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I had to do some layout tonight when I ran across an idea and a problem.The idea: To measure from a center punch point to another with no help. And I came up with some scrap, 3 neodenium magnets and a pin slightly longer than the tool is tall. I could pull until the tape was straight and it would not move. Worked out great and is giving me more ideas on it's improvement. The problem: Out of 5 tapes, not one of them were the same after 20 feet. 4 were different Stanleys and the 50' tape was of a brand that I cant think of right now. I settled on the 35' Stanley since it was in the middle of the pack. What really sucks is that two of them were brand new and were still over 1/16" different than each other. What can be done in a situation like this? Attached ImagesCommon sense in an uncommon degree is what the world calls wisdom.
Reply:Are they the same at 1 foot?If they are off at 1 foot then the little metal piece might be slightly bent.Your 50 foot is a lufkin I think, I have one that looks just like it , and someone told me once "the 80s called and wants their tape measure back"Aaron
Reply:get starrett tapes from ebay for $7 eachDynasty 200DXPassport plus w/ spoolmate 100victor 315c oxy/(act and prop)Miller digital elitemilwaukee power tools
Reply:Yeah, they all match up in the beginning and progressively get worse from there.Common sense in an uncommon degree is what the world calls wisdom.
Reply:1.-A tape is NOT a precision measuring tool. 2.-most of the time we are NOT building a piano so a sixteenth means NOTHING. 3.--If you need precision, use a PRECISION measuring tool.--Just my .026 Miller Big Blue 600 Air Paks2 Miller 400D6 Lincoln LN-25's4 Miller Xtreme 12VS2 Miller Dimension 812 4 Climax BW-3000Z bore welders Hypertherm 65 and 85Bug-O Track BugPair of Welpers
Reply:I really like your measuring tool, I'm sure someone is making one right now. As for the tapes, I also look at them as rough measurements because the sliding tab is bend pass 90 degrees in order to hold on to something and it will give different mearsurements say when placed on sheetmetal or when placed on 1" bar stock. I know your test is all on the same thickness metal, and that surprised me. I guess they don't have any tape measure standard police.
Reply:Originally Posted by ExpatWelder1.-A tape is NOT a precision measuring tool. 2.-most of the time we are NOT building a piano so a sixteenth means NOTHING. 3.--If you need precision, use a PRECISION measuring tool.--Just my .02
Reply:I did some factory work for P&H a couple of years ago, there was an engineer that set up the welding machines, we weren't allowed to change the settings, anyway they had to use a "calibrated" tape measure to check WFS, it even had a calibration sticker on it. I thought it was bizarre, but they were paying so I was playin.6 Miller Big Blue 600 Air Paks2 Miller 400D6 Lincoln LN-25's4 Miller Xtreme 12VS2 Miller Dimension 812 4 Climax BW-3000Z bore welders Hypertherm 65 and 85Bug-O Track BugPair of Welpers
Reply:I have the answer. use the same tape for everything. this way it will all match up. lol!www.thefusionsolution.com
Reply:Most structural shops I have worked in demand Lufkin tapes be used. From my experience they are the most accurate/consistent.The other variable is the end of the tape. Never trust it is my motto. In some ISO 9000 shops they have a meter long bar by the time clock or in some other key location. The idea is that you will check your tap each morning. The end hook is easily bent. I avoid using the end of the tape. I mark the first 100 mm or foot on the beam without using the end of the tape then set the tape at the reference mark I have made. I use a spring clamp or an old speaker magnet to hold the tape in position. By setting to my reference mark I avoid the common mistake of setting the tape at the foot mark and forgetting that I have to add a foot to the final dimension. I have worked as a checker and this is a common mistake. I then mark out all my running dimensions with notations and sometimes the actual RD so I will know which is which. At that point I do not just retract the tape. I walk the tape back with print in hand and confirm all the dimensions again. Also new tapes have quite a bit of spring tension and the tape snaps back into the case quite violently. The rivets on the cheaper tapes will shift in their holes and cause problems. I often take the case apart and release the tension by one revolution so that the tape will not "snap" back but will stop a few inches out then I push it closed. On long tapes there is a note in the first foot or so that the tape has to be pulled with a certain tension in order for it to read correctly. A slack 100 foot tape will not read correctly.Last edited by lotechman; 09-28-2011 at 10:46 AM.Reason: long tapes
Reply:Originally Posted by DSW....I've got a 300' steel surveyors tape we used for setting points for basement walls so there wouldn't be any stretch...
