Sharpening coffee grinder burrs!

[DDoug]

So where did all the metal go that wore off .....

 

[AlexyL]

I'd assume these are center feed, and that the bigger gashes are spaces for the whole bean to get in between a pair of plates. Are they precisely shimmed so that the blades don't contact, or do you have a specified clearance for a particular grind coarseness?

I can see after extensive or repeated resharpening, that you'd loose some capacity if the larger beans cannot fit into the big gashes, so you might have to regrind that part a little deeper if much material is removed.

However, I still think a flaring cup CBN wheel could be configured to work on a VMC, but that's not a DIY project either. Sounds like you're only paying about $10 per blade, ($350/12)? That is so cheap you'd have to automate it. T&C grinding with a soft pink toolroom wheel would have you pulling your hair out, IMO. Nice to grind with, but the stone wears quickly. Round and round and round, you'd go, trying to keep the wheel flat so it doesn't turn over the edge. Or am I wrong? A super-abrasive like CBN would probably not wear significantly. I don't see any need for a razor sharp corner in the bottom of the flutes, so maintaining an acute corner on the wheel wouldn't be a big priority, perhaps.

its 350$ per set of blades and i have 12 sets! so 12x350$! thats when they offered the regrinding. now they dont offer it anymore and sell those sets of blades for 750$ per so 12x750$ it goes pretty far since i have to regrind em each year pretty much! You got it right they are center feed! As far as clearance i can still adjust the numbers on the adjusting wheel so i get the grind i want!

Thanks alot !!

 

[AlexyL]

So where did all the metal go that wore off .....

You would be surprised to see what we find in green coffee bags, pieces of concrete and 3 inch nails are pretty common lol!

 

[Milland]

As long as you can keep the blade edges from touching, this may be a good application for DLC (diamond like coating). Even with the natural mineral uptake of the growing beans, there should be a significant lifespan added when coated, and it should reduce excess heat by staying sharp and having lower inherent friction.

If the blades do contact one another (and it looks like they do), then it's possibly not worth it. Is blade contact a given, or is it due to improper adjustment?

I don't even drink coffee, but this is of academic interest...

 

[AlexyL]

As long as you can keep the blade edges from touching, this may be a good application for DLC (diamond like coating). Even with the natural mineral uptake of the growing beans, there should be a significant lifespan added when coated, and it should reduce excess heat by staying sharp and having lower inherent friction.

If the blades do contact one another (and it looks like they do), then it's possibly not worth it. Is blade contact a given, or is it due to improper adjustment?

I don't even drink coffee, but this is of academic interest...

They usually are not supposed to contact! But you know sometimes it happens if we are not careful when we install them! Id say they maybe contacted 1% of their whole life. They list their new blades to 15k pounds of coffee untill you have to change them!

Thanks for the idea i will look into that

Alex

 

[Limy Sami]

Thanks for an interesting topic, .....and from what little I know of cutter grinding - that is definitely a job for a proper grinding shop that really knows what it's doing.

 

[Illinoyance]

I am thinking that a tool & cutter grinder with a universal grinding fixture like the Uni Head could be adapted to do the job. It would just need a locating flange that can be rotated. I suspect the teeth could be indexed with a spring finger. I would be tempted to try it just to see if I could do it. It would help to look at a new burr to see what the angles and tooth heights are supposed to be.

 

[HuFlungDung]

So where did all the metal go that wore off .....

We eat and drink it All sorts of food processing equipment wears out imperceptibly over many hours/days, even when operating properly: hammer mills, screw expellers (oilseed pressing)....it's in the product.

 

[Milland]

We eat and drink it All sorts of food processing equipment wears out imperceptibly over many hours/days, even when operating properly: hammer mills, screw expellers (oilseed pressing)....it's in the product.

Well, this puts the BBQ grill I made from leftover plutonium into a whole new light!

Speaking of, am I the only person that doesn't need to turn on a night light when a nocturnal bathroom visit is needed?

 

[Drroaster]

Most of the damage to the burrs comes from the material found in coffee rocks nails wood. As coffee is dried on cement patios and raked then when it’s dry to proper moisture it’s shipped. Roaster can use a destoner to separate the coffee bean from any debris they also use rare earth magnets to collect stones.
B

 

[HuFlungDung]

its 350$ per set of blades and i have 12 sets! so 12x350$! thats when they offered the regrinding. now they dont offer it anymore and sell those sets of blades for 750$ per so 12x750$ it goes pretty far since i have to regrind em each year pretty much! You got it right they are center feed! As far as clearance i can still adjust the numbers on the adjusting wheel so i get the grind i want!

Thanks alot !!

Yes, that is some serious money. I find it crazy that they can make new ones, but cannot sharpen old ones. Something rotten there.

 

[HuFlungDung]

Most of the damage to the burrs comes from the material found in coffee rocks nails wood. As coffee is dried on cement patios and raked then when it’s dry to proper moisture it’s shipped. Roaster can use a destoner to separate the coffee bean from any debris they also use rare earth magnets to collect stones.
B

I recall from my youth while on the farm, that we used to grind 'chop' for animal feed with a 'double disk grinder' I think my Dad called it. He used to really jump for the quick release when a nail got in there. He had to be mighty quick though, a nail didn't last long in there

Grinding chop was a big deal, getting ahold of some borrowed farm tractor that still had a belt pulley on it, getting it all hooked up and blocked for stability. We ground a small granary full at a time, enough for a year, as I recall.

 

[bhigdog]

Well, this puts the BBQ grill I made from leftover plutonium into a whole new light!

Speaking of, am I the only person that doesn't need to turn on a night light when a nocturnal bathroom visit is needed?

If you need a light to find your wang there's more problems than metal in your coffee........Bob

 

[DDoug]

George Carlin had a good piece about the government regulations
concerning maximum allowable "Bug parts" and "Rodent Droppings"
in hot dogs......

 

[TDegenhart]

Most of the damage to the burrs comes from the material found in coffee rocks nails wood. As coffee is dried on cement patios and raked then when it’s dry to proper moisture it’s shipped. Roaster can use a destoner to separate the coffee bean from any debris they also use rare earth magnets to collect stones.
B

Magnetite maybe but granite and limestone?

Tom

 

[RDL]

There is a landing area on the circumference for times when the machine is turning without coffee beans. Usually the beans keep the burrs separated even when they are really close together such as when set for a turkish grind.

 

[johansen]

Magnetite maybe but granite and limestone?

Tom

Depends on the granite. my black granite surface plate can hold up a neodymium magnet, i've tried a few other granites and can't feel any magnetic attraction.

 

[AlexyL]

Ive called a couple tool/knife sharpening shop and found one that has done some before so im going to let him do his job on one set and see if its going to work! Ill post a picture here!

Thanks alot guys!
Alex

 

[WizardOfBoz]

Alexy, you have 12 sets of these things, and each set is supposed to handle 15,000lb between sharpening. And you resharpen every year. That's 180,000lb/year of coffee. 700 lbs a day. Wow!

 

[adama]

^ And i thought i had a problem now a days needing 2 cups to get the day rolling.