Need suggestions on how I can make this part (similar to washer)

[YeeP]

Still trying to learn what a fillet is and how to define it.
The use case is this: It will go in the hub of my offroad vehicle to act as a "blank" hub flange. The outer cap will need to bolt to it. Here is an example of a setup that comes with the "blanks"
https://www.tmrcustoms.com/axle-drivetr ... line-black

Mine did not come with them, so I am trying to make them. You essentially use them like you would unlock your hubs when going back on the road, except these cannot be unlocked. The drive flange has to be pulled out of the inner hub, then replaced with this blank, so the cap can be bolted back on to protect from the elements.

As I do not have the whole setup right here, I can at least give some dimensions/constraints that should apply. If there is any way you guys could talk to me like I'm 5 years old in explaining this, I am still trying to teach myself how to use freecad.

Outside diameter: 3.25"
center to center of bolt holes: 2 & 9/16"
Bolt diameter: 1/4" (only given so the tabs would have enough "meat" to be able to drill a hole)
axle shaft diameter in center of hub: 1.5" (I would call this ID, but since this is no longer a washer, it is really just a measurement to show where the "washer" would contact the axle shaft)
Plate thickness: 0.25"

Keep in mind though, this is going on a plasma table and the bolt holes (I dont think) can be that accurate. I am probably better off drilling and tapping, or welding a nut to the back of the washer after drilling)

I will continue to download these files to try and learn, thank you for your time and I appreciate your patience.

[YeeP]

My own try with only one sketch, extensive use of reference geometry, and fewer dimensions as reasonably possible.
As said by others, not better, just different.

Your use of these constraints is beautiful! Much easier for me to understand. I will try and see if I can change them and get it to work.

[kisolre]

Still trying to learn what a fillet is and how to define it.

Look at chrisb and openBrain designs. In the sketches you will notice those small arcs tangent to there connected edges/arcs. The surfaces created by those are the fillets. They are defined by their radius. You can measure them with a radius gauge (like a feeer gauge but with exact radius arcs for each radius). But if there is no problem with interference with other parts this is not critical in your case.
Dimensioning openBrains design will be the easiest way I think.

[YeeP]

kisolre - thanks! That really helps me understand what I am looking at.

[openBrain]

A bit more time now. There is a high chance this post will clutter the thread. Sorry for that.

I am really just trying to learn more about how to use freecad and the best way to make this part.

Just be aware that learning FreeCAD is one thing, but learning 3D CAD is another one. Most of time people that are beginners with both encounter more obstacles, but IMHO it is worth the effort.

Here is where I am at so far, I started with the Parts workbench, and used the method described here: https://www.freecadweb.org/wiki/Washers to make this:

Notice that using Part WB wasn't a bad idea actually, but as you discovered it, the users replying to you ATM are essentially PartDesign WB addicts.

Thank you @kisolre. Can you explain how you did this so I can learn? I will open the files you uploaded to see if I can learn from that.

This a good way of learning. Do not hesitate to ask for further explanations if needed (I myself didn't deliver too much details at the 1st reply, but answer further questions when they raise).

Interesting how much can be learned from a washer.

Definitely. Despite as a washer, this is a complex one. Advantage of "simple" parts is that we can, in a reasonable amount of time, open the designs made by others to look how they're done, and hopefully propose another one.

Could you send some R3 drills
Better dimension diameters More clutter but still...

Sorry @kisolre, but I didn't get the point here.

Your use of these constraints is beautiful! Much easier for me to understand. I will try and see if I can change them and get it to work.

Huh... Thanks. I have to admit that I cheated a bit as the drill "ears" seems to have tappered sides when I just applied raw horizontal & vertical ones. I attach to this post a slightly modified design that will improve that (physically it will slightly improve the part robustness).
Good thing if you can modify dimensions by yourself, I should say that imperial units aren't very natural to me.

Still trying to learn what a fillet is and how to define it.

kisolre explained it well. Fillet are basically rounded junctions between faces. They can be needed for design purposes (a square junction between faces is highly sensitive to crack if a shear stress applies on it) but also for manufacturing purposes (eg. machined part obtained through milling).
Fillets can be obtained either by sketching them directly (Sketcher CreateFillet) or as an extra operation on the solid (PartDesign Fillet). The latter will lead to breakage in some cases in FreeCAD while the first way is more stable.

[YeeP]

openBrain, I downloaded your file and cannot see any of the lines. Sorry for the newb question, but how do I toggle them to be shown? If I open the sketch I can see what I think are the constraints, but thats it.

Edit: Ok I see how I can toggle visibility. I will try and see if I can adjust these constraints to make the "washer" the correct size for what I need.


Also: Since this is a Plasma table, doesn't it just take a 2D cad file? One that has the shapes but no depth. I know that on the table, the user defines a burn in area on each drawing, hoping the table owner can do that for me, but how do you output this file in the proper way for someone to use it in that kind of device. I am guessing he has a preferred file extension, but on my end is there some sort of transformation I need to do on the data to make it usable for the table?


Thank you again.

[kisolre]

By some reason the Pad in openBrain's last file is hidden. Select it from TreeView and press "space" (toggle visibility).

Sorry @kisolre, but I didn't get the point here.

I was just typing about measurable real life dimensions. And in your sketch all constraints are radii so the R3mm is D6mm hole - you can have a D6 drill but I have not heard about R3 one
On that note one could use a drill bit as radius gauge to check size of internal fillets...

[kisolre]

You should ask the manifacturer what he needs/prefers as file format. Probably a DXF will work. Select the washer body and File/export to file type "Autodesk DXF 2D (*.dxf)"

[openBrain]

By some reason the Pad in openBrain's last file is hidden. Select it from TreeView and press "space" (toggle visibility).

openBrain, I downloaded your file and cannot see any of the lines. Sorry for the newb question, but how do I toggle them to be shown?

Indeed. Don't know why too, but the part was set as not visible in my saved file. I edited my previous post to fix the attached file.

I was just typing about measurable real life dimensions. And in your sketch all constraints are radii so the R3mm is D6mm hole - you can have a D6 drill but I have not heard about R3 one

You're right. And my habit is to dimension all drills (and complete circle in general) with diameter. But FC defaulted to radius, and I did it quick.

Also: Since this is a Plasma table, doesn't it just take a 2D cad file? One that has the shapes but no depth. I know that on the table, the user defines a burn in area on each drawing, hoping the table owner can do that for me, but how do you output this file in the proper way for someone to use it in that kind of device. I am guessing he has a preferred file extension, but on my end is there some sort of transformation I need to do on the data to make it usable for the table?

I indeed guess that plasma tables use 2D format, probably DXF.
The advantage of having everything in one sketch is that it is easy to export. To do so, just enter in sketch edit mode (double click the sketch in the tree view), then select the lines to be exported (only real "white" lines will be exported, so you can basically select everything in the sketch), and finally File -> Export / Autodesk DXF 2D.
Oppositely if you used a construction with several sketches & operations, you have to use the TechDraw WB to draw then export the shape.

[intufreecad]

Hello everyone,

I think the solutions with sketches are very elegant. But there is also another way, working only with part workbench and draft workbench.
The power of freecad makes that even such solutions stay parametric.
Of course ther might be cleaner ways to model the thing than i did. but it serves to show another way.

By the way i love freecad and i am enjoying this community too much