Judging Broach Marks

[Terry M.]

Re: Judging Broach Marks

As I said, I do not suggest anyone else try this, and had he told me what he was going to do I would have strongly recommended against it. Even with the outcome as it was -- I would still today recommend against putting acid of any kind on the machined surface.

It was not a case of rust or anything else obscuring them -- they were not visible even under high-powered magnification. Please note that the car would have received the 38-point deduction for lack of machine marks without the extraordinary lengths he went to. I don't know how long they remained visible after his acid wash, and frankly I didn't/don't care.

In the dozen or fifteen years I was Team Leader that is the only case in which I saw invisible machine marks that were raised from the dead. I still regard it as a highly unusual case, and while I can't say that it has never happened to another Corvette -- I have never heard of it happening in another case.

Most of the NCRS judges who are in a position to judge the engine at regional or national events have a lot of experience at it. While no system and no group of people are perfect, I think as a whole NCRS has the judging of engine pads down pretty well. Sure at a given Chapter meet the skill level may be less than one might want in some classes, I have been to some chapter meets where there were judging teams that consisted of the same people who judge at national or at Bloomington Gold. I think you guys are selling the people and system short.

[Timothy B.]

Re: Judging Broach Marks

How about navel jelly, do you think this would be gentle enough?? Thanks, Tim

[Michael H.]

Re: Judging Broach Marks

I recently saw an NCRS Judge who was judging an engine, pull out one of those high-powered "Broach Busters" scopes and proceed to view the stamp pad though its lens. I later asked him if he used the scope to judge all, or only some, pads in this manner. He responded that he used the scope only if the pad appeared irregular in some fashion to the naked eye. He said that if the pad looked normal to the naked eye, he would not resort to the scope; but if the pad looked unusual, he would use the scope.

Does anyone know if the NCRS has some standard protocol specifying the circumstances or conditions under which these high-powered scopes can be resorted to at the judging meets, and if so, is this published anywhere? Or does the NCRS allow judges to exercise their individual discretion as to when to use these scopes? Do all NCRS "mechanical" judges even own such scopes, and does the NCRS supply them to judges for use at the meets (like they supply the Judging Guide manuals)?

[Terry M.]

Re: Judging Broach Marks

Does anyone know if the NCRS has some standard protocol specifying the circumstances or conditions under which these high-powered scopes can be resorted to at the judging meets, and if so, is this published anywhere? Or does the NCRS allow judges to exercise their individual discretion as to when to use these scopes? Do all NCRS "mechanical" judges even own such scopes, and does the NCRS supply them to judges for use at the meets (like they supply the Judging Guide manuals)?

NCRS has no such standards, and the individual judge supplies his/her own mirror(s), flashlight(s), kneepads, scope(s), camera(s) and whatever else they might want. At a meet judging manuals, or portions of them, are usually loaned to the judges, but the more experienced judges have their own manuals -- with their own notes and high lights on the pages. Some judges even bring photos of original components to show the owner when explaining deductions.

[Terry M.]

Re: Judging Broach Marks

How about navel jelly, do you think this would be gentle enough?? Thanks, Tim

I have no experience with Navel Jelly on a pad, and I would experiment on somethign I didn't care about first.

[E S.]

Re: Judging Broach Marks

Sure you can, Stewart, if you dedicate yourself like several in this organization have. Your trip to the builder would be a good start. If that had been on the Judging Field, you would have earned one or two judging points for OJ'ing.
Repeat that process at an NCRS Judging Event and the other events all over the country, attend the Judging Schools and Retreats, with the tutorage of Master Judges, say for 10 or twelve times a year for fifteen or 20 years plus and earn 300 or 400 Judging Points or more and you should be able to Judge a pad at a glance.
HaND

Hi Mike-Do I understand you to say that there are several in our organization who can positively identify factory original broach marks?
If yes- then that would also prove that the vin#, engine assy. date,and hp suffix are also factory original to this vin# car, since they are stamped on top of these factory original broach marks. Correct?
If yes- that would be positive documentation that a particular car came from the factory with a particular horsepower engine(435,FI,250,390,etc.) Correct?
That would be great for those who have their orig.mtr; but lack the window sticker,order copy,etc.-Regards-EJ

[Dick W.]

