GB/T1804-m

Anyone familiar with this? I have a print from a customer with the note "DIMENSIONS WITHOUT TOLERANCE ARE ACCORDING TO GB/T1804-m." The part is a simple sheet metal angle so I'm not too nervous, but we've been bit before with unclear standards. I googled GB/T1804-m and didn't find anything useful.

Thanks in advance for any help. Diego

This type of thing happens to me all the time...Odd spec callouts usually turn out to be your customer's internal documents/standards that you would know nothing about. Most companies create internal standards documents....Anyway, your best bet is to call up your customer for their spec that should have been included when they submitted the job.

IYM

You may have more luck searching for GB/T 1804, it appears to be a Chinese standard. The "-m" indicates the tolerance class. This standard is equivalent to ISO 2768-1. A copy is posted here:

Keith

Appears I was wrong....Good find...Any day you learn something new is a good day :)

I didn't know the Chinese had standards except with lead based paint!

IYM

Thanks Keith. Please excuse my ignorance but this link opens a Word document with SimHei font. All I see is a few lines of English and then rows of squares representing text. Is there a translated version, or a font that displays this document in English?

Diego

I don't know of a translated copy, but I only just learned that GB/T

1804 existed yesterday via Google ;-) Even the copies that ANSI sells are in Chinese. The header mentions that the standard is equivalent to ISO 2768, a standard which is available in English, so that may be your best bet.

Keith

the docuiment opened for me with a combination chineses & english characters. i translated via

and got the following.

People's Republic of China country standard The general common difference has not poured the common difference the linearity and angle size common difference General tolerances Tolerances for linear and angular dimensions without individual tolerance indications GB/T 1,804 ?2,000 eqv ISO 2768-1:

