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Realistic Costs – Shredder

This topic contains 53 replies, has 25 voices, and was last updated by  Fabrizio Forte 3 years ago.

Fool paulfreed

Realistic Costs – Shredder

09/05/2016 at 16:39

I started out building the shredder enthusiastically. At the time I did realize the cost of 180 euros wasn’t realistic, which didn’t bother then, thinking it would come to a bit more or maybe double. I’ve got the actual shredder done, the frame costed, worm gear costed, motor bought, and now the total is probably going in the direction of 750 euros. I think mostly because some of it just has to be bought new. Is anyone experiencing the same issue?

Realistically, would someone (from near here of course) still be interested in buying these things when those are the material costs alone? I’m not so convinced anymore that this is still all viable.

Please help restore my faith someone!

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09/05/2016 at 18:05

Well, conversely, my shredder is half finished and so far I’ve spent less than 100 euros on it, most of that being raw materials (steel). However I’ve done all the machining of the parts myself and it takes a long time! Probably 50+ hours and counting, and my design is different (about half the size). I’ve yet to source a motor, which will probably be the most expensive part. I do think some of the pricing in the bill of materials is ‘optimistic’!

I think it can be built cheaply if you are prepared to spend time on it, or are lucky enough to be able to source parts cheaply/ for free. But by the time mine is finished I’m sure I wouldn’t part with it for 750 euros.

09/05/2016 at 18:14

I’m working out the costs right now in Indonesia. I’ll be sure to get back to you as soon as I find sources for everything.

For example though, I found a source for 3mm steel plate, but it’s a 4’x8′ hot rolled steel. The quantity is quite large and the price equates to 32 euros. 6mm hot rolled steel is double the cost at 64 euros and the 5mm hot rolled steel is priced where it should be between the two. I know the blueprints are basically calling for stainless steel, but i have yet to locate a source for this.

Sourcing for hexagonal has me looking at a 4 meter length when i only need 320mm. Unsure of the price just yet.

So for now, it seems everything comes in bulk…except for the bearings and the motor. The motor i have not tried to look for just yet but will start looking this week by asking around.

I believe you really need to work to hit that price target. If you don’t, then you start paying more. It’s a matter of convenience vs frugality. Keep the faith.

10/05/2016 at 01:05

Some good points made guys, I personally have put in a lot of time looking at all the resources available to me, I’m looking at around the $1,600.00 AUD at the moment, I’m trying very hard to get thats price down. What doesn’t help, unfortunately I don’t have hack shops or machine shops where I can do the milling myself, so there is a lot I will have to pay someone else to do. Example, the axle alone will cost $90 just to machine, that’s with me providing the Hex bar which I have sourced from one of my crow bars.

Also I’m looking at a other things, so if I have to, because of the high cost &/or what’s available/accessible to me, I mite make a different type of Shredder

10/05/2016 at 05:38

Hi Enviro,

$1600 seems a bit on the expensive side to me. I am looking at paying less than half of that for the shredder (and I don’t have anything for milling etc).

What is costing you so much?


10/05/2016 at 07:58

I think its Australian dollars.
Yup, same here. No machine/hack shop near me either. I feel your pain – had to get my hex bar made up too for about 60 AUS including bar.

What are you guys doing for the frame? Welding yourselves, or getting it done? I looked into slotted strut, but it is way too expensive!

@andyn half the size you say? Sounds good! Please post pics when you’re done!

@bulegila I went for the mild steel option and had issues with the 6mm thicknesses. It threw my blade spacing off and i ended up getting it done again in stainless.

Stainless vs. Mild steel grinder parts

10/05/2016 at 08:11

Hi Paul,

I am in Australia too and was quoting AUD prices πŸ™‚


10/05/2016 at 08:12

@andyn Are you also machining your own gears?

10/05/2016 at 08:15

@simonm oh bugger! πŸ™‚
You gonna have to let us in on how you did it then!

10/05/2016 at 09:00

@simonm this is the best laser cut price I could get in stainless $954, would still need to get someone to weld it all up + $90 for the axle, then the stand, motor + gear box. easy cost $1600.

If I use mild steel, the laser cutting is $356. however worried I’ll have the same probs as @paulfreed or if they get wet at all have black stains contaminate the plastic.

