67 BB Hood Stripe

[Stephen L.]

I am about to lay out the stripes on the BB hood. Looking at the AIM on page L36 sht A17, I am trying to determine the dimension of the stripe portion located on the front valance in front of the hood. The dimension is -50 S.V.
Does that mean 5.0 inches from the hood edge opening to the tip of the internal large stripe????

[Louis F.]

Re: 67 BB Hood Stripe

I ASKED THIS QUESTION TO AN EXTERIOR JUDGE AT THE NATIONAL CONVENTION IN HERSHEY 2003.HE TOLD ME THE "A DOLLAR AND A DIME".WHEN YOU LAY A DOLLAR AND A DIME ON THE PIECE IN FRONT OF THE HOOD, THAT IS THE CORRECT LENGTH. NOT SCIENTIFIC BUT CORRECT HE TOLD ME.I PAID $125.00 PLUS SHIPPING FOR MY STENCIAL FROM, STENCIALS AND STRIPES A FEW YEARS AGO AND HE TOLD ME ITS TO LONG.

[Stephen L.]

Dollar & a Dime

Hey, that is a real "accurate" dimension! Evidently that judge didn't have a "clue" as to measurement in inches.....
Did that "dollar and dime" go to the most forward point or to the larger "Stripe" area point. (There are 2 points and the AIM dimension goes to the larger area)
With the National convention in Windsor Ontario this year, will they be using Canadian dollars and dimes on the 67 judging.......

[Wayne W.]

Re: Dollar & a Dime

Here is an original. It should give you an idea how it was.

[Stephen L.]

Re: Dollar & a Dime

Thanks Wayne. You wouldn't happen to have this car where you could get a measurement from the hood opening to the tip of the inner point. I have the rest of the dimensions in the AIM. That dimension is confusing as shown in the AIM. It states -50 S.V. I don't know how to interpret that.

[Jack H.]

Interpretation...

Steve, you've said several times you didn't understand how to interpret the AIM when it specified the position of the accent lines on the hood....

Navigate in your copy of the AIM book to UPC, Section 1, Sheet C3. See the detailed dimensional check drawing given for the car from a frontal view standpoint. Now, flip a page to UPC, Section 1, Sheet C5. You'll see similar information listed for the car's front side view.

See where -50 is in this SV drawing.... Now do a mental check of the -50 S.V. call-out associated with UPC, L36, Sheet A17. Does it make more sense now?

This is GM designer-to-assembler parlance. The AIM books were never intended to be distributed outside GM as they were limited use in nature to support internal communication.

Also, on the 'dime and dollar' comment. At NCRS we don't use measuring tools when judging (slows the process down, can generate disputes, the Flight portion of our sport/hobby is geared to 'appearance'). Plus, there's a question of once you start, where do you stop?

If we allow rulers, why not micrometers? If that, why not haul down a gas chromatigraph and measure the PPM of DDT residue in the air filling the tires? DDT was used as a pesticide back.... Heck, we could determine if that's 'real' St. Louis air from 1967 in the tires!!!!

No, there's a point where the craziness has to stop. So, you'll see judges using 'ordinary' objects (dollar bill, dime, quarter) to get a 'feel' for the appropriateness of this/that.

BTW, if there are National Team Leaders or Judging Guide contributors out there reading this thread, here's an input.... STOP making these references in NCRS printed text unless they're truly universal in nature!

The first time we Flight judged in the UK, I found myself explaining what a 'dime', 'quarter', 'dollar' was.... Some references we take for granted in the US are not universally understood by those beyond our shores. While they may be clear to us, they're nation/time specific. They can confuse non-US NCRS members as well as give a reason for making yet another revision of the Juding Guide....

[Stephen L.]

Re: Interpretation...

Jack, thanks for the input. I have some pictures of my findings based on the AIM drawings. I'll send them to you for your input. I don't know the procedure for posting here but I better find out.........I put some dimensions on them so maybe someone else can benefit in the future

[John H.]

Re: Interpretation...

Steve -

The dimensional references in the A.I.M. are based on the GM 3-D Body Design Grid System of "inch lines" from master datum points, and are only useful when a body is set up on a surface plate to design datums for dimensional inspection (which was done every day on at least one body, and still is today, except today it's done with automated computer-driven coordinate measuring machines instead of by inspectors with height gages and clipboards).

In those days, we made drill fixtures in the plant from a prototype body that had been "scribed" in all three planes on a surface plate in the 10" increments that formed the "body line" grid system. They don't mean much today unless you happen to have a scribed body handy; the only design datum that physically exists on the body is the flat face of the firewall, which is the fore-aft "0" line

[Mike Cobine]

Re: Interpretation...well, umm, you see...

If we allow rulers, why not micrometers? If that, why not haul down a gas chromatigraph and measure the PPM of DDT residue in the air filling the tires? DDT was used as a pesticide back.... Heck, we could determine if that's 'real' St. Louis air from 1967 in the tires!!!!

No, there's a point where the craziness has to stop. So, you'll see judges using 'ordinary' objects (dollar bill, dime, quarter) to get a 'feel' for the appropriateness of this/that.

Let's see, back a few months ago, there must have been 50 or more messages on this very issue.

Of course, that was over the "sacred" broach marks. But I guess they really do match up. $1.10 to measure a stripe, a buck and a half to observe a stamp.

[Stephen L.]

Re: Interpretation...Datum point

John, (This is a long reply but....)
I did look at the AIM "grid" drawings after the suggestion by Jack Humphrey. I'm familiar with grids like this, used in industry. What threw me initially (and initiated this subject thread) was the stripe has all the dimensions in the AIM on sht L36-A17 to lay it out in decimal inches except for the starting point on the front valance (which I now know references the grid). That is where the confusion came in. After looking at the grid I could see the "0" datum and 10" grid lines but there is no clear reference to a point on the actual body....at least I don't see it on the drawing. Your thread made things perfectly clear when you said the "0" datum is the "flat face of the firewall" Now I have a starting point for measurement for correct layout. I measured 50" from the flat face of the firewall (no engine, body off frame) and that point is only 3-3/4" from the forward hood opening edge which does not look even close to correct for the stripe.....
I have now found a point on the grid -10 S.V. that corresponds with a physical location on the body...the lower vertical rear edge of the front fender opening as`shown on sht1 C5 of the AIM. Working rearward toward the flat firewall face from -10 S.V. I measured the firewall face to be 12.75" or a point +2.75 S.V.
That would make the large stripe forward point (-50 S.V.) 52.75" from the firewall. That measurement comes out looking very good AND it passes the "dollar" test. As an alternate point of reference this also equates to 6.12" from the hood opening forward edge which also just happens to be the length of a dollar bill........
After all that, I believe the firewall face to be grid point +2.75 S.V. not "0" datum.
Thanks for getting me pointed in the right direction to find a physical reference point. I hope this helps others when laying out a stripe on a BB hood.