How to make screw mounts on a box..

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Ank
Posts: 12
Joined: Thu Sep 19, 2019 5:22 pm

Re: How to make screw mounts on a box..

Postby Ank » Fri Sep 20, 2019 8:21 pm

@kisolre - thank you.
>>Symmetry for the base sketch for easy placement of later features. (I did not knew that would help later)
>>Sketches drag/dropped over the body name to place them inside the body.(I usually used the "map sketch to face" - did not know drag'n'drop was possible)
>>Mapped to base planes for propper attachment. (will try to learn what base-plane is, and why that is better than whatever I did)
>>Screw holes connected to supports with CarbonCopy. (must learn that feature)

thank you, I'll study what you did and learn to do that myself.
This is my first CAD of this type, I were using OpenSCAD for years, but it is not "the right tool" for every project.
kisolre
Posts: 1359
Joined: Wed Nov 21, 2018 1:13 pm

Re: How to make screw mounts on a box..

Postby kisolre » Fri Sep 20, 2019 9:13 pm

Ank wrote:
Fri Sep 20, 2019 8:21 pm
I did not knew that would help later
Here we are using mirror to create other supports from the first one. Since the basic shape can be symmetric it is easy to mirror over base planes (XY, XZ, YZ) instead of defining extra planes. So creating the model around the center helps later.
Ank wrote:
Fri Sep 20, 2019 8:21 pm
I usually used the "map sketch to face" - did not know drag'n'drop was possible
If you check Dependency graph you will see that in your model those sketches are outside the body. They can still be used inside the body but this is not proper. If you move the body sketches will stay in place and this will change the body. Drag/drop makes them to be inside the body as a container and their placement will be later relative to body placement. Attachment creates a rule to calculate the placement from other things - placement of another face, plane defined by 3 points,...
Ank wrote:
Fri Sep 20, 2019 8:21 pm
CarbonCopy
Sketcher_CarbonCopy is used to copy all geometry from another sketch (real and construction) as real or construction geometry in currently edited sketch. It also copies all constraints but dimension constraints are linked with expressions to the respective constraints from the first sketch. Thus changing dimensions oin the first sketch moves respective elements in the CarbonCopied one - here hexagons follow circles.
chrisb
Posts: 18029
Joined: Tue Mar 17, 2015 9:14 am

Re: How to make screw mounts on a box..

Postby chrisb » Sat Sep 21, 2019 12:48 am

Ank wrote:
Fri Sep 20, 2019 8:21 pm
(will try to learn what base-plane is, and why that is better than whatever I did)
Base planes - also called main planes or, according to my dictionary, principal planes - are the XY, XZ, and YZ planes. They never change and that's the advantage over attaching sketches to faces. Redimensioning or even adding new edges in previous steps can renumber the faces in a way that the attachment gets lost.

If you don't care about that, the easiest way to proper attach and place the sketch inside of a body is to switch to PartDesign workbench, select the face and then create the new sketch from inside PartDesign, not from Sketcher workbench.
Ank
Posts: 12
Joined: Thu Sep 19, 2019 5:22 pm

Re: How to make screw mounts on a box..

Postby Ank » Sat Sep 21, 2019 11:25 am

Screenshot from 2019-09-21 09-15-03.png
Screenshot from 2019-09-21 09-15-03.png (34.88 KiB) Viewed 33 times
1: how/why did you choose to place the "revolution" sketch centered in the corner?

it appears to be manually placed there. , and yet works fine for mirroring.

2: What is the advantage vs placing it a certain distance from the origin ?
I guess using variables it would still resize even if related to origin,(if the box size changed) - but I guess what you did makes it properly stuck to the corner, thus handle resizing of the box without the use of variables.
kisolre
Posts: 1359
Joined: Wed Nov 21, 2018 1:13 pm

Re: How to make screw mounts on a box..

Postby kisolre » Sat Sep 21, 2019 3:05 pm

I just manualy edited attachment offsets of the sketch untill it was exactly in the corner. But you could give names to dimension constraints in the first sketch of the box and then use expressions to link sketch position to edge of the box. Thus changing box dimensions will move the sketch to allways stay in the corner. I placed it there to be easy to rotate around its axis to create the feature. No extra axis needed. It works well for the mirrorings because the basic box is symmetric around vertical axis and so symmetric around XZ and YZ planes - mirrors go exactly to the other side.
Ank wrote:
Sat Sep 21, 2019 11:25 am
thus handle resizing of the box without the use of variables.
It will not follow the box since it is in fixed position in space. Using expressions as described above will make it follow the box.