Angles Other than 90

[Chazz]

I am learning more and more. I have experiments that I have done and some I have yet to do. However, once in a while, I come across something that should be do-able; but I just don't see how. One such principle can be illustrate by the following example....

Consider something like a flange. Consider a flat board (say 1 inch thick) and an intersecting pipe (3 inches outer diameter). If the pipe intersects at 90 degrees -- pretty simple. However, what about 80 or even 60? It would seem that we can get mostly there so long as we are willing to flip the board for part of the cut. Even if it were at 45 degrees (part of the cut would be perfect for the 90 degree V-bit), most of the cut would not be 45 degrees. And yet, it seems like it should be do-able.

Thoughts?

Thanks, Chazz

[Brady Watson]

If you have the Z clearance, a wedge of the appropriate angle, can simulate the router/head being tilted on an angle - provided that the azimuth of the bit to part & subsequent edge angle is OK for what you are doing. Then your programming would be the same as you would any other part without the wedge, with the exception of Z depth in order to get the entire profile cut at the lowest portion of the wedge. There are of course exceptions.

The easy way to do this would be to program the part to go as deep as the lowest part of the profile wedge - and you would also eat into the wedge itself. The preferred method, requires some advanced toolpathing, where you would create an underlying 3D shape to represent the part being propped up on the wedge, and then a 2D profile cut projected onto that 3D shape to prevent cutting too deeply into your wedge jig. There comes a point where you reach the law of diminishing return - the closer you get away from 'normal' perpendicular 90 degree 3-axis machining.

Make sense?

-B

[Chazz]

Tilting the material was my first thought; however, the desktop doesn't really have a lot of Z to work with and it would only work for a small portion of the possible uses. It won't work for larger parts or shallower angles.

My suspicion is that is will wind up being a special case for a ball-nose bit that will be working pretty much in 3D mode. I have just stumbled upon gadgets (although the gear gadget that I tried to load does not seem to have done so) and that looks like the right place to put something that can do it so long as I can figure out what to do.

That said, if someone else has already figured it out... well, I like inventing but not re-inventing.... lol

Chazz

[Brady Watson]

You can cut it from 2-sides but it will take a little bit of tinkering. Yes, you can certainly use a 3D strategy - but that is overkill. If the design lends itself to being split down the center, you could get pretty close doing 2 halves, with one side that gets flipped over & face joined - and veneered if you need it to look pretty.

Not sure exactly what you need to do, but keep playing...you may discover something new that would benefit everyone ;)

-B

[bleeth]

Drilling an angled hole is easy with a drill press. Small table top drill presses are pretty inexpensive.
For a CNC strategy to work with the board flat, even with the necessary flipping, I can't see a v-bit doing it at all. In your 45 degree example only two points in the hole are actually 45 degrees from the flat plane. Call them the "ends" of the hole. The angle then reduces as you go towards the sides of the hole.

[Chazz]

Well, I am just in capability exploration mode at this time. I have heard of a job which called for angled instrument holes to be cut for a dashboard. I just wanted to figure how to do that so that I would not have to say "no" if asked to do it.

For my own use, I was looking at possibly making some of the junctions for my vacuum system. I know that they could be purchased for $6 or so each; but then you don't get to customize it.

But really, I am just experimenting with the edges of the capabilities of the desktop.....

[twelchPTM]

there was a SB for sale on here a while back that had bin fitted with a custom tilt-mount for the router...