Reply:Great idea, Don't forget to offset half of the pins diameter for center line if you are working to a tight tolerance
Reply:Wow, I have known about this problem for a long time from a bunch of angles but I didn't realize folks were using those type tools to work to such accuracy. Quality control is a distant memory in too many cases.In carpenter type work many times I don't even use a tape. I use the wood I want to put into where ever, stick it in place and mark it, cut a tad long, test again and maybe shave a tad more off, gets the best fit up I probably am doing to do. Measure twice, cut sort of twice. Get the starter piece to the best accuracy I can see if required.That and jig cut a bunch to whatever, least those are all the same size (we hope) to the best accuracy that the equipment will produce.Even if you have a truly accurate tape, what do you do for temperature changes??? Both in the tape and the materials being measured if you are working to those tolerances??? What temperature change is required to give 1/16" error over 100 feet? Glad I'm not a working guy any more. I can't even really see a 1/16" let alone cut to it any more, first time around.Great idea with the magnetic gizmo tho.
Reply:Nice doo-dad there. Next generation, you'll have to put a compression spring and mounting collar around the locating pin so that it can 'float' and adjust to various punch depths. Cause otherwise you might end up being off by maybe a degree on your pin perpendicularity or something. Did you match-grind the angle on the registration pin to the angle on your centerpunch? Serious though, nice doo-dad. re: tape measures. They are not precision measuring devices. As you saw. Or, as you measured, because you didn't saw it although you did see it. For consistency in measurements, the 'trick' with a tape or scale (or any other non-calibrated, non-precision device) is to use the SAME tape or scale. That eliminates any device-to-device variance, although it doesn't give you any assurance of accuracy. (note:accuracy and precison are not the same thing).And 1/16 inch variance over 23 feet is a difference of 0.023%. Which is actually pretty darn close! If you need to measure down to the thou range, then a retractable steel tape is not the tool to use, try DSW's call to MSC for that 0-25 ft caliper. (note that for those considering such things, you have to take into consideration temperature and the various thermal coefficients of expansion for the materials in question in order to measure 'precisely'. As well as sag/deflection and such. Yeah, I worked with some Metrology guys for a while. )MSC -does- list a Mitutoyo electronic carbon-fiber 1-61 inch (1525 mm) caliper though. $2080, 3 in stock. Reads to 1/2 thou, accuracy listed as 3.5 thou.http://www1.mscdirect.com/cgi/NNSRIT...-SearchResultsTemperature controlled and vibration isolated CMM, maybe? The best laid schemes ... Gang oft agley ...
Reply:I just had a house apprasal and the guy used a small hand held laser measuring device, I wonder how accurate they are..it worked like a charm.you didnt have to get to the other end of what you where measuring, so if you needed to get a roof or eve height no ladder needed..Of all the things I lost I miss my mind the most...I know just enough about everything to be dangerous......You cant cure stupid..only kill it...
Reply:Originally Posted by roadkillbobbI just had a house apprasal and the guy used a small hand held laser measuring device, I wonder how accurate they are..it worked like a charm.you didnt have to get to the other end of what you where measuring, so if you needed to get a roof or eve height no ladder needed..
Reply:I like your tape holder.We are on our way to being farmers! Our site is always under construction so check back often for updates. http://www.philosophyfarmstyle.com/
Reply:hehe, I want to find a 25' digital caliper On the more serious side, I have one of the little laser measuring devices and it is pretty darn accurate. I can get about 1/64th of an inch accuracy over 50'. I've used it when measuring long pieces of steel as well and when cut they all did actually come out to the same (and correct) length.Aside from that, there's a contractors rule for using a tape measure: Measure your length and measure to cut with the same tape.If you use a different tape, for one measurement than you do for the other you will almost always end up off by at least 1/16th if not more. I've seen two tapes be off by more than 1/8th over 10'.--Wintermute"No man's knowledge here can go beyond his experience." - John Lockewww.improvised-engineering.comManufacturer Agnostic:Blood----------Sweat---------Tears----|------------------|----------------|----Lincoln Red, Miller Blue, Esab Yellow
Reply:i think 'theodolite' is the best tape measure , but it'll set u bak a few bucks thermal arc 252i - millermatic 350P - miller XMT, cp300ts, 30a 22a feeders, buttload of other millers, handfull of lincolns, couple of esabs - Hypertherm 1250 G3
Reply:Originally Posted by wintermutehehe, I want to find a 25' digital caliper
Reply:Wow I never would think that.Some Blue , Some Red & Some GreyProverbs 16:2-3.2 "All a persons ways seem pure to them, but motives are weighed by the Lord. 3 Commit to the Lord whatever you do, and he will establish your plans."
