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#1

Donny
Member
Joined: 26 January 2018
Posts: 12
Member
11 February 2018 08:36 pm

Hi everyone,

I’m tossing around the idea of making a rock crusher, an impact mill is what I’m aiming for.

My question is what motor do you guys believe would be best. I don’t have a lot of money to play with. I had considered the idea of trying a lawn mower motor. Only problem I can see is how to build the casing for it.

I have a local recycling yard that has quite a lot of mowers/whipper snippers and but I’ve yet to see anything else.

2 users like this post: Hunting the yellow, mudgee hunter

#2

Hunting the yellow
Member
From: down a hole
Joined: 20 December 2012
Posts: 1,687
Member
15 February 2018 03:05 am

Donny wrote:

Hi everyone,

I’m tossing around the idea of making a rock crusher, an impact mill is what I’m aiming for.

My question is what motor do you guys believe would be best. I don’t have a lot of money to play with. I had considered the idea of trying a lawn mower motor. Only problem I can see is how to build the casing for it.

I have a local recycling yard that has quite a lot of mowers/whipper snippers and but I’ve yet to see anything else.

take the motor off it turn it on its side go to your local tip get a 25mm or thicker steel bar for a shaft wack 2 bearings either side put a pulley on one end and a belt to your motor you can go direct drive to your motor but ill explain why belts maybe better later. get thick 3 to 5mm thick steel plate if you have a welder weld the thick panels together cut the plate into like a hex shape drill holes in the bottom of your hex shape box for a screen for the crushed sand to pass through after that make like a snorkel on the top of your crusher this will be for the feed feeding rocks into it from the top make the feed a zig zag shape as if you just have it strait the rocks will be shot back out to you put a few angles into it.

here's why belts are better in my opinion if a rock jams between the small space in your crusher wall and the hammers and its direct drive I've seen either the shaft snap or bend if its a powerful motor or if its a smaller motor it really can't over come the jam and just runs flat out or simply stops with belts if a rock jams all it dose is either breaks your belt if the belt is too tight and you have a large motor. or it just simply spins on the pulley in witch case you turn your motor off pull off the bolt able service plate off get the jammed rock out put it back on and keep going or you can always make the screen part at the bottom into a small door to get jammed rocks out too.

here's my one for and idea it depends too how much rock you want to crush and how big it is if your crushing football size rocks make a jaw crusher use that as your primary crusher then make a hammer/chain mill for your secondary crusher to get it down to sand size then if you want it like a power or supper fine use a ball or rod mill to get it down even further.

other ideas for rock crushers

this last one I like very simple to make too if you have a hammer drill set it to hammer only not drill weld a large nut or thick flat washer to a drill bit you may have to make your own somehow then just turn it on in a dolly put really quick and easy but use a mask because there will be a lot of dust.


born 150 years too late and missed all the gold rushers

#3

magneticsand
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Joined: 13 July 2014
Posts: 122
Member
15 February 2018 06:35 am

I have a 80 year old Stationary engine that I've sometimes thought of using for this. Its presently hooked up to a alternator and car battery + inverter to use during blackouts. 1-2 times a year.

Not sure how my neighbors would feel about it though. It makes enough noise already lol

#4

jethro
Member
From: North East , VIC
Joined: 06 September 2013
Posts: 461
Member
15 February 2018 09:41 am

Donny, Ebay has some cheap honda knock offs. $139 for a 6.5 hp petrol engine. The one I bought for use on my crushers etc has a 2:1 reduction and a centrifugal clutch so that the machine can be stopped by throttling back to clear jams easier also helps make starting easier as you are not trying to turn over the whole crusher on the rope start.

1 user likes this post: Hunting the yellow

#5

Rexrmx450
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Joined: 20 January 2018
Posts: 10
Member
15 February 2018 09:53 am

Cool

#6

1968falconxt
Member
From: , VIC
Joined: 29 January 2018
Posts: 174
Member
15 February 2018 11:23 am

I am also going to make one of these in the coming weeks. I don't mean to hijack the thread and hope this question is helpful to Donny:

I just made these dolly pots using a mild steel 20mm solid bar to crush the rock and tried one on the weekend. It left small bits of steel in the crushed rock and when I panned it in the turbo pan, I had quite a lot of steel flakes left. They stayed in the pan which I was surprised about.

So, these whipping/chain style crushers in general apparently wear out the chains quickly which I understand to mean the sand will be full of metal flakes. Am i just panning wrong or will the pan always be left with metal flakes in the bottom?

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X-terra 705 with 13x10" MARS DD coil, Garrett pro pointer, Black Widow Prospecting Shovel & hand digger, dry blower, recirculating sluice with 6" Dream mat

1 user likes this post: Hunting the yellow

#7

jethro
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From: North East , VIC
Joined: 06 September 2013
Posts: 461
Member
15 February 2018 01:01 pm

If you are getting metal flakes in your pan concentrates you are doing things exactly right. The only ways to reduce the wear that you will get from smashing hard quartz with steel is to either pre soften your rock or use hardened steel. You can soften quartz by burning it in a hot fire. Do this outdoors away from everyone else and stay upwind as this process can release some noxious gases. the other alternative is to build your impact plates and hammers out of some sort of toughened steel like bisalloy. Or you can hardface your hammers with hardfacing rods designed to resist impact wear rather than abrasive wear.

3 users like this post: Hunting the yellow, Goldfreak, Moneybox

#8

Donny
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Joined: 26 January 2018
Posts: 12
Member
15 February 2018 04:15 pm

Thanks everyone for the responses.

