How to create a countersunk hole?

4DeltaEDU

I am trying to create a countersunk hole using various commands on Onshape but I have been unsuccessful.
I tried to create a large circle on the top surface and a smaller on the lower and loft it. Didn't work. I tried the chamfer command in various ways (it does kind of word but not with the dimensions that I want)

Specifications
Top hole: 8.5mm
bottom hole: 4.5mm

Is there anyway to achieve the result shown in the photo with the specifications mentioned above?

Many thanks.

I have attached a photo of the countersunk hole the way I want it to look

nav

Hi @george_papageorgiou there is a workaround if you don't mind doing a little math, I`ve used your values as example.


Then use the draft feature, input the result above and the lower hole should have the dimensions you need.

3dcad

Is this what you need?
https://cad.onshape.com/documents/d29ff8e74a0f49809e533f48/w/48fedb2064cc4f30a27ee6e8/e/2b59680947d64f9298ea4978

I used material thickness of 2mm, so both values in chamfer are 2mm - change the first value according to your material thickness.

lougallo

@george_papageorgiou Currently we do not have a hole tool but we are working on it.  I can add you down for the request.  At this time you will need to either do a hole with a chamfer or a revolved profile.

michael3424

Lou - please add me to the hole tool request.

andrew_troup

If you know the outside diameter of the chamfer, an easy method (once extrudes are provided with a "Draft angle" option, hint hint!) will be to sketch a circle of that diameter on the outside face, then extrude (removing material) with draft of the desired angle.
In the meantime you will need to draw that circle for the purposes of construction, in order to "pierce" it with the orthogonal sketch used as the revolve (removing material) profile.

3dcad

Doesn't chamfer with option 'Two distances' give full control over creating intended geometry? Create circle with 4,5mm dia - extrude and chamfer top to 8,5mm and set another dimension according to material thickness.

Or are you asking for one step solution?

andrew_troup

@3dcad
Rightly or wrongly, I assumed @george_papageorgiou was looking for a solution which would recalculate correctly when a single diameter dimension was changed. Rather than him having to do maths to derive a chamfer dimension which resulted in that diameter. (Admittedly, the necessary maths ops could be captured fairly transparently in the dimension entry box)

But I could easily have the wrong end of the stick.

4DeltaEDU

First of all a big thank you to everyone here for the quick response. I appreciate it guys!!

I have tried with the two direction tool but all it does is expanding the bottom hole. It does not alter the gap between the bottom and top hole. Maybe I am not using it right, I don't know. Andrew, all I want to do is create a hole exactly like the one on the picture attached (not my design). I thought Chamfer would be the best option. Its either not or I am not using it right. I also tried loft. Next thing I am gonna try is create a cross sectional plane and design a 2D profile of the screw hole, then revolve it. It's a little bit too much of an effort for something that looks so simple and quick but I can't think of another way, given the tools I have.

Thank you all!

George 

nav

Hi @george_papageorgiou there is a workaround if you don't mind doing a little math, I`ve used your values as example.


Then use the draft feature, input the result above and the lower hole should have the dimensions you need.

3dcad

Is this what you need?
https://cad.onshape.com/documents/d29ff8e74a0f49809e533f48/w/48fedb2064cc4f30a27ee6e8/e/2b59680947d64f9298ea4978

I used material thickness of 2mm, so both values in chamfer are 2mm - change the first value according to your material thickness.

4DeltaEDU

Thank you 3dcad and nav!!

3dcad, this is exactly what I am after. Now can you walk me through how you did it? 

Did you sketch large hole on top then small hole on bottom then create a hole,using the small hole then Chamfer command?

Or you created one hole and used chamfer to covert or divert to the next?

thanks a bunch 

George 

3dcad

Check out the link I posted, there is public document you can look..

Just create hole with 4,5 dia and then chamfer 2mm