Are Sharp 90 Degree Inside Corners Possible without Intersecting 2 pieces

[zeke]

Anyone know if it is possible to cut an inside corner of a closed rectangle (an ' L ' shape cut) where the results are not rounded in the corner without having to intersect 2 or more separate pieces? The challenge is using a round bit to cut the inside corner yields the shape of the bit. I guess I could go down to a 1/16" bit and then file from there but it sure would be nice to the let the Bot do the work somehow. Anyone figure out a way around this? I included a drawing to look at what I am trying to cut which is the inside rectangle.

4963

[Gary Campbell]

Zeke...
The inside corner will always match the radius of the bit. A V Bit can be tooltpathed to yield a square inside corner, but the sides of the cut match the angle of the V bit. Sorry, no magic.
Gary

[tmerrill]

Zeke,
What are you trying to make? If this will be exposed and you want/need square corners than it's like Gary said.

But if you are trying to make mortises, or some other application that will be hidden, doing a dog bone fillet will allow a square cornered object to be inserted. The latest versions of Aspire and PartWorks has an option that will do this for you. Not sure about other software packages.
Tim

[richards]

Most cuts in the pre-CNC days were made on table saws and then the various parts were assembled to make a finished product. Today, with the CNC router as the primary tool for cutting, we need to rethink the situation. I've told my customers, those who wanted sharp non-V-cut corners, that with my machine I could produce a softer effect that didn't have the harshness of a sharp corner. In other words, sell what you can produce. You can still offer sharp corners at a higher price - because you'll be busy with a file or chisel or saw to 'sharpen' those corners.

[blackhawk]

Zeke - I have done this trick that works pretty well. I have Vectric software. I use a V-bit a run a profile toolpath and select the "sharp corner" check box. Then I go back with a 1/4" endmill and pocket out the area. This will give you a perfect square at the top surface. Then you can go in with a chisel and clean up the small beveled area left by the V-bit in the bottom of the corner. You may have to play with the offsets in the profile toolpath to get the V-bit and endmill to line up, but it works.

[zeke]

Great feedback, sounds like a V bit is the way to go without manual labor with a slight angle cut or perfect squares with a little manual labor. Decision time for me, this helps, thank you!