# EK43 Burr Screw Mystery



## JKK (Feb 19, 2014)

Hello

I have just unscrewed and taken off the stationary burr for cleaning,

and I put it back into the chamber and began to put the screws back in

the top screw ( 12 o'clock ) doesn't screw all the way down.

I cleaned the threads with compressed air etc, and the screw still did not

screw down.

I had a look at the thread hole in the chamber, and found that it is not deep enough

and has bare aluminium behind it - the other two screw holes are very deep with no metal

behind.

A lot of head scratching, this has never happened before.

Any one have an idea ?

cheers


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## Dylan (Dec 5, 2011)

Does one of the screws not have a different thread to the other two to suit the hole its going in? If there is no thread there there must have been a screw/bolt to suit it.


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## JKK (Feb 19, 2014)

Dylan said:


> Does one of the screws not have a different thread to the other two to suit the hole its going in? If there is no thread there there must have been a screw/bolt to suit it.


Hello

All bolts are the same length, with the same thread.

The top hole is not deep enough for the bolt.

It's so weird they all fit yesterday !


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## Phobic (Aug 17, 2016)

having just had all these bolts out many time in the past couple of weeks I'm pretty sure they're all the same and interchangeable - the spare parts list has them list as the same part number as well.

I don't remember seeing anything in the top hole either, and looked at the exploded parts diagram I don't think there is anything that should naturally be there, in fact I think there should be a void.

could something have dropped in and got stuck? or maybe something broken off and got trapped?


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## Phobic (Aug 17, 2016)

https://www.youtube.com/watch?v=stRV0muXvxA#t=03m50s

if you look at 3m 50s on this video you can see what appears to be something behind the top hole, is that what you're seeing?

https://www.youtube.com/watch?v=stRV0muXvxA#t=03m50s


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## grumpydaddy (Oct 20, 2014)

Question: Are there other threaded holes in the plate perhaps.... an optional position?


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## JKK (Feb 19, 2014)

Phobic said:


> if you look at 3m 50s on this video you can see what appears to be something behind the top hole, is that what you're seeing?


Hello

Yes the top hole has the solid aluminium behind it, the bottom two holes have a void

behind them.

The absence of void, stops the bolt screwing completely into the top hole.

But I am sure it used to . . . . [ going mad perhaps ] . . . it's a bit odd.



grumpydaddy said:


> Question: Are there other threaded holes in the plate perhaps.... an optional position?


There are only the three holes for the bolts.


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## Phobic (Aug 17, 2016)

the holes in the burrs do get full of grinds, have you cleaned them out fully, and cleaned the back of the head of the screw?

checked that the screw hasn't gotten threaded?

maybe try swapping the screws around and testing them in other holes. I know that these screws are a bit softer than I'd expect, maybe 1 is a bit damaged.

might also be worth checking the screw hole to see if the threads are damaged at all.

bit puzzled to be honest...


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## El carajillo (Mar 16, 2013)

According to the drawing all three screws are M5 X10 mm. Can you use a thin screwdriver inserted into the hole to see if it is something loose that has dropped down / rotated ? Or insert the S/driver and measure the depth of the hole ? =deeper then 10 mm ? faulty thread


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## JKK (Feb 19, 2014)

Hello

I have checked the bolts, and tried all three in the hole - no difference.

I have checked the depth of the hole, it is not deep.

I have cleaned the threads and the hole very deligently, all good.

I wonder if the top bolt never actually holds the burr on tight.

When I usualy put the burr on, and tighten up the bolts, I make

sure I tighten them up a bit one by one, so to have an even amount.

The bottom two bolts can hold the whole burr tight across its surface

so perhaps I just never noticed the top bolt does not screw in enough

to hold the burr tight.

If anyone has the lid off their EK, it would be great if they could check this.

Thanks

JKK


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## Phobic (Aug 17, 2016)

I had mine off recently and the top screw definitely does screw in tight and hold the burr on firmly, and can do so all on it's own.

something not quite right.

how deep can you go in with a screw driver? (unplug it 1st







)


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## JKK (Feb 19, 2014)

Phobic said:


> I had mine off recently and the top screw definitely does screw in tight and hold the burr on firmly, and can do so all on it's own.
> 
> something not quite right.
> 
> ...


Hello

The top hole is about 5mm deep.

The screws protrude about 7mm from the back of the burr, so

when screwed in, the top screw is about 2mm too long.

Very odd.


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## El carajillo (Mar 16, 2013)

Can you access a vernier gauge/ depth gauge ( beg , borrow buy), this would give you an accurate depth of the recess.

