feature request, extend fillets to have a 'dogbone' option

david_lang457

when CNC cutting, it's impossible to eliminate a corner radius from parts. The fillet option allows you to round the corner, with the edges of the curve tangent to the sides, but when you have to mate that piece with the corresponding angle that's not rounded, it doesn't work and manual work is needed to make the pieces fit. The 'dogbone' solution to this is to cut a little more in the concave corner to give clearance for the actual angle to fit.

the naieve approach to doing this is to move the cutter so that the center of the cutter is at the corner of the angle, but this is making a much larger cut than is actually needed.

Please consider extending the fillet tool with a checkbox that would instead make the curve touch the corner of the angle (and if the angle is < 90 degrees, have a slot the same width as the diameter of the fillet)

I created an example doc that lets you change the corner angle and shows that angle, and that angle + 90 degrees, comparing this 'dogbone' version to what a fillet would produce.

https://cad.onshape.com/documents/933036b68befc7cadd1faa6d/w/16319fd3e32ea8876de6c23b/e/5e9a31bf32b327c5cf0f251e

david_lang457

If you look square on from the top, you see the matching pieces fit, if you look square from the bottom you see that the matching piece would not fit with the fillet

S1mon

This seems like a great opportunity for a custom featurescript. It doesn't really make sense as part of the regular fillet tool.

I could see adding options for a small tolerance clearance at the sharp, and also an option for adding fillets to get rid of the sharp corners.

eric_pesty

Does this help?
https://cad.onshape.com/documents/b99915c0b73924ca981bc57f/v/231175f206330e24f92ddfab/e/aa559abd05b5610c0ffb6b81?jumpToIndex=1871

david_lang457

@eric_pesty
I think I've seen that before, and it makes a full hole centered on the corner (square or round), what I'm looking for is the easy ability to make a smaller cut in the part.

@S1mon
I am suggesting it as a modification to the fillet tool as the work that's being done is so similar. for angles >= 90 degrees it's just a change to have the curve touch the point instead of having the edges of the curve be tangent to the surfaces. (a little more complex when the angle < 90). I'm trying to avoid yet another special tool to be added to the toolbar :-)

S1mon

@david_lang457

Fillet currently does so many things, adding this option makes perfect sense for your needs, but for many others it would be something that they might never use. It probably wouldn't be that hard to take @MBartlett21's feature and improve it to have the options that you want. That's the beauty of custom feature scripts, and so many of them being public. An extra tool added to your toolbar is a small price to pay for the functionality that you want, but added complexity to the fillet tool that nearly everyone uses in Onshape would bog down a lot more people.

david_lang457

It may be that this belongs in the CAM step.

michael3424

Would the Laser Joint featurescript be useful for you?  If not directly, you might be able to re-use some of the code in your own fetaurescript:

https://cad.onshape.com/documents/578830e4e4b0e65410f9c34e/v/d2bbf038b14307b6c4b70c15/e/7af109b2f1cead90850525ae