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thru to bore note
with the change to symbol based hole notes does anyone know if the note "thru to bore" is still the accepted way to describe the depth of a hole that intersects another hole but does not go all the way thru?
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that is still an accepted use of the terminology. i would check the asme web site for further info.
regards,
namdac
i would call out a depth. it would reduce errors of a machinist drilling through.
chris
systems analyst, i.s.
solidworks 06 4.1/pdmworks 06
autocad 06
i think calling out a depth would be more confusing to the machinist. they may think you did not intend to go into the hole and made an error. how do you measure that anyway? my experience is that any of the following are clear to a machinist. thru to bore, thru to cross-hole, thru one wall just a few examples i've seen used. for further clarity you may want to put the note in spanish as well...just kiddin'
does asme have anything to say about this? i am in the process of convincing my company to purchase a copy of the y14 series but i haven't been able to get my hands on a copy yet.
if you say 'thru to bore' you are assuming that the 'bored' hole is in the part before the hole being defined as 'thru'. what if the machinist puts in the 'thru' hole first and the 'bore' hole second?
the hole to a depth will work no matter how the machinist makes the part.
a drawing is to be a standalone document without sopecifying manufacturing processes.
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sr is technologist
l-3 communications
how can you apply any tolerances to the depth of such a hole? how can it be inspected to determine if it is within tolerance? do you make the depth a reference dimension so that tolerances would not apply? what then if the hole is not thru to bore, or kisses the other side of the bore? it would still be to the drawing, since there would be no depth tolerance involved. do you make an exception to the standards for this type of dimension? i realize that i'm getting a little anal about this, but it is one of those gray areas that doesn't have to be.
machinists have to be able to do simple math. it should be no problem to determine the hole length based on the bore locating dimensions. a simple work around that i have used is to call out "thru to bore" and include a reference depth.
the hole can be a max dim or a loose tol. inspection can measure that. to have the hole say "thru to bore", the bore has a tol and it is more difficult for the machinist to know exactly where the bore is. drilling a hole can be measured and drilled at the same setup regardless where the bore is. it is up to the drafter, designer or engineer to figure out how depp to make the hole and have the proper callout on the dwg.
we don't know the details of the design. the hole could have ref dim's or have a tight tol, i don't know.
aardvarkdw, can you show us a pic of the detail?
chris
systems analyst, i.s.
solidworks 06 4.1/pdmworks 06
autocad 06
here is an example of where my problem is.
a reference depth dimension sounds like a good way of doing this. that way the overall goal is clear but you are not telling the machinist how to do his job. if asme doesn't address this, why? this seems to me to be something that engineers deal with every day.
at one time it was not proper to specify the process to achieve the required geometry of the part. therefore, if you would indicate the diameter and the required depth in a clear manner that would eliminate part of the "bore" problem, no? |
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