The search for the perfect spikes has been the topic of discussion for many decades among those of us who hand-lay our track. Most of the commercial ones available are grossly out of scale, especially for those who model in HO Scale or smaller. Even us O scaler’s find it difficult.
Proto87 Stores has been selling small spikes for the Proto87 modelers for some time. The spikes come in sheets and are milled from half-hard steel. For O Scale’s, you're in luck. Proto87 Stores also makes oversized short as well as long spikes which are suitable for S and O Scales. The short spikes measure 0.120" long by 0.015” and the longer measure approximately 0.225” in length.
I have used them on laying smaller sections of rail up to 8 feet in length as well as on switches and seem to hold the rails in place well. The shorter spikes are great for rail that is laid directly to the ties however, for rail used with tie plates, I like to use the longer spikes.