Author Topic: Home made grain mill . . . . that could crush a brick!  (Read 6522 times)

Offline littlejohn

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Home made grain mill . . . . that could crush a brick!
« on: January 30, 2013, 03:04:03 AM »
I wasn't too keen on spending around $250 on a grain mill so I made this from an old Chrysler Borg Warner auto gearbox drive spline and universal gears. Next step is to pretty it up a bit with some paint, so far it works really well and it doesn't get any cheaper than free! (free scraps and leftover car parts anyhow)



I chose the drive splines because they were made of extremely tough steel and had grooves already cut longitudinally which are perfect for grabbing grain and crushing it.



I dismantled the universal gears which gave me two crosscut gears, the tooth depth is deep enough that it allows for adjustment I welded a blob on top of the spline then lathed it down to the inner diameter of the gear which then sat snug with a few hits.




I filled the cavity with weld and lathed it flat on the end with a countersink (the other end already has one from the factory) for the turned brass pivots to hold it in place and adjust the crush width.



The body is steel plate, thick enough to tap a good thread into to hold the pins. The splines were buffered and lined up with a few thin washers (which are plentiful in the gearbox). The brass bolts were tapered to match the countersunk holes and a nut is on each to prevent them from tightening and jamming in use.



While I was at it I welded a hopper to the top and burnished it flat covering the sharp edges with a protective auto strip from 'rare-spares'. The handle is just there while I was testing but the shaft has two nuts to put the chuck of a drill over.

** in practice: The mill works great and there is no give in the set width so that everything that goes through it is properly crushed and I have not needed to run it through twice.

The hopper bottom feed could be wider to let the grain fall freer.


Online mtnrockhopper

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Re: Home made grain mill . . . . that could crush a brick!
« Reply #1 on: January 30, 2013, 06:44:37 AM »
Nice! I like this sort of repurposing. Is the box holding the rollers part of the original gearbox or did you build that?
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Online hopfenundmalz

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Re: Home made grain mill . . . . that could crush a brick!
« Reply #2 on: January 30, 2013, 07:20:25 AM »
Nice! I like this sort of repurposing. Is the box holding the rollers part of the original gearbox or did you build that?

He built that.

I would like to see how the crush looks. My guess is that it looks pretty good.

Nice work, and as a retired automotive engineer, I really like the application of previously enjoyed gear shafts.
Jeff Rankert
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Offline jeffy

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Re: Home made grain mill . . . . that could crush a brick!
« Reply #3 on: January 30, 2013, 10:11:31 AM »
Yeah, I saw that first picture and recognized the parts as transmission shafts.  Very cool.  I have some of those laying around, but my welding skills and spare time are lacking.  Nice job.
Jeff Gladish, Tampa (989.3, 175.1 Apparent Rennarian)
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Offline littlejohn

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Re: Home made grain mill . . . . that could crush a brick!
« Reply #4 on: January 31, 2013, 12:54:24 AM »
Thanks for the feedback guys I will post a photo of what the grain looks like on the other end shortly.

Some of the comments so far touch on the initial issued I had building it:

The box had to be made because there wasn't anything existing in all the parts, i toyed with using aluminium housing but there are no parallel sides

One issue there was fixing the ends so it turned nicely, the first prototype had the ends held around the end using large washers welded to the plate not by pins, and the end plates would be bolted on for easy dismantling. While this covered up the beveled ends (stop grain falling through) it meant that it was difficult to place the rollers close together and stop them wobbling.

It only took a lazy Sunday to build (including failures)

Offline AmandaK

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Re: Home made grain mill . . . . that could crush a brick!
« Reply #5 on: January 31, 2013, 05:52:17 AM »
Very cool!
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Re: Home made grain mill . . . . that could crush a brick!
« Reply #6 on: January 31, 2013, 06:50:55 AM »
Back in the Muscle Car days, Chevy had a manual transmission known as the "rock crusher".
Jeff Rankert
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Offline weithman5

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Re: Home made grain mill . . . . that could crush a brick!
« Reply #7 on: January 31, 2013, 07:27:04 AM »
maybe you could make a mechanical  hopper out of an old ford "Top loader"  transmission
Don AHA member

Offline surfin_mikeg

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Re: Home made grain mill . . . . that could crush a brick!
« Reply #8 on: February 02, 2013, 12:51:27 PM »
I'm impressed.  Can you help with the terminology - a gearbox drive spline, fitting into what?   Gotta hit up the few gearheads I know!

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Re: Home made grain mill . . . . that could crush a brick!
« Reply #9 on: February 02, 2013, 01:24:56 PM »
I'm impressed.  Can you help with the terminology - a gearbox drive spline, fitting into what?   Gotta hit up the few gearheads I know!
There is a selection ring that has the sychronizer cone(s) that will slide along the shaft and engage the gear that is free spinning via dogs on the side of the gear and ring. This might help.
http://www.youtube.com/watch?v=8KDuk2-4s6E

Don't ask about automatics.  8)

I am a recovering automotive engineer, not a gearhead.
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Offline reverseapachemaster

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Re: Home made grain mill . . . . that could crush a brick!
« Reply #10 on: February 26, 2013, 03:44:23 PM »
I want to see video of it crushing brick.
Heck yeah I blog about homebrewing: Brain Sparging on Brewing but I'm also a lawyer: The Kielich Law Firm