Safety oops from the Shop.
I was working on a jig last Saturday evening. This jig would allow me to use a hole saw on the edge of a turning when the center of the hole was outside the turning (like taking a small bite out of a large cookie). These specifics don't matter much, but the physics do.
The hole saw I was using was larger than I usually use, in that this one was 4 inches in diameter. The teeth of the 4 inch hole saw are similar to the teeth of a 6 TPI bandsaw blade. I was using a corded drill motor (3/8 inch DeWalt).
I wanted an angled hole (another important point).
ALWAYS: when using a hole saw make sure the pilot bit remains in the wood. The importance increases with the diameter of the hole saw.
• It is easier to have the contrary happen when trying to drill an angled hole.
• It is easier to have the contrary happen when drilling a larger hole.
ALWAYS: When advancing a hole saw in an existing hole, always start the drill rotating slightly disengaged from the wood and slowly introduce the bit to the wood.
• If the bit starts already in contact with the wood and the diameter is large, the chances are there will be more torque than your grip can manage.
• Just like on your lathe, rotational inertia is greater with larger diameter item, thus the larger diameter item is not likely to stop quickly once its rotating.
What DID happen: From what I have said above you can quickly figure out that bad things happened quickly
. Upon re-starting to deeped an existing hole the drill motor and large bit were torn from my grip, but only after I managed to fully pull the trigger of the variable speed drill, and started only what I can describe as a chaotic dance across my workbench only to return to attack the hand that was using it. The teeth of the saw took a liking to the thick fleshy part of my right palm
. It proceeded up my palm to my wrist before I was able to back out of the “line of fire”. The good news is this is an area of the hand has thick skin. No muscle or nerves were involved.
I have included a photo, not for any added gore factor
, but so that everyone reading this article will understand that even our small hand tools need to be respected and used with care. The photo was taken two days after the event. On the day following the event, I went to the range and sighted in a new handgun (I am right handed), and although this injury was on my right hand and less than 18 hours old, it was not bad enough to stop me from continuing my day-to-day plans ( I also mowed the lawn, but no one wants to show off photos of a lawn
). I finished the jig later that evening and I will use it tonight.
Stay safe everyone!
Tom