Re: Judging Broach Marks

Naval Jelly will not harm the pad surface. I have used it several times in the past

[Terry M.]

Re: Judging Broach Marks

Hi Mike-Do I understand you to say that there are several in our organization who can positively identify factory original broach marks?
If yes- then that would also prove that the vin#, engine assy. date,and hp suffix are also factory original to this vin# car, since they are stamped on top of these factory original broach marks. Correct?
If yes- that would be positive documentation that a particular car came from the factory with a particular horsepower engine(435,FI,250,390,etc.) Correct?
That would be great for those who have their orig.mtr; but lack the window sticker,order copy,etc.-Regards-EJ

Faulty logic EJ. Have you ever seen a cylinder case with original broach marks and NO stamp at all? They do exist. As do cylinder cases with original broach marks and only an assembly stamp -- no VIN. So original broach marks are no assurance that you are looking at the factory original engine.

Beyond that, no judging organization has factory authenticity as their judging standard. ALL of them state the APPEARANCE of factory authenticity. You are seeking a standard that exceeds that of every Corvette judging organization.

[Roy B.]

Re: Judging Broach Marks

It's like any other part ,get two different judges and you can have two different scores it's human nature . Sense NCRS started I've seen this happen over and over

[Lynn H.]

Re: Judging Broach Marks

Reading all the threads on broach marks on the engine stamping pad, I though I would chime in on this one. While I would NOT consider myself to be an expert on judging of engine stamp pads for broach marks, I would consider myself a self described expert on broaching in general. I have been in the business of the manufacturing of broaches', and the production broaching of just about every type of production part you can imagine for 30 years. I believe that a large number of members are looking for an absolute type of definition when it comes to the stamp pads and that is just NOT possible. A couple of the threads are very accurate in describing the process. A broach is a perishable piece of tooling (much like a drill bit or reamer), that is used, sharpened, and used again. I can assure everyone that "back in the day" when most of our Corvette engines were produced, they got every possible part they could get before changing out the broaches' in the machines for new or more times than that, resharpened tooling. Quality control was certainly NOT what it is today in the industry. The broaching marks that we all look for are actually due to a chattering condition in the machining process. Certainly not something considered ideal from a machining standpoint. This condition was most likely most noticable with the sharpest of tooling, and lessened as the broach dulled. This condition would be constantly changing due to all of the variables in the process such as, sharpness, coolant flow, relief of the cutting edge, just to name a few. Two blocks machined one right after the other, would most likely appear to very similar, while another one that was done in the same set up with the same tooling 500 pieces later could look much different. I would bet this is something that Mr. Grenning could attest to, as he has probably seen more than most of us, to be able to make that type of comparision. While I believe from some of what I have read here, and also from personally speaking to a number of people on the subject over the years, is that most people do not have a clear understanding of what the marks are, and how they can differ from one piece to the next. For that reason they do not understand why someone cannot tell them exactly what they should look like. This is one of the variables in judging that will never be perfected to the satisfaction of everyone who has a Corvette judged by the NCRS. For that reason we have to put our faith in the judges, and remember why it is we all do this in the first place. IT'S ALL ABOUT THE CARS AND THE PEOPLE, AND HOW MUCH FUN WE ALL HAVE BEING INVOLVED IN THE HOBBY!!

[Dick W.]

Re: Judging Broach Marks

Very well put Gilbert. I get asked the question about broaches all the time, and without examples to show, there is NO way to tell anyone what they look like. No two are identical, but the surface will "talk" if you look at enough pads

[Roy B.]

Re: Judging Broach Marks

Well stated and the same thought can be used on paint markings and over spray

[Kenneth B.]

Re: Judging Broach Marks

[quote=Jack Humphrey (17100);400671]Well, Ken, here are my last comments in this thread. I think we've beaten the dead horsie WAY too long.

