vintage metal

80cui · Nov 21, 2020

Is there a metallurgy test that can determine if Alloy crank cases are from the 1940s or relatively new castings. These Wood patterns were on ebay about 3 months ago.

There is fake patina out there so Im wondering. metal quality 80 years ago was porous.
hope pic works ...

Limy Sami · Nov 21, 2020

I know some 50's thro' 70's Alu / magnesium crankcases (especially 2 strokes) were painted with oil based goldsize, I was told??? due to porosity issues.

Milland · Nov 21, 2020

80cui said:
Is there a metallurgy test that can determine if Alloy crank cases are from the 1940s or relatively new castings. These Wood patterns were on ebay about 3 months ago.

There is fake patina out there so Im wondering. metal quality 80 years ago was porous.
hope pic works ...

View attachment 305390

An appropriate Geiger counter may work - metals made before the atomic bomb testing tend to have lower inherent radiation levels.

You might have to find a true metallurgical testing lab to do a proper metals assay. I'm not sure a good-enough handheld XRF exists for light alloy work.

R. Dan · Nov 21, 2020

I know low background steel is a thing. Low-background steel - Wikipedia
But I don't know about pre-war alloys.

SAG 180 · Nov 21, 2020

Modern cast aluminium alloys can have newer grain refining additives that weren't around at the time like strontium and titanium boride.

boslab · Nov 21, 2020

We used ICP and xrf a lot on Ali, (inductively coupled plasma, sample dissolved and injected into a plasma torch via a nebuliser, spectrum analysed)
I wouldn’t be to hopeful, common 40s alloys, Reynolds, RR (rolls Royce), Hiderminium (hawker siddley high duty alloys) you’d just have to try to match, bare in mind practically no metal on earth is sold by specific analysis, ( ok there are exeptions but confined to specials and standards) they get sold by mechanical properties, chemistry is normally stated as within a range, I don’t think forensic id is possible without a genuine 40s casting to compare with
After saying all that I once got caught, after the heat number on a sample was the date!
Mark

80cui · Nov 21, 2020

OK, those patterns were sold as early 1990s patterns for Crocker mc engine. We all know those bikes fetch a pretty penny, but it is unlikely that genuine 1930s - 40s parts fell out of those patterns.

Im writing about Crocker bikes, I have a Register list from the 1970s and the last one from 2010.
The engine numbers were dodgie to begin with before those turned up on ebay.

In the 70s there was 31 bikes, by late 70s there was 48 listed, by 2010 there was 72 bikes, since then 2 more have sprung up.

the ideas you guys have mentioned are pretty good, the bikes were made 1936 to 1941. Any Nuke testing back when would definitely have an effect. Id imagine possible trace of sand maybe.
Modern alloy Id imagine has different grain.

at the end of the day , cases from a casting from those patterns requires one thing .... an Engine Stamp, and thats when it gets legal. These bikes go for $500k to $750K, obscene money without even considering if it is a replica

some good ideas Ill have to research, I didnt even think of. thanks guys

Rob F. · Nov 21, 2020

Nice write up on crockers in this old hemmings article, with pics

https://www.hemmings.com/stories/article/1939-41-crocker-big-tank

Dan from Oakland · Nov 21, 2020

Those patterns are not old original patterns if that is what you are wondering. Those core boxes are cast epoxy, which has been used in the pattern business for probably the last 30 years- lots easier to build a male plug and cast the core box around the plug than it is to build the core box from pieces. Hope that helps.

tdmidget · Nov 21, 2020

I need to buy those patterns. I'll make you a sweet deal on Crocker engines. However, you are going at this wrong. Date the wood in the patterns. Surely much cheaper and likely more accurate than the metal itself.
Nuclear radiation testing would tell you before or after 1945. But will it tell you if the radionuclides are in the metal or on it?

Newman109 · Nov 21, 2020

Limy Sami said:
I know some 50's thro' 70's Alu / magnesium crankcases (especially 2 strokes) were painted with oil based goldsize, I was told??? due to porosity issues.

That goldsize process was used on the crankcases of some British racing motorcycles. One in particular that I recall was the AJS "Boy Racer". It had magnesium crankcases.

Harley-Davidson had very porous sand castings in the early bikes, They used an orange shellac or enamel to seal the pores which other which otherwise would leak.

I once owned a 1957 Ariel Red Hunter racing bike. It leaked from a pinhole hole in the left crankcase, I took it to a dealer and he tapped the leak with a ball peen hammer and the leak stopped.

adh2000 · Nov 21, 2020

You won’t figure this out with much certainty. Low background steel is a “thing” but low background aluminum is not because aluminum isn’t produced by the Bessemer process. Besides that someone could have melted prewar scrap and poured new castings. These machines were made by man and man can make another one. If enough care is taken you won’t be able to tell. They are reproducing Crockers today:

The New Crocker Motorcycle Company - Classic American Motorcycles - Motorcycle Classics

On top of this there is the fact that many of the existing Crockers were built from left over original parts. Do those count? What if someone had 80% of the parts and fabricated the remaining 20% does that count? If you’re buying you can’t really know what you are getting unless you know the ownership history of that exact bike.

Harry Sucher did a good write up on the Crocker. It’s at the end of his Harley or Indian book, can’t remember which.

