I found an old Lachmiller press with a nice long throw for my new 470 Nitro, but where do I find a shellholder which will fit?

Try CH-4D:

http://www.ch4d.com/

Herters Shell Holder Adapter
Fits all Herters & Lachmiller presses which retain the shell holder with one or two screws, adapting them to standard snap-in shell holders such as our No. 408.

Order No. 409190: $ 17.50



New Item: Herters Shell Holder Adapter for threaded ram presses

Order No. 409195: $ 36.75

Note: Inspect your press before ordering, Less than 5% of Herter's presses used threaded shellholders.

Huntington says to order the .470 by caliber. I don't know if there is another that will also fit.
The Lachmiller/Herter shellholder adapter eats a little of the window, and may limit the length of the load.
Cheers from Darkest California,
Ross