How to identify an old compression stem in order to find a replacement

Question

I have an old (circa 1920s) bathroom faucet with a compression stem that started to leak unless tightened extremely tightly. When I took out the compression stem to replace it, I found that the screw attaching the seal at the bottom was seized and corroded. Replacing the faucet would be difficult because of limited access - I would need to remove the toilet cistern in order to get in there. So I am looking for a replacement compression stem for this faucet.

I am having a very hard time identifying it and finding a replacement. I have tried several local plumbing supply stores. I sent images to American Brass and American Standard - both told me they could not identify the part as theirs. I also contacted Tapco who is supposed to specialize in things of the sort. They told me they would need to know the product line in order to identify the part. I have no idea how to determine the product line though. How can I better identify this part?

Answer 1

How many splines are on the broach, how long is it and what's its diameter?

As according to faucetpartsplus.com, that's all you need to get started. They have an entire list for spline counts, listing them (below) to specific manufacturers. If you can't figure it out, they suggest sending them a photo, as they're very interested in selling you parts; manufacturers and their employes might not be so inclined. It's more than likely they'd only be able to refer you to who makes or has the replacement parts these days; not their prerogative.

Even though the link goes to an excellent array of pictures and contains most of the leading brands, I implore you to contact your local parts suppliers who are usually more than willing to help you.

You mentioned plumbing suppliers. Those are places you buy pipe and fancy toilets, you need a repair part supply house.

4 point square broach - Milwaukee, Royal Brass, Speakman, Sterling, American standard, Chicago, Concinnity, Gerber, Price Pfister, Symmons, Zurn
8 point broach - Briggs
12 point .335" broach - Crane Dialeze, Michigan Brass, Wolverine.
12 point .375" broach - Arrowhead, Artistic Brass, Harcraft, Glauber, Price Pfister, Scoville, Universal Brass.
12 point .39" broach - Bradley, Elkay, Fisher, Sears, Universal Rundle.
12 point .415" broach - Symmons.
12 point .485" broach - Crane, Symmons.
15 point broach - Santec, Savoy, Wolverine.
16 point .360" broach - Gerber, Sayco.
16 point .370" broach - Acme, American Standard Cadet & Colony, Barnes, Burlington, Central Brass, Concinnity, Eljer, Glauber, Harden, Kohler Trand, Milwaukee, Newport, Phylrich, Royal Brass, Scoville.
16 point .40" broach - Sterling.
17 point broach - American Brass, Mansfield, Midcor, Phoenix, Streamway.
18 point broach - Briggs, Indiana Brass, Union Brass.
20 point .285" broach - Broadway, Concinnity, Danfoss, Dornbracht, Eljer, Grohe, Jado, Kohler, Milwaukee, Paul.
20 point .415" broach - Broadway, Speakman, T & S Brass.
22 point .375" broach - American Standard old 3/8".
22 point .438" broach - American Standard current 7/16".
38 point broach - Import, Pegasus, Glacier Bay.
D Broach - Delta, Milwaukee, Universal Rundle, Valley.
Oval Broach - Delta, Moen, Mixet.
_{faucetpartsplus.com}