Impact Mill Build

[Rickrofe]

After months of procrastinating, indecision and dealing with higher priority projects I have finally got around to (attempting) building an Impact Mill. I have watched 30 or 40 YouTube videos, researched on line and following a few threads in this forum on the subject, and I think I have got my head around what to build.

I am new to prospecting and I am guessing that there are others in this forum that are just as inexperienced. So I intend to document my approach and add some context to the approach I am taking. I hope that others may be able leverage my experiences or learn from any mistakes along the way.

I decided to use a 274 mm X 10 mm hardened steel pipe as my starting point. I am not lining the pipe with hardened plate at this stage, I want to see how the mill wears with use. The following illustration is what I am hoping it will look like when completed.

So my starting materials consist of a couple of 25mm bearings (including housings), a 2020 X 300 X 10 mm steel plate, a couple of meters of 10x40 Flat Bar and 50x50x6 Angle; and the pipe.

After a couple of hours work I managed to get the end plates cut and welded to the pipe. The whole thing was cut in two, ready for the next stage; building the support frame. Below are a few photo's of the process. I will update this thread over the next couple of weeks as the project progresses.

Rick

Cutting the end plates (with jig).

The pipe with end plates welded.

The two halves of the Mill....

 

[MJB]

That looks like it will be a solid, well built crusher Rick.

One of that size will fly through the material.

Look forward to see your updates with it and good luck

 

[cracka]

I was studying up on this yesterday, Will be following this thread closely. We built a dolly pot 3 days ago and now i have blisters from using it.

Cracka

 

[cracka]

Oh yeah, and good luck with the build. A few questions i would like to ask, Are they hardened D-Shackles? Where do you get them and how much. Also how long does the chain attached to the d-shackles have to be? I gather just long enough to nearly reach the outside pipe without hitting it? Is there any recommended clearance? Thanks

Cracka

 

[old hand]

Very impressive well done hope to see video of it in action regards john

 

[Rickrofe]

Oh yeah, and good luck with the build. A few questions i would like to ask, Are they hardened D-Shackles? Where do you get them and how much. Also how long does the chain attached to the d-shackles have to be? I gather just long enough to nearly reach the outside pipe without hitting it? Is there any recommended clearance? Thanks

Cracka

Thanks for your encouragement....

The chain I am using is 70 Grade, it is used for tying down loads and is hardened carbon steel, I source mine from https://www.nobles.com.au/Products/Chain. I intend using standard D-shackles to attach the chain links. As for tolerance, I will be running the mill close tolerance. I am not using a punch plate on the outlet, I don't want to over grind the ore, so the closer the tolerance the better. I will be in a better position to advise after the mill is up and running and we have had a chance to analyse it's operation. I will post updates regularly.

Rick

 

[Rickrofe]

We made good progress today, we managed to weld on the hinge plates, build the mounts for the electric motor and attach the angle supports for the bearing housing....

more updates to come......

 

[MJB]

looking awesome mate

 

[Rickrofe]

looking awesome mate

Thanks, we hope it will process 1 to 1.5 tonnes per hour. Any comments or advise is welcomed.....

 

[Wintersnake]

Any thoughts on the feed chute design as that seems to be the biggest issue with these mills I hear?

 

[backcreek]

That's one solid piece of gear Rick, it should hold up to a lot of use and abuse.

 

[Wally69]

.......I LOVE IT.......

I am also impressed by the space you have to play......darn my city living 8.(

My memory fails me but the guys in our work workshop used to run beads of weld to act as a hard-wearing surface for ground engaging tools. Hopefully some of the mining fitters on the site could point you/me in the right direction as to what is used.

Did I say, I love it !!

 

[backcreek]

That would be hard facing rods or hard facing mig wire.
Any welding supplies should have them but with something that heavy I'd just give it a go and see how it holds up.
You can always hard face it later.

.......I LOVE IT.......

I am also impressed by the space you have to play......darn my city living 8.(

My memory fails me but the guys in our work workshop used to run beads of weld to act as a hard-wearing surface for ground engaging tools. Hopefully some of the mining fitters on the site could point you/me in the right direction as to what is used.

Did I say, I love it !!

 

[Wintersnake]

Yep run it as is, find the wear points and glue some ceramic tiles in there with wearmax. hard facing wont last as long as lining it.

 

[Rickrofe]

Any thoughts on the feed chute design as that seems to be the biggest issue with these mills I hear?

The feed chute will be placed on the top half of the mill, and will be positioned so that feed enters the mill on the downwards stroke of the spin cycle. I am using 5 mm thick tubing which will be attached at a 90 degree angle to the mill body but bends out at 45 degrees about half way up. This design will help avoid any material being kicked back out the feeder chute. The chute will be about 75 mm wide but will be choked to restrict feed size to no greater than 50 mm.

 

[Rickrofe]

That's one solid piece of gear Rick, it should hold up to a lot of use and abuse.

Thank mate, I hope you are right.

 

[Rickrofe]

.......I LOVE IT.......

I am also impressed by the space you have to play......darn my city living 8.(

My memory fails me but the guys in our work workshop used to run beads of weld to act as a hard-wearing surface for ground engaging tools. Hopefully some of the mining fitters on the site could point you/me in the right direction as to what is used.

Did I say, I love it !!

It's so nice to be loved, keep the accolades coming... I just hope the design results in it meeting expectations.

 

[Rickrofe]

Very impressive well done hope to see video of it in action regards john

I will post a video when we start testing, probably in a week or two.

 

[cracka]

What are the specs on your motor?

Cracka.

 

[HeadsUp]

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.