How to pack speakers w/out original boxes?


Help! I need advice on how to pack speakers,[Dahlquist 9c's], that don't have their original boxes. Speaker dimensions, Height: 23in., Width: 15in., Depth.: 12in.. Does anyone sell boxes big enough to ship these? They weigh 55lbs. each. What other packing materials should I use to protect them? Thank you in advance for your experienced Audiogoner wisdom! I'll take any advice that you all can give me.

Dave
128x128comedychief
Thank you for all of your great advice. I really appreciate it. I feel much more confident, that my speakers will arrive safely at their destination. Thanks again.

Dave
Forgot to mention re0infrcing the corners. Sfar's method sounds like it should do the trick; for very heavy items, perhaps use 1/4" plywood.
I'd recommend a piece of plywood in the bottom of the carton, and perhaps attaching it to the speaker underneath with screws. That's what I'm thinking anyway. Further.. build a mini-pallet for each which will force the shipper to use a hand truck. Please comment on any downside to this idea.
We ship aerospace parts. No matter what box you use buy four of them. Cut two of the boxes up and line the assembled boxes with the cut up cardboard pieces. You will in essence be building a double walled box. Much better and stronger. Double tape all the sides/corners of the assembled boxes on the outside.
Using the methods noted above, you should be in good shape.
Good luck, John