HTY I was of the assumption that turning a motor like that on it's side was no good for the motor and would starve it for oil and seize?
Thanks for the links also they will be very helpful. Some i have seen as I've been trying to research the best way to make it.

Jethro thanks for the heads up mate, I'll defiantly look into it.

1 user likes this post: Hunting the yellow

#9

mudgee hunter
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Joined: 02 January 2017
Posts: 755
Member
15 February 2018 05:02 pm

Nothing a magnet wont get out of your pan. Im also looking at a portable petrol crusher myself for my next project.
And also considered a good 5-6 hp motor. So this thread will keep me interested. The clutch idea seems the go.
In the old days of using the cornish oven to heat the quartz, was it also quenched in water to aid in cracking?
If not, would it help?

#10

Tathradj
Moderator
From: Tathra, NSW
Joined: 17 February 2014
Posts: 7,249
Moderator
15 February 2018 06:06 pm

Highly advised to use belts as a drive.
They take the shock out of the hammers/chains.
4 stroke lawn mower engine is designed to be used flat. It will starve for oil.
Two stroke can be set upright as long as you can tilt the carby to suit but,
The crusher itself will be only a small one and only use a chain type.
About 150 mm id max as it would not have the power to run.
I have put a lot of research into crushers and I hope to build one one day.
Not hard to do so don't give up. thumbsup thumbsup thumbsup thumbsup


A couple of HiBankers inc. accessories, , 4500, SDC2300, Gt1600,
Aldi, Phantom 4 Pro, A Prado 4x4, A'Van Cruiseliner and a heck
of a lot of determination.Not to mention Luck.
Most importantly, A lot of Good Honest Friends.

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#11

travelergold
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Joined: 19 May 2015
Posts: 44
Member
15 February 2018 07:17 pm

If a rock jambs unit it will stop in a hell of a hurry. This will either bend your motor crank or snap the crank or drive shaft. I have had this happen to stationary motors but was using for a different purpose. Belt drive is the way to go, when it locks up the belt will take some of the shock and will then hopefully slip for you. TG

2 users like this post: Hunting the yellow, mudgee hunter

#12

1968falconxt
Member
From: , VIC
Joined: 29 January 2018
Posts: 174
Member
15 February 2018 08:22 pm

I'll be following this thread. I like that cheap Honda copy on ebay. I agree with the idea of a belt. Solid mount to the shaft is asking for trouble


X-terra 705 with 13x10" MARS DD coil, Garrett pro pointer, Black Widow Prospecting Shovel & hand digger, dry blower, recirculating sluice with 6" Dream mat

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#13

Hunting the yellow
Member
From: down a hole
Joined: 20 December 2012
Posts: 1,687
Member
15 February 2018 09:56 pm

Tathradj wrote:

Highly advised to use belts as a drive.
They take the shock out of the hammers/chains.
4 stroke lawn mower engine is designed to be used flat. It will starve for oil.
Two stroke can be set upright as long as you can tilt the carby to suit but,
The crusher itself will be only a small one and only use a chain type.
About 150 mm id max as it would not have the power to run.
I have put a lot of research into crushers and I hope to build one one day.
Not hard to do so don't give up. thumbsup thumbsup thumbsup thumbsup

yes two stroke I meant not 4 and only tilt it slightly forgot to add make up a steel frame with wheels to move it around too

Last edited by Hunting the yellow (15 February 2018 09:59 pm)


born 150 years too late and missed all the gold rushers

#14

Hunting the yellow
Member
From: down a hole
Joined: 20 December 2012
Posts: 1,687
Member
15 February 2018 09:58 pm

hence in my first post I said belt driven not direct drive off the shaft smile


born 150 years too late and missed all the gold rushers

#15

Hunting the yellow
Member
From: down a hole
Joined: 20 December 2012
Posts: 1,687
Member
15 February 2018 10:07 pm

Donny wrote:

Thanks everyone for the responses.

HTY I was of the assumption that turning a motor like that on it's side was no good for the motor and would starve it for oil and seize?
Thanks for the links also they will be very helpful. Some i have seen as I've been trying to research the best way to make it.

Jethro thanks for the heads up mate, I'll defiantly look into it.

yes this is true I was meaning if using a 2 stroke motor but a stationary motor would suit much better. but if you want something quick and fast I would just go buy a hammer drill set it to hammer only not drill and attach a thick metal plate on the end make a dolly pot as seen above and simply turn on and crush it without even lifting a heavy steel rod. quickest cheapest easiest way of making a basic crusher that works better than using a dolly pot by hand.


born 150 years too late and missed all the gold rushers

#16

Moneybox
Member
From: Capel, WA
Joined: 10 October 2014
Posts: 1,412
Member
16 February 2018 12:15 am

I've only dollyed one quartz rock but cooking it first made all the difference. It was a solid white rock but set the detector off. I cooked it with the oxy and then dropped into a bucket of water. It came out on multiple pieces and could be broken further by hand. From there it only needed a light hammering in the dollypot to reduce it to sand and one nice little nugget. I'm sure if you threw your rocks into the fire first it would take a lot of load off your machinery.

Last edited by Moneybox (16 February 2018 12:16 am)


Phil & Sandra - GPX4500, SDC2300, White's Goldmaster GMT, Go-Find 40, pans, sieves and Garrett Propointer in a 4WD motorhome.

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#17

1968falconxt
Member
From: , VIC
Joined: 29 January 2018
Posts: 174
Member
17 March 2018 05:36 pm

Haw did you go? Have you started work on the crusher yet?


X-terra 705 with 13x10" MARS DD coil, Garrett pro pointer, Black Widow Prospecting Shovel & hand digger, dry blower, recirculating sluice with 6" Dream mat


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