Age of old singer
 

Can anyone tell me is on older sing if the model number is higher if it means its a newer machine
.Such as a model 401 is newer than a 301, and a 401a is newer that a 401 and is a Stylest newer than the 401A or how can I find out
Thanks

The higher numbers generally are newer.

You can always look up the serial number. The site I use sewshop.com gives the date the machine was released. Many of the models were made for several years.

for the older cast iron, the model numbers are all over, and many were made at the same time, over a 30-50 year period, with modifications.

With the aluminum, it sort of runs that way, though I've run into a few exceptions where a higher number was used and then Singer jumped back to a lower range because it was an update of an older model, and not really a new model.

66 99 185?

457 500 347?

As a general rule, usually you would find the bigger the number the newer:
27 - 127
28 - 128
99 - 185 / 192 / 285

15 - 115 - ha! gotcha! ;) The 115 was only produced for a "Few" years, the 15 was produced for over 100. There can be newer 15s than 115s, and older than the 115s. Rarely did they run concurrently, other than the 15 / 115

The (1)27, (1)28, 15, and 66 all ran concurrently and none would supersede each other.

221 - 222 - concurrent, and only slightly different models.

Somewhere in the 60s-ish they started backtracking with the numbers. Especially in the 3xx 4xx and 5xx numbers.