I am no expert but I think you need what I call a spring compressor. I have made three fo them out of wood and a long one out of some 1/4 inch plate. You have to compress the spring with the hammer in place while you put the holding pin in. I use a vise with led jaw inserts and get by.
You are in Arlington. I am in Mesquite. Call me at 972-681-4240
Regards, Gordon


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