A nail driven as a toenail is driven in it at an angle through the surface it penetrates. In framing studs, the toenail method of nailing is often used at the top or bottom. There is an art to the toenail, since if done incorrectly it can split the wood piece and become ineffective.
The Toenail on Finished Wood Pieces
If there is a toenail done to a more finished piece of wood, such as on staircase balusters or spindles, a special nail and tools are used. In this case, finished nails would be used and care must be taken in doing the toenail, so as not to dent the wood spindle with the hammer.
The toenail would be done in such a way as to penetrate the wood piece partially, leaving a small amount of the nail protruding. The toenail at that point would be finished with the use of a nail set, driving the finished nail cleanly into the wood spindle. At that point, wood filler can be used on the small remaining hole made by the toenail method of attachment.