1,989 Replaces GB/T 1804-1992 GB/T 11335-1989 1 scope this standing operating procedure has not poured leaves common difference linearity and the angle size general common difference grade of tolerance and the limit deviation value. This standard is suitable for the metal machining size, also is suitable for the general ramming processing size. The nonmetallic material and other technique processings sizes may refer to the use. This standard is only suitable for following has not poured the common difference the size: A) linear dimension (for example outside size, ???, steps and ladders size, diameter, radius, distance, ?? radius and bevel edge highly); B) the angle size, including usually does not pour leaves the angle value the angle size, for example right angle (90°); GB/T 1,184 mentions or and so on the polygon angle is an exception; C) machining group support linearity and angle size. This standard ill uses in the following size: A) other general common difference standards involve linearity and angle size; B) in parenthesis reference size; C) rectangular ?? in theory correct size. 2 quotations standards following standard contains the article, through quotes when this standard constitutes for this standard article. this standard publication, shows the edition for to be effective. All standards can revise, use this standard all quarters to be supposed to discuss the use following standard newest edition the possibility. GB/T 1800.l ?1,997 limits and coordinate foundation l partial: The glossary GB/T 1,184 ?1,996 shapes and the location tolerance have not poured the common difference value (eqv ISO 2768-2: 1,989) GB/T 4,249 ?1,996 common differences principles (eqv ISO 8,015: 1,985) the GB/T 6403.4 ?1,986 components ?? 3 define 3.1 this standard with the bevel edge to use the related terminology and the definition which GB/T 1800.1 produces. 3.2 general common differences general tolerances refers to the common difference which may guarantee under the workshop usual processing condition. Uses the general common difference the size. not to have to pour after this size leaves its limit deviation value. Note: Appendix A (prompt appendix) has produced the general common difference concept and the explanation. In when 4 general rules selections pattern has not poured common difference the size general common difference grade of tolerance, should consider the usual workshop precision and by the corresponding technical article The national quality engineering supervision bureau 2,000 ?07 ?24 authorizes 2,000 ?12 ?01 implementations Or the standard makes the specific stipulation. To any sole size, like in the function requests compared to a general common difference smaller common difference or permits a bigger common difference and the more economical time. its corresponding limit deviation must after the related basic size the note to leave. Uses this standing operating procedure when the pattern or the related technical document the linearity and the angle size general common difference, should carry on the sign note according to this standard 6th chapter of stipulation. (For example cutting and casting) separately process between two surfaces by the different type craft which forms not to pour the common difference the size to be supposed according to in the stipulation two general common differences value greater value control. The general common difference stipulated which by the unit of angular measurement only controls superficial the line or ??the total direction, does not control their shape error. The line total direction obtains which from the actual surface is the ideal geometry shape ???the direction. ???and between the actual line maximum range is the smallest possible value (to see GB/T 4249). 5 general common differences grades of tolerance and limit deviation value general male difference precise f, medium m, rough c, thickest v altogether 4 grade of tolerance. According to has not poured the common difference the linear dimension and the angle size has separately produced various grade of tolerance limit deviation value. 5.1 linear dimension table 1 has produced the linear dimension limit deviation value; Table 2 has produced ?? the radius and the bevel edge highly size limit deviation value. Table 1 linear dimension limit deviation value mm grade of tolerance basic size partitions 0.5 ~ 3 3 ~ 6 6 ~ 30 30 ~ 120 120 ~ 400 400 ~ 1,000 1,000 ~ 3,000 2,000 ~ 4,000 precise f ±0.05 ±0.05 ±0.1 ±0.15 ±0.2 ±0.3 ±0.5 ?medium m ±0.1 ±0.1 ±0.2 ±0.3 ±0.5 ±0.8 ±1.2 ±2 rough c ±0.2 ±0.3 ±0.5 ±0.8 ±1.2 ±2 ±3 ±4 to be thickest v ?±0.5 ±1 ±1.5 ±2.5 ±4 ±6 ±8 Table 2 ?? radii and the bevel edge highly size limit deviation value mm grade of tolerance basic size partition 0.5 ~ 3 3 ~ 6 6 ~ 30 30 precise f ±0.2 ±0.5 ±1 ±2 medium m the rough c ±0.4 ±1 ±2 ±4 thickest v note: ?? the radius and the bevel edge high meaning see also GB/T 6403.4. 5.2 angles sizes table 3 has produced the angle size limit deviation value, its value according to angle leg of right triangle length determination. to ??? according to circular cone ??length determination. Table 3 angles sizes limit deviation value grade of tolerance length partition, mm ~ 10 10 ~ 50 50 ~ 120 120 ~ 400 400 precise f ±1°±30 ' ±20 ' ±10 ' ±5 ' medium m rough c ±1°30 ' ±1°±20 ' ±15 ' ±10 ' is thickest v ±3°±2°±1°±30 ' ±20 ' 6 general common differences pattern methods of portrayal if use this standing operating procedure the general common difference, should nearby the pattern title block or the specification, the technical document (for example enterprise standard) center the note leaves this standard number and the grade of tolerance code number. When for example in selection rank, the sign note is: GB/T 1,804 ?m 7 determinations except has the stipulation in addition, surpasses the general common difference the work piece like not to achieve when harms its function, usually should not determine refuses to accept (sees A5). Appendix A (prompt appendix) linear and the angle size general common difference concept and explained A1 constitution components all essential factors always have the certain size and the geometry shape. As a result of the size error and the geometry characteristic (shape, direction, position) the erroneous existence, will have to perform for the guarantee components use function to them to limit, surpasses can harm its function. Therefore, the components express in the pattern all essential factors all have the certain common difference request. The not special request essential factor may produce the general common difference to the function in. The general common difference may apply in geometry essential factor and so on the linear dimension, angle size, shape and position. Uses the general common difference the essential factor to be possible not the independent note to leave its common difference in the pattern, but is in the pattern, the specification or the technical document (for example enterprise standard) center makes the always explanation. The A2 linearity and the angle size general common difference is under the workshop ordinary craft condition, the engine bed equipment may guarantee the common difference. in the normal maintenance and the operation situation, it represents the workshop usual processing precision. The general common difference grade of tolerance common difference value conforms to the usual workshop precision. According to components operation requirements selection corresponding grade of tolerance. The linear dimension general common difference mainly uses in the low accuracy non- coordinate size. Uses the general common difference the size in under the normal workshop precision guarantee condition, generally may not examine. A3 to some definite common difference value, enlarges the common difference usually certainly not to be able to be economical in the manufacture. For example is suitable "the usual medium precision" the level workshop to process the 35mm diameter some essential factor, stipulated ±1mm the limit deviation amount usually cannot bring a bigger benefit in the manufacture to the workshop, but selects ±0.3mm the general common difference limit deviation amount (center rank) is enough. When in the function permits the common difference was equal to when or is bigger than the general common difference, should use the general common difference. Only has works as essential factor function permission compared to general common difference big common difference, but this common difference when the manufacture is more economical than the general common difference (for example when assembly drills ?? depth), its corresponding limit deviation value must the note leave after the size. Because in the function need, some essential factor request uses compared to "the is ordinary common difference" the small common difference value, then should the note leave its corresponding limit deviation value after the size. Certainly this has not been the general common difference the category. A4 uses the general common difference below, may bring the advantage: A) simplifies the charting, ?? is clear legibly, but highly effective carries on the exchange of information. B) saves the pattern design time. Designs the personnel not to need to consider one by one or the computation common difference value, only must understand some essential factor in function whether allows to use is bigger than or is equal to the general common difference the common difference value. Which essential factors c) was the pattern clear about to be possible to guarantee by the general technological level that, might simplify the examination request, was helpful to the quality control. D) has highlighted the pattern ?? common difference size, these sizes mostly are important also need to control, causes when the processing and the examination takes and makes the plan arrangement. E) because signed in front of the contract on already to know the factory "the usual workshop precision", the buyer and the supplier could conveniently carry on the ordering negotiations; Simultaneously the pattern expressed the integrity also may avoid when the delivery buyer and supplier's argument. Only has the specific workshop the usual workshop precision reliably satisfiedly to be equal to when or to be smaller than the general common difference condition which uses, can completely manifest the above these advantage. therefore, the workshop should achieve: ??the survey, appraises the workshop the usual workshop precision; ??only accepts the general common difference to be equal to or to be bigger than the usual workshop precision the pattern; ??the sample survey guaranteed the workshop the usual workshop precision is not reduced. The A5 components function permission common difference frequently is bigger than the general common difference, therefore when work piece any essential factor surpasses (accidentally surpasses) the general common difference the components function usually not to be able to harm. Only has when the components function receives the harm, surpasses the general common difference the work piece to be able to refuse to accept.

Well, um, thanks. Makes you hope there's no dispute over where the hole is located. I saved a copy in WORD and will give it to QC if they dare question any dimensions - then I'll leave early.

regards, Diego

Id say it looks like your scheduled 3 month vacation starts tomorrow doesn't it. :-)