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ON topic: 8 or 9? And what dimension did I cut it to.

Bobw

Diamond
Joined
Feb 8, 2005
Location
Hatch, NM Chile capital of the WORLD
Background. Probably made 100 of these and assembled some of them over the past 15 plus years.

TODAY.. There was a problem, the first problem on these EVER. It was a qty of *1* that
I did like 6 months ago. Apparently there are 2 holes in the wrong place now. So I check
my cad model. I check a backup drive from 10 years ago. Yep that's what it is.

They have been the same every single time. I've already gotten paid for this by the way.

So.. Is this an 8 or a 9?

Standard printout, photographed.

50275846203_3bd9e2866f_c.jpg


Zoomed in a bit on the PDF

50276685112_88f2b59007_c.jpg


Zoomed in a LOT.

50276530961_404e99f907_c.jpg



So is that an 8 or a 9? And should I fix it for free, even though there are
close to 100 of these out there that assembled fine, and are WRONG, and not
a single one of them has come back(for this, one did come back once, to fix
a weld problem, and that really was wrong).
 
I was under the impression that a CAD model stores data in digits that can be called up on the monitor in any size type and are quite legible. So why are you looking at a low res printout for an answer?

Larry
 
I was under the impression that a CAD model stores data in digits that can be called up on the monitor in any size type and are quite legible. So why are you looking at a low res printout for an answer?

Larry

Because the CAD model is made off of the print that I get.

I pulled up an old version in a backup to make sure that I hadn't
accidentally changed anything.. and I didn't.
 
Something is goofy. Those are hand-written characters. None of the same digit look alike. Why are they not computer-generated characters?
In all but the largest magnification I'd have said 8. How do you go about making a cad drawing from a paper print? Do you have to trace everything?
edit: I think I'm understanding a bit more, maybe. Did you make the cad drawing from the printout?
 
Because the CAD model is made off of the print that I get.

I pulled up an old version in a backup to make sure that I hadn't
accidentally changed anything.. and I didn't.

Well, I was taught never to scale a print, but it seems in this case that would be just as accurate as creating a CAD model from dimensions that are illegible.

Larry
 
Bob: You have a lot more experience than me but for me if it was not too much time or if it's good customer I would probably take the "customer is always right" route and eat it but??
 
Something is goofy. Those are hand-written characters. None of the same digit look alike. Why are they not computer-generated characters?

Yeah, they are hand written. Mechanical drawing used to be a thing. DRAWING prints with your hand/straight edge/compass etc..
This stuff is from the mid 70's. There is one part I do quite often, and I just finished up a pile, and quoted more today.
1965. 3 revisions, 1965, 1975 and 1986. There is NO cad model, there is a blue print.

You don't TRACE. You make a model from scratch, as little or as much as you need, and you use the dimensions on the HAND DRAWN print, that has been scanned 1000 times.
 
I would say 8. Even .9xxx doesn’t fit the rest of dimensions. Old drawings tend to go in 1/16 or 1/8 th. .875 is 7/8, .625 is 5/8. The .12 is a 1/8 depending on which direction wind is blowing. 1970’s, a hundredth would be a machined part, not plus minus a 1/16 as drawing calls out.
 
I would also agree with an 8. Looks like the scanner filled in the right hand side of the 8, and the 9 in the note "View I Zone G9" is not obscured like that.
 
Yeah, they are hand written. Mechanical drawing used to be a thing. DRAWING prints with your hand/straight edge/compass etc..
This stuff is from the mid 70's. . .

Got it now, thanks. I actually did some of that drawing in the early 70s but I've never really learned CAD. Somehow I got it in my mind that you'd been provided a CAD drawing by the customer. Its all clear now.... except the 8 vs 9!

So tell us, which would put the wrong holes in the right place, an 8 or a 9?
 
You could make a valid argument for either case, it's effectively illegible and completely ambiguous. It does look more like an eight to me. Either way, since the customer failed to supply you with a legible drawing I'd absolutely be inclined to dig my heels in and say "your fault, I'm not fixing it for free".

Having been bit by similarly unreadable drawings before, and playing the inevitable blame game, I have a policy to reject drawings that I don't consider to be completely legible, 10 times out of 10 the customer will gripe and moan about it and then somehow produce a better copy. Scanners and copiers and ignorant office staff have a lot to answer for.
 
Looking at it I'd call it an 8, but the customer should know best.

Yes they do.. Its been an 8 for over 15 years.

So tell us, which would put the wrong holes in the right place, an 8 or a 9?

The 8 puts it in the wrong place. Its "supposed" to be a 9.

I have a policy to reject drawings that I don't consider to be completely legible,

I get that, or I'll at least question, but there was no question, to me, that was an 8.
The rest of the print is pretty darn clear, if not a little crowded. There are somewhere
around 70 of these I've done over the years out in service with those holes at 8.625.

Just one of those "F** Really???" Days. I'm not even mad at this one. More
inconvenience than anything else.
 
Looks like an 8 to me. Especially so compared with other dimension.

Been there done that, same situation, modeled a part off a hand drawn sketch, misread a number it sucks, but I think customer should eat that type of mistake...
 
Last edited:
The shops I deal with don't make dimensional changes based on verbal instructions - they want an updated drawing. Tell the customer you'll remake it using "9" when they give you an updated print. I suspect the pain of redrawing a decades old paper print will have them rethinking the importance.
 
Bob,
Obviously the 100 or so "wrong" parts are okay out in the field.
How come this has just been noticed?

The part that hangs from those 2 bolt holes could be almost anywhere and work,
as long as they are the right distance apart. 7.875. There is a piece of
rubber with a hole in it that gets glued over one of the bolt holes, the hole
in the rubber exposes the head of the CS head bolt. The rubber never fit
particuarly well, but it worked. Looking at the print for the rubber, I'm
guessing that the rubber piece is from a new batch/manufacturer and is finally
correct and now covers the entire bolt head.

I would have just cut a bigger hole in the rubber and called it good.

The parts in this assembly get a little complicated. One part/casting that
has never been made "perfectly" ever has just under 400 dimensions over 8 pages.

Another part of another part that goes with this whole mess has never once been
made correctly. Probably 3-400 of them over the years, I have 6 of the welded
assemblies sitting over here right now ready for final machine, and that part
of it is wrong. The print on that is so damn busy and complicated that I had been
dealing with that one print for 12 years or so before I saw that that one piece was wrong,
apparently nobody else has caught it either. Pretty pathetic, I know this.. But
its about 5 section views deep, each view on a different page of the print. And
the whole thing works, even though the part is wrong.
 
The shops I deal with don't make dimensional changes based on verbal instructions - they want an updated drawing. Tell the customer you'll remake it using "9" when they give you an updated print. I suspect the pain of redrawing a decades old paper print will have them rethinking the importance.

I'm not remaking anything. This thing is already welded, painted, and half assembled. Make 2 plugs,
drag it down the street to get it welded (I can't weld aluminum to save my life), smooth it out, drill
2 new holes and tell them to come and get it.

As far as documentation, getting the print corrected, or even just clarified could take years, there are
many more levels than just my customer. I NOW know that its a 9, and hopefully they will make a note
in their system so when the next PO is issued it will say "the dim that looks like 8.625 in sec ?-?
pg? is actually 9.625".
 








 
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