↧ Depth / Deep
Depth / Deep · Indicadores dimensionales · ISO 1101 + ASME Y14.5
Example in plan
How to interpret it
The L-shaped arrow indicates the depth of a hole or cavity, measured from the reference face shown on the drawing.
What controls
A symbol indicating that the dimension following it is the depth of the feature, measured from the entry surface inward. It is used on blind holes, pockets, slots and threads, and applies to the feature preceding it on the same dimension line, so a stepped hole carries several diameter-and-depth pairs. On a blind drilled hole, it must be clear whether the depth is measured to the end of the full cylindrical portion or including the drill point cone: they are different values and the drawing must make it clear.
How to verify
A depth gauge, the depth rod of a caliper or a depth micrometer resting on the correct reference surface; in small or deep holes, depth gauges or coordinate measurement with a probe. It is essential to rest the instrument on the face the drawing dimensions from: resting it on an adjacent face introduces an error that is not a manufacturing error but a method error.
Common mistakes when interpreting it
- Counting the conical drill point as usable hole depth.
- Measuring with the instrument resting on a face other than the one the drawing dimensions from.
- Confusing hole depth with usable thread depth in blind tapped holes.
How to get it in the workshop / if it comes out of tolerance
In drilling, the conical part of the point adds length that normally does not count as usable depth; program the travel taking the point angle into account. In blind threads, the usable thread depth is less than the hole depth: you have to leave clearance for the tap. And always check whether the depth is measured from the as-cast face or from the machined face, because on castings it changes the result.
Depth consistently short in drilling: check whether the drill point is being allowed for and whether chips packed at the bottom are stopping the drill from reaching depth. Irregular or non-flat pocket floor: review the floor finishing strategy and tool deflection, especially with long tools. And if the measurement varies depending on who measures, it is almost always the surface the instrument is resting on.
Alternative symbol:T
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