Alternatively use a longer thinner bolt with a nut, with the nut close to the bolt head insert the bolt then wind down the nut until it touches the casting face, withdraw and measure from end of bolt to face of nut, this should be accurate enough to asses depth. (also check depth of other holes to compare)

If the troublesome one is shallow the only answer is to saw off a little more than 2 mm off the screw (junior hacksaw).

As someone mentioned previously, is there highly compressed coffee grounds at the bottom of the hole ( it could be like a solid piece of wood )


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## Terranova (Feb 15, 2014)

JKK said:


> Any one have an idea ?


Hi,

it is a very simple answer.

Your grinder left the factory like that, we had the same on an EK43 of a customer.

The burr was only held by 2 screws, the other one just made no sense because the hole wasn´t deep enough.

Nobody noticed it before.

Best thing to do is grind your screw by some mm to make it hold the burr again.

If you need some more screws / a spare screw let me know, I can send you one, same like some additional shimming material for your alignment "party".

You guys should calculate the angle, so if the dial indicator shows a difference between highest and lowest point of lets say 80 micron, an 80 micron shimm would be too thick to compensate it.

Regards

Frank


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## El carajillo (Mar 16, 2013)

So much for German Engineering and quality control:whistle:

Is this a faulty batch ? or are they all the same and no one has noticed


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## DavecUK (Aug 6, 2013)

One check I would make, the 3 screws were in the burr when you took it off and all fitted (presumably), or you would have said one sits proud. Might be worth removing the burr from the carrier and see if there are holes behind and whether there are different orientations for the burr, such as to allow for 3 deep enough holes?

*
Or - drill out the burr carrier hole that isn't deep enough.*

P.S. I am making the assumption that the burrs have holes in and these line up with blind ended holes in the back plate


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## unoll (Jan 22, 2014)

I can't help you out much and can only repeat what others have said: My machine works fine with any coarse pitch M5x10 screw, the screws go in fully and there definately isnt any play or a 2mm gap.

My only thought is that one of the screws has failed and the fractured tip is still in the hole. Have you measured the length of each screw? If they're not all 10mm then maybe this is the problem.

Also, have you been trying to allign the burrs by adjusting tightness of the faceplate? If so, it could be possible that tightening the top bolts has pushed the plate closer to material that was already tightly tolleranced. Sounds unlikely but it just occured to me.

Edit: missed Frank and Dave's post when I posted this.


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## Phobic (Aug 17, 2016)

Terranova said:


> If you need some more screws / a spare screw let me know, I can send you one, same like some additional shimming material for your alignment "party".
> 
> You guys should calculate the angle, so if the dial indicator shows a difference between highest and lowest point of lets say 80 micron, an 80 micron shimm would be too thick to compensate it.
> 
> ...


that's very kind of you Frank, thanks.

not sure 2 people is quite yet a party though


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## unoll (Jan 22, 2014)

Phobic said:


> that's very kind of you Frank, thanks.
> 
> not sure 2 people is quite yet a party though


I'm confused a little by the statement Frank @Terranova made regarding angle calculation and shimming. Could someone give a bit more explanation and if possible and example calc and/or diagram?

I'm probably just being thick but some extra advice would be appreciated.


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## dan1502 (Sep 8, 2012)

If the gauge probe hits the burr surface at an angle rather than perpendicular then the distance it measures won't be the front to back of grinder plane distance. If you know the angle then trigonometry can be used to calculate the correct distance.


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## JKK (Feb 19, 2014)

Hello

Thanks for the replies from everyone.

It's interesting to hear that I am not the only one.

The top hole is clean, no debris or grounds etc.

I used a vernier caliper to meausre the depth, it is exactly 5mm, so

a bit short.

I have ordered some M5 x 6mm screws, which hopefully will be short

enough to hold the burr properly.

Thanks for the tips.


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## El carajillo (Mar 16, 2013)

I think Frank means that the maximum shim point reduces around the periphery getting closer to the high point and also reduces diametrically across to the high point Ie If you fit an 80 micron shim which covers more than just the low point it will raise the burr too much.


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## Phobic (Aug 17, 2016)

El carajillo said:


> I think Frank means that the maximum shim point reduces around the periphery getting closer to the high point and also reduces diametrically across to the high point Ie If you fit an 80 micron shim which covers more than just the low point it will raise the burr too much.


that makes sense and aligns with what I saw when I tried to shim too many places at once


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## mazi (Jan 21, 2015)

Just to add look at this and use google translator:

https://www.kaffeewiki.de/wiki/Alignment_der_Mahlscheiben


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