Larry Jackman writes:

Personally I do not under stand why there was any thing for the tool
maker to convert. Drawings should have contained the correct dimensions
for him to work with. Had it done so there would have been no problems
for a court case.

As I understand it, the conversions from prototype dimensions to HO were done by the toolmaker to only two significant figures (five would be more like it) and this led to the undersize dies. Larry makes a good point: provide the toolmaker with actual dimensions of the desired part (I assume that's what Larry means), unless of course that's not the normal practice in the hobby.

Tony Thompson Editor, Signature Press, Berkeley, CA
2942 Linden Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@...
Publishers of books on railroad history

Hmmm...
I'm curious as to what the errors were. Did it turn out, say, a
scale 12" too short in all directions? Or were there missing
details? I saw one of the test shots at a hobby shop southeast of
here, and the thing was pretty impressive. Of course, this comment
refers to the general, overall quality, not detail accuracy. I
didn't have a set of drawings to compare it to....

All I can say is that if that thing was the reject, I hope the
good ones eventually get produced!

Phil Buchwald


--- In STMFC@..., Anthony Thompson <thompson@s...> wrote:

Larry Jackman writes:

Personally I do not under stand why there was any thing for the

tool

maker to convert. Drawings should have contained the correct

dimensions

for him to work with. Had it done so there would have been no
problems
for a court case.

As I understand it, the conversions from prototype

dimensions

to HO were done by the toolmaker to only two significant figures

(five

would be more like it) and this led to the undersize dies. Larry

makes

a good point: provide the toolmaker with actual dimensions of the
desired part (I assume that's what Larry means), unless of course
that's not the normal practice in the hobby.

Tony Thompson Editor, Signature Press, Berkeley, CA
2942 Linden Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@s...
Publishers of books on railroad history

I saw one of the test shots at a hobby shop southeast of here, and the

thing was pretty impressive<
The statement says the error was corrected but he would not finish the
work. Following is part of the statement;

"just over a year since the error was corrected. Rather than complete the
rest of the work he contracted for, the toolmaker for the CNR version of the
Dominion car has abrogated his contract, claiming he lost too much money
correcting his error."

I'm going to guess (I like to do that as without facts, well) that the
body is done but none of the supporting parts. And who actually has the
mold is anybody's guess.


Jon Miller
AT&SF
For me time has stopped in 1941
Digitrax, Chief/Zephyr systems, JMRI user
NMRA Life member #2623
Member SFRH&MS

Actually Don himself posted the following in message 21131 on July 8 2003.

"This will be a bit long but will serve two purposes. First, it will
bring everyone up to date on our Dominion car project. Second, it will
illustrate why three decimal places in HO scale ain't going to make it!

Last Thursday was the pre-arranged day to test shoot the four-slide
mold for the body of the first of our Dominion car series. This is the
floor, sides and ends. We SHOULD have been doing this on May 1st but have
experienced some delays even with allowances made for same when setting up
a schedule. In any case, our molder's production manager had already told
me we had a "jewel" of a mold and my hopes were running high, though the
first effort in molding such large and complicated mold is always....
shall we say interesting. The mold had already been "hung" on a nice new
Nigata molding machine by the time I arrived. The Nigata's are really nice
machines, all electric, no hydraulics and far better and cheaper to run
than any Arburg or Newberry hydraulic machines we have used for some of
our line. The machine was turned on to warm up and away we went. We ran
about fifty shots to see where we were at. As often happens with a new
mold having a lot of detail, some of the details, such as the door latch
mechanism wanted to hang up and tear off as the carbody was ejected from
the mold. O.K., so we found a couple of areas that need a little more
polish to assist with the release of the molded carbody and found another
area where an adjustment needs to be made to the mold so it doesn't knock
off the top door stop on one side of the body during the ejection process.

Our moldmaker had warned me three weeks ago that there were four small
spots where one detail was repeated that might not be quite right and he
was correct. This, however, is simply a question of taking the detail to
slightly greater depth in the cavity. We also need to beef up the
horizontal flange of the top angle in the car's frame so that it will not
be so thin as to tear off in the ejection process. Again, no biggie! In
many ways we have pushed this mold to the limits of what can be done
with both molds and styrene in HO scale. So the moldmaker, the production
manager and I sat down for twenty minutes to review what needed to be done
while the shop crew dismounted the mold to enable the toolmaker to make the
necessary adjustments, afterwhich I took a bunch of the test shots and
headed home to review all measurements.

After supper I dug out scale rules and calipers and went to work. My
first measurement was the length.....and I knew immediately we were in
deep manure no matter how good the detailing was! The 36 ft. 4 in. outside
measurement of the carbody came in at 34 ft. 9 1/2 in.!!!! You can bet
that measurement was double checked quickly...and then triple checked with
the same result each time! Then the width and height were checked with the
same result being found. I'm not the toolmaker but immediately began to
suspect we had a math problem....probably with the conversion factor. Thus
I called the production manager at home and left word for him to call when
he got in, which he did. He decided to review the math with the plant owner
in the morning and then bring the toolmaker in. What was found was that the
conversion factor is a seven decimal number when carried out. It works out
all right if one uses at least five decimal places but the toolmaker had
only used four! That small difference compounds into an error of between
4% and 5% over every dimension in the carbody and that is just plain not
acceptable!!! Our toolmaker has learned a VERY expensive lesson and is
now recutting all cavities for the carbody so we will have it RIGHT when
it is introduced to the marketplace, not afterwards. While we had planned
to have the car available at the now cancelled NMRA Convention in Toronto
next week, my best "guesstimate" is that it will be early November before
the cars are ready for sale. If you think I'm unhappy you are absolutely
correct but I'd a damn site sooner have the car the way it is intended to
be before it leaves our place of business at all.

In any case, we know everything other than the size is correct, with
the exception of the mentioned detail that was to be corrected anyway. And
the molder's production manager was right, the tool is a jewel and so is
the product.....at least it will be when it is in the proper size! I will
put the caliber of the detailing up against anything else out there. You
don't have to take my word for it. Dick Dermody had a test shot put into
his hands just after noon today and can add whatever comments he wishes
since this tale is partly in response to his posting anyway. I will
also try to get a photo of a test shot up on our website at
www.newenglandrail.com. But please, guys, let's not hear any more about
three decimal places when it takes at least five to get it right in HO
scale! If you don't think so just ask our poor toolmaker! It is not a
topic for discussion with him at the moment, however, and I can understand
why.

Take care, Don Valentine
New England Rail Service"

Brian J Carlson P.E.
Cheektowaga NY

On Apr 11, 2005, at 7:56 PM, Brian J Carlson wrote:

Actually Don himself posted the following in message 21131 on July 8 2003.

"The 36 ft. 4 in. outside
measurement of the carbody came in at 34 ft. 9 1/2 in.!!!! ...<snip>...What was found was that the
conversion factor is a seven decimal number when carried out. It works out
all right if one uses at least five decimal places but the toolmaker had
only used four! That small difference compounds into an error of between
4% and 5% over every dimension in the carbody and that is just plain not
acceptable!!!"

You know, that's just about impossible. If the measurement was 1", rounding to four decimal places results in a maximum error of 1 in 10,000 or roughly 0.01%. If you get it wrong at BOTH ends of the car, that winds up with a WHOPPING 0.02% which on the real car would have been a miniscule 0.0872" and on Don's car the maximum error would have been a nearly unmeasurable 0.001". In order to get the error Don had, you would need 400-500 measurements end to end in each dimension, or the measurements being made would have had to have been on the order of 0.0025" in length (not accuracy). Don's explanation aside, somebody screwed up a lot worse than just getting the wrong decimal... kudos to Don for trying to fix it.

I'm surprised I beat Larry Jackman on this one <VBG>.
Regards
Bruce

Bruce F. Smith
Auburn, AL
http://www.vetmed.auburn.edu/~smithbf/

"Beer is proof that God loves us and wants us to be happy" - Benjamin Franklin
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Bruce Smith notes about the error in the Dominion car:

You know, that's just about impossible. If the measurement was 1",
rounding to four decimal places results in a maximum error of 1 in
10,000 or roughly 0.01%.

Put another way, if the error was truly 36.3' - 34.75' [ forgetting the half inch ], the difference is a significant 1.55'. This is an error of .042699 or 4.2699% of the expected 36.3'. If one were to just use .0426, the error would be 1.546' producing a car of 34.754'. If one uses another decimal place, 4.269, the error becomes 1.549' producing a car of 34.751'. The difference in these values, .003' or 0.036" would be rather difficult to read in HO scale...unless one used an electron microscope. A puzzling aspect of all this is the term "conversion factor". If the drawing that was being used was 36.3 X 100 billion feet long, [ 3,630,000,000,000' ], it would have to be converted by a factor of 8,700,000,000,000 to produce an HO scale car of 0.41724 ft or 5.0068" long. If one used a conversion factor of 8, 700,000,000,000.00009 instead, the car would be 0.41724 ft long also.

I suppose one day we'll find out the "Rest Of The Story".

Mike Brock

Mike Brock wrote:

Bruce Smith notes about the error in the Dominion car:

You know, that's just about impossible. If the measurement was 1",
rounding to four decimal places results in a maximum error of 1 in
10,000 or roughly 0.01%.

Put another way, if the error was truly 36.3' - 34.75' [ forgetting
the half inch ], the difference is a significant 1.55'. This is an
error of .042699 or 4.2699% of the expected 36.3'.

