Hello, I’m newly with cnc. I would like to know if I can use a 45 degree bit to do 90 degree joint for boxes? Using a 3/4 red oak.
Thank you,
Lets define angles for Carbide Create. A 90 degree vee bit is two 45 degree angles meeting at the center. In the past and on some applications the vee bit is defined not by the 90 degree angle but the half that shows which 45 degrees. The standard for #301 90 degree vee bit is the application calls it 90 degrees consisting in two 45 degree angles.
So if you want a 45 degree edge on a board then you use a 90 degree vee bit which would cut at 45 degrees. Likesise a 60 degree bit consists of two 30 degree angles equaling 60 degrees total.
If you have a bit defined in Carbide Create as a 45 degree bit then the effective angle for cutting would be 22.5 degrees. Cutting a 22.5 degree angle on the edge of your work piece and joining two 22.5 degree angles would result in 45 degrees and not 90 if you are trying to make a box.
See John Clark on youtube.com Cubism: Making Cubes on Shapeoko - YouTube about making angled side boxes.
Your question about making a 45 degree angle on 3/4 inch oak may be possible but the length of the cutting bit is the determining factor for cutting the depth of an angle. Other applications like Vetric and Fusion 360 and others are easier to make the long cut on 3/4 inch material but others will chime in on how to do that.
You would use a 90 degree bit for that. A 90 is 45 degrees each side for a total of 90, but it’ll give you the 45 degree at the end of the board that you want. A 45 degree bit is 22 1/2 degrees each side.
Edit: @gdon_2003 beat me to it
It is not a race. Both our answers are correct.
I understand. Can I use any other 90 degree bit? Because of the depth issue that you mention.
That I cannot answer. I have never cut a 45 degree angle on 3/4 material. You would have to look for a different bit maybe. It may be possible with the #301 or another but I just have not made one. In John Clarks video I linked to the material size is .24 inches. The #301 bit is 1/2 inch cutting depth.
You could experiment and set up two squares like John Clark did but with the cut depth you would have to adjust your material to get the 45 degree and still have the size box you want. Sometimes it is just trail and error finding a solution. a2+b2=c2 so .75 Squared + .75 Squared =C Squared (use square root of C Squared) 1.06 inches length
Someone mentioned earlier on the forum the 70 Maximums for Mercenaries and #70 says:
Failure is not an option - it is mandatory. The option is whether or not to let failure be the last thing you do
Hopefully someone that has done this can chime in.
I’ll try… thank you
Yes, see:
and
Another newbie question - is there a reason that you wouldn’t use a table saw to do this in one step?
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@clintonmagus Right…or this bit using a handheld router or in a router table?
Couldn’t you also model the edge as a 45 degree chamfer in CM Pro?
Wait for it …
With hammer in hand … everything looks like a nail!
If we use a 45 degree bit, we can get it in there:
I’m not poking fun at the original idea…but if we’re going to other software packages and doing all sorts of manipulations to get a box to join, why not do it a more tried-and-true way? We’re after precision…I get that…and a 45 degree tablesaw cut might not get you what you want (depending on a lot of factors), but the chamfer bit will. And there’s still the idea of modeling the grade - but I don’t think it will be smooth enough to be a joint.
I tried doing joinery with the 3D modeling features, but never felt quite comfortable enough with the dimensions since it wasn’t possible in Pro to rotate parts and subtract one from the other to check the fit.
@WillAdams Yes…and given the variances of a ball-end for the finishing pass, I can’t imagine the joint would be very tight anyway.
That’s a good point about possible variations — I’d like to think the machine would be precise enough to make them small enough to fit w/in a glue line, but I’m having enough trouble just directly drawing and cutting joints it hasn’t seemed feasible to be looking into yet — maybe once I finish up the mortise and tenon joints I’m working on now.
I’m not sure I understand that, Will. Wouldn’t it (theoretically) work if I rolled one of these into a 90 degree orientation with the other? You’d have to work out the rest of the geometry for the pieces, but just having these two edges at 45 angle elevations would do the trick if the cut was clean enough…yes?
Yes, it should work — I just found the need to extend past the stock a pain, and was trying to do slightly more complex joinery than a mere 45 degree miter (which I found easy enough to do with a V carving as noted at the links I posted).
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