Does it matter who is on top? (Burr locaton)

tompoland

New thread so as not to derail the Duo thread.

The general consensus seems to be that it doesn’t really matter which burr goes into the fixed position and which burr goes into the rotating position. Top or bottom, is doesn’t make any difference.

Or does it?

Entirely conindentally, I opened up the DF64V this afternoon to swap the burrs that the V cames with (SSP Lab Sweet) with a set of Fiorenzato F64s Red Speeds.

In doing so I noticed that the SSP Lab Sweets had “Fixed” and “Rotary” printed on the top of each burr.

I’ve taken pics of both sides of the burrs and I’d LOVE to know if anyone can figure out why the Fixed burr needs to be in the fixed location and the Rotary burr needs to be rotating.

The floor is yours…

DavecUK

tompoland I’ve taken pics of both sides of the burrs and I’d LOVE to know if anyone can figure out why the Fixed burr needs to be in the fixed location and the Rotary burr needs to be rotating.

How does the rotary burr know it’s the one rotating….It could be stationary and the top one rotating, or it could be rotating and the top one stationary, or they could both be rotating. This is the whole principle of relativity invented by Galileo (circa 1600). When you sit on the train, and it leaves the platform, is the train moving or the platform moving. The only clue is the initial acceleration “accelerated motion”. In a steady state, it would be impossible to tell.

you might say well the fixed burr is on the top and the bottom burr is moving….not always, or the burrs can be horizontal. it’s this whole concept of “ I am moving”, which has little meaning.

dfk41

The obvious answer is for normal burrs it matters not, but for some burrs designed to be top and bottom it will say so on the burr. Tom, you could always reverse them for a bit of fun and see if you can spot any difference

whinmoor85

No idea. Maybe email SSP?
http://www.sspgrind.com/

MediumRoastSteam

DavecUK This is the whole principle of relativity invented by Galileo (circa 1600).

You may think you are stationary… but that’s only in relation to the observer. 😉

In fact, we are all spinning… 😬🙃🤌🤣🤣🤣🤣🤣🤣

Cuprajake

Loonster

edit: Posted on the wrong topic…. Grr bug. Not allowed to delete either. Well now to edit the post with something on topic so it doesn’t seem like I’m incompetent…

If it didn’t have a label on it, some user may call and ask which one goes where. This shuts them up before they call and ask dumb questions..

(I could see certain burr geometries being more balanced with a certain burr on the rotary section… Since both of those burrs have 12 teeth and 3 c’bores, I don’t think that is the reason)

giampiero

Off topic….just a curiosity, apart the complexity and cost, does a grinder with both rotating burrs ( obviously with opposite direction of rotation) would work or the ground would stuck between them?🤔

🤪

Loonster

I think It would double the power requirements with no change in output.

Think of it like two cars (of same mass) hitting each head on at 50kph vs one car hitting a brick wall at 50kph. It’s the same amount of damage, but intuitively we would expect the two cars to be more.

DavecUK

how does a burr know which one is moving…when you sit on a train, is the train moving or the station when it very gently pulls away….there is no way to know by looking out the window.

MediumRoastSteam

DavecUK - Check 6 posts above. We’ve gone full circle, literally :-)

MWJB

MediumRoastSteam No, we’ve stayed where we are & the circle has moved! 😀

giampiero

I forgot to write the comment…despite i’m in the older generation.

Anyway, imo, neither the burr factories really can give you a logic, trustable, scientific explanation why a burr does not develop yet the consciousness…..to decide who should rotate and who should stay🤭