Are the rollers on your grain mill stainless steel?

[Joe_Beer_1 (Joe_Beer)]

I recently purchased a two roller adjustable grain mill which specifies 304 stainless rollers in the listing. When I received it, I checked the rollers with a magnet and it stuck to both of them (pretty sure 304 stainless is not magnetic).  I’d rather not have rusted rollers sometime down the road. I have a message in with the merchant to clarify but looking at other options in case I send it back. Many mills look dubiously similar in construction to the one I purchased (Cereal Killer, Kegco, NB Hullwrecker) which makes me wonder which mills actually have stainless rollers.

If anyone gets some time, would you mind testing your mill rollers with a magnet and see if it sticks? If not, would you please post the model?

[roger]

Magnetic testing is not a reliable test for stainless, even grade 304. All 300 series stainless steel is non-magnetic only when freshly formed. All 300-series, but 304 in particular becomes magnetic when cold worked, such as pressing, cutting, etc. The process of manufacturing mill rollers would cause this.

For more information, check out this link. There are plenty of other sources.

The Magnet Test for Stainless Steel is Not Accurate

I had an affordable mill for about 20 years that was not SS. Even though it lived in the garage, it never had a rust issue. Just got a replacement for Christmas and did not opt for the SS option.

[Joe_Beer_1 (Joe_Beer)]

@roger

304 in particular becomes magnetic when cold worked, such as pressing, cutting, etc. The process of manufacturing mill rollers would cause this.

Well I’ll be durned! It IS a deep knurl on the rollers which must have done it. Thanks for that!

@roger

I had an affordable mill for about 20 years that was not SS. Even though it lived in the garage, it never had a rust issue. Just got a replacement for Christmas and did not opt for the SS option.

Good to know!

[chinaski]

My old JSP malt mill isn’t stainless as far as I can tell.  I store it in a cabinet and keep it dry, no rust in the 20 or so years I’ve had it.

[goose]

@chinaski

My old JSP malt mill isn’t stainless as far as I can tell.  I store it in a cabinet and keep it dry, no rust in the 20 or so years I’ve had it.

+1

Finally had to buy a new mill after the rollers in my JSP mill wore out. Had it for over 20 years and could not send the rollers back to Jack Schmidling to be re-worked after his shop was destroyed in a fire and he decided not to rebuild.

Mine lived in my brewery and had to deal with the humidity issues during a brew day.  Never saw any rust at all.

[jeffy]

@goose

@chinaski

My old JSP malt mill isn’t stainless as far as I can tell.  I store it in a cabinet and keep it dry, no rust in the 20 or so years I’ve had it.

+1

Finally had to buy a new mill after the rollers in my JSP mill wore out. Had it for over 20 years and could not send the rollers back to Jack Schmidling to be re-worked after his shop was destroyed in a fire and he decided not to rebuild.

Mine lived in my brewery and had to deal with the humidity issues during a brew day.  Never saw any rust at all.

Mine is still just fine and it has lived outside in Florida for over 25 years.

[hopfenundmalz]

@roger

Magnetic testing is not a reliable test for stainless, even grade 304. All 300 series stainless steel is non-magnetic only when freshly formed. All 300-series, but 304 in particular becomes magnetic when cold worked, such as pressing, cutting, etc. The process of manufacturing mill rollers would cause this.

For more information, check out this link. There are plenty of other sources.

The Magnet Test for Stainless Steel is Not Accurate – Ausko Pte Ltd

I had an affordable mill for about 20 years that was not SS. Even though it lived in the garage, it never had a rust issue. Just got a replacement for Christmas and did not opt for the SS option.

Roger has it right.

I often condition malt so the husks stay better intact. The malt is damp. I popped for SS rollers on my Monster Mill 3 roller version.

A magnet just showed the knurled surface to be magnetic on the rollers. The shaft on the driven roller is not magnetic, that roller is from the same hunk of material. Working the knurled surface caused that to be magnetic.

[Joe_Beer_1 (Joe_Beer)]

@hopfenundmalz

A magnet just showed the knurled surface to be magnetic on the rollers. The shaft on the driven roller is not magnetic, that roller is from the same hunk of material. Working the knurled surface caused that to be magnetic.

Thanks all and Thanks hopfenundmalz for checking out your rollers. Looks like my shaft is not magnetic either, and yeah, seems to be all one piece. It’s weird how things work sometimes.