Impact Mill Build

[Rickrofe]

What are the specs on your motor?

Cracka.

The motor is 1 HP and designed to be outdoors (Waterproof). We will be running the mill wet so this is important.

 

[G0lddigg@]

great project there Rickrofe cant wiat to see your results after s afew months in the field crushing rock.

 

[Rickrofe]

When it comes to rotating mass , as diameter increases , the effect of balance / imbalance increases exponentially

did the shaft stay straight after welding the flat bar to it ? , if you mount the shaft in the bearings and give it a spin , is there any axial distortion showing in the shaft where the pulley mounts to it ? If you can rectify any distortion in the shaft it will decrease vibration in the drive significantly

You might want to countersink the holes that the D shackles go through and make the holes around 3 mm oversize to stop the D shackle pins from shearing off when the chain hits something between a rock and a hard place.

Did you find hardened load rated D shackles yet instead of soft mild steel ones ?

Will you have a safety switch "E-stop" mounted within reach in case it has an event during operation and you find yourself using both hands to hold on to it and one leg being used to kick the plug out of the socket ?

(Kidding) I am sure it will hold together nicely and those cast iron bearing blocks won't crack from the vibration for ages

:8

Seriously . Have fun with it and hope you find some good reef gold to get a payback for your work.

Thanks for the advice, it seems you have done this before?

I have thought about the shaft vibration issue quite a bit. I have decided to TIG weld the flat bar to the shaft, it should reduce the tendency of the steel to distort due to excessive heat. I'll run 4 or 5 lines across the seam to provide additional strength. We are also counter sinking the D-shackle holes as per your advice, thankyou

I am intending to add an emergency stop switch when we get to that stage; additionally I am adding a water proof power switch (essential when running the mill wet)

Cheers

Rick

 

[Rickrofe]

great project there Rickrofe cant wiat to see your results after s afew months in the field crushing rock.

Thanks mate, I recon I might get over your way soon and try my luck on some of those Vic gold fields... Rick

 

[Wintersnake]

For what it's worth.
I'd be inclined to use the stick welder on the shaft plates, the stick isn't as aggressive as the Mig. ie: doesn't cool as fast because the process is slower.

I'd also tac both plates on as the opposite side will act as a strong back and alternate stitches side to side, back to front.
If your really concerned about warping and or cracking post heat the rod then bury in sand over night.

You got a pretty flash welder there so I'm sure you'll do it right.

 

[Rickrofe]

An update on progress. We have the Mill and motor connected to the supporting frame and we are now starting on the shaft, inlet and outlet bits of the build. We are not sure about what approach we should take to connect the chain to the shaft. We would prefer to use a method that allows for adjusting the chain length (tolerance), using D-Shackle does not provide enough flexibility for adjusting tolerance. If any one with experience can advise I am all ears?

The Mill is now a single unit with both top and bottom connected..

We added a belt tension spring today..

The machine is quite when running, that will change when it starts grinding.

That's it for now, more updates in a day or two...

Cheers

Rick

 

[Wintersnake]

Dome head cap screw bolt and nyloc nut straight through the chain link into the retaining plate.

 

[Jaros]

"Rock and Roll"---This is looking good!!

 

[MJB]

looking really good mate,

superb engineering skills

 

[Guest]

Just a thought on wet milling.
I have used my mill for over 25 years with many different rotor and screen configurations and the best results have always been when I dry crush.
When I introduced a water feed in the belief that it would keep the dust down and I could crush straight into my sluice, I found that the water would wash the crushed quartz through the screen, but the particle sizes increased to a point where they would sit on top of the screen and clog it.
The water going through the mill slowed down the particle flow, and cushioned the blow from the hammers onto the quartz. The wet quartz simply stopped in the bottom of the mill, on top of the screen.
If you dry crush, the quartz remains mobile, is shattered properly by the hammers, and is finer as it leaves the mill which frees the gold and makes it easier to recover.
Just make sure you wear a good dust mask, safety glasses, and ear plugs.
The product I get from my mill is .25mm or finer.
With a wet feed, I had 3mm pieces clog the screen.
Hope this helps.

 

[Rickrofe]

Progress Update

We have now finished the major parts of the build, including attaching the chain to the shaft. Today we started on the inlet and outlet openings. We have decided to use a punch plate and add an emergency stop button based on advice from 'HeadsUp' (thank you). The electrics are just about complete. We will probably do a test run over the weekend sometime, I'll post a video. In the meantime I have added a couple of photos of progress to date:

The flatbar has been welded to the shaft with minimal axial distortion.

The outlet has been designed to run wet, a punch plate is located where the outlet meets the body of the Mill.

Chain and D-Shackles are attached and ready to go..

Still tidying up the electrics.

Cheers

Rick

 

[Dug]

Awesome bit of work ,Great skills !

 

[flashinthepan]

great project rickrofe,, gotta get me one of them circle cutters for the plasma , save looking around for a suitable template , how did you decide on the optimum speed of the shaft or are you going to try it and see first ? i see its about 1-1 on the pullies ,is the motor 2400 rpm or so?
flash

 

[Rickrofe]

great project rickrofe,, gotta get me one of them circle cutters for the plasma , save looking around for a suitable template , how did you decide on the optimum speed of the shaft or are you going to try it and see first ? i see its about 1-1 on the pullies ,is the motor 2400 rpm or so?
flash

Hi

As I understand it the optimal rpm for a crusher of this size is about 1400. The pullies are 1:1.22 which gives us a rotation of between 1420 - 1470 rpm; which seems to be working well. We have had the mill up and running now for about a week, it is running a .75 horse power motor at 1400 rpm. It eats through anything 6cm (a bit over 2 inches) squarish. It reduces ore down to between -100 mesh and -30 mesh.

I will put up a video as soon as we are finished tweaking a few bits and pieces. probably in a week or so...

Cheers Rick

 

[vk1989]

anymore info rickrofe?

 

[drystone]

Hi mate,
just found your post and it's fascinating...
...any latest pics or feedback as to how it has performed?
Any modifications since?
currently doing TAFE welding course (as mature age noob!) so bit excited at potential to make stuff!
great thread
cheers
Drystone

 

[Rickrofe]

Hi

The design has since gone through three iterations and the latest is currently being Power Coated. I'll check back with you in a week or so with a video and additional detail...

Cheers

Rick

 

[Rickrofe]

Finished making final changes and finally got it running nicely. Its for sale if anyone is interested. [video=480,360]https://youtu.be/6WIw6L1InH4[/video]

 

[dunollyman]

How much ?

 

[Mackka]

Hey mate I love it but I do have a question, at a handful every 10 seconds how does that equate to 300kg per hour and what were you crushing?
Just askin.
Mackka :Y: