a call from a customer who is having a problem with a lampshade. Sometimes they have the Lamp Clamp and sometimes they don't. Because the Lamp Clamp relies on knowing the angle between two adjacent panels people often get confused about what that angle is.
For example: If you look at the picture above, you're looking straight down into a six sided lampshade. The shape of the top edges and bottom edges is a hexagon. Since everyone knows that the angle between the sides of a hexagon is 120 degrees, they assume the angle between the panels is also 120 degrees. That's true only if the all the sides are straight up and down as in a box. As soon as you tilt the sides inward things change drastically. In reality, the angle between the panels of a typical six sided lampshade varies from about 128 degrees to 138 degrees depending on the shape. That's how the Lamp Clamp works. It uses that actual angle to set the alignment guides. Then when you clamp the guides to the top and bottom of one panel, you can easily clamp the next panel to the side of the guides that sticks out.
From the time Pam had her first stained glass shop up in Michigan, she had asked me to design a fixture for making panel lampshades. I thought up all sorts of things but not one of them was easy to use or even easy to manufacture. Then one day it came to me. If the "fixture" was adjustable and only needed to be placed at the ends of the seams, it could work. So along came the Lamp Clamp.
The first design was based on 18 of the most popular panel lampshade books then on the market. We gathered all the books and accurately measured (to the nearest 0.01 inch) the pattern pieces for every tier of every lampshade in the book. That data was then input into a computer program I wrote that calculates the interior angle between the panels based on the panel geometry and the number of panels in the lampshade. This was all combined into a data base we called "The Angler" in which you could look up your book, then your lampshade within the book, then the tier of that lampshade, and we would reference you to a "Figure Number" with that angle printed for you. Your task was then to match the alignment guides to that particular angle and you could then clamp your lampshade together.
Later we added more books to bring the total to 30. "The Angler" data base kept getting larger. Finally, we decided to take a whole new approach to the Lamp Clamp.
We still publish "The Angler" and a comprehensive set of instructions. But now we've put all this information on a CD in a .pdf file. You can review and/or print any part of the instructions or data base at any time and the CD makes it much easier to use photos to enhance your understanding. Once we did that, we decided to include the computer program that we use to design lampshades or simply find the interior angle of a given design. So the CD also includes a set of instructions for the program (they're really simple) and a copy of that program contained in an "executable" file called erclamp.exe. Now your flexibility to make panel lampshades is virtually unlimited.
Here are a few details of how the Lamp Clamp works. Click on the images to see them full size.
This is a photo of the first two panels being clamped together. The panel on the left is #1. You can see that the "wings" of the alignment guides define the plane on which the subsequent panel will fit. Panel #2 (on the right) has alignment guides already clipped in place on the top and bottom right hand corners as do the remaining panels except the last one. Panel #1 has alignment guides clipped to all four corners to start. Notice how the inside edges of the seams line up exactly.
This is an inside view of the first two panels after clamping.
This is a view of the first 5 panels clamped together. You can see that the alignment guides are in position to accept the last panel.
Here's the clamped lampshade resting on a set of Wedgies and the Lamp Wedgie. Notice that the top seam is level and ready for finish soldering from the outside. Notice also how the inside edges of all the panels line up and that you've got two hands free to do the soldering.
In order to give you some idea of just how powerful the Lamp Clamp package is, here's a copy of the instructions for using the computer program, "erclamp.exe" which is included on the CD. Some of the formatting was modified slightly when converting the file to the html format for the web site. It does look a lot better when viewed from the CD.
USING ERCLAMP.EXE
What is "ERCLAMP.EXE"
"ERCLAMP.EXE" is a computer program that does several things. It will allow you to design your own lampshade using your lampshade dimensions and then compute the setting angles for the Lamp Clamp alignment guides. It will also allow you to input the dimensions of a lampshade panel and then compute the lampshade measurements and the setting angle for your Lamp Clamp alignment guides and, in many cases, tell you what Figure number to use from "The Angler" to set the guides. It is a powerful tool to have at your disposal.
How do I use it?
It's really pretty easy. Insert the CD that came with your Lamp Clamp into the CD drive on your PC.
Click on the "START" button at the lower left corner of your screen.
Click on "RUN"
Type "erclamp.exe" (without the quotation marks) in the box labeled "OPEN."
Click on "OK" and the program will start.
The program will display the opening screen. Read the copyright information and press any key.
The screen will then display:
Select one of the following options:
Lamp Dimensions Known - Need Panel Size
Panel Size Known - Need Resulting Lamp Dimensions
End Session
Option 2
We'll start with Option 2 because this is probably the option you'll use most frequently. If you are making a lampshade using a pattern from a book not included in "The Angler," this is where you'll want to start. Simply provide the information asked for and the program will provide you with all sorts of information including the size of each tier, the setting angle for the Lamp Clamp alignment guides and, if the program can find a match, the Figure Number to use from "The Angler." If the program can't find a match, it will simply show "NFA" (No Figure Available) for that particular combination of geometry and number of panels.
