The problem I encounter most often while doing woodturning is that the finished piece does not reflect the
original design idea. I have found that first using SketchUp to model the concept helps quite a bit
in realizing my ideas much more accurately. Even if you don't have a clear idea of what you want to
turn, you can use the techniques you will learn in this article to explore design variations before
heading out to the shop. Once you have created a model you are happy with, you will see how to create a section-cut of your
model to use as a template when working on the lathe.
The "follow me" tool is used to extrude a shape or profile along a path. You can use this tool
one of two ways. First, you can select the tool from your toolbar or from
Tools>Follow Me
, click on
the profile or shape you want to extrude and drag it along a path. I find for simple tasks this
works fine. However, if your path is long or complicated, or when doing a turned model, I prefer to
select the path first, then click the profile face with the "follow me" tool to extrude it along the
selected path. I use the second technique most of the time because the results are much more
predictable.
STEP 1:
Draw a rectangle along the red and blue axis in your modeling window. Size isn't important
right now, as we will re-size the model later in the process. The reason for starting with the
rectangle is so that you will have a surface to draw your turning profile on. (The red, green and
blue axis do not show up in the screen shots shown here, so I will indicate where the axis in the
model should be considered)
STEP 2:
Draw the outside profile of the bowl on the rectangle's surface. Your design doesn't need to
be exactly like this one. However, in the second part of this article, you will be working with this
model to create a footed bowl with handles and a lid. Keep this in mind when coming up with your own
design. HINT: When drawing on a surface, it is best to be facing that surface.
STEP 3:
Use the offset tool (
TOOLS>Offset
) to create the inside face of the bowl. This tool works
well when making things like concentric circles or frame and panel cabinet doors. When working with
a more complicated shape, like this one, a bit of clean up will be necessary. Erase the extra lines
and draw new lines to create a profile similar to the one shown here.
STEP 4:
Using the circle tool, make a circle on the floor plane that is aligned with the center of
your bowl (as shown in the figure). The size of the circle does not matter. It is only the path that
your profile is going to follow when using the "follow me" tool.
STEP 5:
You can now erase all of the lines on the rectangle not associated with the bowl profile.
STEP 6:
With your "select" tool, click on the face of the circle to define the path your bowl's
profile will follow. Next, using the "follow me" tool, click the profile and watch the magic. NOTE:
When pre-selecting a path in this step, your selection will seem to disappear as you pick your
"follow me" tool. Don't worry – the selection is still active.
STEP 7:
Now that you have a completed model, we will make a template to use while working on the
lathe with the section plane tool. Start by drawing a rectangle (just like you did in step 1) beside
the bowl along the red axis. The size does not matter.
STEP 8:
Choose
TOOLS>Section Plane
and click on the face of the rectangle beside your bowl. You will
notice that the section plane rotates to align to the face that it is in contact with. By creating
the rectangle, you create a face that is aligned with the center of your bowl. By selecting the
rectangle with the section plane, you get a proper cross section view for your pattern. You can go
ahead and erase the rectangle.
STEP 9:
If you haven't been building your model to a specific size, we will take a moment to re-size
it now. Choose
Tools>Tape Measure
. Pick a specific distance on your model such as the diameter of
the bowl opening. Click once to begin your measurement, then click a second time at the end of your
measurement. Type the value you want for this measurement (e.g. 3") and hit enter. You should see a
dialog box asking if you want to re-size the model. Click "yes."
STEP 10:
In order to print your model to scale, there are two things you have to do. You have to
turn off the perspective view. Choose
Camera>Parallel projection
. You will also need to be in one of
the standard views (top, bottom, left, right, etc.) If you have built everything as indicated, you
will want to choose the front view from
Camera>Standard Views>Front
. After doing this, you should
notice that the view you picked is indicated in the upper left corner of your modeling window.
Before you get ready to print, choose
Camera>Zoom extents
. This will fill your modeling window with
your entire model. This also comes in handy when you have either lost your model or have gotten lost
in your model.
STEP 11:
Now you are ready to print. Your view should be similar to the picture.
Choose File>Print
Preview to open the print dialog box. In the "Print Size" section, deselect the "fit to page"
option. You will see that you can now adjust the scale to your preference. Make sure the value "in
the printout" matches the value "in SketchUp." In the bottom right corner you will see an option to
print the 2D section slice only. Select this option and print away. You can now use these printouts
to make templates by gluing them to some heavy card stock and cutting them out. You will probably
want to make several templates for different sections of your turning.
I hope you found this information helpful. Please join us next month to see how to complete your
bowl with a lid, feet and handles.
Sean Headrick, a former Atlantan once seen frequently at Highland Woodworking, now lives
in San Jose, California where he does woodworking and design.
His website is
www.headrickdesigngroup.com
.
Sean was
interviewed by Wood News
in 2007.
