# Machined Mods Episode 1: Mazzer 'Dropper Hopper' Mod



## risky (May 11, 2015)

Here we have the first in what will hopefully become a series of machined mods I will experiment with.

Here we have my 'prototype' (read: crummy first attempt) of a 'Dropper Hopper' for single dosing with the Super Jolly. Anyway, enough chat! On to the pictures.

The new hopper/nozzle. This is machined from aluminium. This view shows it in its normal position, as it will sit in the grinder.









The bottom of the same piece.









The Dropper. Solid stainless steel. Approximately 650g.









Assembled. I'm happy with the fit. Less than 0.1mm difference between the two pieces, so no stray coffee working its way out.









Showing the view from below when the Dropper is in the fully dropped position. The Dropper drops until it is sitting less than 1mm from the bolt head of the lower burr carrier.


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## Sk8-bizarre (Jan 22, 2015)

Bloody hell that's really nice man. Have you tested it?


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## GCGlasgow (Jul 27, 2014)

Saw this earlier when I picked the pin up, looks class and should work a treat.


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## risky (May 11, 2015)

Top down view of the hopper in situ.








Side view of the hopper in situ.









Hopper loaded with 18g of the good stuff from Coffee Compass.









Dropper in the start position, ready for grinding to start.









Grinding complete.


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## Jon (Dec 3, 2010)

That is a thing of beauty!


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## scottomus (Aug 13, 2014)

Want.


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## Spazbarista (Dec 6, 2011)

Who lathed it?

Taking orders????


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## Rhys (Dec 21, 2014)

What's the dia of the 'dropper'? Is it by any chance 58.35mm? and could it come with either a flat or convex top?


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## Sk8-bizarre (Jan 22, 2015)

So I take it that it doesn't actually quite touch the axle bolt at the end? By a fraction.....

Be surprised if it works well man that you can't shift a good amount of them easily!


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## AdzJackson (Jun 3, 2015)

Nicee! Only had my SJ two days now but was thinking about making something like this on the lathe at work, don't think it will be as shiny though.. Lovely work


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## coffeechap (Apr 5, 2012)

That really is good man, can you mill out the nut from the bottom as this will mean no popcorning, as the las few beans to be ground will still jump around


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## Rhys (Dec 21, 2014)

Looks good, I think you're on to a winner there..


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## Sk8-bizarre (Jan 22, 2015)

coffeechap said:


> That really is good man, can you mill out the nut from the bottom as this will mean no popcorning, as the las few beans to be ground will still jump around


Yeah i was saying that to him only the other night minus the popcorning bit but looks like he was well underway already, sneaky bugger.

Something that looks that smart with the potential to work as good as it looks well who wouldn't want one!


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## Rhys (Dec 21, 2014)

You just need to work out a price now.


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## coffeechap (Apr 5, 2012)

Rhys said:


> You just need to work out a price now.


Totally, you will have a long queue on here for them


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## Xpenno (Nov 12, 2012)

Wow, really nice mod dude!!!

Problem with cutting a hole for the bolt is you will get beans trapped and it will stop the weight getting all the way down, probably better without. Would love to see if you find a solution to it though. Looking forward to seeing the progress.


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## risky (May 11, 2015)

Spazbarista said:


> Who lathed it?
> 
> Taking orders????


Me. I don't really intend to. I managed to do it in the spare minutes here and there between other jobs at work. I'm also not entirely sure there is any more material. Any others I make would possibly need to be brass. The design needs to develop a bit more first anyway.



Rhys said:


> What's the dia of the 'dropper'? Is it by any chance 58.35mm? and could it come with either a flat or convex top?


No the Dropper is actually around 37mm. This is the same diameter as the narrowest bore in the grinder 'neck' which is the bore of the upper burr carrier. If you're thinking tamper, it's on the list of projects.



Sk8-bizarre said:


> So I take it that it doesn't actually quite touch the axle bolt at the end? By a fraction.....
> 
> Be surprised if it works well man that you can't shift a good amount of them easily!


