Mr. Harrell has a great interview published in Collector's Weekly, and I'll link it here. You can get more information there than I could give you by cutting and pasting together his writings and information.
If you enjoy learning about fine, old guitars, you'll enjoy his amazing website. I'll just leave you with a few photos of some interesting instruments and parts.
|1956 Gibson Lap Steel Guitar|
|Vintage Martin D-28|
|Interesting interior shot of a Martin guitar|
|Bridge from a 1885 Martin Guitar|