What is "No Chamfer"
What is "No Chamfer"
(OP)
We are a contract manufacturer and I run into the same issue over and over.
What is the minimum chamfer allowance on a drawing callout for (No Chamfer)
Is there a measurable and or standard?
What is the minimum chamfer allowance on a drawing callout for (No Chamfer)
Is there a measurable and or standard?





RE: What is "No Chamfer"
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: What is "No Chamfer"
Is this information based on any standard and if so what standard.
RE: What is "No Chamfer"
For ISO it might be different as envelope principal does not apply - one to ponder on.
Note, it doesn't explicitly say what the definition of 'No Chamfer' is or similar. I'm simply extrapolating from ASME Y14.5M-1994 para 2.7.1
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: What is "No Chamfer"
No particular callout, uos, means I don't want a chamfer or edge break, and I don't want a burr, either. If I want a chamfer or a burr, I will put them on the drawing, with a dimension and a detail drawing if appropriate.
The callout "no chamfer", means that I am damn sick and tired of the apes in your factory "knocking off the edges" with a 60 grit snag grinder, and I am not going to buy any more product like that.
Mike Halloran
Pembroke Pines, FL, USA
RE: What is "No Chamfer"
When the definition of something on a drawing isn't clearly defined by a referenced standard or similar then you should probably ask your customer.
Now, don't get me wrong, you may have a legally defensible stance using what I say above, but it may not do much for your customers opinion of you.
Alternatively, you could put in your quote what you take "NO CHAMFER" to mean. However, again while legally it may hold, it may not do much for customer service.
The whole area of edge breaks is one that's surprisingly poorly addressed in any standard I'm aware of. I had someone asking me questions about it today. There are devices that will test if something is a 'sharp edge' they're basically some kind of tape roll you run along the edge and if it cuts the tape then it's a 'sharp edge'.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: What is "No Chamfer"
ISO 13715 makes attempt to regulate workpiece edges.
It provides terminology, examples, graphical symbols, and recommended tolerances.
Generally, having more material then shown on the drawing is called "burr", less material "undercut".
According to the standard, if no state of the edges is specified, part may be delivered "as is" directly from the machine, without any edge treatment.
Burr size of +0.02...+0.05, and undercut size of -0.02...-0.05 are considered "sharp edge".
Unfortunately all of the above is based on textbook rather than real standard.
Anybody from ISO background, especially in the possession of standard book, please confirm or disprove.
RE: What is "No Chamfer"
"In technical drawings, the ideal geometric shape is represented without any deviation and, in general, without consideration of the states of the edges. Nevertheless, for many purposes (the functioning of a part, or out of safety considerations, for example) particular states of edges need to be indicated. Such states include those of external edges free from burr, sharp edges or those with a burr of limited size, and internal edges with a passing. In principle, all the edges of a part should be produced in their requisite states. In practice, unless those states are specified in the technical drawing or related documentation, the part will be delivered direct from the machine without the required treatment.
This International Standard is aimed at enabling this situation to be avoided, through specification of guidelines for the indication and graphic representation of the states of edges in technical drawings."
RE: What is "No Chamfer"
Call the customer. Tell them that you want to give them what they want, if they could only explain exactly what they want is.
Don't talk to the buyer. Talk to the responsible engineer or designer.
RE: What is "No Chamfer"
It seems to me that the customer is wanting sharp corners, though I don't understand why it isn't being specified as such. I agree with the others; ask the customer to elaborate.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: What is "No Chamfer"
Peter Truitt
Minnesota
RE: What is "No Chamfer"
RE: What is "No Chamfer"
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RE: What is "No Chamfer"
Matt Lorono, CSWP
Lorono's SolidWorks Resources & SolidWorks Legion
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RE: What is "No Chamfer"
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RE: What is "No Chamfer"
When a drawing says 'No Chamfer', it means just that. Most drawings have a general note saying that no burrs are allowed or break all sharp edges .005 max. The concept 'No Chamfer' doesn't bother me, especially if it is pointing to a specific edge.
"Wildfires are dangerous, hard to control, and economically catastrophic."
Ben Loosli
RE: What is "No Chamfer"
Peter Truitt
Minnesota
RE: What is "No Chamfer"
I was wondering if there's a difference between 'do not break sharp edges' and 'no chamfer'.
I'm definitely second guessing my initial response, but I'm just not 100% sure that 'no chamfer' over rides the variation allowed by the tolerance of the surfaces.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: What is "No Chamfer"
I think this situation is handled well by ASME GD&T. After all, the posting is here because there is an 'issue' and there are quite a few varied opinions. I hear that ASME and ISO are different when it comes to the transition of two form control boundaries. It might be handled as simple as flatness intersecting perpendicularity or as explicit complex as non-linear profile boundary lines. We should ask: What is the design intent?
Peter Truitt
Minnesota
RE: What is "No Chamfer"
It further suggests that they are wits' end, and if you send them one more chamfered part, not only will you not be paid for it, but they will also send in a squad of very intimidating "Quality Control" people who will comb every square inch of your plant and kill anyone in possession of a chamfering tool.
It is, in other words, your last warning.
Mike Halloran
Pembroke Pines, FL, USA
RE: What is "No Chamfer"
I think MintJulep has the right idea.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: What is "No Chamfer"
I disagree with ptruitt; trying to use GD&T for this would just confuse some people that hardly ever use GD&T or they would make up their own definition of what is on the drawing. I have actually had this happen.
RE: What is "No Chamfer"
Peter Truitt
Minnesota
RE: What is "No Chamfer"
I'm a fan of specifying what you want, not what you don't want. I agree with the suggestion to ask the customer what exactly it means.
RE: What is "No Chamfer"
So, if the general note said "APPLY .01 MAX CHAMFER TO ALL SHARP EDGES," then it makes perfect sense to include a "NO CHAMFER" note on a specific edge.
That's not what the OP asked, though. KENET hit the nail on the head very quickly in the very first response. The note may be redundant, unless Halloran's scenario is encountered, in which case I would recommend looking for a new vendor.
Matt Lorono, CSWP
Lorono's SolidWorks Resources & SolidWorks Legion
Follow me on Twitter