Full Version: Cutter types & sizes
From: Harvey only (HARVEY-ONLY) [#1]
27 Oct 2004
To: ALL
I'll try to keep it short.
<font size="3" color="#0000FF">Types of bits:</font>
<font size="3">Drag:</font> Sharp pointed diamond for scratching lines in metals. If used on stainless steel without a featherweight will damage the bit first letter, the very tip will chip and the bit will be bad for coated metls.
<font size="3">Bunishing:</font> Diamond (also called rotating diamond (RD)), carbide: used for metals, especially black brass, for a thick line. You need diamond for aluminum. Use high spindle speed.
<font size="3">FLX:</font> A cutting bit that removes material for engraving flexable sign stock and acrylic. Once used for acrylic, reserve for acrylic until resharpened or it will give poor results on flex. Use mediun spindle speed for flex, and fairly low spindle speed for acrylic. Keep acrylic cut shallow for each pass for best results, I go generally .004. [I used to have to go .022 a pass but that is a different story.]
<font size="3">BAL:</font> Brass and aluminum material removal. Do not try to remove much in each pass, especially on aluminum, or you might get burrs at the edges.
<font size="3" color="#0000FF">Bit Sizes:</font>
The best formula for bit sizes is as follows. Divide line height by 8, then by the number of lines in the font. Then if you want the font solid, (e.g. Roman), multiply by about 1.3. If you want to see the lines, (e.g. Old English), divide by 3. For filled letters always select the first bit bigger than calculated, for lines always select the first bit smaller than calculated.
I keep columns of bits for Burnish, Acrylic, Flex, and BAL:
Rows of bits are in the following sizes:
.005, .010, .015, .022, .030, ,045, .060, (for a special job also .070), .090, .135.
That is a lot of bits but the final job shows the difference. When you order bits you can get them made in any size at no extra cost. (New Hermes may not supply the oddball sizes, but the cutter companies do.)
I think that is the nutshell version.