How to model a knife/blade?

tj_thorniley

Any ideas? Doesn't have to be fancy. Just need the basics.

3dcad

As always, there is many ways to do it. I would probably first model the shape from side and then add chamfer for the blade.

Paul_J_Premakumar

I'd start with a profile + extrude. Here is an example of a blade : https://cad.onshape.com/documents/de085365664663b2eb321a12/w/c075b911e136093c9f606468/e/005e3aaabdd1bb2c783012b5,

For a more detail version : https://cad.onshape.com/documents/577e70d0e4b03be38b75a64e/w/61c599a0b344de45bc668211/e/3bdf1b3660491e15e6c516dc . I found this by searching for "Knife" in the public models.

tj_thorniley

Nice suggestions, guys. I'll share mine when I'm done.

Jake_Rosenfeld

Here's one I made for 3d printing a keychain a while ago:
https://cad.onshape.com/documents/ec4d9c75a4f6b2b6741f2799/w/ce408aac3197e266c0b46523/e/2a1630ebfa945ac5703a4289

It can be sharpened by changing the "cutFromSides" variable.

tj_thorniley

Thanks @Jake_Rosenfeld. 
Heres a double edged blade I've been trying to figure out: 
https://cad.onshape.com/documents/c6c84af53c8c6df7bbc4af65/w/1c9bccd88d084be1294750d8/e/10bd9fd89a3bba7368045884
I've attached an image to the document. It depicts several blade types, for illustration purposes.
I'm trying to build the one called "Spearpoint".

Tony_C_

I'd have to import this in to OS.  One of those side projects that never gets finished.....

tj_thorniley

I made some progress, but I'm stuck again with this groove in the middle:

Tony_C_

If I recall how I made my knife, I think I started with the profile shape then used angled planes to remove what I didn't want. 

John_P_Desilets

tj_thorniley



 Tony_C. I completely agree.

You can try designing the blade the way you would cut it on a grinding wheel or on a cnc machine for example. Start off with a steel blank, and cut away at it. Below is a simple extrude with a series of splits made a various angles. You can use the final feature to see how the geometry will change on the blade as you move forward. 


https://cad.onshape.com/documents/bc8c9f4966a9f725e0a6afa2/w/57a99f2da89a0fad0cdb4c20/e/1b796cf3caa79f8884a0aeab

tj_thorniley

I kinda got it by chamfering and specifying an angle >80º:

Except the flat bit is supposed to be towards the base, and away from the tip. Like this:

Not really sure how to get it the right way around, because in Onshape, the bevel naturally follows the edge of the blade.

John_P_Desilets

 tj_thorniley

For making this style of blade you can try using surface lofts. Below is a quick example I made of what you can do with our surface tools.

https://cad.onshape.com/documents/c445a2a98e822aa0e6d524ac/w/e6ec8c754244ce6857b78a3e/e/cd4992999a933e1d50ad8702

soul_wish

If I don't forget how I made my knife 3D design with sharp blades knife review, I assume I started with the profile form then used angled planes to dispose of what I did not want.