Blue agate?

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john elder
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Blue agate?

Post by john elder »

I believe this is just an 80 yd Montague, but it has a bearing cap with a blue agate. Has anyone else run across one like this?



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Mike N
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Re: Blue agate?

Post by Mike N »

Very cool reel, John. I’ve not seen another. Abu did use blue agate pivots in some of its high quality Record tournament casting reels.



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Re: Blue agate?

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Re: Blue agate?

Post by Mike N »

Ron, that is a beautiful reel. I love the name.

My admittedly superficial research indicates red and white “lace” agates are the most common, followed by green and then blue in scarcity. Blue agate was typically found in the US in Oregon.

Agate is essentially quartz, and its physical properties are in general the same. All agates, regardless of color, have a hardness rating of about 7 on the Mohs scale of hardness. Steel cannot scratch it. This prevents wear of the two agate pivots while the steel spool is turning.

Here are some representative hardness figures:

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David Lehmann
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Re: Blue agate?

Post by David Lehmann »

The glassy appearing jewels in end caps aren't really agate. Garnets were frequently used. The blue ones may be synthetic sapphires or glass. Agates are opaque and weren't used a lot for bearing jewels, probably because they have a tendency to crack. They are hard, but brittle (from water trapped in their atomic structure). I've notice that agates do show up in reels that were made during World War I and have wondered if the war made it tough for reel makers to get jewels from overseas suppliers. Here's a 1918 Model Shakespeare Precision that utilized agates in the end caps and close ups of the jewels.


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Mike N
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Re: Blue agate?

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“The glassy appearing jewels in end caps aren't really agate. Garnets were frequently used. The blue ones may be synthetic sapphires or glass. Agates are opaque and weren't used a lot for bearing jewels, probably because they have a tendency to crack.”

David,

That’s good info that’s only available from folks here. Thanks. I knew that blue garnet and blue agates have the same hardness and rarity, but was not unaware that synthetic gemstones were made that early for consumer goods. Cubic zirconia for commercial use was not prevalent until the 1970s. And, I doubt the end pivots of any bait casting reel could be made of glass, because steel scratches and wears glass.

I ordered a custom bait casting rod a few years ago with red agate guides (shown below): now I wonder if “agate” is just a generic term in the tackle industry?


Since we know that “jeweled bearings” are also used in watches, etc. it piqued my interest enough to go to that most reliable of all sources, Wikipedia.” Synthetic sapphires or synthetic rubies are often used in mechanical watch movements.

“A jewel bearing is a plain bearing in which a metal spindle turns in a jewel-lined pivot hole. The hole is typically shaped like a torus and is slightly larger than the shaft diameter. The jewels are typically made from the mineral corundum usually either synthetic sapphire or synthetic ruby. Jewel bearings are used in precision instruments where low friction, long life, and dimensional accuracy are important. Their largest use is in mechanical watches.”

Interesting stuff.
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Re: Blue agate?

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Glass is harder than you may think. It is typically above 6 on Mohs hardness scale, but if made carefully will approach 7, since good glass is just remelted and quickly cooled quartz, which also has a hardness of 7. Steel is less than 5, and bronze is still softer. (Higher numbers are higher hardness.) A piece of glass will scratch a steel pocketknife. Synthetic sapphires have been made for 150 years but became relatively inexpensive to make around 1900.

That's a great question about agate guides! I wonder what percent are synthetic vs. natural in rods that look like they have agate guides. I would think that guides that are advertised as "agate" really are.
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Re: Blue agate?

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David Lehmann wrote: Sat Oct 01, 2022 3:29 pm Glass is harder than you may think. It is typically above 6 on Mohs hardness scale, but if made carefully will approach 7, since good glass is just remelted and quickly cooled quartz, which also has a hardness of 7. Steel is less than 5, and bronze is still softer. (Higher numbers are higher hardness.) A piece of glass will scratch a steel pocketknife. Synthetic sapphires have been made for 150 years but became relatively inexpensive to make around 1900.

That's a great question about agate guides! I wonder what percent are synthetic vs. natural in rods that look like they have agate guides. I would think that guides that are advertised as "agate" really are.
Steel has a Mohs of 4 or so, but hardened or tempered steel has a Mohs rating of 8, and can scratch glass, not vice versa. I am a fan of amateur knife making (Forged in Fire tv show) but I’m not sure if vintage reel makers used hardened steel for the spool shaft. I assume they were not hardened, or even agate could not have been used as pivots.

Great topic, even if we are a bit far afield from John’s original inquiry.
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Re: Blue agate?

Post by john elder »

The early makers used hardened steel for foot screws, pawls, and gear posts… all the places that took lots of wear and/or required extra strength. Seems the UK makers used it a lot for screws… sometimes makes for difficult repairs!
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Re: Blue agate?

Post by Reelman2 »

Here are a couple of other examples of early jeweled end caps. The ones on the right are green. The milky red and white are on the left. They came off of an early Shakespeare Leader.


Collect mostly Ky style reels; Meek, Heddon, Horton, Pflueger Redifor and Worth, etc.

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Re: Blue agate?

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Mike's point about hardened steel probably explains cost differences - especially cost differences in jeweled bearings - between the most expensive reels and other reels. The very best reels (Talbot, Meek, Pflueger Supremes) did use good, hardened steel for spool pivots. The harder the steel, the more expensive the material and finishing costs. Talbot bragged about using some of the hardest steel that could be obtained. So, agate, garnet, and glass jewels were out of the question. They must have used synthetic or non-jewelry-grade sapphires, which were more expensive. That is why jeweled bearings for a Talbot cost $7 extra and only $1 extra for Shakespeare, who used "tool steel" for their reel pivots. Standard tool steel has a hardness of 6.5, so agate, garnet, and glass jewels could be used for jewels. This is also why the 1573 Pflueger Supreme never had agate or garnet caps, while lesser--but still good--reels (Summitt, Akron, Redifor, Worth) did. In the 1923 Pflueger catalog the bearing caps are described as having "a Jewel Inset made of a special material which wears better than Agate or any other stone jewel," (italics added for emphasis). A few things to point out: first, that's a blatant false statement; diamonds are harder than what they used. Second, they were using synthetic sapphires, which--because they are synthetic--are not a "stone" jewel.
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Re: Blue agate?

Post by Mike N »

Good points, David, that I’m not sure I’ve ever seen explained elsewhere.

Now we’re cooking with peanut oil…

ps - Above, I used the terms “hardened” and “tempered” steel interchangeably. But there are differences. Per a chemistry website: “ As the names imply, hardening makes the metal more rigid but more brittle, and tempering (from "temperate", moderate), forgoes some hardness for increased toughness. Iron alloys are hardened by rapid quenching …”

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Re: Blue agate?

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Great thread! Thanks all.
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Re: Blue agate?

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Use of garnets and sapphires for jewels is absolutely correct (same in watches)
certainly this is glass
Image
along with all the shattered "jewels" we find in some of our spindle end caps
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Manmade, not unlike today's Alconite, etc.
Image

certainly these are mineral
ImageImage
Even those opaque grey Hardy agates will light up with reflected light from the nickel silver bezel transmitted through
Image Image

Mike, leave it to a chemist to over-simplify metallurgy. Hardening and tempering are not opposites (annealing is opposite).
Tempering is required to have usable hardness, and most steel is isothermally transformed down a designed cool-down curve to give both hardening and tempering over controlled cooling and time.
Image
The cooling rate has to clear the bainite nose to get maximum usable hardness, and quench and temper is one way to get the desired result. The TTT curves are shaped by the steel alloy content, moving the bainite nose to the right.
A-grade tool steels are designed to air-harden and don't require quenching.
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Re: Blue agate?

Post by RAM »

Deke: Pflueger claimed use of real sapphire (corundum) bearings in earliest top of the line models. Not cheap stuff but as Mike (and Moh) say its harder than quartz-and typically (though not always) blue. But quartz is a lot harder than the metal spindles in reels.
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Re: Blue agate?

Post by RAM »

Mike: I erred in saying quartz was harder than metal reel bearings. Too general. Probably true in early reels but I was not aware that modern tempered steel approached 8 hardness. Have had knives that didn’t scratch quartz (but then, I buy cheap knives!)
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