Convert the real car length to inches and then mulitiply by 0.011481 (that's
1/87.1). If I've done my math right the result is a model Dominion car that
5.005716 inches long. Now if you multiply by 0.011 instead you get a model
Dominion car that's only 4.796 inches long. And 4.796 is just 0.003 inches
off of being a 34' 9.5" car. Sound familiar?

I dunno if that's what really happened -- I know nothing of the facts -- but
this math comes out real, real close to what's been reported here.

Dave Nelson

On Apr 13, 2005, at 1:29 AM, Dave Nelson wrote:

Convert the real car length to inches and then mulitiply by 0.011481
(that's
1/87.1).  If I've done my math right the result is a model Dominion
car that
5.005716 inches long.  Now if you multiply by 0.011 instead you get a
model
Dominion car that's only 4.796 inches long.  And 4.796 is just 0.003 inches
off of being a 34' 9.5" car.  Sound familiar?

I dunno if that's what really happened -- I know nothing of the facts
-- but
this math comes out real, real close to what's been reported here.

Dave Nelson

Don reported the difference was between 5 and 4 decimal places (not 3
vs 6)... thus, between conversion factors of 0.0114 and 0.01148 if the
tool maker was an idgit and didn't round, and 0.0115 if they did. At
436", the conversions are as follows:

0.0114 * 436 = 4.9704"
0.01148 * 436 = 5.00528"
0.0115 * 436 = 5.014"

Now (5.00528 - 4.9704)/5.00528 * 100 is 0.69% This is not the 4-5%
reported by Don. The difference in car body lengths would be 0.03488"
or 0.035" on a good caliper... about 3 times the thickness of a grab
iron.

Class dismissed
Bruce

Bruce F. Smith
Auburn, AL
http://www.vetmed.auburn.edu/~smithbf/

"Beer is proof that God loves us and wants us to be happy" - Benjamin
Franklin
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Bruce Smith, following Dave Nelson's explanation:

Don reported the difference was between 5 and 4 decimal places (not 3
vs 6)... thus, between conversion factors of 0.0114 and 0.01148 if the
tool maker was an idgit and didn't round, and 0.0115 if they did. At
436", the conversions are as follows:

0.0114 * 436 = 4.9704"
0.01148 * 436 = 5.00528"
0.0115 * 436 = 5.014"

Now (5.00528 - 4.9704)/5.00528 * 100 is 0.69% This is not the 4-5%
reported by Don. The difference in car body lengths would be 0.03488"
or 0.035" on a good caliper... about 3 times the thickness of a grab
iron.

Class dismissed

Whoa, Bruce - you're confusing theory with reality! I was about to post the same explanation as Dave, because it's grounded in reality: the car body really is 4 to 5% undersize, and Don reported the problem was caused by the toolmaker using an incorrect conversion factor. If you accept those premises, the more likely explanation is that Don mis-stated the 4 vs. 5 decimal places cause and it was really 3 vs. 5. I was working on another project with Don back when all this happened, and my recollection was that Don told me it was 2 vs. 5. That recollection may be wrong, but I definitely remember it wasn't a matter of one decimal point difference.

Don called Monday night to order some more Pullman ice A/C sumps and with great trepidation I asked him how things were going with the Dominion car. He said he didn't want to talk about it. (Don't read too much into that - it was pushing midnight in VT and Don didn't want an adrenaline rush just before bedtime.)

Tom Madden

On Apr 13, 2005, at 9:20 AM, Tom or Gail Madden wrote:

Whoa, Bruce - you're confusing theory with reality!

No, I think its just different realities <G>

I was about to post the
same explanation as Dave, because it's grounded in reality: the car body
really is 4 to 5% undersize, and Don reported the problem was caused by the
toolmaker using an incorrect conversion factor. If you accept those
premises, the more likely explanation is that Don mis-stated the 4 vs. 5
decimal places cause and it was really 3 vs. 5. I was working on another
project with Don back when all this happened, and my recollection was that
Don told me it was 2 vs. 5. That recollection may be wrong, but I definitely
remember it wasn't a matter of one decimal point difference.

OK, THAT makes sense and would be right on for the error... each addition decimal place ignored increases the error by a factor of 10. Bottom line is that I'm forced to wonder why the toolmaker even used such an awkward factor to multiply the dimensions rather than simply dividing by 87.1? After all, most calculators do have that little button these days <G>.

Regards
Bruce

Bruce F. Smith
Auburn, AL
http://www.vetmed.auburn.edu/~smithbf/

"Beer is proof that God loves us and wants us to be happy" - Benjamin Franklin
__
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Wow! Neat! A calculator with a canned function to convert prototype
to HO! Has the NMRA gone digital? ;>

To leave the thoery behind, I'll bet that Mr. Valentine takes
real pride in getting the stuff dead on, but...
If the body has been corrected, I wonder if he would consider
either doing a resin underframe or selling just the body, and
include a drawing in the box to scratch up or bash the underframe.
He could recover some of his investment and we could get a kit!

