You want to minimize the work your dovetail cutter has to do and they're not really designed to do the full slot. Be sure to open a slot as wide as you can with a regular endmill that is also slightly deeper than the dovetail. They're all delicate, but the dovetail is perhaps the most delicate of all. The concepts are applicable to any form cutter if you think about it. I came across a great thread on PM while researching Dovetail Cutter Feeds and Speeds.
Cnc dovetail program free#
If you haven't tried G-Wizard, sign up for the free 30-day trial. You might also consider dialing the "Tortoise/Hare" slide all the way left if you're not in a great hurry-you'll get better surface finish, and since these cutters are delicate, and that will further minimize the stress on the cutter. To calculate feeds and speeds for a Dovetail, use the Geometry menu (circled in red) and select the closest angle to your dovetail's.įor diameter, be sure to use the diameter of the dovetail, not the shank. It's simple to use, just pick the nearest angle to your dovetail (a lot of angles are available) from the dropdown Geometry Menu: Our G-Wizard Feeds and Speeds calculator has support for Dovetail Cutters. If you're not a registered G-Wizard user and you'd like to try our free 30-day trial, check it out on this page. It also allows the engraving to follow a contour if you aren't engraving a flat surface. I assume the spring-loaded holder helps cushion the V-Bit's delicate tip from undue shocks and lets it sort of find its own feedrate that works by backing off the depth if there is too much force involved. G-Wizard's Feeds and Speeds for V-Bits assume a rigid holder, but you can double the feedrate if you have a spring-loaded holder.
I bring them up because one of the things they mention for CNC'ers is you can run a lot higher feedrates if you use one of their spring-loaded holders for your V-Bits. There's more there than engraving, but take a look for tips. If you don't use G-Wizard, you can see that the trig needed to figure out the effective diameter is pretty simple.īTW, 2linc is a great manufacturer for all things engraving and is one seller of V-Bits. If you're working with really nasty material (tough stainless or the like), you might consider using the gas pedal (Tortoise and Hare slider) to go a little more conservative. Equally as important, it will dial back the feedrate quite a lot to account for the fact that the pointed tip is more delicate than a typical endmill. That will cause it to figure out the rpm and feedrate differently. It starts figuring out the effective diameter based on the angle of the V-Bit (30, 45, 60, or 90 are the commonly available tip angles) and the diameter. Once you select a V-Bit from the geometry menu, G-Wizard does several things: Geometry menu for selecting ballnose or V-Bits. You'll use the geometry menu to tell G-Wizard that this is a V-Bit and not an ordinary endmill: Choose either HSS or Carbide, depending on what material your V-Bit is made from. To select a V-Bit in G-Wizard, treat it like an endmill. The effective diameter in an 0.010" depth of cut is only 0.020"! Here is a diagram showing the effective diameter for a 90 degree V-Bit with a 0.010" depth of cut: It turns out that since you're only down in the cut 0.005-0.010", you need to run a lot more rpms and treat things much differently, even though you may be running a 1/4" shank tool. That brings me to the second issue, which is that the "diameter" of your cutter is, well, not the diameter in the cut!īecause of that, G-Wizard needs to do compensation to figure the effective geometry just like it does for a ballnosed endmill. That at least means that chip clearing should be easy and the cutting forces shouldn't be too great. The good news is they're best used with depths of cut of say 0.005 to 0.010" (0.1 - 0.2 mm). First, that sharp point is a bit delicate and the geometry is not nearly as optimized for plowing through tons of material as a helical endmill. They do a very nice job engraving, but feeds and speeds can be a bit tricky for a couple of reasons. They come in all shapes and sizes, but usually they look something like this: Let's go through the G-Wizard support for a couple types of these cutters.Ī V-Bit is a special purpose bit intended for engraving. Deciding how much to derate the chipload from that of a standard endmill. Deciding what part of the cutter's geometry to use when calculating diameter and from that, surface speed. When calculating feeds and speeds, it's a matter of dealing with at least two issues: V-Bits for engraving, and Dovetail cutters are two good examples. Milling form cutters have special profiles and are used for special situations. Feeds and Speeds for V-Bits, Dovetails, and Other Cutters
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