The three basic pieces of information required are:
The width of the panel across the top corners
The width of the panel across the bottom corners
The length of the panel from top to bottom OR the length of the seam on the side
NOTE:
Computers, being the way they are, will want you to input all the dimensions required here in decimals. Since I know most people don't keep decimal scales (rulers to the more non-technical types) around the house in easy to find places, I have included a table of Decimal Equivalents of Fractions, a few pages hence. It will give you the decimal equivalents of each 1/32 of an inch. It also includes 1/16 's, 1/8's, and 1/4's. Just remember - when you measure, measure as accurately as possible. For example: "Just about 2-3/8 inches" doesn't cut it. If it's 1/32 less than 2-3/8 then the correct dimension is 2-11/32 and the decimal equivalent for 11/32" is 0.344. If you're measurements are not accurate, neither will be the program output. There's a very old acronym used by computer programmers called "GIGO." This stands for "Garbage In - Garbage Out." So take the time to measure accurately. It really is important.It's usually easier to measure the length of the seam (which should be the same on each side unless you have a panel made of lefts and rights) especially if the bottom of the panel is curved. The computer program assumes the panel is actually a trapezoid where the top and bottom are parallel. So in the case of the program input when it asks for "length of panel," just press "ENTER." The program will then ask you for the "seam length."
As to the number of panels, the program will compute the setting angles for a series of panel numbers starting with 4 and going all the way up to 20 for each panel geometry used. You can get the series for a set of even numbered panels (4, 5, 6, 8 .20) and, by changing the option on the "modify data screen," for an odd number of panels (4, 5, 7, 9 19). This allows you the flexibility of getting the information you need for just about any pattern you'll ever run across. I realize that each sequence starts with "4, 5." There was a reason I programmed it that way, but for the life of me, I can't remember why.
For each "number of panels" the program will compute:
The inside diameter at top corners
The inside diameter at bottom corners
The overall lamp height (NOTE: the height shown is only for the tier being analyzed-not the whole lampshade)
The angle of the lampshade seams to the horizontal
The aspect ratio panels only (Again - this is just for the tier being analyzed)
The internal angle between the panels (This is the alignment guide setting angle)
The Figure Number to use from "The Angler" or "NFA" if no match is found.
OK you ask, what's an "aspect ratio"? The aspect ratio is the widest width of the lampshade (usually at the bottom) divided by the total height of the lampshade. The best range for the aspect ratio of an entire lampshade is between 1.5 and 2.25. When you get outside this range, the lampshade will appear too tall and narrow (ratio to small) or too short and wide (ratio too high). The aspect ratios shown by the program are absolutely correct if you're making a one tier lampshade with no crown and no skirt. You can compute the aspect ratio for a multi-tier lampshade simply by determining the largest inside diameter at the bottom corners divided by the sum of the individual tier heights.
If you're interested in getting an idea of what your lampshade will look like, you can quickly plot out the individual tiers to scale on a piece of grid paper and then connect the dots to define the shape. You may find out that you want to add or subtract a panel to get a more desirable shape.
As you peruse the data from the program, you'll see that as the number of panels increases, three things happen:
The height of the tier decreases
The inside diameters at both the top and bottom increase
The internal angle between the panels (or alignment guide setting angle) increases
The maximum possible internal angle between panels is 180 degrees. This means that the panels would lie flat on the table and your lampshade (or at least that tier) would look like a pizza with a hole in the middle. Thus, when this angle exceeds 180 degrees, you will see the notation "Not Possible with This Panel."
Option 1
Use this option when you want to design a lampshade of a particular size. The program will ask you for the dimensions across the inside corners at the top and bottom of the shade and then the height of the shade. Bear in mind that the dimensions across the inside corners will be about 1/4 inch less than the dimension across the outside of the corners. So if you want to use a 3 inch vase cap, you'll use 2-3/4 (actually 2.75 since the computer doesnt work with fractions) for the inside dimension at the top.
This is really easy when you're working with a single tier lampshade. However, when you're working with a multi-tier shade, you have to understand that the program only works one tier at a time. Here's where you have to sketch out your lampshade on some grid paper and indicate where your tiers will be. The easiest way to do this is to draw a vertical centerline on the grid, draw a horizontal line representing the top of the lampshade and another one representing the bottom of the lampshade. Then sketch in your tiers and draw horizontal lines across the tops of each tier. The distance between these horizontal lines becomes the "height of the lampshade" for each tier and twice the distance from the vertical centerline to the top and bottom of each tier becomes the "diameter across the top and bottom corners" for that tier. Input that data (and the number of panels you want your shade to have) and the program will tell you what size panel you need for that tier. When you input the data for the adjacent tier, just bear in mind that the "diameter across the top corners" of the lower tier must be exactly the same as the "diameter across the bottom corners" for the tier above it. As long as you adhere to this requirement, your panels will match perfectly. The program will also tell you what the setting angle for your Lamp Clamp alignment guides will be for each tier and, if it can find a match, will tell you what
Figure Number to use in "The Angler."
