video - horrifying home made wood splitters

[Ashful]

I'm an avid woodworker myself but I've never heard of that jointer cutter you're referring to. Could you share with the group please? I also love old tools.

The clamshell cutterhead was a pretty substantial and famous invention, aimed at saving the fingers of many jointer operators. The jointers made prior to WW1 had square cutterheads, which had a tendency to suck your whole hand in, if you were so unlucky as to brush the spinning knives with a finger. The clamshell cutterhead was the first fully round cutterhead, before the invention of the gibs type used today. They basically took a square or "double-D" cutterhead, bolted rounded cheek blocks to either side, and made it round.

The various makers of these new cutterheads flooded the market with gory photos of hands subjected to the old square head (in which half the hand is usually missing), versus those subjected to the newer clamshell designs (in which only the tips of fingers are missing. My grandfather was one of those, and I still have the little 4-inch Champion jointer that took the tips of his presumably-then-teenage fingers, sitting on a display shelf in my basement.

Unfortunately, these clamshell cutterheads tend to throw a blade, from time to time. The blades in mine were 1/4" thick x 2" wide x 16" long, nearly as heavy as a walk-behind lawnmower blade, and razor sharp. There are many stories of them flying out of the cutterhead, spinning somewhere near 5000 RPM, and flying straight thru the shop roof or wall. I know one guy who had one fail on him, went whizzing past his head at a thousand miles an hour, and embedded itself in a timbered roof rafter so deep he had to hang on it to pull it free. After that, I'd always crouch to the floor for a three-count, when turning on my own unit.

As of my last research on this, there was no conclusive proof of the cause of failure in every case, but most suspected stretching of the bolts which clamped the clamshell (and thus the blade) to the cutterhead. There was also very little literature on whether these things failed back in the day, or if we were only today seeing failures due to age, as most observed failures were on machines built well before WW2.

Eventually the clamshell design was replaced by the modern gibs design, which you will find on all jointers today. Even my 1960's Powermatic is a gibs style, so I guess they've been doing them awhile now.

There's a nice little wiki on the design and marketing, here: http://wiki.vintagemachinery.org/Clamshell Heads.ashx

 

[bholler]

The clamshell cutterhead was a pretty substantial and famous invention, aimed at saving the fingers of many jointer operators. The jointers made prior to WW1 had square cutterheads, which had a tendency to suck your whole hand in, if you were so unlucky as to brush the spinning knives with a finger. The clamshell cutterhead was the first fully round cutterhead, before the invention of the gibs type used today. They basically took a square or "double-D" cutterhead, bolted rounded cheek blocks to either side, and made it round.

The various makers of these new cutterheads flooded the market with gory photos of hands subjected to the old square head (in which half the hand is usually missing), versus those subjected to the newer clamshell designs (in which only the tips of fingers are missing. My grandfather was one of those, and I still have the little 4-inch Champion jointer that took the tips of his presumably-then-teenage fingers, sitting on a display shelf in my basement.

Unfortunately, these clamshell cutterheads tend to throw a blade, from time to time. The blades in mine were 1/4" thick x 2" wide x 16" long, nearly as heavy as a walk-behind lawnmower blade, and razor sharp. There are many stories of them flying out of the cutterhead, spinning somewhere near 5000 RPM, and flying straight thru the shop roof or wall. I know one guy who had one fail on him, went whizzing past his head at a thousand miles an hour, and embedded itself in a timbered roof rafter so deep he had to hang on it to pull it free. After that, I'd always crouch to the floor for a three-count, when turning on my own unit.

As of my last research on this, there was no conclusive proof of the cause of failure in every case, but most suspected stretching of the bolts which clamped the clamshell (and thus the blade) to the cutterhead. There was also very little literature on whether these things failed back in the day, or if we were only today seeing failures due to age, as most observed failures were on machines built well before WW2.

Eventually the clamshell design was replaced by the modern gibs design, which you will find on all jointers today. Even my 1960's Powermatic is a gibs style, so I guess they've been doing them awhile now.

There's a nice little wiki on the design and marketing, here: http://wiki.vintagemachinery.org/Clamshell Heads.ashx

I am missing the tip of my ring finger from a jointer. It didn't even hurt at the time.

 

[blades]

newest heads are those sprial insert types . haven't heard of any disaters involving those yet.

 

[bholler]

newest heads are those sprial insert types . haven't heard of any disaters involving those yet.

I had one cutter come of of a spiral head. But it was on a planer so it was contained. The screw broke. Probably over torqued.

 

[Ashful]

newest heads are those sprial insert types . haven't heard of any disaters involving those yet.

All of the modern (as in < 30 years) hobbiest and commercial jointers and planers I see today use replaceable knives, which are as light as foil, compared to older machines. Superbly convenient, and likely a hell of a lot safer, if a knife ever is thrown. The knives on my 16 inch jointer weighed several pounds each, deadly frightening to even consider one of them flying out at you.

