There is a post on the Redwing collector site that asks the same
question basically. It looks like this same patent was stamped with
Ideal Equipment Co. Looking through the Redwing history area, they
never called themselves by this name or anything like it, and going
through the photo collections it appears that Redwing was very solid
about stamping their stoneware with "Redwing". So I doubt highly that
they manufactured this under a different company name. Also, it was
Redwing that combined several small companies into the same banner.
Ideal Equipment could have been one of these "absorbed" companies, but
I can't find any proof of this. Even so, if the smaller company had
made it, and then was "absorbed" by Redwing, it would not, in a
collectors or historian point of view be a Redwing manufactured item.
Another observation for Redwing is I found no items at all, either on
this site or other places that suggest they made anything like a salt
feeder for cattle. All of the items I saw were of the household type.
"Ideal Equipment Co, Morriston, Minn. It is model "C" and also is
stamped F.H. Ahlman's Patent - 1909244. "
If yours is stamped with the patent number and the Ideal Equipment
mark, you may consider believing the stamp. There is a hint in the
above links, (the third one) that suggests that Ideal may have made
these for Redwing under contract. Please see that link for comment on
this, its rather informative, and the woman asking the question has
left her email address, so you might be able to contact her and see if
she has found out anything else about her salt feeder.
Links of interest
Patent for 1909244
+Redwing +Stoneware +"Salt Feeder"
+"Western Stoneware" +"Salt Feeder"
Thanks for the question