My Custom Piece (Measures are in mm)

My Custom Piece (Measures are in mm)

I'm designing a custom mechanism that needs this piece to be able to function, but when i started thinking about how to manufacture it, I started getting confused about how to make it.

what I know is:

  • how to make a material block into a cylinder using a "Lathe" (For Example).
  • How to make the hole in the middle of the cylinder using the "Lathe" or the "Milling Machine" (For Example).

but when i get to making the saw shape every 60°, I don't know what to use.

  • should I use a CNC Machine? But is it gonna be able to make that shape, since there isn't much space for the "Drill Bit" "Endmill/Cutter"?

I know that a similar piece is also used in some one way rotation mechanisms so there should be multiple ways to get this shape.

So if you know some ways to make a saw shaped cylinder,
if you have any advice or suggestion on practically making this piece, or if you even have have some corrections or other ways to get the cylinder or the hole.

it would be appreciated.

EDIT: some remarks:

  • This drawing is measured in mm
  • The purpose of this part is to stop the rotation of a similar part sitting on top of it
  • So the sharpness of the edges is tolerable, as long as it blocks a similar part's rotation
  • I like @Jonathan.R.Swift comment about separating the inner cylinder from the outer cylinder.
  • yes i didn't know at first what Endmill is called in English.
  • $\begingroup$ People who design things tend to need to understand how the parts can be made AND how to assemble them, otherwise they draw things that cannot be made. Check out Escher. $\endgroup$
    – Solar Mike
    Commented Aug 14, 2022 at 17:31
  • $\begingroup$ is this drawing in mm o or inches? $\endgroup$
    – joojaa
    Commented Aug 15, 2022 at 14:04
  • $\begingroup$ If the central 15mm dia cylinder were a separate part, this would be much easier to manufacture. There is no keying feature on that bore so a bushing would work? $\endgroup$ Commented Aug 16, 2022 at 6:13
  • $\begingroup$ This is one of those things where engineer go nuts because you don't have rounded inner corners. Drawings are to be taken very literally. If not then specify a ISO 13715:2019 unspecified corner allowance. BTW you should make your summery axes obvious. $\endgroup$
    – joojaa
    Commented Aug 16, 2022 at 16:25
  • $\begingroup$ @joojaa all the measures are in mm/deg. $\endgroup$
    – ZOus7
    Commented Aug 22, 2022 at 14:18

2 Answers 2


should i use a CNC Machine? But is it gonna be able to make that shape, since there isn't much space for the "Drill Bit"?

On a mill, it is called an endmill, not a drill bit. I assume this is just a language issue though since I can't imagine anyone who knows how to use a mill doesn't know the proper name for an endmill.

But endmills aren't the only cutting tools you can run in a mill, and there are multiple types of endmills. Dovetail endmills for instance, and angular cutters which are not endmills at all.

If nothing need to actually sit in that sharp corner then why do you care if it's sharp or not? Just specify a fillet radius which will also spread out stresses. And if something does need to sit right in that corner then it can't be sharp anyways because you need to specify a relief which is round a cut into corner to to give room so debris and burrs on the other piece don't prevent it from being unable to sit flush against the corner. That's why you see a little circular cutout on the inside corner of machinist squares.

enter image description here


Also read this: https://makeitfrommetal.com/machining-square-inside-corners-the-nightmare/

You can do it with the disc laying flat and have the end mill cut incrementally step up the Z-axis to cut the slope.

Or you could mount the entire disc to an angle plate of the same angle as the sloped face. Then the the mill can stay in the same Z-plane and just move around in the X-Y plane to cut the sloped faces which may make them smoother. In this case I suspect you might want to cut most of the face with a facemill if you could fit on in there. Then you go in with a dovetail end mill to get the undercut on that corner (that vertical face will be an undercut relative to the mill if the disc is sitting on an angle plate).

There exists a lot of metal working machines that most people don't know about. There exists more than just mills and lathes. Even amongst mills and lathes there are many different types. I bet you never even knew a horizontal mills or vertical lathes existed.

Now that I brought up horizontal mills, I believe you can also cut most of that sloped face by mounting the disc flat on a rotary table and use a horizontal mill with an single-angle angular cutter. You won't get the vertical edges around the shaft hole with that alone though it will be a radiused toward the center.

And finally, a 5-axis CNC mill does this easily: enter image description here https://www.youtube.com/watch?v=2tankRyWaEs

  • $\begingroup$ My appreciation of your answer surpassed my remarks about your style of giving advice, and i would thank you and appreciate your answer since you did give me multiple solutions i did not think of, and i did overall learn new things from you. so i would thank you again, and i would like to express my satisfaction of your answer and solution that solved my problem. $\endgroup$
    – ZOus7
    Commented Aug 22, 2022 at 14:30

To add to DKNguyen's answer, it depends on the required strength of the part. If the part is highly-stressed, you would hot forge it out of steel alloy in a press.

If the stresses are significant but not excessively high, you would machine it from steel or aluminum in a CNC machine. All the slopes and angles shown in your drawing are easily cut on a 3-axis CNC milling machine.

If the stresses are relatively low and minimizing cost is important, you would die cast the part in copper-aluminum die casting compound in a closed-mold molding machine.

If the stresses are minimal and production volumes are very large and the part will not be subjected to hot conditions during use, you would injection mold the part in glass-filled polymer in an injection molding machine.

  • $\begingroup$ I guess I was also thinking from the perspective of making a one-off. If you're making many you wouldn't use method I mentioned. $\endgroup$
    – DKNguyen
    Commented Aug 16, 2022 at 19:05
  • $\begingroup$ Thank you a Lot, you gave me a lot of insight on how to go on, you're answer helped me a lot, and if i could make two answers correct i would definitely mark yours correct as well. $\endgroup$
    – ZOus7
    Commented Aug 22, 2022 at 14:42

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