I have a henderson piano company made piano serial number 31782 how old is my piano

try this

Kohler and Campbell Pianos ' Serial Numbers - Total Piano Care

www.total-piano-care.com/kohler-and-campbell-pianos.html

Piano Serial Numbers Search - Find the Age & History of Your Piano

www.total-piano-care.com/piano-serial-numbers.html

Kimball piano values vary based on age and condition; as of 2015, many uprights sell for $10,000 or more. Kimball is a well-known brand, and several of its antique pianos are considered highly collectible.
The Kimball Piano Company, based in Chicago, was one of the largest piano manufacturers in the world. At the turn of the century, Kimball built approximately 20,000 pianos annually. Kimball produced pianos under different brand names such as Hinze, Dunbar, Whitney and Harrison. Styles were influenced by Victorian, Greek Revival and Arts and Crafts architecture, and upright models were often available as player pianos. Kimball was sold to the Jasper American Corporation in 1959, and its pianos were discontinued in 1996.

https://www.alphapianostudio.com/

"Great teacher (Sandy) with lots of patient. Friendly and nice and also passionate till I have little time to rest my poor little hand. Learned for about a year plus and now can play more fluently and confidently. Price is acceptable and duration is just nice."

Here is a good place to look for your piano by make & serial number.
There are times when your piano name or number is not listed. They can help you find the year your piano was manufactured in most cases. Since you have the name & serial they should be able to answer your question. About the value... they can't possible know without seeing the piano.
http://www.bluebookofpianos.com/serial1.htm

That serial number is from 1925. The piano's value would depend on it's condition and your local market.

Milton Piano
From http://antiquepianoshop.com/online-museum/milton/ :
The Milton Piano Company was established in New York in 1892. In the early 20th Century they offered a full line of uprights, player pianos, and grand pianos, and they enjoyed a reputation of building very well made instruments. In the mid 1920s, Milton built a coveted new state-of-the-art factory on West 51st Street, New York City. There is some evidence that Brambach and Milton were somehow affiliated with one another, and their factories were located within blocks of each other. The Milton Piano Company built pianos until the late 1950s era.
From http://bluebookofpianos.com/agesm.htm#MILTON :
This name is a familiar one to the magical world generally. Milton pianos have been manufactured for many years and always with the care that produces most satisfactory results. The modern factories in which the Milton piano is produced are new, large structures located at 626-630 West 51st St., New York City. Milton pianos and player-pianos are thoroughly well-made, beautiful instruments, designed for a class of discriminating music lovers. They possess a tone at once powerful and sweet. They are pianos in which purchasers are assured good values and they are pianos that give exceptional satisfaction. Milton reproducing pianos are equally representative and popular.
All of which is great, but:
Be aware when dealing with antique pianos:
Many of the old (say, 1850 to 1940) pianos were made by companies that are no longer in business (failed, or bought out by a competitor), or companies that built the instrument under another name.
Pianos back then were not really mass-produced, they were hand crafted- and each manufacturer made their piano very differently, so:
Short Version: there will be parts that will work on only that *one* model of piano, so getting parts will be difficult if not impossible.
Long Version: Musical instrument craftsmen (craftspersons?) love to innovate, for a variety of reasons: they may find a new way, for instance, to connect the key to the hammer that strikes the corresponding note. It might be a better way to do it, or, more often, it was to come up with a cheaper way to do it.
The point I'm making is that your Struz Brothers piano will have parts that are totally different from, say, a piano made by either Krakauer Brothers, Doll, Jacob & Sons, or Mathushek & Son Piano Company (companies that started around the same time as Sturz Brothers). The parts may vary from one year to the next, or even one model to another.
So, if your Sturz Brothers piano needs a key replaced, or the harp has bent under pressure, the soundboard is cracked, or any number of things that can plague an old instrument, you'll need to either
A) find someone that is willing to sell parts from a similar model (if they're parting it out, it has more problems than yours does), OR
B) you'll need to have the part manufactured from scratch by craftsmen that specialize is rejuvenating old pianos. This will be expensive far, far beyond what the piano is worth- and these craftsmen live very well, BTW...
Last Caveat: Upright models sell for much less (and the term "Upright Grand" was just an advertising phrase, there is no such animal.) Uprights (spinets particularly) sound very... tinny, is the best description I can think of. Tinny like the toy piano your granma gave you when you were five- remember, the black keys were painted on? Tinny like that.
So, unless the piano is a Steinway & Sons, a B?sendorfer, or a Fazioli, don't count on huge offers for your instrument. And if it came to you from your great-aunt Tilly and you can't bear to part with it, that's great, I understand sentimental value. Just know that this will cost a great deal to bring to playing condition.
I'm often told "But the keys all work, the pedals are still tight, and the tuner told me that it's not a bad piano!" All this is true. But please remember that professional buyers know all of these potential pitfalls won't offer much, and the guy on Craigslist that needs to replace the piano for Great-Aunt Tilly can't afford much.
Good luck!

Here is a good place to determine value and history. Baldwin Pianos Company History Serial Number Search

Sorry, but at the very least, we need the BRAND of piano, style, and model number.

If your piano was made for the U.S. and is a grand or upright, this serial number would show that this piano came from the mid 70's 1973-77 and was manufactured in Hamamatsu, Japan. You should be able to google your piano from here to find others similar to it to get a price or call your local piano tuner!

Hi.
I did some research for ya, and here's what I've come up with.

The E. Belling piano's were manufactured in the 1920's and 30's.
Their serial number uses 1920 as 01000 for sereal number, so I am assuming that the first two numbers means years in business.

12 years gives us 1932 as the date of manufacture.

The company was one of those that kept getting bought out over and over and over again.

The majority were made under the Patings brand, until 1936, when the company closed.

All were made in the UK, some were for local use, and some for international sales, under the Victor & Belling label.

As far as current value is concerned, I would say that is should be worth at least a few hundred dollars, and possibly much more, depending on condition, and whether any famous songs were ever written on that particular piano.

I hope that I helped you out some, and good luck !!