If Ohio Ordnance doesn't come through with what you need.....this
"might" be another option. Contact Bill Ricca on his web site he list replacement elevating screws....and acknowledges them being a common broken item. The big question would be...."Is it the same screw pitch and size on the 1928 argy tripod"...it might very well be. Go to Ricca's web site and look at the pictures and report back.
1917A1 Tripod Elevating Screw, Ordnance Part Number 6150309. Long known as the weak link in the elevating mechanism, these usually break where the threads meet the squared tube. PHOTO Most tripod parts on the market are from de-mils, often stored outdoors, with pitting. Each is new, still sealed from WWII production. PHOTO $30.00 plus shipping. I have a few assemblies consisting of:
1. Screw Elevating 6150309
2. Bushing, Elevating Screw 5141086
3. Screw, Retaining, Elevating Screw Bushing
4. PHOTO $40.00 plus shipping