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Loading ...Measuring and cutting
syrillian
“Thank you” to the individual that sorted out the image issue. Please bear with me as I am an old dog trying to learn new tricks.
Safety is once again paramount. I forgot to mention in my last post that loose clothing, dangly jewelry, and long hair can be quite dangerous. Dressing and coifing appropriately will see you through the day with all your digits, limbs and scalp still in place.
There are basically three types of cuts that apply to this build; rotary tool, circle saw, and router bit. These are listed in the general order of cleanliness of the cut from roughest to smoothest. This may vary depending upon the condition of the tools and the cutting implements, but all things being equal, a rotary tool cut is the roughest, and router bit cut is the smoothest.
Note that a table saw with a 10” (75-80 tooth) blade designed for cutting plastics will yield a cut comparable or exceeding the quality of a flush-rout cut. Also bear in mind that these blades can be rather costly; the last one I priced was about US$ 100.00
Before I move on it is notable to mention that there are two basic types of acrylic; “cast”, and “extruded”. Cast acrylic will not suffer the “melting” syndrome that extruded acrylic seems to suffer from when exposed to the gentle ministrations of a power tool that cuts.
Here is an image depicting the cuts (from top to bottom: Dremel, Circle Saw, Router)
The rotary tool cut will require some sanding before it can be used for capillary bonding, and a considerable amount of sanding prior to polishing (capillary bonding and polishing will be covered later on in this Log). Both the saw cut and the Router cut are ready for bonding, and need far less sanding for polishing prep-work.
One subtlety that can ruin a project is how out of square the panels are. “Square”, as in how close to 90-degress all applicable angles are. This project will be constructed with all angles at 90-degrees. For the most part angles that are off-square by 1/32” across a 12+ inch edge can be fudged to work and look okay. One pitfall is that such errors and inconsistencies may cause minute gaps between two panels that need to be bonded together; the gap prevents a full and proper bond.
When I mark a place to be cut I use a “v” shaped mark with the convergence-point at the line to be cut. This allows for a more accurate visual marker than a single line. Using a dot also works well, but can be a strain on the eyes.
Cutting with the Circle Saw:
Measuring and accounting for built-in measuring gauges and guides on tools will save a lot of frustration, time and money (speaking of measuring, please be patient with me as I may switch between Metric and SAE throughout this Log).
I use a 2’ level as a straight-edge guide when I use the cordless saw. To ensure that a cut is right the first time, there are several things to consider: Blade width, Guide width (on the saw) and which side of the line on the acrylic that the saw blade will cut.
There are several methods to use, but I will describe the one that works best for me and keeps me from making too many mistakes.
The guide on the saw is 1” wide
The Blade is 1/16”, but with the angle of the teeth the effective width is 1/8”.
You may notice that in the next image of this acrylic panel that the line is not entirely bisecting the “v” mark. There are 2 basic methods for cutting along the line:”Leave the line”, and “Remove the line”. I choose the former as I can see that the cut is correct, wherein removing the line removes the marker. This allows a little leeway for sanding when necessary.
1” out from the guide, and 1/8” less to account for the blade (but you will want to make certain that the measuring tape is butted up against the rail… unlike me in the pic below.
Using an angle, level and tape measure to set up the guide:
Clamped down:
Ready to cut:
Always: Measure twice, cut once. When the guide or jig is clamped into place I always check all relevant measurements again prior to cutting.
As I cut the panels to size I mark them appropriately with what panel it is (front, back, top, bottom, etc., and the orientation (up, down, front, back, etc
A rotary tool can also be used to cut straight lines; it will require the sideways bit.
You will also need the straight cut guide attachment.
The simplest way to guide the cut is with the edge of the panel that is being cut.
This attachment should also have its own markings for measurements which makes it very handy to use.
The next installment will cover profiling and cutting holes in the acrylic.
My apologies for the inconsistent image sizing and quality. I am still trying to work out the error that seems to exist somewhere between the chair and the keboard.