Lacquer & stamp pads; Philosophy 101 (again)

[Dale Pearman]

Re: Cincinnati Milling Machine Co.

Thanks for the info Terry. Is your understanding of the operation the same as mine? Do you feel that these Cincinnatti broaches left traces of tooling marks? I've never seen any on unmolested engines without magnification. Are you positive that Cincinnatti called the milling machines broaches? If so, Ill change my act and start calling them broaches. I'm sure you've seen the sander number many times.

Varooom!


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[Patrick T.]

Any Comments On My Original Post?

During the last 2 hours, I have looked at the stamp pad 3 separate times, THIS time with a drop light, and maybe my eyes fooled me the first time, but I will have to (honestly) recind my statement about the straight lines on the pad which run from the front to the rear.

The stamp appears to be smooth, but there are many microscopic pits which cover the entire surface, which maybe what I thought were machine lines. These pits are from age, you don't have to be a judge to know that.

I've looked at a lot of engine stamps from Noland Adams 53-57 and 63-67 manuals and would welcomely challenge ANY NCRS judge to tell me mine are not original.

While I'm on the subject could anyone tell me how to spot a good restamp, and were the VIN numbers stamped on the engine at St. Louis or Flint? Any information would be appreciated. Thanks, Patrick

[Dale Pearman]

Re: McManmon = 1 Pearman ?

This is gonna rattle your thinking a bit but I've NEVER restamped an engine. I've watched it done many times however and coached a lot of restampers on how to do it. Never had one of my efforts challenged anywhere. I might consider actually restamping an engine if only I could keep my thumbs out of the way!

Varooom!


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[Dale Pearman]

Re: Any Comments On My Original Post?

Vin derivatives were done at St. Louis. Sounds like you've got an original, unmolested pad. The charistic of a "good" restamp is that it can't be detected. Therefore there is no technique for detecting a good restamp. There are techniques for detecting a Bad restamp or one that IS detectable. Detecting a good restamp is an oxymoronical situation.

Varooom!


CLICK HERE

[Juliet P.]

Magnaflux? & P-38 Restoration / Original Air...

So, have any of you who have seen these Broach or Sander or Varoooooom or whatever marks also Magnafluxed the stamp pads? Don't they use that process at the friendly local police department to determine original STAMPED numbers in guns which have been ground off or restamped? The first time the numbers were stamped into the surface metal (looser) it compressed the grain in the metal below the stamp. Even if you grind off the top layer the original numbers are still there in the higher density metal (result of stamping) beneath.

Question is whether anyone has had this done and does it work on engines like it supposedly does on guns? Supposedly even if it was restamped, traces of the original number should still show up. Might it be possible to check out some of these questionable types of marks etc? Not at a meet, but perhaps for research purposes? I'll volunteer my 44k mi '70 (I'm 99% certain original smooth to the nekkid eye pad) for magnaflux testing. (Maybe I've been watching too much Discovery channel or something.... )

One of the P-38's which landed in Greenland during WW2 was buried under 200 feet of ice. Recently it was recovered and is being restored. Part of the restoration process involved removing the 1942 air from the tires at the beginning of the restoration and storing it. Plans are to return the original air to the tires at the end.

Now I ask you NCRS officianadoes, does you still have your original air in the tires? Just razzing! There are some other crazy restorers out there who eclipse even us NCRS folks. :p ~Juliet


Juliet's 1970 Corvette

[Terry M.]

[Terry M.]

Re: Who was it.... *TL*

who said: "I can't define it, but I know it when I see it!"

Oh maybe the wasn't a Corvette judge, but surely he was talking about a "restmap," wasn't he?

Terry

[Lou Lapham]

Re:Al Grenning article on stamps in Restorer

Patrick-If memory serves me Al Grenning did an article awhile back on the subject of engine stamps and some of the variations in the Restorer.Perhaps one of the other board members remembers the specfic issue.The broach marks vary depending on when the broachs were sharpened or changed.Early motors in a model year had different marks versus later in the model year when the broachs were worn.My 66 has the marks still showing even without heavy magnification. Lou

[Larry Boden]

Re: Magnaflux? & P-38 Restoration / Original Air..

