This is the distance between the front of the blade and the back support bracket. Motor H.P., table support, etc. is not stated in the description and must be evaluated on an individual product feature basis. Two different types that are produced for a scroll saw are pinned, or blank end blades. Pinned blades have a small pin on each end, while blank end blades have none, therefore, requiring blade holders. Blank end blades allow for smaller radiuses to be cut, because with the omission of the pin, the blade can be made much smaller.
Pinned blades are quicker for blade change, because no holders are required.
Only the tension knob on the machine need be adjusted. Pin end blades work equally as well as the blank end blades and are easiest to use by the novice. Whether you use pinned or blank end bIades, proper tension is very important. In both cases, the tension on these blades must be very tight. With the machine disconnected from its power source, you can test this tension.