Reply:I've got a set of Browne & Sharp mics, biggest one in the box runs 28-30 inches - covers every length up to that. Given what I had to shell out for those, I don't even want to consider a 25 footer then add a few HUNDRED Benjamin's for the matching standard.When any government, or any church for that matter, undertakes to say to its subjects, "This you may not read, this you must not see, this you are forbidden to know," the end result is tyranny and oppression, no matter how holy the motives.
Reply:My last job,before I got laid off & went back to school, at sweeny steel I ran big old verson presses stamping out blanks for ford stamping plant down the road, ford is ISO certified so we were too. Well once a year we would have our ISO audit & that's the only time they would either get out the calibrated /certified tapes & micrometers for us to use or "calibrate" the ones we had, & by calibrate I mean slap a sticker on them,give us new ones if they were blatantly worn, & update the log for the past months.Millermatic 211 Lincoln Idealarc 250-250, ~500lb water cooled tig
Reply:Just do what the old timers did, eyeball it, an use conversation lingo, like just a hair more, or back just a shade, you purtin near got it. or over to your left bout this far "showing with hand signals" An then to level. bring out a clear jar half full of water.In the words of the great philosopher Quagmire.Gigedy Gigedy Gigedy Gigidey Goo.
Reply:Its just a **** hair shy! (saying used by an old timer)JoshI was watching Who it's made the other day, and they were making Steel Tapes. I was surprised (or not) to see they checked the tapes for accuracy, and depending on how they fair depends on where they go, in the world FFS.
Reply:Originally Posted by wskynajarJust do what the old timers did, eyeball it, an use conversation lingo, like just a hair more, or back just a shade, you purtin near got it. or over to your left bout this far "showing with hand signals" An then to level. bring out a clear jar half full of water.
Reply:When i was in school, we spent some time talking about accuracy of measuring devices and tapes. In the end we came to the point where its best to invest well into your measuring devices, so i buy stanley at the minimum - 20 - 35' - but most importantly, if accuracy is needed, then its best to use the same tape for the entire project if possible
Reply:Originally Posted by Shox DrI was watching Who it's made the other day, and they were making Steel Tapes. I was surprised (or not) to see they checked the tapes for accuracy, and depending on how they fair depends on where they go, in the world FFS.
Reply:My favorite one was always the new guy on the crew.when yelling out for a measurement, the new guy with a confident loud voice yells back. "It's huh lets see 1,2,3,-its 3 marks past the long mark in the middle of 6 an 7"In the words of the great philosopher Quagmire.Gigedy Gigedy Gigedy Gigidey Goo.
Reply:tapes used by surveyors are still called chains and the process of measuring with a 100 foot tape is called chaining. originally they used gunters chains, which was 66 feet long and 100 links. they could be easily folded up and put in a pocket, and most importantly 80 chains=1mile. if you look in old surveying documents that are still on file in government offices, they still use chains as a measurement.nowadays if not using some kind of digital apparatus, a steel or invar tape is used. invar has less in the way of thermal expansion/contraction. there's formula used to correct for temp, its Ct=k(T-Ts)L for a steel chaink=.00000645 for F, and .0000116 for Celso for feet with farenheitCt=0.00000645(T-68)LT=temp of tape during measurementL=distance measured in feetstandard conditions for using a tape are 68 F, tape fully supported and tape under 10 lbs of tension. theres a tension grabber thing to measure the tension, but im pretty sure nobody uses it.
Reply:We had a new guy who called out 87 1/3".??? A THIRD? Where the F@#H is the marks for THIRD's on the tape?!! .No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:its 2/3" from 88"
Reply:another such story that i think was true involved a job applicant for an inspector position at the budd stamping plant in detroit (about 1970 ).they asked if he could read a 6" scale--yeah ----ok how many of the small marks (100ths )are in an inch ? "must be a million of the mother f#$@ers " goodbye.miller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet
Reply:Was browsing eBay and saw this item and thought of this threadhttp://www.ebay.com/itm/Flange-Wizar...#ht_3749wt_922
Reply:Originally Posted by AMC724Was browsing eBay and saw this item and thought of this threadhttp://www.ebay.com/itm/Flange-Wizar...#ht_3749wt_922
Reply:Originally Posted by BrainfarthSpendyA survey buddy told me that they haven't used tapes or chains in 20 years. It's all done with EMD's and GPS locaters. If their within a dime, it's acceptable. Which still brings me back to the original question of how do you know what is correct without the use of high-end laser, or before laser?