I just pulled up the few doc's I had remaining on it (I gave my binder of notes to the guy who bought it from me), and it says I had a 3-1/2" cutterhead spinning at 4000 rpm, so roughly 61 ft/sec. Memory tells me the knives were 16" x 1/4" x 2", so roughly 2.4 lb. each, or kinetic energy around 377 J (if I'm doing all the Imperial to metric conversions right in my head), or about the same as being hit by an old Police issue .38 Special.

 

[SpaceBus]

All of the modern (as in < 30 years) hobbiest and commercial jointers and planers I see today use replaceable knives, which are as light as foil, compared to older machines. Superbly convenient, and likely a hell of a lot safer, if a knife ever is thrown. The knives on my 16 inch jointer weighed several pounds each, deadly frightening to even consider one of them flying out at you.

I just pulled up the few doc's I had remaining on it (I gave my binder of notes to the guy who bought it from me), and it says I had a 3-1/2" cutterhead spinning at 4000 rpm, so roughly 61 ft/sec. Memory tells me the knives were 16" x 1/4" x 2", so roughly 2.4 lb. each, or kinetic energy around 377 J (if I'm doing all the Imperial to metric conversions right in my head), or about the same as being hit by an old Police issue .38 Special.

Your math is good, that's about average for a .38 special.

 

[Mutineer]

Per FirefighterJake above: " .....although we were allowed to run the splitter and to help move and stack firewood...."
Tried that several times with my wife and kids, I was offering to bend the very rigid rules and allow them to stack the wood off the splitter, for some unknown reason they usually demurred.

 

[Caw]

Per FirefighterJake above: " .....although we were allowed to run the splitter and to help move and stack firewood...."
Tried that several times with my wife and kids, I was offering to bend the very rigid rules and allow them to stack the wood off the splitter, for some unknown reason they usually demurred.

When we run the splitter it's a while family effort. We take the time to educate them about power tools/safety and let them participate when able. Two years ago my then 5 year old snuck behind me while I was running the splitter. I was tossing splits into a pile behind me and he ate one right on the top of his head. He was fine but it bled like a stuck pig, needed a stitch, and took 8 hrs to deal with. He knew better and he'll never make that mistake again. I felt terrible but stuff happens. All we as parents can do is educate and give them experience so they are prepared for next time.

 

[Ashful]

When we run the splitter it's a while family effort. We take the time to educate them about power tools/safety and let them participate when able. Two years ago my then 5 year old snuck behind me while I was running the splitter. I was tossing splits into a pile behind me and he ate one right on the top of his head. He was fine but it bled like a stuck pig, needed a stitch, and took 8 hrs to deal with. He knew better and he'll never make that mistake again. I felt terrible but stuff happens. All we as parents can do is educate and give them experience so they are prepared for next time.

Yes and no. My attitudes used to match my perception of yours, until I caught my son (then 2 or 3 years old) poking his finger toward the exposed fan belt and pulley on the generator of my Cub Cadet 123. Why IH ever thought it was a good idea to have a generator with fan belt and cooling fan sticking OUTSIDE the hood of the tractor was a good idea, I'll never understand, I guess they just didn't value human life as much in 1963. In any case, I was ten feet away, realizing just a few seconds too late that I was a little too far away to stop him, if things had gone just a bit differently. Thankfully, he stopped an inch short of putting his finger into the pulley when I yelled, an unusually attentive and obedient kid, who was startled by a very rare yell from me.

It'd be tough explaining to him or myself, why he was missing several fingers, if we hadn't been so lucky that day. I didn't go as far as putting safety covers on our electrical receptacles, or any of the other extreme kid-proofing I see some parents put themselves through, but I also don't invite them to join me when running chainsaws and splitters. Too many things can go wrong, even with other adults around, let alone an ignorant kid.

That reminds me of another story, when I dropped a tree on my cutting partner's 45 year old son. In that case, it was his own fault, but I'll tell that one another day. He survived, but not without some serious bruising.

 

[Caw]

I respect the opinion of parents who doesn't want their kids near tools at all but to me there is a line at which point you allow them to participate and when you don't. For example, I don't allow my kids to help or even be nearby when I'm using a chainsaw. It's simply too dangerous. However I will teach/allow them how to use a drill, palm sander, drive the tractor, take apart engines, split wood, and use the splitter etc with me depending how old they are at the time. I want them to have a healthy fear/respect for tools and have the confidence to use them properly. I also feel like they are less likely to go try and use something on their own not knowing what to do because they participate with me and if God forbid they did try it they'd at least have an idea what's going on.

The one tool I can pretty safely say I'll never allow anyone to use is my chainsaw. Kids, wife, friends, anyone, with the exception of my father. He's an expert and if he asked I'd let him use it but he has like 3 so I don't anticipate that happening. It's just way too dangerous and when it goes wrong it usually goes catastrophically wrong. I'll come over and help if people need something cut versus loan out the saw.

 

[bigealta]

I'll come over and help if people need something cut versus loan out the saw.

Me too.

 

[fbelec]

yes that guy with the big flywheel in the first video using that is a er visit waiting to happen