0013// Drafting practice for knurling
Knurling is a manufacturing process to roll or cut pattern of straight, angled or crossed lines on the material.
However, sometime when knurled diameter is critical to the fuctional requirement ( such as assembly), the drafting practice become extremely important to ensure machinist produce the part within desired specification.
Based on ANSI/ASME B94.6-1984, 4 Dimensioning, to maintain uniform drafting practice with high clarity, we should include essential information such as:
1. Width
2. Outer diameter after and before knurling
3. Selected tolerance
4. Diametral pitch
5. Style of knurling
Below is one of the example with ambigous information regarding its knurling,
Based on the drawing above, we understand that designer want a Ø 40 +/- 0.1 shaft with 10-11 mm diamond knurling. From the drawing itself, we know that outer diameter after knurling is not important because this is implied if designer not specify it. (Based on ASME Y14.5, 1.8.18 Knurling)
So, if outer diamter after knurling is critical, how to specify it?
There are many ways to specify it. But, that is recommended to specify all the necessary information by note,
All in all, maintain uniform drafting practice and provide all the essential information on the drawing are important. This can help to ensure machinist/supplier deliver the parts which meet your/designer expectation without any unnecessary disputes.
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