Not sure

10/05/2016 at 13:10

@paulfreed https://youtu.be/Md6oub5nw5A

These will be the two gears that link the shafts of my shredder. My design is actually more like the FilaMaker shredder than the Dave Hakkens one. I hope to find a worm gearbox for the main drive from the motor, I’m considering using a wheelchair drive unit if it can handle the torque, but swapping the DC motor for an induction motor.

Pictured are my cutters, CNC’d from 6mm gauge plate, this is not stainless so not rust-proof, but it is very accurately ground to 6mm thick and it can also be hardened.

For the frame I’m using 12mm thick mild steel, drilled and tapped and also bored for the bearings to be pressed in directly.

10/05/2016 at 21:41

I just got a paper shredder from my local value village, I tried shreading a xbox dvd case (PP) with it but it was having alot of expected struggle being that it can only shread 5 pieces of paper at a time, but luckily I thick I can pull thr cutters out of it and save alot on materials and machinery costs. I’ll keep you many posted once I get home and take it apart.

10/05/2016 at 23:56

I’m back! So I got home and plugged in the paper shredder, cut a small square out of a sodapop bottle (PET) anddd… it shredded! Maybe not the best pieces but its alot smaller than it was, then I tried two pieces layered and that worked too, meaning (without the neck and harder bottem of the bottle) it can shred water and sodapop bottles πŸ˜€ yay! On the left is the shredded bottle and on the right is the xbox dvd case from my previous post, as you can see it didn’t go as well

12/05/2016 at 04:55

Hi @enviro

My machine is cut with HA250 Plate steel. It all arrived today, but I am at work and can’t check the accuracy of the thickness – I will provide an update later re: that.

The way I see it, this project is a new concept. Dave Hakkens has done a good design to start with, but with any open-source project, once more minds get involved, with different perspectives and ways of thinking, the designs evolve. It is still in the Proof-of-concept stage. I suspect that the designs will morph – I have already identified an improvement to the internals of the machine to make obtaining the hex bar easier and cheaper. Other people will have other ideas.

Once I get the machine running, I will then start on the Injection Machine. Once I have got that up and running, I will be getting templates made and using them to make items to sell at markets. I will not know how they will be accepted, or if there is a market for them until then.

At this stage, I don’t want to spend a fortune to get a gold-plated system, only to find that the market isn’t there, or that a better design had evolved that is cheaper/easier/more efficient etc.

If I find that there is a strong market, I could then get the internals replaced with stainless steel (if required) or even replace the entire machine. Until I have established the market, I don’t want to get a premium system (eg – stainless over mild steel) because the risk is still too high.

That’s my opinion anyway…

12/05/2016 at 05:02

Absolutely @simonm I agree 100%, look forward to seeing how it all goes. πŸ™‚

12/05/2016 at 14:37

@andyn cheers for sharing that – sounds good!
I think I know which type you are talking about. Does it still only one shaft or two?

12/05/2016 at 16:42

To whom it might concern….

I looked up the laser costs we paid (in the Netherlands) for the Laserfiles in the downloadpackage. It was 250Euro incl. VAT and material and a delivery time of 2 weeks (makes a big difference for online laserservices).

To cut the costs a little and to adapt the gauge system a little easier I posted some dxf knife files with Hex. 1″ holes and a frame made from square tube and flat iron.
Should reduce the laser costs πŸ™‚ .
new files

Regards Kees

12/05/2016 at 22:32

Awesome @keesdeligt you are a legend mate thanks for the new files πŸ™‚

That’s about $479 AUD or $655 USD for S/S at the current conversion rate.
Date: 13-05-2016

14/05/2016 at 07:34

@enviro aka Hansie?

I was interested in shipping prices.. So All shredder lasered parts (without shaft/bearings/angled iron/sieve). Weigh about 12Kg.. Shipping them by post would cost 110€, to get them From the Netherlands to Australia (No idea about importing costs, on your side).
250€ for the parts and 110 for shipping, makes 360€ if ordered in the Netherlands..
369€ would be 560 AUD$ ??

regards kees

17/05/2016 at 23:12

Maybe for the people who are interested in the ‘raw’ steel prices.
I’m working for a steel constructor, at the moment the prices we use (in Belgium) for calculation are:
S235JR (steel) – €0.62 / kg
RVS 304 (stainless) – €2.45 / kg
Of course this is without the work like laser/plasma etc.

