Chanfers? The quest for the finished edge.

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MeanderBolt
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Chanfers? The quest for the finished edge.

Post by MeanderBolt » Thu Jun 25, 2015 10:30 pm

Another topic for conversation. I have been watching several videos of things being milled. I know, it is a really weird habit, that started when I got the machine.
There, I said it, and I refuse to be ashamed. Heh.

I have several guys who run a chamfering pass at the end of cutting their aluminum bits. It adds a really classy touch. I have several engraving bits (30, and 60 degrees), but I fear that they would not hold up to the abuse. Or perhaps they would. I am still shocked that these little mill bits do everything they do. I am not really sure how I would set up my profile cuts to use the V bit. Would I enter a radius of something like .2 mm as my shaft width, then just mill to the desired depth? It would seem that this should work, and each pass would give carve just a little more of a chamfered edge than the previous, but it seems like this would spell the end for a V bit as they are relatively thin.

Or is there more to the process?
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Hans
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Re: Chanfers? The quest for the finished edge.

Post by Hans » Fri Jun 26, 2015 5:45 pm

I think a lot of places put the chamfer on by hand, and leave it pretty small. Basically just deburring. There are a few different ways to do this, but I have liked the deburring tools from Noga and I've always seen that style in machine shops. If I did a lot of work in metal I'd get a set, they're not expensive.

Since it's easy enough to add chamfer toolpaths in CAM for 2.5D work, go for it. I've had good results chamfering with a 90-degree "drill mill" which is still a solid carbide endmill just with a 90-degree end grind (not a router-style tool, which I also got and was disappointed with). The very tip is fragile and SFM goes to zero there, so use the outside of the V and make sure you consider the actual radius of the part you're using not just the outer radius. When I say fragile I mean the tip would break off in steel, but it works great in wood and probably would also in aluminum.

EDIT: Like this http://www.lakeshorecarbide.com/14coate ... 90deg.aspx
Last edited by Hans on Fri Jun 26, 2015 5:47 pm, edited 1 time in total.
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madhatter
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Re: Chanfers? The quest for the finished edge.

Post by madhatter » Fri Jun 26, 2015 5:46 pm

I have also been wondering this myself, as I am interested in putting either a chamfer or fillet on some of the parts I cut out. I was thinking of using carbide router bits and making some test cuts to determine what settings would be best.

For instance, clamp down a piece of 1/2"-3/4" scrap wood and mill a bunch of outside profile rectangles, maybe 2" x 2" about 3/4 of the way through the scrap. Then experiment with depths and offsets to find what works best.

I think the chamfer will be easier to do than the fillet since with the chamfer you really only need to back off from the edge to make sure you don't end up putting a step in the side because the tip (which is going to be greater than the ideal" 0" thickness) is too close to the edge and you end up with this:

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So, make a bunch of squares, and then you have four sides for different depths and offsets to work with. When I get done with my brackets for the drag chain, I'll post them here and see about working on the chamfer and fillet offsets. I am starting to think I enjoy finding the answers to things like this than making things.
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Hans
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Re: Chanfers? The quest for the finished edge.

Post by Hans » Fri Jun 26, 2015 6:10 pm

You're going to have to be pretty accurate with everything for a corner rounding bit to work. Maybe it would make more sense to use the router like a router, with a bearing-tip roundover bit. Big radii might be tough to do in the machine because the tool diameter has to be something like 3X the radius you want to cut, which might really hammer the machine. There's got to be a way to do it though, at worst with some fine-tuning and multiple passes.
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MeanderBolt
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Re: Chanfers? The quest for the finished edge.

Post by MeanderBolt » Fri Jun 26, 2015 6:36 pm

I can't find the video that I was watching, but this guy pretty much does the same thing. At about 11:40ish He mentions a
Spot Drill / Chamfering mill.
This mill solves my question about killing the engraving bit.
The question is, how to set it up. In his video you can see the bit is offset from the piece, which eliminates the worry of what you described.




Edited to fix link and add second video, and timing info.
Last edited by MeanderBolt on Fri Jun 26, 2015 8:18 pm, edited 1 time in total.
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Hans
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Re: Chanfers? The quest for the finished edge.

Post by Hans » Fri Jun 26, 2015 6:55 pm

For signs and other projects that need the profile to be the very last thing cut, you can actually run the chamfer before you cut the profile. The drill mill will be sturdy enough to go full width in wood. Just remember that for chiseled-looking inside corners, you'll have to do a 3D move like a V-carving program would give you.
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MeanderBolt
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Re: Chanfers? The quest for the finished edge.

Post by MeanderBolt » Fri Jun 26, 2015 8:19 pm

Sorry, I just checked back in and saw that the link was bad.
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MeanderBolt
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Re: Chanfers? The quest for the finished edge.

Post by MeanderBolt » Fri Jun 26, 2015 9:40 pm

For all you CamBam users, I just found this... It's a video on the CamBam page it self. At 10:10 into the video, he talks about how to set up a chamfering op. I had not seen this before, or perhaps, I was not ready to deal with the idea the last time I went through the videos. But it does show how to set it up.
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RobCee
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Re: Chanfers? The quest for the finished edge.

Post by RobCee » Mon Jun 29, 2015 3:42 pm

Haha! I was just about to point you at that CamBam video, as I thought it answered your question nicely!
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