Possible Clues:

• By this, sir, one might get to the end of this device
• Useful item
• One's clever enough to get an egg with a TD
• Gee! That's how Father would get up to get to the end of the device
• By this, Sir, get to be useful
• Mechanical contrivance
• Rush around and secure a useful appliance
• Go and fetch device
• Good advertisement? Then obtain the gismo!
• A TD is handy with an egg