What do I do if the program can't find a Figure Number from "The Angler"?
We've thought about that. So we have included a copy of a protractor on the last page of this section that's very accurate and probably larger than one you can buy in an office supply store. Cut this out along the outer arc. When you want to draw an angle to set your alignment guides, here's all you have to do:
First, get your angle. Let's assume it's 133.72 degrees.
Set your protractor on a clean piece of paper - preferably card stock.
Hold the protractor flat on the paper, and with a pin or thumbtack:
o
Poke a hole into the card stock right at the end of the "0" degree lineo
Poke a second hole at the center of the crosshairs at the center of the bottom edgeo
Poke a third hole at 133.72 degrees. To do this, round the number off to 133.7 degrees. Now find 133 degrees on the protractor. It's 3 lines past the 130 degree mark. Now 133.7 is 7/10 (or 70%) of the distance between the 133 degree line and the 134 degree line. Poke a third hole in the card stock right at the edge of the protractor at the 133.7 degree point.o
Using a fine line pencil, draw a line from Hole #1 to Hole #2 and another from Hole #2 toHole #3. Make sure the lines go directly from the centers of the holes.
The two lines you've just drawn form the setting angle for 133.7 degrees.
You can reprint a copy of the protractor any time you need to. You may think the setting angle you've just drawn is way too large compared to your alignment guide. There's a reason for that. It's very difficult to draw angles accurately using tools with a small angle scale. The protractor you print should be about 8 inches across at the bottom. At that size, the degree marks are far enough apart to allow you to find 1/10 of a degree easily. Your lampshades require at least that much accuracy when you set the alignment guides.
NOTE:
The protractor is supposed to print in "landscape" mode. If it doesn't, you can check the "Auto Rotate and Center" box on the Adobe pdf printer. If you wish to have a larger protractor, feel free to enlarge the printout to whatever size you wish. The larger the better. The original "original" of the protractor is actually 10.2 inches along the base. However, every time the image is transferred from program to program, it shrinks and I haven't yet figured out yet how to stop it from happening.The angles in "The Angler" were drawn using a program that gives us much more precision than using a protractor. That's why the angles shown in the Figure Numbers are not as large. Unfortunately, we were not able to put that program on the CD. You'll be glad to know though that the protractor was drawn using that program. That's why we know it's very accurate. So you'll be fine using the protractor. Just don't let it move between poking the holes.
ONE LAST VERY IMPORTANT NOTE:
You can use The Lamp Clamp to do many things including making multiple sided boxes. However, if you wish to find the required setting angle for something where the width of the top and the bottom of the panel are identical, the program will "bomb" because of a "Division by Zero" error. (Computers HATE that!) Since the program subtracts the width of the top of the panel from the width of the bottom, if they are the same you'll get a zero and eventually the program will try to divide by that zero. The solution is really simple. Just subtract 0.001 from the top width. Let's say it's 2 inches. Input 1.999 for the top and 2.000 for the bottom. No more zero and no more problem.
DECIMAL EQUILAVENTS OF FRACTIONS
(Please Note: The following table, while accurate, did not format the same for the web as it does in Microsoft Word - go figure. The table on the CD will print properly. The copy of the protractor did not convert to the website format at all. It is, however, on the CD.)
1/32 = 0.031
2/32 or 1/16 = 0.062
3/32 = 0.094
4/32 or 2/16 or 1/8 0.125
5/32 = 0.156
6/32 or 3/16 = 0.188
7/32 = 0.219
8/32 or 4/16 or 2/8 or 1/4 . 0.250
9/32 = 0.281
10/32 or 5/16 = 0.312
11/32 0.344
12/32 or 6/16 or 3/8 . 0.375
13/32 = 0.406
14/32 or 7/16 = 0.438
15/32 = 0.469
16/32 or 8/16 or 4/8 or 2/4 or 1/2 = 0.500
17/32 = 0.531
18/32 or 9/16 = 0.563
19/32 = 0.594
20/32 or 10/16 or 5/8 . 0.625
21/32 = 0.656
22/32 or 11/16 = 0.688
23/32 = 0.719
24/32 or 12/16 or 6/8 or 3/4 .. 0.750
25/32 = 0.781
26/32 or 13/16 = 0.813
27/32 = 0.844
28/32 or 14/16 or 7/8 . 0.875
29/32 = 0.906
30/32 or 15/16 = 0.938
31/32 = 0.969
32/32 = 1.000