I think it probably stops ever so slightly short of the bolt. It did start to rotate earlier during testing when a part of a bean must have got jammed underneath.

Anyway here's the low down. There are a few issues.

1) The hopper being made of aluminium is too light (about 220g). When the burrs start and the beans start moving they are able to lift the hopper. This allows them to get trapped underneath between the hopper and the 'flat' created by the backside of the screws that hold the upper burr to the carrier.

2) The hopper sits on the previously mentioned flats. This flat does not extend around the full diameter (just 3 small flats where the screws are). This means there are 3 gaps where partially ground beans can get in. Even when holding the hopper down so it can't jump, partially ground beans manage to get in here. What I really should have done is made the bore narrower and made it extend past these flats so this area is totally sealed from beans.

So I need to have a think and see if I can improve the existing one. Either by putting foam or something similar over the gaps between the flats. This doesn't solve the problem of the hopper being too light though, so I may have to remake it all.

Thanks for the encouragement anyway. It certainly looks the business.


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## Sk8-bizarre (Jan 22, 2015)

risky said:


> Top down view of the hopper in situ.
> View attachment 15034


Ahhhh it comes inside those three inner lugs also, I seem to catch beans on there. Nice.

Edit: and just read your post about extending it further past them which is even better.

For a proto with improvements already in-line man this shows massive potential.


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## risky (May 11, 2015)

coffeechap said:


> That really is good man, can you mill out the nut from the bottom as this will mean no popcorning, as the las few beans to be ground will still jump around





Xpenno said:


> Wow, really nice mod dude!!!
> 
> Problem with cutting a hole for the bolt is you will get beans trapped and it will stop the weight getting all the way down, probably better without. Would love to see if you find a solution to it though. Looking forward to seeing the progress.


Xpenno has the same concern I have with that. At the moment, the flat bottom of the Dropper comes down to meet the bolt and forces any beans to the side. If this hasn't happened and a bean has got caught it's very obvious as the Dropper starts to spin. I give the Dropper a tap and the bean dislodges. If I bore out the bottom of the Dropper to accommodate the nut, I feel it is more likely that beans will get caught in the bored out area.


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## risky (May 11, 2015)

I forgot to share the most interesting observation though.

Typical extraction (not saying this is good, just typical for what i currently get) : CC Mediterranean Mocha. 18g > 30g > 30s

With Dropper Hopper (no adjustment to grind setting!)

18g > 30g > * 1m20s*

Incredible change in grind consistency! I thought I'd choked the machine to begin with. (In typical CC fashion it was still drinkable.)


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## grumpydaddy (Oct 20, 2014)

Gotta get me a lathe to play with


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## garydyke1 (Mar 9, 2011)

Good work - You need a lip on the weight so it catches the top of the guide with 0.5mm spare between the bottom and the centre bolt.


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## risky (May 11, 2015)

garydyke1 said:


> Good work - You need a lip on the weight so it catches the top of the guide with 0.5mm spare between the bottom and the centre bolt.


Is there a reason it needs to be 0.5mm?


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## garydyke1 (Mar 9, 2011)

risky said:


> Is there a reason it needs to be 0.5mm?


Just a random small number plucked out of the air for clearance. presumably it can be that accurate.?


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## risky (May 11, 2015)

garydyke1 said:


> Just a random small number plucked out of the air for clearance. presumably it can be that accurate.?


I would say it's already closer than that.

It can be far more accurate if needed, but I don't think it is needed.


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## jamfit (Apr 27, 2015)

That is a sweet piece of engineering...... I'm now looking for a Mazzer to go with it!!


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## coffeechap (Apr 5, 2012)

How about milling a longer thicker bolt like your collar adjustment pin that would protrude above the level of the beans in the hopper, make it cylindrical and drill out the weight to exactly fit the extra long bolt. The bolt could have a flat head slot or hex in the top to tighten, this new bolt should be the same diameter as the lower burr carrier, thus it will creat a straight bean free chute to the burrs and allow you to machine something all the way down.