This is a great HOBBY. But when I step up to plate for judging the last thing I want to be challenged is my integrate. If I have to have my word verified by a high teck procedure on my engine pad I'm out of here. You've missed the joy of it all. Larry

[Dave W]

The skinny...from ex-Machinist

The technical term of BROACHING is to cut (single or multiple teeth) in a LINEAR motion (straight back and forth), versus MILLING which is to cut (vertically or horizontally) with a ROTATING bit (most commonly posessing multiple helically wound cutting teeth). Since GM used a large single bladed broaching machine (think giant putty knife) to deck the surface of these blocks, one would expect to see (to some extent) perfectly linear lines front to rear if and when the blade dulled. Milling vertically will leave curved lines (radius of curves can vary from large to small..depending on the diameter of the bit used). Milling horizontally will leave 15-18 degree lines off linear as the helical blade(s) sweep across the surface and peel off the material (think snow plow). I would surmise that belt sanding (linear cutting)with some fine touching up (perhaps with a flat file) would give todays best approximation to the original broaching executed by GM. Side note: broaching valve guides does indeed use a small linear cutting bit, but the bit is rotated as it cuts down into the guide creating the common spiraling groove. -Dave

[Tom B.]

Re: the National Corvette Replica Society

Everett,

In my book, re-stamping the identical matching numbers on an original engine stamp pad is a restoration. STAMPING (not re-stamping) the matching original numbers to a non-original engine stamp pad is at worst, a forgery and at best, a replica. Call it what you want.

Judging is silly. If you want the award go for it. The problem is, once someone has the award the next step is to go for the BIG BUCKS that the award supposedly now "proclaims". If we're all getting to the point that a non-original (stamped or re-stamped) engine is just as valuable as the Corvette that has it's original engine, then someone else, other than me, can be just the guy those sellers are looking for.

Re-paint, replacement frame, and other reproduction parts, anyone can take those for what they're worth as well. TBarr #24014

[Terry M.]

Re:Al Grenning article on stamps in Restorer *TL*

Lou,

I doubt early or late int eh year made a difference - they ran the engine line continuously - except for work stoppages.

There was a nice blow up of a stamp pad on the cover of The Restorer a few years ago. That one had nice broach marks even Dale could see. Of course it was big enough maybe even Jerry could have seen them. (no offense Jerry - I just sometimes can't resist).

Terry

[Jerry Clark]

Never

Never any offence taken Terry, but they would have to appear as Engine Turnings for me to see em

jer

[Jerry Clark]

I trust ya Larry..

But are we to assume all of the pervious owners were as honest, then again, as many have said before us, are we assigning too much significance here ?

From a personal viewpoint I WANT TO KNOW that way when it comes time to sell I will be certain, ( or as certain as currently possible ), that the information I impart to the buyer is correct and sleep well that night, starring at an empty garage, I don't think so...

jer

[Dave - NCRS#24235]

I agree, keep restoring the vin pads & paint jobs!

Restorers are not the keepers of "survivor" cars. If we change one belt, hose, or bolt on the car, we are restorers. If you want to blank out belt sand marks and produce "age" pitting, have the block magnafluxed a couple of times - but the vin number gets finer and lighter with each magnaflux - you may have to "restore" it.

Same thoughts on paint restoration. If everone is so worried about the legality and morality of restoring vin pads, why do they think it's okay to repaint a car - let alone do it with lacquer, which involves exposure to EPA illegal toxic substances? Restore the finish to correct gloss and surface? Show me a stored paint chip of a factory assembly line paint job that has been in a vacuum for 30 or 40 years - and I'll agree that it does or doesn't match the restoration in question. - Dave