Is 303 Stainless magnetic?

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BrandonS

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I recently got a new MM2 mill and did the stainless upgrade on the rollers. I was kind of surprised to see a magnet sticks to them. I was under the impression this shouldn't happen for 303. Are there any other MM owners with the stainless steel that could try it for grins? Maybe a metallurgist that can explain this one to me?
 
After a quick google search 303 stainless is non-magentic. I do know some grades of stainless are magnetic.
 
I saw this as well so I'm hoping another MM owner can try it. It is probably just a steel core.
 
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McMaster-Carr reports that 303 Stainless "may become slightly magnetic when worked." My interpretation would be that "slightly magnetic" is more in the range of "may screw with super-sensitive electronics" than "macroscopic magnets will actually stick to it" so steel core gets my vote.

Note that there ARE grades of Stainless that are magnetic (much of the 400 series, for instance). I'm assuming they specifically quoted it as 303?
 
Just went and checked mine...mm2 pro. Has a .50 solid steel rod through both rollers
 
I thought that 303 stainless was not a good choice for the rollers since it's a softer grade of stainless? I would think 406 stainless or the harder carbon steel would last longer without the knurling wearing off.
 
I thought that 303 stainless was not a good choice for the rollers since it's a softer grade of stainless? I would think 406 stainless or the harder carbon steel would last longer without the knurling wearing off.
From their site:

"There are two roller material options available for the standard 1.5" mills. They come standard with 1144 alloy steel, which offers fantastic wear for home brewers. Plain steel mills kept indoors, and used regularly won't have rust issues. Non climate controlled areas, or minimal usage could see some corrosion come up that is easily removed with a wire brush. As an upgrade to 1144 steel we offer 303 Stainless Steel. It will wear just about the same as our 1144 steel, but will not rust. Recommended for those that live in salty or moist environments, and those that want to wet mill. We do NOT recommend this mill for any commercial operation, brew shop, brewery etc."
 
From their site:

"There are two roller material options available for the standard 1.5" mills. They come standard with 1144 alloy steel, which offers fantastic wear for home brewers. Plain steel mills kept indoors, and used regularly won't have rust issues. Non climate controlled areas, or minimal usage could see some corrosion come up that is easily removed with a wire brush. As an upgrade to 1144 steel we offer 303 Stainless Steel. It will wear just about the same as our 1144 steel, but will not rust. Recommended for those that live in salty or moist environments, and those that want to wet mill. We do NOT recommend this mill for any commercial operation, brew shop, brewery etc."

Well the last comment kinda says either choice would wear out with heavy use... I know some mills sold for home brewers have hardened steel rollers. I would have thought this would have been one of them.
 
Well the last comment kinda says either choice would wear out with heavy use... I know some mills sold for home brewers have hardened steel rollers. I would have thought this would have been one of them.
I guess the questions are:

1) How many homebrewers have worn the knurls off their Monster Mills? How much grain did it take? How does that compare to other mills?
2) What are the other manufactures with hardened rollers and what is the price of those mills? Monster Mill does offer other models with hardened rollers.
 
I guess the questions are:

1) How many homebrewers have worn the knurls off their Monster Mills? How much grain did it take? How does that compare to other mills?
2) What are the other manufactures with hardened rollers and what is the price of those mills? Monster Mill does offer other models with hardened rollers.

Actually I posted in a thread last week where someone complained there mill rollers had worn out... If you do a search here you will see it happens.

I though I remembered heading my cheap cereal killer having hardened rollers.
 
Actually I posted in a thread last week where someone complained there mill rollers had worn out... If you do a search here you will see it happens.
Ok found that thread, and it wasn't a Monster Mill that wore out. My questions were specifically about the standard Monster Mill, how long do the rollers last and how that compares to other mills on the market (with hardened or non-hardened rollers).

And yes, eventually everything will wear out.
 
303 SS is odd for this application. For what it gives you in corrosion resistance, it loses to wear because is a relatively soft alloy.

chrome plated steel would be ideal, in my opinion.
 
Vesteroid, thank you for checking. What's weird to me is the drive shaft on mine is not magnetic, but the rollers are. I have an inquiry in to monster and I am waiting to hear back.

As for the wear, there is a post on here from MM addressing it. The non-hardened steel still has a life of something like 30 years depending on usage. If I can find it I will edit with the link.

EDIT: https://www.homebrewtalk.com/showpost.php?p=3819333&postcount=25
 
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After dong some research it really just the barley crusher that seems to have the issues wearing out.... I found multiple complaint's but it was always the BC mills that were the cause..

If the mm stainless rollers are magnetic its more likely a good thing since if its not from machining, it just means its actually a harder grade of stainless lke 401 which should still be fairly corrosive resistant for this application.
 
Stainless develops some magnetic qualities when cold worked. If you pick up a 304 ss bolt you will see that a magnet sticks to the head and the threads but not really to the shank.

303 is very similar to 304 but it is easier to machine. 304 is a pain to machine but welds much nicer. 316 is slightly more resistive to corosive environments or solutions higher in chloride.
 
303 is the softest of standard stainless grades is it not? That's the reason I questioned it for an application where hardened material is preferred normally.
 
Monster stated that the 303 they use gives the same wear as the steel they use as standard. 303 may be a soft "stainless" alloy and still be as hard as the non stainless.

I don't know about wearing out, but I have been watching threads on mills for years and IMO Monster Mills get the fewest complaints. And conversely the best reviews. It is at the top of my list for when I upgrade from my Corona style mill to a roller mill.
 
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