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## mrsimba (Mar 17, 2014)

Awesome work! I'm always very envious of people with so much skill!!!


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## Brewer in training (Feb 7, 2015)

That looks very nice indeed.......

Would you like me to beta test it for you, purely observational?

I promise to pass it on to the next name on the list......

(Well it's not my fault if the post office lost the bloody thing is it?)

And you're sure you can produce them for ONE ENGLISH POUNDS?

DELIVERED?

(Worth a try!)

Seriously though, interesting looking piece.

If you aren't going to produce, could I have the measurements?

Don't have access to a lathe....... Do know an engineer though......

Small donation to a charity of your choosing...........

Campaign Against Stupid Hedgehogs?


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## Xpenno (Nov 12, 2012)

Here's a link to my (very much more amateur) thread on my royal mod, might be of interest for reference. I had the parts printed as it was easier. I went through a few variations before my EK turned up and then sold it.

http://coffeeforums.co.uk/showthread.php?14042-Mazzer-bean-weight-4000&highlight=mazzer


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## Xpenno (Nov 12, 2012)

coffeechap said:


> How about milling a longer thicker bolt like your collar adjustment pin that would protrude above the level of the beans in the hopper, make it cylindrical and drill out the weight to exactly fit the extra long bolt. The bolt could have a flat head slot or hex in the top to tighten, this new bolt should be the same diameter as the lower burr carrier, thus it will creat a straight bean free chute to the burrs and allow you to machine something all the way down.


I achieved a similar result with my barrocca tube, problem is the further down the weight goes the more bean shards were left in the bottom of the grind chamber, it was a strange phenomenon.


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## urbanbumpkin (Jan 30, 2013)

Looks really nice Risky


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## jeebsy (May 5, 2013)

Top work. Who needs a 3D printer when you've got these skills?


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## urbanbumpkin (Jan 30, 2013)

I welcome the day when you produce more of them. Apart from looking really smart it's also a fantastic idea that allows you to have a consistent weight in the beans (if single dosing).


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## risky (May 11, 2015)

Quick update. Had some craft foam laying about. It's a few mm thick. I used it to pack the gaps between the flats on the upper burr carrier. Voila! Nothing remains in the burr 'chamber' or in the area near the flats.

Had to move the collar about a quarter inch to compensate for the change in the grind it caused!


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## Sk8-bizarre (Jan 22, 2015)

risky said:


> Had to move the collar about a quarter inch to compensate for the change in the grind it caused!


See that alone says quite a bit to me!


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## El carajillo (Mar 16, 2013)

coffeechap said:


> How about milling a longer thicker bolt like your collar adjustment pin that would protrude above the level of the beans in the hopper, make it cylindrical and drill out the weight to exactly fit the extra long bolt. The bolt could have a flat head slot or hex in the top to tighten, this new bolt should be the same diameter as the lower burr carrier, thus it will creat a straight bean free chute to the burrs and allow you to machine something all the way down.


This would need a shoulder to be formed at the bottom for the thread to finish against ,otherwise the bolt would not fix / retain the burr carrier. Not insurmountable.


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## risky (May 11, 2015)

Maybe worth pointing out that because the dropper is such a good fit into the hopper (I would normally say 'tight' but I must stress that it doesn't feel tight, it slides beautifully if I do say so) that if you lift the dropper once it has reached the bottom, and pump it back down (whilst the grinder is still running) it forces air through the chamber/burrs just like blowing through. A few pumps ensures that there is nothing left partially ground in the burr chamber.


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## coffeechap (Apr 5, 2012)

El carajillo said:


> This would need a shoulder to be formed at the bottom for the thread to finish against ,otherwise the bolt would not fix / retain the burr carrier. Not insurmountable.


