I have some advice for those who are on the quest to be able to make fire consistently using the hand drill method.
Firstly, materials. Material choice is critical for success with the hand-drill. It's not like the bow drill where any woods will do. For consistent success, you'll want the best possible materials.
For the drill, dead woody flowering stalks are superior to anything else. Elder is a second-rate drill in my experience, because it's too hard. You want the softest woods possible for BOTH the drill and hearth and woody flowering stalks are softer. Make sure to collect the stems in autumn or early winter before they become too rotten to use. There are many, many options, far more than is commonly believed. So far I have had great success with the dead flowering stalks of great mullein, burdock, teasel, ragwort and common sorrel but there are many more that will likely work. Other ones to try are mugwort, dog rose, bramble, sow thistle, thistle (cirsium sp.), willowherb species etc.
For the hearth, again, it's about using the materials with the lowest specific gravity, the ones that are very soft and easy to carve. Many people ignore the possibility of using roots. Well, it just so turns out that the wood from roots generally makes for superior hearth boards to the wood from the above-ground branches from the same trees. The wood in the roots isn't as dense as the branch-wood and is noticeably more flexible and easier to carve, so it definitely has different properties. Search for roots in steep banks or where trees have been uprooted and fallen over. I have had great success with willow root (10 second embers) and spruce root works great too. Alder root is another good one. For above-ground materials, lime is excellent, poplar is fairly good, willow is ok.
Technique. My advice is to learn the floating technique. It eliminates the need for longer drills and makes for more relaxed drilling with a more constant rhythm. Apply a decent amount of pressure and speed from the very beginning to prevent the hole and drill glazing over. Eventually, there will be a sudden increase in resistance to the spinning of the drill and a change in the sound the drill makes. This is the point at which you begin to see smoke and powder starts falling down into notch. Maintain this steady pace until the notch is filled with a decent amount of powder and then speed up to full pace and increase downward pressure greatly and drill like this for as long as it takes to produce the ember ( or until you're exhausted!).
It is a long journey and it took me several months of dedicated practice to get to the point where I feel I really have the skill under my belt, so practice regularly and don't give up because it's all worth it in the end! Just take everything I've written in this thread on board, combine that knowledge and the material choices I've mentioned, with lots of practice over many weeks and you should start seeing results. Peace