Quick note on how to simply calculate the weight;
width (in m) x length (in m) x thickness (in mm) x 8
e.g. 2m x 1m steel of 5mm thick would be:
2m x 1m x 5mm x 8 = 80 kg -> 80kg x 0.62 = €49.6

27/05/2016 at 09:10

For those who are interested these are my material costs so far. The lasered parts I left as they are because the price for stainless works out to about the same. The last thee items are guessed – still need to be done. All in all I’d say its pretty much what you could do it for as a completely new machine.

Most suppliers I went to would have given about 10% less for bulk orders (I always asked for price of 10 units).

Like I said, just costs, without markup and without the time I put in…

28/05/2016 at 22:14

Thanks @paulfreed, much appreciated πŸ™‚

31/05/2016 at 23:58

Does the hex bar have to be 27? the biggest I get is 22 =S

03/06/2016 at 15:25


You would then have to adjust the size of the lasered parts and the bearings accordingly. The final shaft diameter would come out considerably less – not sure if that would be okay. It seems like plenty of changes that would need to be made with the uncertainty of the shaft diameter being adequate. It may end up being more work than its worth. Then again, maybe not. Have you worked out what the shaft diameter would end up being?

03/06/2016 at 23:37

@lopesviii the bar can be 27mm or 1 inch thick (25.4mm), that’s the one I got and only has 1mm of space left, which doesn’t affect the machine functioning.

A 22mm shaft won’t work, unless you modify the laser cutting files to have 22mm holes instead of 27mm, as @paulfreed suggested

04/06/2016 at 11:13


thanks for the explanation. I manage to get one hex bar. It will cost 20€ plug and play.

I made an extra search after your explanation πŸ˜‰

15/06/2016 at 06:13

@lopesviii Good to hear that. I ended up paying $60 just for the bar. The bar itself wasn’t expensive, the expensive part was the lathe work involved

19/06/2016 at 09:55


I just bumped into this cute “Aldi” finger shredder hack

Curious if the motor can stand long time use, but the shredding blades seem to keep up quiet nice with non-paper objects.

19/06/2016 at 11:41

It seems to struggle with moderately thick plastic, but if you’re prepared to cut your bottles etc. into flat pieces first this might work perfectly well.

I also like this simple design https://youtu.be/HT_7hMs3WBI I’m sure you could build that for only a few $. I wonder how well it would work if you ground teeth into the washers?

21/06/2016 at 03:45

I started to price the shredder in AUD(Australia)

I have been finding it hard to get the motor for anything less than $700.

the lazer cutting was quoted arround $300 and the axel without machining at $85

all stainless steel.

is there a better way?

should I just get it made for cheap out of Indonesia or something?

28/06/2016 at 11:04

Mines a little different. I have 4 sets of blades for mine. 4,6,8,10 & 20mm. That’s 1/8, 1/4, 5/16, 3/8 & 3/4. Cost for mine was a hair under $800aud. I’ll write the price list below. Mines a modification of Thymark – Filamaker as its a stronger design in my opinion. Most of this has lots of excess due to minimum order sizes and using what I had first before buying anything.

Parts list:

2 x 17x335mm Extra long CRV Hex Key $78
5 x 6202 15x35x11 Bearing $20
2 x Drive Sprocket 50T 9.525 Pitch 06B
Chain (20mm bore required welding and machining to 10mm bore) $110
2 x Drive Sprocket 10t 9.525 Pitch 06B Chain (10mm bore) $8
1 x 3HP 2.2kw 1730RPM 4P Hyundai Motor $140
1 x 3m 06B Chain $26
100 x M4x20mm Hex Machine screw Black $13
2 x 20T Spur Gear 35mm 10mm Bore $41
1 x 4mm Hex Tungsten Tapered Tap $5
20 x M5x20mm Black Set Screw $9
20 x M4x20 Black Set Screw $-
1 x 35x30mm Annular Cutter $88
1 x 25x30mm Annular Cutter $55
1 x Pin 6mm for 30mm Annular Cutter $22

All steel was 4340 which was made from offcuts from my work. Electronics where free. Another few hundred for parts and labour. I’m very fortunate as this would have been hundreds of dollars.

It cost 2hrs labour @$60hr Machining and water jet. Water jet doesn’t ruin the factory heat treatment of 4340.

Mine assembles in just a few minutes including it’s 25:1 compound chain gearbox.


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