With best intentions,
Phil Buchwald


--- In STMFC@..., Bruce Smith <smithbf@v...> wrote:

On Apr 13, 2005, at 9:20 AM, Tom or Gail Madden wrote:

Whoa, Bruce - you're confusing theory with reality!

No, I think its just different realities <G>

I was about to post the
same explanation as Dave, because it's grounded in reality: the

car

body
really is 4 to 5% undersize, and Don reported the problem was

caused

by the
toolmaker using an incorrect conversion factor. If you accept

those

premises, the more likely explanation is that Don mis-stated

the 4

vs. 5
decimal places cause and it was really 3 vs. 5. I was working

on

another
project with Don back when all this happened, and my

recollection was

that
Don told me it was 2 vs. 5. That recollection may be wrong, but

I

definitely
remember it wasn't a matter of one decimal point difference.

OK, THAT makes sense and would be right on for the error... each
addition decimal place ignored increases the error by a factor of

10.

Bottom line is that I'm forced to wonder why the toolmaker even

used

such an awkward factor to multiply the dimensions rather than

simply

dividing by 87.1? After all, most calculators do have that little
button these days <G>.

Regards
Bruce

Bruce F. Smith
Auburn, AL
http://www.vetmed.auburn.edu/~smithbf/

"Beer is proof that God loves us and wants us to be happy" -

Benjamin

Franklin
__
/ &#92;
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________________________________

|- ______/ O O &#92;_______ -| | __ __ __ __ __ __ __

__ |

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0

Phil wrote:<snip>

If the body has been corrected, I wonder if he would consider
either doing a resin underframe or selling just the body, and
include a drawing in the box to scratch up or bash the underframe.
He could recover some of his investment and we could get a kit!

With best intentions,
Phil Buchwald

I too look forward to Don's success in producing this car. However, if the above situation were to happen, the scratchbuilding or kitbashing work involved in completing the car would take more work than simply buying and building the excellent Westerfield cars that have been available for a long time.
I envision Don's Dominion car as being somewhat along the lines and complexity of a Tichy kit; all styrene parts with excellent fidelity and detail, somewhat less time involvement than a Westerfield. This would make a great steam era freight car more available to the masses and hopefully help hone their modelling skills for something more.
As an aside, the really ironic thing about all this is the fact that the CNR had actually more of the 5ft door Dominion cars than the 6ft door cars, but nobody makes them.

Rich Chrysler

On Wednesday, April 13, 2005, at 11:10 AM, buchwaldfam wrote:

My whole argument is why should the tool maker have to convert anything? I supplied correct measurements and all he had to do was cut the mold.
Also again I say I never paid one thin dime in advance of receiving a plastic part for approval.
To each his own.
Thank you
Larry Jackman
ljack70117@...
The 50-50-90 Rule: Anytime you have 50-50 chance of getting something right, there is 90% probability you'll get it wrong.

On Apr 13, 3:10pm, buchwaldfam wrote:

Subject: [STMFC] Re: [Dominion Cars]


Wow! Neat! A calculator with a canned function to convert prototype
to HO! Has the NMRA gone digital? ;>

Believe it or not, somebody used to actually make such a calculator, but I
can't find it in the Micro-Mark catalog anymore.

Regards,

-Jeff


--
Jeff Aley jaley@...
DPG Chipsets Product Engineering
Intel Corporation, Folsom, CA
(916) 356-3533

That's why dividing works much better. 435 /87 = 5.000; 435/87.1 = 4.994

Doug Brown

The important thing is the number of significant figures. The zeros only
affect the placing of the decimal point. 0.011481 x 87.1 = 0.9999951;
0.011 x 87.1 = 0.9581. 1/87.1 x 87.1 = 1.0000000.

Doug Brown

Bruce Smith wrote:

Don reported the difference was between 5 and 4 decimal places (not 3
vs 6)...

I note that there are several versions going around of "what Don said," some dating from different time periods. Examples include 5 vs 4, 2 vs. 5, and 3 vs. 5, decimal places. Whether this point has anything to do with the lawsuit, I don't know.

Tony Thompson Editor, Signature Press, Berkeley, CA
2942 Linden Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@...
Publishers of books on railroad history

Greetings,

Any calculator can be used for the conversion. Most calculators
now have a memory function. Enter (12 x 25.4) / 3.5 and store
the result in the memory. This value,
87.0857142857142857142857142857143, is the true divisor for for
the conversion. The inverse,
0.0114829396325459317585301837270341, can be used as a
multiplier, though it is most useful when the measurement is in
inches.

Michael


Schuyler Larrabee wrote: