I wouldn't use hacksaw balde; though producing as many sparks as it does (fine for cotton wool), it does not direct them and concentrate them like a straight 90degree edge, which enables you to light much more difficult materials like Maya resin wood, clematis fibres and grasses. As well, it wares down the flint more quickly. Maybe the striker is just too complicated for such a simple device, you could try getting a 90degree edge on the new version striker or find a durable piece of metal which you can put one on.
Hope that helps
Ian