So, you're saying that when the guy shows up with an engine where he'd decked the lid with a mill and then polished out the swirl marks and hit the pad with a nasty rasp file to lay down HUGE/UGLY 'simulated' broach marks and then wacked the pad with 'K-Mart' stamping dies we ought to accept that without deduction(s) because there WAS some variance at the factory?

JACK
You need to reread my original post. I stated that if casting #,date code & the stamped character's are correct a lot of leeway should be given for the pad surface. I would give no points to the pad that you described but that is not what I was talking about. We might as well give the old dead nag a few more whackers in case she Winny's.
KEN

[Mike M.]

Re: Judging Broach Marks

OK,
Since the term "Broach Marks" has been tossed about without complete understanding, direction and with reckless abandon,
I'll stir it up a bit more.
"Broach marks" are not necessarily a requirement for full credit.
As an example, the Judging Sheet line item for Mid-Years for that category states:
"D. Stamp Pad Surface Finish" Originality Box Only!, NO ALLOWANCE FOR CONDITION!
Yes, we have seen pads that without question appear to be original, that are "Aged" to the point were no "Broach Marks" could be found.
However, without the option on the current Judging Sheets to deduct for condition,
YES, we have given full credit to pads Without Broach Marks.
HaND

[Harmon C.]

Re: Judging Broach Marks

Reading all the threads on broach marks on the engine stamping pad, I though I would chime in on this one. While I would NOT consider myself to be an expert on judging of engine stamp pads for broach marks, I would consider myself a self described expert on broaching in general. I have been in the business of the manufacturing of broaches', and the production broaching of just about every type of production part you can imagine for 30 years. I believe that a large number of members are looking for an absolute type of definition when it comes to the stamp pads and that is just NOT possible. A couple of the threads are very accurate in describing the process. A broach is a perishable piece of tooling (much like a drill bit or reamer), that is used, sharpened, and used again. I can assure everyone that "back in the day" when most of our Corvette engines were produced, they got every possible part they could get before changing out the broaches' in the machines for new or more times than that, resharpened tooling. Quality control was certainly NOT what it is today in the industry. The broaching marks that we all look for are actually due to a chattering condition in the machining process. Certainly not something considered ideal from a machining standpoint. This condition was most likely most noticable with the sharpest of tooling, and lessened as the broach dulled. This condition would be constantly changing due to all of the variables in the process such as, sharpness, coolant flow, relief of the cutting edge, just to name a few. Two blocks machined one right after the other, would most likely appear to very similar, while another one that was done in the same set up with the same tooling 500 pieces later could look much different. I would bet this is something that Mr. Grenning could attest to, as he has probably seen more than most of us, to be able to make that type of comparision. While I believe from some of what I have read here, and also from personally speaking to a number of people on the subject over the years, is that most people do not have a clear understanding of what the marks are, and how they can differ from one piece to the next. For that reason they do not understand why someone cannot tell them exactly what they should look like. This is one of the variables in judging that will never be perfected to the satisfaction of everyone who has a Corvette judged by the NCRS. For that reason we have to put our faith in the judges, and remember why it is we all do this in the first place. IT'S ALL ABOUT THE CARS AND THE PEOPLE, AND HOW MUCH FUN WE ALL HAVE BEING INVOLVED IN THE HOBBY!!

I think you have the broach wear backwords.
I was an inspector in the maching operations at Jeep and Chrysler and as I recall when the broach tooling was new the finsh was low on the chart we plotted every hour or as needed for the operation. When the surface got rough you could hear the dull tooling chatter and the readings got to the limit the inspector and the line forman shut the machine down for tooling change. If the forman kept running parts I called in my boss to red tag the operation and any more parts run by the machine were red tagged . I will say any surface that was broached had marks when new. We had a tool that checked the surface accross the grain and I think it was called a pro flo something. I worked this job in the 60's so it's all memory. This hands on knowledge helps me with judging stamp pads. I have taken no deduction on pads that appear correct but I would not buy the car thinking the block was original.