Reply:unless you are a carpenter and building a very large house where accuracy can be within a 1/16th, then you should never use a tape measure for making any kind of accurate measurement, but - if you plan to do so always use the same tape measure and measure from the same direction, or measure in from both direction then split the difference using the scales not the hook on the end. That is really the only way you will stay consistent with one. Why do you think tape measures are cheap and verniers and calipers are expensive?
Reply:Nobody uses the good old fashioned dividers, or tremel points anymore? very accurate when set up right and saves a lot of fooling around whishing you had 3 hands, not practical for long dimensions I know, but 3 feet and under , no problem."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251 Syncrowave 300 30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200 1 short hood SA250 SAM 400
Reply:I'm a Stanley/Lufkin guy myself. Easy to read!Feel free to correct me, but if your tape is hooked on that pin which centers on your centerpunch mark, won't that be measuring off center of the hole?
Reply:its off by a little. just add a 32nd for half the pin thickness.Common sense in an uncommon degree is what the world calls wisdom.
Reply:how would a 'pro' job shop measure something that long .? theodolite mesuring device .? thermal arc 252i - millermatic 350P - miller XMT, cp300ts, 30a 22a feeders, buttload of other millers, handfull of lincolns, couple of esabs - Hypertherm 1250 G3
Reply:As a registered surveyor (and Brainfarth's survey buddy), let me assure you Rusty Ripple came closest to the truth. We deal with random and systematic errors, and it's all about statistics today. That being said, tools are not the real test for surveyors.... professional judgement is. I would buy a 100' x ¼" Invar steel tape, measure it against several known standards and come up with a correction value, with additional corrections for sag and the always possible misalignment between points. The tape must be held as true to horizontal as possible, of course, and the proper amount of tension should be held. After the temperature correction is applied, you should have a good handle on the true distance. However, in any room containing 5 surveyors, you will almost always get 10 differing opinions....Miller Syncro 250 tigrunnerLincoln 175 migO/A
Reply:Like many have already stated, use the same tape for the entire layout.Honestly, you're not going to do machine work with a tape. I mean you are probably going to cut the plate to size with a torch; zip wheel or a band saw type blade at best.. That's plenty good enough for a tape.Then when you get down to the actual layout, I use starrett scales.I have many from 1" to 36".I lay everything out off of my center lines, never the edge and use a carbide tipped scribe for a nice fine line.You can get a starrett 36" cosmetic second for $120 or 200+ for new.How close do you really want to get? It's up to you Last edited by skelley521; 10-04-2011 at 10:17 PM.Semper FiJesus may have been a Carpenter, but his dad was a Millwright" A grinder and a can of paint, will make a welder what he aint' "I've done so much, with so little, for so long, that now I can do anything with nothing!
Reply:I have never really thought about things being absolutely precise over long spans. Most of my work is pretty large, heavy equipment and the actual "structure" pieces usually just need to be close, like within an eighth or so. Where it gets tricky is in the mounting of some of these big pieces, that's where you need to be spot on. I have an optical alignment scope and 6 targets that will get me to less than .001" over a 40 foot span, but this is just for alignment, not really a meausurment of distance. What we usually do is build the bucket, or whatever it is that we are building, get it as close to specs as possible, then use the mounting bores, holes, or whatever it is to get the "final" and precise specs that we are looking for. Sometimes I have to actually "move" a pin bore to get things right. If I do a line-boring job on a bucket and miss the alignment by even 20 thousanths, It makes it damn hard to assemble, which makes the people trying to assemble it very upset, which has an affect on future jobs, which affects the paycheck. I can't remember the last hole I missed, and usually do a couple hundred per year, some day I might just get it figured out.6 Miller Big Blue 600 Air Paks2 Miller 400D6 Lincoln LN-25's4 Miller Xtreme 12VS2 Miller Dimension 812 4 Climax BW-3000Z bore welders Hypertherm 65 and 85Bug-O Track BugPair of Welpers |
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发表于 2021-8-31 23:32:33