What are the important properties of a billiard ball? • Why would those properties vary? • How much variation in those properties are we ok with? 2.753 Precision Machine Design. Anthony Wong. Manufacturing Error. 2.753 Precision Machine Design. Anthony Wong n – 2.2497” e –.0009”.

'Car 54, where are you?' This is a meaningless question. All positions are relative. They are relative to something.

And, calculate it from WHAT? I suggest that you go (back) to high school and pay attention in math and geometry classes.

I am sure this thread will be closed. Edit: Well, I guess the term 'true position' has a specific meaning that I was not aware of. I apologize if my remarks above were not appropriate. But then, it seems to me that this is a poor choice of terms for what is actually meant.

Last edited by EPAIII; at 01:17 PM. What is the formula for calculating true position? ThanksUsually when the print says put the hole here, I just put it there, thats how I 'calculate' it. The formula would be using a Cartesian coordinate system. (basic XY graph) R EDIT: 'Cause your a newb, ask the right question you must young Padewan. There is no formula for it, it just is true or not true, try getting it there and if it doesn't work then post a question about that.

BUT here's an Olive branch, if you are asking how to measure TP, divide the tolerance for TP by 3 and use that for you linear tolerance between points and Origin/Datum and that will get you really close. Thank you for the input guys, I am sorry if my question offended anyone but I am a newb and it sometimes comes with the territory.

I think people forget that at some point in time you did not know everything but you had to learn and perhaps relearn something's you haven't brushed up on in 10+ yrs. I guess my question pertains to a hole location for example it's nominal is x30. Y30 within.2 true position, But it measures x30.011 and y 30.011. I want a way to fact check our older brown and sharp cmm.

How would I calculate true position based on the given example. As mentioned, true position is the circular tolerance zone around a theoretically perfect point, in your case.100 or R.05. If you inscribe a square, the corner at 45 deg will be your radius (.05) Remember the 45 deg right triangle relationship, 1/1/SQRT2? The quick and dirty way we used to calculate it was: True position tol.(in radius) / SQRT2 In your case:.05/SQRT2 =.0354 So basically, if your measured results are within +/-.0354, you are within that box and within your true position tolerance. If your measured results are outside that box, you will have to trig it out like johnb53405 said.

Better than calculating is to find the survey marker and use a certified chain and then measure. Yes some survey numbers are in Rods. So look that up. Actually true position is most often a certain distance from a certain place so [place + or - distance = position] is the correct formula. To confirm look it up in a book.If you cant find a book to confirm then write one and it will be a big help to everyone who can't find position, A Rod is about 5.0292 meters and/or about 16.5 feet and/or 5.5 yards.They made it not an even number so the Metric/ imperial guys would not consistently argue about it. The Rod was based on how far a Martian could throw his wife.

Yes a grouchy wife would throw her husband so the number was not actual be an assumed average. Enough of this as I am going to Clair Mi, Camp Rotary for a week with the Boy Scouts.Yes we will use fishing rods.Yet another kind of Rod.

And, Yes we sleep in those old army tents spiders and all, and a raccoon if you have any food in the tent. Thankfully not yet a Bear. Last year I got skunked and did not get top fish here. Inspired by this thread, I did some searching on 'true position'. Here's one: According to this, 'true position' is the theoretical position of the feature and then there is an allowable deviation from that 'true position' which is specified as the diameter of a circle enclosing the permissible locations. I suspect you want a way for calculating that deviation from the 'true position'.

That formula is given on that page. Wouldn't that be what we previously called a tolerance but refined into a circle instead of a square? Or am I still missing something here? Wouldn't that be what we previously called a tolerance but refined into a circle instead of a square? Or am I still missing something here?The part you are missing is that GD&T allows you to describe a FUNCTIONAL part.

Plus or Minus tolerances on each axis make the manufacturing easy, but they don't describe what is and is not functional. Take the 'True Position' thing. And most times, at least for me, you will see it with a little M in a circle, Max Material Condition. That hole has to line up with or be within a certain distance of something else, either on the same part, or on another part.

Lets say a clearance hole for a bolt. 1/4' bolt,.275 ±.010 clearance hole. Tolerance on the other bit lets say is.005 TP. IF the engineer is willing to skirt the edges we would see..275 ±.01 TP within.010, and then we would get the Magical 'Max Material Condition'. So a.265 hole could be.010 off TP.

If its.005 off in the Y, it'll still work if its.0000 off in the X. If we had to describe this with simple ± XY tolerances, we would have to be ±.0035, and the part would still be FUNCTIONAL, but would be scrap per the print. Now lets say we drill that hole to nominal,.275. MaxMaterialCondition(MMC), we get a.010 BONUS.

We can be off.010 now in the Y, and ZERO in the X and still have a functional part. We can also be.006 off in the Y and.007 in the X and still have functional part. Much better than the ±.0035 if we went with simple plus/minus tolerances. Now lets take that hole to.285, we get yet another.010 of bonus on the TP.

And we can be even further off. Its pretty darn cool stuff when you made the parts and then do the assembly and can actually see the GD&T in action. And a lot of times it actually benefits the machinist, its just more complicated. I personally prefer it. It makes the prints look scary, and the 'value' of the part goes up, meaning I get more money.

When in reality its actually easier to deal with than straight ± tolerances (mostly). This has always seemed to me to be 'what happens' when I send out a dwg that has a goodly dose of GD&T feature control frames. I think most shops see all that geo tolerance stuff (even if it's dead simple and easy) and fill in a multiplier factor on the quote prep sheet. Sort of like when you buy something whose description includes the words 'clean-room compatible'. Makes the price go up 5X.I agree, but there is a reality in the added cost, even when it is dead simple. IE; I interpret one thing as dead simple, Hole to Hole TP easy!! Now my part goes to Quality, my inspector feels that all GD&T needs to be done on the CMM (ya ya I know, but it's his department) ANY time a part needs to be checked that way, it takes longer.

Now shop rate is not the same for QC as it is for Manufacturing BUT it's still there. And thats just one linear dimension/2 holes.

Contents • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Suggested structure [ ] Probably the hardest part of writing a mathematical article (actually, any article) is the difficulty of addressing the level of mathematical knowledge on the part of the reader. For example, when writing about a, do we assume that the reader already knows?

A general approach is to start simple, then move toward more abstract and technical statements as the article proceeds. Article introduction [ ]. See also: The article should start with a short introductory section (often referred to as the lead).

The purpose of this section is to describe, define, and give context to the subject of the article, to establish why it is interesting or useful, and to summarize the most important points. The lead should as far as possible be accessible to a general reader, so specialized terminology and symbols should be avoided as much as possible.

In general, the lead sentence should include the article title in bold along with alternative names, also in bold. The lead sentence should inform non-mathematicians that the article is about a topic in mathematics, unless the title already does that. The lay reader knows that arithmetic, algebra, geometry, and calculus are topics in mathematics, but does not know that functional analysis or category theory or combinatorics belongs to mathematics. The lead sentence should informally define or describe the subject. For example: Topology (from the τόπος, 'place', and λόγος, 'study') is a major area of concerned with spatial properties that are preserved under deformations of objects, for example, deformations that involve stretching, but not tearing or gluing. In, Apollonius' problem is to construct that are to three given circles in a plane. The lead section should include, where appropriate: • Historical motivation, including names and dates, especially if the article does not have a separate History section.

Explain the origin of the name if it is not self-evident. • An informal introduction to the topic, without rigor, suitable for a general audience. (The appropriate audience for the overview will vary by article, but it should be as basic as reasonable.) The informal introduction should clearly state that it is informal, and that it is only stated to introduce the formal and correct approach. If a physical or geometric analogy or diagram will help, use one: many of the readers may be non-mathematical scientists. • Motivation or applications, which can illuminate the use of the mathematical idea and its connections to other areas of mathematics. Article body [ ] Readers come to our articles with differing levels of experience and knowledge.

When in doubt, your article should define the notation it uses. For example, some readers will recognize immediately that Δ( K) is a common notation for the discriminant of a number field and will understand what that means, while others will have never before encountered that idea. The latter group will be helped by a statement like, '.where Δ( K) is the of the field K.'

Use standard notation if you can. If the article requires non-standard or uncommon notation, it should define those notations. For example, an article that uses x^ n or x** n to denote the exponentiation operation x n should define those notations. If the article requires extensive notation, consider organizing the notation as a bulleted list or separating it into a notation section. When the article is about a mathematical object, the article should provide an exact definition, often in a Definition(s) section. For example, Let S and T be topological spaces, and let f be a from S to T.

Then f is called continuous if, open set O in T, the f −1( O) is an open set in S. Using the term 'formal definition' may help to flag where the actual definition is to be found, after some sections of motivation. (Cf..) This may seem rather empty to a mathematician (a formal definition is a mathematician's definition, as a formal proof is just a proof); but it may help the reader navigate the article. When the article is about a theorem, the article should provide a precise statement. Sometimes this statement will be in the lead, for example, Lagrange's theorem, in the of, states that for any G, the (number of elements) of every H of G divides the order of G.

Other times, it may be better to separate the statement of the theorem into its own section of the article. This is especially true if the statement is long () or has multiple equivalent formulations (). Representative examples and applications are helpful to readers.

These serve both to expand on the definitions and theorems and to provide context for why one might be interested. The organization of the examples depends upon their number and length.

Some examples may fit into the main exposition of the article, such as the discussion. Others may benefit from being given their own section, such as. Multiple related examples can be given together, as in. Occasionally, it is appropriate to give a large number of computationally-flavored examples, such as. You might also want to list non-examples—things which come close to satisfying the definition but do not—in order to refine the reader's intuition more precisely.

It is important to remember when composing examples, however, that the purpose of an encyclopedia is to inform rather than instruct (see ). Examples should therefore strive to maintain an, and should be informative rather than merely instructional. A picture is a great way of bringing a point home, and often it could even precede the mathematical discussion of a concept. Has some hints on how to create graphs and other pictures, and how to include them in articles. A person editing a mathematics article should not fall into the temptation that 'this formula says it all'. A non-mathematical reader will skip the formulae in most cases, and often a mathematician reading outside her or his research area will do the same. Careful thought should be given to each formula included, and words should be used instead if possible.

In particular, the English words 'for all', 'exists', and 'in' should be preferred to the ∀, ∃, and ∈ symbols. Similarly, highlight definitions with words such as 'is defined by' in the text. If not included in the introductory paragraph, a section about the history of the concept is often useful and can provide additional insight and motivation. Concluding matters [ ] Most mathematical ideas are amenable to some form of generalization.

If appropriate, such material can be put under a Generalizations section. As an example, multiplication of the rational numbers can be generalized to other fields, etc. It is good to have a See also section, which connects to related subjects, or to pages which could provide more insight into the contents of the current article. Lastly, a well-written and complete article should have a references section. This topic will be discussed in detail. Writing style in mathematics [ ]. See also: An article about an may include or in some cases in some.

Wikipedia does not have a standard programming language or languages, and not all readers will understand any particular language even if the language is well-known and easy to read, so consider whether the algorithm could be expressed in some other way. If source code is used always choose a programming language that expresses the algorithm as clearly as possible. Articles should not include multiple implementations of the same algorithm in different programming languages unless there is encyclopedic interest in each implementation. Source code should always use. Camus Der Mythos Des Sisyphus Pdf Writer.

For example this markup: primes = sieve [2.] sieve (p: xs) = p: sieve [x x 0] generates the following. Primes = sieve [ 2. ] sieve ( p: xs ) = p: sieve [ x x 0 ] Including literature and references [ ] It is quite important for an article to have a well-chosen list of references and pointers to the literature. Some reasons for this are the following: • Wikipedia articles cannot be a substitute for a textbook (that is what is for). Also, often one might want to find out more details (like the proof of a theorem stated in the article). • Some notions are defined differently depending on context or author.

Articles should contain some references that support the given usage. • Important theorems should cite historical papers as an additional information (not necessarily for looking them up).

• Today many research papers or even books are freely available online and thus virtually just one click away from Wikipedia. Newcomers would greatly profit from having an immediate connection to further discussions of a topic. • Providing further reading enables other editors to verify and to extend the given information, as well as to discuss the quality of a particular source. The article has more information on this and also several examples for how the cited literature should look. Typesetting of mathematical formulae [ ].