Sent from my iPhone using Tapatalk

Bill D · Nov 21, 2020

Pretty much all lead today has a higher count then what comes out of the mines today. Lead is easy to remelt and reuse so anything used in shielding has been remade into modern stuff. It is also pretty valuable and people know that so it is not thrown away like glass, steel and aluminum.
Bill D

80cui · Nov 21, 2020

Not my patterns, they were made in the early 1990s,they went for $5k.

In the Crocker Register there are some bikes that have a percentage of genuine parts, some genuine and some that can only be repop frame ,forks, motor and box.
But when it comes to stamping an Engine with a 1940s stamp, that is DMV stuff. there is also a token DMV stamped Engine, but then that one also changed from a 1938 to a 1942 model since the 70s.

The problem with Harry Sucher's book is that he got everything wrong and since 1977 everyone has quoted him , mistakes and all. He even got the wrong man , Albert G Crocker 1882, who the hells he ? not a mc manufacturer.

Paul Bigsby was quoted as saying 64 bikes were built, today there is more than was built, what kind of magic is that?

It would be possible to use old Indian + HD cases and tranny cases for the melting pot

Ball peen hammer! does'nt get more British than that

boslab · Nov 22, 2020

Degassing was fraught with difficulty early on, loads of secret recipes, stirring with a tree climbed by a virgin on a full moon, birch branches, oak spoons you name it, eventually vacuum degassing appeared, still in use today, the steel industry would be knackered without vacuum degassers, bottom up teeming helped get the gas to the top of ingots also called trumpet teeming, the porous crap was cut off on the crop shear, with Ali, big runners and risers, inverted casting inclined casting, aluminium was the first metal to be continuously cast, a caster was about in 1870s in some Swiss city.
Boron is a really important grain refiner as mentioned, a tiny bit goes a long way, 0.002 or less reduces grain by 10 times, lots of nucliation points provided, others work but not as well, duralamin from the 40s contained a bit, think they called it Y alloy from memory, which isn’t so good anymore!
Also adding Al is a fairly normal steel making process to absorb the oxygen, hence AK Ali killed steel.
Mark

Newman109 · Nov 23, 2020

80cui said:
Not my patterns, they were made in the early 1990s,they went for $5k.

In the Crocker Register there are some bikes that have a percentage of genuine parts, some genuine and some that can only be repop frame ,forks, motor and box.
But when it comes to stamping an Engine with a 1940s stamp, that is DMV stuff. there is also a token DMV stamped Engine, but then that one also changed from a 1938 to a 1942 model since the 70s.

The problem with Harry Sucher's book is that he got everything wrong and since 1977 everyone has quoted him , mistakes and all. He even got the wrong man , Albert G Crocker 1882, who the hells he ? not a mc manufacturer.

Paul Bigsby was quoted as saying 64 bikes were built, today there is more than was built, what kind of magic is that?

It would be possible to use old Indian + HD cases and tranny cases for the melting pot

Ball peen hammer! does'nt get more British than that

Yeah, that same bike later developed a crack at the rear of the crankcase. I took the cases to a welder that I knew and got the crack welded. The guy told me that the aluminum in the engine was pretty bad. He guessed that it was made from old melted Spitfires, LOL

boslab · Nov 23, 2020

Lots of newer castings have a lot of silicon from melting old Ali extrusions in the pot, no chemical control, it’s light, shiny stick it in, old engine parts would be a better feedstock than extruded stuff, I wish I had some old merlin or gryphon ( often people confuse the sound of the merlin with the gryphon and think that’s a spitfire when it’s a hurricane or a typhoon with a gryphon power plant, glad Packard took up the cause when Ford refused, but sticking the merlin with the mustang, genius, wonder if any mustangs had gryphons?) engines to melt, I’d retire, oh wait I have, see age doesn’t come alone
Did you know the statue of Eros in London is Ali!, I’m surprised they haven’t stolen it for scrap.
Mark

tdmidget · Nov 23, 2020

Aluminum casting alloys have a healthy dose of Silicon. It's what makes them casting alloys. The silicon is certainly not coming from 6061 where it is .4 to .8%. It is added and most aluminum die casting alloys have around 10% with some as high as 18. The silicon is what makes the metal flow and fill the mold. It also affects hardness of the casting.

boslab · Nov 24, 2020

Sorry you are correct, my error, silicon, well Ali si Mg alloys quite correctly, what I was trying to say was make castings out of castings, at least without full metallurgical control, OES XRF or as when I started, wet chemistry but that’s so bloody slow, as you say correctly all Ali alloys are silicon inclusive, it affects iron too, fluidity for casting, I apologise for mistake
Mark

Newman109 · Nov 24, 2020

tdmidget said:
Aluminum casting alloys have a healthy dose of Silicon. It's what makes them casting alloys. The silicon is certainly not coming from 6061 where it is .4 to .8%. It is added and most aluminum die casting alloys have around 10% with some as high as 18. The silicon is what makes the metal flow and fill the mold. It also affects hardness of the casting.

Correct. Having worked on Harley-Davidson motors to repair them from time to time as a hobbyist and rider, I can say that there was a big change with the later motors. The early bikes had crankcases and transmission cases that were virtually pure aluminum and were sand cast, Those would well very easily.

In later years, with die casting and the addition of silicon and copper made welding a bit problematical, There are probably others on here with more experience in this, but I do recall my trials with welding the later parts.

I'm not saying that the castings with additions such as silicon aren't weldable, but they can present problems.

I guess if a person or shop had an inverter type welder with extreme high frequency, it would be a lot easier, but all I have is a Miller Syncrowave and I'm stuck with 60 Hz.

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