Spyderco ceramic hones

[Tanuki]

My measurements (made at darn close to 60F 15.5556C ambient but I didn't stick a thermometer in the water bath):

Spyderco - M | 437g mass | 139g H2O displacement | 3.14 g/ml density

Spyderco - F | 496g mass | 137g H2O displacement | 3.62 g/ml density

Al2O3 standard density is 3.95 g/ml

The Wikipedia article uses 'aluminium', not 'aluminum' so I suppose we should play by the rules of Oz and use the oversize degrees of temperature and the un-oceanic freezing point of fresh water.

@captaincaed I would say we are in good agreement.

I do wonder what molecule(s) makes the Medium hone so dark and much less dense.

 

[Empire straights]

I owed it to posterity to do these measurements properly, and in context.

I wasn’t square on the SG measurement method before. Archimedes did not give me a passing grade, but at least I can get things right in detention.

Here are the new measurements, in context with other Arks, against which we might judge them. All done at 61 F if anyone wants to be more precise about density (all water volume is assumed to be 1ml per 1g for these calculations).

In order of appearance:

Stone	Mass (g)	Water mass (g ~ml)	Density (g/ml)
Ark - butterscotch	352	132	2.67
Ark - long black	636	238	2.67
Ark - short black	844	320	2.64
Ark - trans	523	198	2.64
Ark - holstein	624	237	2.63
Washita - pink	123	54	2.28
Washita - unlabelled	552	244	2.26
Washita - #1	548	250	2.20
Washita - Lily White soft (1)	589	295	2.00
Washita - Lily White soft (2)	444	200	2.22
Spyderco - UF	457	122	3.75
Spyderco - F	479	130	3.68

View attachment 1759638

Conclusion:
The SG difference between the two Spyderco stone equates to a 2g measurement error. I submit this is well within my own human error (especially considering my track record). I have no compelling evidence to doubt the product insert, and I submit these stones are the same, only with alternate surface preparation.

I bet that 2.00 lww is blazing fast.

 

[captaincaed]

I bet that 2.00 lww is blazing fast.

It's pretty darn quick. Picked up on BST here in fact. Very lucky to have it.

The unlabeled and pink ones are comparably quick. I'd be hard pressed to part with any.

 

[captaincaed]

I do wonder what molecule(s) makes the Medium hone so dark and much less dense.

They are porous at least, which explains part of it.

 

[Empire straights]

It's pretty darn quick. Picked up on BST here in fact. Very lucky to have it.

The unlabeled and pink ones are comparably quick. I'd be hard pressed to part with any.

I have a little pinkish brown one similar to yours I've been trying to find the mfg. It's probably the lowest sg one I have and it's pretty fast under light pressure. I love that little stone.

 

[JPO]

I don't follow. I'm sorry I'm not trying to be obtuse but if it's a gag I missed it.

 

[Gamma]

I wouldn't be quick to rule out a density difference between the UF and F stones. From hands-on esperience, very small changes in abrasive density can have a very big impact on a stones performance. Same for particle shape, and PSD. Part of the JIS standard rules over the amount/percentage of abrasive per volume, and for good reason. You can have a so called 8k abrasive but if you don't use enough of it in the vehicle there won't be 8k performance.

Metric concerns, here, meh -- It wouldn't matter if you used units of furlongs per fortnight, if you did the measurements in series, in a reasonable time-frame, the relative results will probably be accurate enough. Kitchen table science is never super accurate and here it doesn't have to be. SG, on it's own, really isn't of much importance as some want it to be. The SG of these stones has zippo to do with the SG of hematite or Arks, or Eschers, etc. And the numerical difference in SG between a modern regular hard Ark or the finer harder versions doesn't need to map out to be all that great anyway. Not on paper anyway. In reality, most regular hard Arks are probably closer to the opposite end of the spectrum. But there is a line in the sand and it's not all that wide.

It's not a matter of doubting the merchandizing paper in the box - scientists didn't put that there, the ad team did. To a manufacturer, two identical chemical mixtures with different densities might very well be referred to as 'the same' for the sake of simplicity, saving space on the card, and not having to field a million questions from inquiring minds.

At the same time, it could purely be a surface condition thing, especially with a stone where the abrasive is fused into a block. And, the numbers here certainly could be skewed due to human error also.

At the same time, I think it's interesting that 2-3 different people, over many years, have come up with a SG discrepancy at least one time. To make any real determination a much larger sample size has to be in the picture, along with many repeated trials, and a bunch of other concerns, But this is still interesting enough to file away in the vault.