But of course, the thread is a smaller diameter than the diameter of the top of the burr carrier, so making a threaded pin would ensure the burr carrier is still fixed securely


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## coffeechap (Apr 5, 2012)

risky said:


> Maybe worth pointing out that because the dropper is such a good fit into the hopper (I would normally say 'tight' but I must stress that it doesn't feel tight, it slides beautifully if I do say so) that if you lift the dropper once it has reached the bottom, and pump it back down (whilst the grinder is still running) it forces air through the chamber/burrs just like blowing through. A few pumps ensures that there is nothing left partially ground in the burr chamber.


Can you make the pin that replaces the bolt on the burr carrier? Then drill out the weight part?


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## Mr O (Jan 14, 2015)

risky said:


> Had to move the collar about a quarter inch to compensate for the change in the grind it caused!


Thats a huge amount. Just shows what difference a bit of weight makes.


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## urbanbumpkin (Jan 30, 2013)

Mr O said:


> Thats a huge amount. Just shows what difference a bit of weight makes.


Absolutely, and a consistent weight / pressure all the way down.

It's one of the reasons I was looking at fitting the Auber timer to my Major. That and not having to weigh every dose. However the for the amount that use my grinder 1 or 2 shots a days it's a lot of bean wastage.

Something like this would be a great solution.


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## risky (May 11, 2015)

coffeechap said:


> Can you make the pin that replaces the bolt on the burr carrier? Then drill out the weight part?


If I'm understanding you correctly then what you're suggesting is possible. It just seems like a lot of work and I'm not sure what the added benefit would be?


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## coffeechap (Apr 5, 2012)

risky said:


> If I'm understanding you correctly then what you're suggesting is possible. It just seems like a lot of work and I'm not sure what the added benefit would be?


It means you could eliminate popcorning the destroyer of consistency by having weight on the beans all the way to the burrs


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## Taff (May 5, 2015)

I need to buy a Lathe! (I used to work as a machinist..) Lovely work.


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## urbanbumpkin (Jan 30, 2013)

Shame you're in South Wales Taff I might know of a lathe coming up.


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## Rhys (Dec 21, 2014)

coffeechap said:


> It means you could eliminate popcorning the destroyer of consistency by having weight on the beans all the way to the burrs


That one did cross my mind, but there can't be any play on the 'pin' (it would be easy to bend I guess) plus it'd need some sort of bearing or nylon collar to eliminate friction as it spun inside the weight?


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## risky (May 11, 2015)

coffeechap said:


> It means you could eliminate popcorning the destroyer of consistency by having weight on the beans all the way to the burrs


As it stands there can only be a very minimal amount of popcorning occurring in the last few beans. There is only the free space around the bolt the holds the carrier. I can't see a solution which allows to improve on this without being detrimental in some other way.

As it stands, in my opinion this is a significant improvement over the standard hopper-less grinding performance of the SJ. If I had a better coffee machine, and significantly improved coffee making skills, then perhaps I would try and develop this a bit further. At this stage though...


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## Xpenno (Nov 12, 2012)

risky said:


> As it stands there can only be a very minimal amount of popcorning occurring in the last few beans. There is only the free space around the bolt the holds the carrier. I can't see a solution which allows to improve on this without being detrimental in some other way.


I agree, if you start making holes in the bottom then beans will get jammed as it falls and it will just end up annoying you and there will no gain in performance


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## Rhys (Dec 21, 2014)

Wonder if anyone will invent a grinder that uses compressed air to force beans down the throat, it'd eliminate retention as well and cool them. Though would it be powerful enough to stop popcorning?


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## urbanbumpkin (Jan 30, 2013)

Xpenno said:


> I agree, if you start making holes in the bottom then beans will get jammed as it falls and it will just end up annoying you and there will no gain in performance


I think I'm with you on if you make a recess in the bottom of this, beans would get jammed.

I suppose if you lifted it up and lowered it, it would clear and grind the remainder few beans as well a blowing through the grinds.

Unless of course CC has a different design.


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## risky (May 11, 2015)

urbanbumpkin said:


> I suppose if you lifted it up and lowered it, it would clear and grind the remainder few beans as well a blowing through the grinds.
> 
> Unless of course CC has a different design.


