Riving Knife Holder modifications

Preamble : I don't want to write another list of what each woodworker should know in order to work safely. Everybody may find what matters using a search engine with key words "woodworking safety". Albeit all these articles talk to the others and I would have liked to find someone writing : "for my own safety I try to..." which means many more people convey a standard point of view about safety without wondering anything. I avoid these kind of topic that lead to nothing most of time. On the other hand I get involved in every exchange that tend to explain why something would be unsafe et try to find out a better way. It's all about mental attitude and the last one requires the point of view to be argued. Nothing good nothing bad but keeping open minded.WhyDi
Although the riving knife don't line up properly with the saw blade as well as stand parallel to that one, the specific design of the knife holder allows some play for the component to swivel and keep in alignment when ripping or cross cutting. It works well in conjunction with my former hanged guard but the new design of my shop-made overhead saw guard which is close to the origin one demands to improve accuracy but also find out an easier way of locking and releasing the nut. Until now the spanner allows blade and riving knife shifts without any adjustment as you may see in the document that describes how I made my previous riving knives. There was no drawback as both riving knife and saw blade were replaced together.

Origin Holder


The new holder needs a fine adjusting mechanism that allows the knife to be accurately lined up but also kept parallel with the saw blade. The two-position riving knives require a stop gauge so that they can be switched from the low to the high location and conversely without adjustment. That last feature demands a lock and release device without tool because of the riving knife could be shifted whereas the saw blade may not. That handling has to be quicly performed as it may turn extremely annoying. The good news is the riving knife can now be removed and replaced without tool. Of course that device should not get in the way tilting the blade at a forty five degrees angle.

Overview


Due to the one knife matching one diameter choice the lock mechanism doesn't have to slide along its groove. That is the first step aiming the switch from the low to the high location without any adjustment. The second one is to build a stop gauge the riving knife can sit on. Made out of a spare steel angle the horizontal bracket holds a threaded rod adjusted and locked with two nuts. The drawing shows a bolt screwed in a threaded hole and a counter nut. The alignment and parallelism between the saw blade and the knife are performed one for all, at least I wish. Four threaded holes in the cast aluminium housing accommodate four screws with their counter nut. They guide the rear flange and enable fine adjustments in all directions. The two bottom ones also clamp the stop gauge. As for the lock mechanism I used the existing nut and added a lever cut out from a scrap steel angle. I drilled one millimetre less than the nut diameter then squeezed the assembly in a vice and completed with some hammer strokes. No welding by the way.

Details