My wife, who loves me more than I deserve, let me get a new lathe a few months ago. A Powermatic 3520b.
I love this lathe, especially better than the old Craftsman tube-types I had.
Anyway, I’ve flung a few pieces of wood off the lathes over the past 40+ years, and I’m always conscious to keep my face shield/mask/goggles in place (unless I forget in the heat of the moment.)
But the safety cage just looked better holding a couple of worklights than down in its intended position.
Sooo A couple of days ago I started turning a little blank from some scraps of Indian dontknow I use for most of my smaller works. It was square so I thought I’d chuck it up and try something like a winged bowl, just to get used to working near spinning square corners.
The piece is only about 8 inches across, two larger pieces of one wood with a smaller “center” piece in another.
It only weighed a few ounces, so after I drilled a 2” recess (using a forstner bit) for the chuck I mounted it and did a test spin.
Everything looked good so I cranked the speed knob to the right and brought the RPMs up to about 1300.
I finished turning and sanding the top and decided to work the bottom without remounting it, i.e. from the headstock side.
(Hmmm your thinking…is this a good idea.)
I made a few passes on the backside when WHACK…a reddish/yellow blur flew off the chuck, hit the toolrest, (somewhere in here it broke into two parts), whacked my big worklight (mounted on a plywood backstop about 2 feet behind the lathe) and bounced up (and down….[two parts, remember]) into the wood stack behind the lathe.
I knew I wasn’t hit (not this time at least, but that’s another story) so I shut everything down and did a quick survey of the damages.
I was ok (see above.)
Lathe was ok (take more than a few ounces of wood to hurt that.)
Safety cage was ok….it was safely flipped back out of the way.
Worklight wasn’t….the bulb was broken (a nice compact florescent one too) which wasn’t a surprise.
But, just beside what was left of the bulb there was a tear, in the aluminum reflector, about 3/8 by 1 1/4 inches. Now the reflector isn’t a heavy duty thing…but it’s WAY thicker than a soft drink can.
I was duly impressed by the damage from that little piece of wood.
So here’s a little math for you…
8 inch diameter (corner to corner) equals 25 inch circumference.
1300 RPM of a 25 inch circumference gives 32,500 inches per minute.
Divide that by 12 (inches per foot) and you have 2,700 feet per minute, or 45 feet per second.
I don’t know about you folks, but I can’t dodge ANYTHING going 45 feet per second when my face is about 10 inches away.
So, I took the lights off the safety cage and will at least use it until anything I’m turning doesn’t have any sharp corners left.
As a side note, the blank broke at a glue joint, very unusual I know, but I don’t think it was the cause of the dismount. (In retrospect I am habitually too stingy on glue….that will be different in the future.)
Because I used a forstner bit to drill the mounting hole there was no dovetail for the chuck to hold into.
When I started working from the headstock side I think I pushed the piece off.
A simple tailstock block would have stopped that…typical me…get in a hurry and forget the common sense.
But this block isn’t going to beat me….it’s already glued back together, with a LOT of glue, and is chucked back on the lathe, where I’ll finish it under the watchful gaze of an in-place safety shield.
Here are some photos of the event.
The recovered blank, split at the joint.
The worklight, bulb shattered and spun 90 degrees by the impact of a few ounces of wood traveling 45 feet per second.
When I turned the worklight back around the hole was visible.
Closeup of the hole.
The aluminum tore part of the corner of the wood off as it spun out, it was easy to match the corner to the hole.
The view as it would have been just before the event….working from behind the piece, with no tailstock block to hold it on….bad Pete, bad Pete.
-- Pete, "It isn't broken, you just aren't using it right."