That last bit is what happens anyway if I move the weight up and down







You may also be correct and CC is thinking of a different design entirely.


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## urbanbumpkin (Jan 30, 2013)

Weirdly when I had a SJ, there was always 2 stray beans left when you lift the tamper up.

With the Major it doesn't happened.


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## Xpenno (Nov 12, 2012)

urbanbumpkin said:


> I think I'm with you on if you make a recess in the bottom of this, beans would get jammed.
> 
> I suppose if you lifted it up and lowered it, it would clear and grind the remainder few beans as well a blowing through the grinds.
> 
> Unless of course CC has a different design.


When I made a device similar to this the weight would always jam and you had to lift it up which defeats the object of it moving past the screw if the first place (as it didn't). I eventually found a way round it but the throat was so narrow that it became a pain to use.

One option would be to shorten the centre column on the burr carrier and then increase the length of the weight in this mod. That would help reduce popcorning near the end of the dose I guess. there may of course be a reasons why the centre part is that tall though.

I am still convinced that the best design would be to have a corkscrew/spiral device that fits over that middle section and would effectively pull beans into the burrs at a constant rate a pressure without the need for weights. It would also stop pop corning until right at the very end. Kind of like the EK43 does.


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## Dylan (Dec 5, 2011)

You could add a shaft that replaces the bolt that holds in the lower burr carrier, protruding upwards out of the throat, then the drop weight could be an elongated doughnut that slid over this shaft and pressured the beans all the way down to the burrs... this may well cause the space for the beans in the throat to be too small.

Alternatively you could just add a peak or some similar design to the center bolt of the lower burr carrier, and a corresponding indent in the dropper, of a design that would see the beans fall into the burrs naturally... if such a design exists.


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## Xpenno (Nov 12, 2012)

Dylan said:


> You could add a shaft that replaces the bolt that holds in the lower burr carrier, protruding upwards out of the throat, then the drop weight could be an elongated doughnut that slid over this shaft and pressured the beans all the way down to the burrs... this may well cause the space for the beans in the throat to be too small.
> 
> Alternatively you could just add a peak or some similar design to the center bolt of the lower burr carrier, and a corresponding indent in the dropper, of a design that would see the beans fall into the burrs naturally... if such a design exists.


Yeah I used the doughnut method but my tube overlapped the centre column rather that extending it which would have been the better solution but beyond my skill/budget for the project









Adding a point to the top of the bolt didn't work either as beans still got stuck and stopped the thing from making it's way down towards the burrs.


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## urbanbumpkin (Jan 30, 2013)

I'd have thought adding a top to the bolt might also either cause a wobble or just be liable to fly off.


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## risky (May 11, 2015)

As an update, this seems to have settled down nicely now. I don't really see any need to change it. Before I would get a lot of grounds retained in the burr 'chamber' but now being able to 'puff' them out by plunging the weight up this has been virtually eliminated.


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## funinacup (Aug 30, 2010)

Video of it in action?


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## urbanbumpkin (Jan 30, 2013)

Sounds great Risky. I found the SJ responds well with the blow though, Major and Royal don't seem to. The quick after pulse seems to work better.

Great bit of machining I have to say.


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## urbanbumpkin (Jan 30, 2013)

funinacup said:


> Video of it in action?


Definitely


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## oursus (Jun 5, 2015)

Bat**** crazy the lot of you! Mods of that standard belong on 2 wheels... Most impressive! I'd be really interested to see how grind uniformity is affected by the higher force.


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## Rhys (Dec 21, 2014)

urbanbumpkin said:


> Sounds great Risky. I found the SJ responds well with the blow though, Major and Royal don't seem to. The quick after pulse seems to work better.
> 
> Great bit of machining I have to say.


That's all I do with the major, brush the grinds out of the chute - quick pulse - brush again - quick pulse and pretty much empty.






(yes I know one got away.. lol)


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## Sk8-bizarre (Jan 22, 2015)

funinacup said:


> Video of it in action?


seconded!


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