I have been using a 1935 Smith-Corona Silent, and it doesn't have an End-Of-Page indicator either.
So I cobbled one up based on the Smith Corona Skyriter's "Page Gage," which has a line counter on the left end of the platen.
You insert a fresh sheet of paper with the platen aligning the Page Gage at a certain spot, and the 11" long page will align with the count-down numbering, indicating how many lines you have left.
I just used a length of 2-line-high white correction tape, put it in sideways (vertically), and typed the line numbers 24 down to 1, vertically on the correction tape.
Then I peeled off the adhesive backing, and put the tape onto the far left side of the platen.
Voila! My very own Page Gage for my 1935 S-C Silent.
I marked line -7- as the line for the starting number when inserting a fresh page, and then roll the page into position.
Then I'll type away with wild abandon until some 60 lines later, I'll see the number "6" roll up - One inch remaining.
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If you are going to make your own page gage, you'll have to make adjustments for the size of your platen, so you know what number setting to use as the start position, and the paper margins so you don't cover up the page gage.
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I used Avery CR-26 Correction tape because it is 2/6-inch tall, and already self-adhesive, but you are free to attempt to use ordinary paper, trim it as required, and use double-stick tape to stick it onto the far left - or far right - side of the platen, out of the way of your left- and right- margin settings. .
You will probably need to add or subtract the total number of rows, depending on the diameter of your platen, and you will need to determine for yourself which counter number you need to start with, so the counter will properly count down to 1 at the correct spot.
Happy typing!