Warning About Copied Plans

[Dick Pacini]

I recently started to build Walter Umland's Coyote Kit.  I didn't want to spoil the plans for building, so I took them to the local copy shop and had a copy made, which I cut up and used on the bench to build over.

Everything went well until I went to assemble and install the laser-cut trailing edge parts only to discover that the trailing edge was 3/16" too short.

I sent an email and pictures to Walter Umland and also made a post here asking if anyone had built the kit yet.  I received a reply from Walter and he asked me to check his plans.  To my embarrassment, his plans measured exactly 48" rib to rib and the copy I had made measured 48 3/16" rib to rib.  Apparently, the copy is about 4% larger.

So, now I have to make another splice in the trailing edge parts to match the oversize plan.  I guess you can't depend on the copy shop.

So, just a warning.  A copied plan would probably be OK for a scratch built model but risky if you're building a laser-cut kit.  Check and double check.

[Wayne J. Buran]

The best thing to do is to have the copies made at a Archetectual/builder blueprint shop. The one I go to here in Ohio has always been right on the money with reproductions. They also have reduced prints to the dimensions I need. It was more than reasonable considering the alternative problems. The other alternative is to befrind someone who works at a place that has the internals for having to make large prints. It might  be no problem if you offer to pay.
Wayne

[Randy Powell]

I go to a UPS store that has a 36" photo copier. You have to be careful to insure the machine is set to 100% (as me how I know), but as long as that is done, the plans on dead on.

[Geoff Goodworth]

It's a common problem Dick. I used to use one copy shop who caused me a real problem. The operator invested a lot of time in adjusting the printer—which printed my original computer files correctly—so she called their tech who found the scanner out of alignment. A problem that was not operator adjustable.

[Tom Luciano]

I have plans made 2-3 times a week for work. 90% of the time it's operator error. Not having the scale set to 100% or when printing, most printers default is to scale to fit the printable area (you want non scaling and to select paper from document size). I normally look over their shoulder and keep an eye on them. Ty's method is spot on, and I always have a ruler/engineers scale with me to verify. Geoff's case is not the norm but, I have heard of it happening.

[don Burke]

That goes for plans printed from CAD files also.  I generally include 10" scale axis lines on my plans just for that purpose and I will draw a border box 34" high to accommodate the usual 36" max printers margin requirements.  Length is never a problem.  And as noted, the hand held scale for a post printing check is a necessity.  I also make sure just for ease of alignment that the drawing origin is at the left bottom corner of the border box.
 
I have had to "assist" the operators in any Kinko's/FEDEX, Staples, etc every time I go to get something done full size.   Fortunately they've all been cooperative in getting me what I need.  They don't get "full scale" requests very often so they're just not used to it.

[dankar]

Don't need no stinking plans !! I never had problem with Kinkos. Just tell them scale you want and good to go.

[Larry Cunningham]

That's to keep you from copying your $100 bills..

L.

"My grandfather invented Cliff's Notes. It all started back in 1912... Well, to make a long story short..." -Steven Wright

[builditright]

I would think the real fix to end problems like this from happening is to simply buy an extra set of plans with the kit.

The cost for the extra set should save you the time, the gas and the cost of purchasing the copy.
Let's not forget the problems that can occur from the plans stretching; like did in this case.

[Serge_Krauss]

As I've posted several times over the years, I do as Ty suggests about including marked perpendicular scales and never go to a copy place without my calculator. Even when set at 100%, plans have yet to be "right on" in my experience. A 1% error on a 55" wing span is over 1/2" in span. So you can expect up to 1/4" error. I have had vertical and horizontal scales distorted relative to each other and sometimes, when feed is improper, lines are curved or scales vary along their length. You must find a conscientious person who has some idea of simple mathematics and expects to have to adjust from the first try to get the second one right. Too many are not so inclined and skilled; so I go prepared. Last time the guy was pretty good, but still got it wrong. When I showed him the error, he fixed it with the scaling I presented.

SK

[Paul Smith]

At GM we had the best available Zerox photo copiers.  A 2% error was standard.  If we ran 8 1/2 x 11 documents several times, we cranked in a 98% scale factor or else the content would grow off the page.

On the other hand, the "old" Ozalid blueprint machine gave exact-size prints, at the expense of smelly ammonia and the need for transparent originals.

That's why the title block always says "Do not scale this print."

[Larry Cunningham]

It helps if the original is on mylar instead of paper. Mylar doesn't suffer the stretch problems of paper, or at least hardly at all. Without access to the original, it would be worthwhile to check the accuracy of your print before making a copy.

I like to emit my plans as full scale PDFs, which seems to be a good start, but no real guarantee. I haven't been putting a scale on my plans = I suppose that should be standard practice.

Accuracy ultimately boils down to the quality of the reproducing device(s), paper and supplies.

L.

"Don't LOOK at anything in a physics lab. Don't TASTE anything in a chemistry lab.
Don't SMELL anything in a biology lab. Don't TOUCH anything in a medical lab. And,
most importantly, don't LISTEN to anything in a philosophy department." -Bill Lye

[Mike Griffin]

As a cottage kit maker like Walter, I agree with him 100% about ordering an extra set of plans to cut up.  If the laser cutter is plotting his own plans like I know Walter does and I do from where I get mine, this is not going to be an issue.  However there are times when I have had to outsource copies and plan stretch can become an issue at places like Kinko's, Office Depot, Staple (I have used them all in the past).  If you have a blue print service in you area named ARC, give them a try.  I have never had this problem with them and they charge .25cents a square foot.  That is really reasonable. A 3 x 4 plan is only $3.00.  You sure as heck cannot beat that..

Mike