Really confused with one chamfer that should be exactly the same as the opposite chamfer but doesnt

steve_gladding

Anyone tell me what I've done wrong with this, please?
It works one side and that side seems to be exactly the same as the side that doesn't work.
The drawing is https://cad.onshape.com/documents/c4850c65a704823f825d54c8/w/5b0776dd82c68eb2df03c95d/e/8acb3624f2967138cb251cc6?renderMode=0&uiState=659cb06bd76b9f489969f261
If anyone would like to take a look I would really appreciate it.

dirk_van_der_vaart

I'm not a fan of using Camfer in this case, so I removed them, and added an Extrude en remove extrude.
And another tip, since your design is symetric, make only 1 half and when your finished, mirror add.
https://cad.onshape.com/documents/45cfd502e8032355f11e0371/w/91a2b5aebd3a6880505f7c79/e/343f00603124bdf5f3e45f68

steve_gladding

Ah, brilliant thanks. Not sure how you did what you did but it looks good so I'll carry on

dirk_van_der_vaart

Copy my file and use the roll-back bar and you can see what I have done

martin_kopplow

steve_gladding said:

Anyone tell me what I've done wrong with this, please?
It works one side and that side seems to be exactly the same as the side that doesn't work.

This, in most CAD systems, happens a lot with "Chamfer: Two Distances": The tool does not know which is distance one and which is distance two, so it estimates. First time it is either okay, or you'll switch direction in the dialog. No big deal. Now the tool still does not know about possible symmetries and such, so for the second edge, especially when it does not share topology with the first one, it estimates once again, based on what it can find locally or from the view direction, moon phase, or whatever. Chances it misses are simply 50%, and according to Murphy's Law, much worse if you are not expecting. Not your fault.

eric_pesty

martin_kopplow said:

steve_gladding said:

Anyone tell me what I've done wrong with this, please?
It works one side and that side seems to be exactly the same as the side that doesn't work.

This, in most CAD systems, happens a lot with "Chamfer: Two Distances": The tool does not know which is distance one and which is distance two, so it estimates. First time it is either okay, or you'll switch direction in the dialog. No big deal. Now the tool still does not know about possible symmetries and such, so for the second edge, especially when it does not share topology with the first one, it estimates once again, based on what it can find locally or from the view direction, moon phase, or whatever. Chances it misses are simply 50%, and according to Murphy's Law, much worse if you are not expecting. Not your fault.

Note that Onshape recently added the option to "flip" the direction of individual edges in the chamfer feature.

nick_papageorge073

Chamfer is really the wrong tool to use for what you are after. The way Dirk did it is much better. Or the draft tool.