Introduction: Arrow Shaped Knife
This is the finished product and to make this all you will need is:
1. Auto Cad 2015
4. 3D printer (Optional)
Step 1: Main Body
First you want to start off by drawing a line that is 4 inches long and then you want to make another exact copies 2 inches away so they are parallel. You can do this by typing in offset and for distance just type in 2.
Step 2: Finger Hole
Next when what to make a circle with the radius being 2 after the circle is made you want to place the circle on the ends of the line so that they are intersecting.
Step 3: Removing Part of the Circle
Now to make the knife 1 piece we need to get rid of the part of the circle in between the lines. To do this we click on the cut command, and select the 2 lines as are cutting edges. Then you click enter and click on the part of the circle in between the lines. when finished it should look like the picture above
Step 4: Adding a Line to the Middle
Now you can offset one of the straight lines but this time offset it only 1 inch so that it is in the middle of the 2 parallel lines. Now you want to extend this line so that its new length is 6.7321 inches. You will see why this line is so important in the next part.
Step 5: Making the Edge of the Knife
Now we will begin to construct the edges of the knife. We will you the measurements in the first photo to make the edges. Start from the top of the new line made and make a new line that is 4.0355 inches then before you click enter click the tab button to set the angle in which the line will be at and type 45. Now if you did this correctly you will notice that the 2 pictures aren't exactly alike that because the edges aren't rounded yet. We will get to that soon.
Step 6: Making the Other Edge of the Knife
Now for the other edge you could just follow the same instructions or you could save some time and use the mirror command. First type in mirror then select the objects that need to be mirrored. Click enter then select the tall line to be the line that the object will be mirrored over. Now when it asks if you want to delete the original type NO.
Step 7: Rounding Edges and Finish Finger Hole
Next you want to make another circle with in the original circle. This time make the radius 1.25 inches. Now to round the edges go to the fillet command and type in radius and make the radius .5 inches. Next click on all the corners where 2 lines meet except for the top tip.
Step 8: Preparing for 3D
Now you should switch to 3D basics on Autocad 2015 and use the union command to unite all the outer line work into 1 piece.(Do not combine the inner circle with outer line work).
Step 9: Making It 3D
Now that the line work is combined you can press/pull it up .5 inches to make it 3D. Now switch over to conceptual mode to view your masterpiece. Now you can sharpen the edges by sanding them down.Thank you for taking the time to read my instructable and I hope you enjoyed it. Good luck trying to make it. I will add the full completed version if you request it.