CAD Forum

Is this chamfer dimension is correct? Not 30 degree it should be 60 degree for 1 mm depth. In the part file sketch shows in red color.

It's right. The angle I indicated below is 30°.

@Glenn Schroeder

Diagram shows angle 30 degree measured from the flat face.

The part appears to be wrong. The chamfer feature in the part needs to be changed to 60 degrees if you want it to match the drawing as far as I can tell.

@mattpeneguy

You say this is 60 degree. My understanding is 60 degree is correct.

Maha Nadarasa wrote: ↑Mon May 10, 2021 9:03 am @mattpeneguy

You say this is 60 degree. My understanding is 60 degree is correct.

The 60 Deg you are showing in the sketch is the complement angle of the 30 degree angle that is shown on the drawing. Both are correct assuming that is the type of chamfer you want.

The part you posted has that feature as a 30 degree chamfer which results in a 60 degree dimension as you show in the picture you posted.

This is how you need to change the settings to get the feature in the part you posted to match the drawing: Ultimately, no one here can tell you whether the part is correct or the drawing is correct (unless somebody that uses piston rods and knows what fits up against this can tell you). But, they don't match, and I suspect it was that the feature wasn't assigned correctly.

Is there a way you can sort this out?

mattpeneguy wrote: ↑Mon May 10, 2021 9:27 am
Ultimately, no one here can tell you whether the part is correct or the drawing is correc

The way I'm looking at it the Part and drawing match. No one here can tell him whether the chamfer is correct or not.

mattpeneguy wrote: ↑Mon May 10, 2021 9:27 am The part you posted has that feature as a 30 degree chamfer which results in a 60 degree dimension as you show in the picture you posted.

This is how you need to change the settings to get the feature in the part you posted to match the drawing:
image.png

Ultimately, no one here can tell you whether the part is correct or the drawing is correct (unless somebody that uses piston rods and knows what fits up against this can tell you). But, they don't match, and I suspect it was that the feature wasn't assigned correctly.

Is there a way you can sort this out?

I think what a lot of us skipped over is that which I bolded and underlined, and that is most likely Maha's original questionning.

I do not have the answer though.

MJuric wrote: ↑Mon May 10, 2021 9:58 am The way I'm looking at it the Part and drawing match. No one here can tell him whether the chamfer is correct or not.

image.png

I don't understand Matt (hey we disagree, must be over my fever...). My take on it is that the drawing clearly doesn't match the part.
The dimension from the horizontal face to the chamfer is 60 degrees in the part, but 30 degrees in the drawing vs:

mattpeneguy wrote: ↑Mon May 10, 2021 10:34 am I don't understand Matt (hey we disagree, must be over my fever...). My take on it is that the drawing clearly doesn't match the part.
The dimension from the horizontal face to the chamfer is 60 degrees in the part, but 30 degrees in the drawing
image.png
vs:
image.png

Red line represents the 0. arrow represents surface the dimension is taken from.

mattpeneguy wrote: ↑Mon May 10, 2021 10:34 am I don't understand Matt (hey we disagree, must be over my fever...). My take on it is that the drawing clearly doesn't match the part.
The dimension from the horizontal face to the chamfer is 60 degrees in the part, but 30 degrees in the drawing
image.png
vs:
image.png

Where are you getting the picture you show at the top? The pictures I'm seeing are not that clear. The picture that the OP posted appears, to me anyway the way it looks when I download it, to have the chamfer going the other way than what you have in the top picture.

AlexLachance wrote: ↑Mon May 10, 2021 10:40 am Red line represents the 0. arrow represents surface the dimension is taken from.

image.png

so you're saying the two pictures in the OP are 90 degrees to each other? Again, hard for me to tell since the drawing picture is pretty fuzzy for me. The drawing, again as far as I can tell, appears to have the 60 degree going the other way and then the two would match. If indeed the angles are switched then I would guess someone picked incorrect geometry to get the angle on the drawing.

MJuric wrote: ↑Mon May 10, 2021 10:48 am so you're saying the two pictures in the OP are 90 degrees to each other? Again, hard for me to tell since the drawing picture is pretty fuzzy for me. The drawing, again as far as I can tell, appears to have the 60 degree going the other way and then the two would match. If indeed the angles are switched then I would guess someone picked incorrect geometry to get the angle on the drawing.

It's a little "free of interpretation", until Maha adds more details.

Okay I can understand now. Drawing is correct, it shows opposite to PM angle, where as PM shows exact angle, both of these angles are equal. I do not know how they call this equal angle in English because my mother tongue is not English.

Maha Nadarasa wrote: ↑Mon May 10, 2021 11:19 am Okay I can understand now. Drawing is correct, it shows opposite to PM angle, where as PM shows exact angle, both of these angles are equal. I do not know how they call this equal angle in English because my mother tongue is not English.

Careful @Maha Nadarasa, check that dimension dialog carefully. The only combination that will get you what is shown in the drawing is this: The reason you have to use 60 degrees is because they dimensioned the other dimension for the chamfer as 1mm in the vertical direction. SW uses horizontal, and that's why you have to use "Flip direction" and 60 degrees.
Take a look at the result and compare it to your drawing:

@mattpeneguy

What you say is to get the vertical dimension 1 mm as shown in drawing you must have a horizontal dimension 1.73 mm.

Yes what you've posted should work, but you must also uncheck the "Flip direction". So, yes there is more than 1 method to get it to show correctly, but what you posted requires calculating that dimension (1mm/tan(30deg)).

@mattpeneguy

Thanks for clarifying the issue.

@jcapriotti

Drawing is not by me. Why is the drawing having 30 degree chamfer?

When applying chamfers less than 45°, you'll need to watch how the chamfer is applied and as mentioned above, use the "flip direction" option to place it in the correct perspective relative to the vertical or horizontal edge.

Chamfers or "bevel's" less than 45° are often used as weld preps where a reduced amount of weld in the joint is required although judging by this part that may not be the reasoning, but it's just a guess.

@TRKemp

Thanks for the information.

TRKemp wrote: ↑Tue May 11, 2021 10:40 am When applying chamfers less than 45°, you'll need to watch how the chamfer is applied and as mentioned above, use the "flip direction" option to place it in the correct perspective relative to the vertical or horizontal edge.

Chamfers or "bevel's" less than 45° are often used as weld preps where a reduced amount of weld in the joint is required although judging by this part that may not be the reasoning, but it's just a guess.

Yes, I agree. In this case it appears not to be a reason stemming from welding...I'm not sure anyone would be welding at this location on a piston rod. My interpretation was that the 30 degrees was necessitated by whatever part butts up against the piston rod at this location.

Even though @jcapriotti was being sarcastic, you really shouldn't be using chamfers <> 45 degrees without a good reason.

mattpeneguy wrote: ↑Tue May 11, 2021 10:52 am
Even though @jcapriotti was being sarcastic, you really shouldn't be using chamfers <> 45 degrees without a good reason.

Yeah, I couldn't find the sarcastic but seriously code. @matt ?