An Expensive Friday the 13th Lesson...

[Marty Tippin]

I took the afternoon off from my regular job and was enjoying working on an end-grain cutting board. After cutting the initial glue-up into 1-5/8" wide x 7/8" thick "slices" (that will eventually get turned on edge and become the cutting board), my wife asks if I can make the slices a little bit thinner (from 7/8" to 3/4" thick) to improve the look of the final end-grain board. Sure, shouldn't be a problem.

So, I fired up the Grizzly G0453PX planer with spiral cutterhead, dialed up 3/4" thickness on the DRO and sent a leftover test "slice", about 1-5/8" wide by 15" long by 7/8" thick, through the planer.

Best I can tell, the piece made it most of the way through the planer before the strip broke apart near one end, with the roughly cube-shaped leftover piece flipping sideways (I guess), jamming against the cutterhead and shattering one (or several) of the carbide inserts. The shattered pieces of carbide whirring around inside the planer then started a chain reaction that was pretty spectacular to hear and sent me running for cover. I eventually was able to cut the power and start to assess the damage.

Not good.

In all, I now have 32 shattered, cracked or nicked carbide inserts, damage to an equal number of the Torx screws that hold the inserts in place, and a completely mangled chip breaker.

And to top it off, the cutter head itself has numerous gouges and gashes from the bits of carbide flying around inside - and if I'm not able to clean up the gouges in the area where the individual cutter inserts register against the cutterhead, I will essentially have a junk planer - if the inserts don't register cleanly against the cutterhead, it will be impossible to get an even cut from the planer. And a new cutterhead costs almost as much as a new planer.

I haven't completely disassembled the machine yet, but I fully expect to find more damage inside.

My mistakes, as I realized just about the time the clatter started, include (at minimum):

* I was attempting to plane with the grain parallel to the cutterhead instead of perpendicular as you would normally do.
* Compounding the problem was my foolish decision to take a 1/8" deep cut in a single pass.
* And to top things off, I had not fired up the dust collector so none of the shattered bits was being sucked out of the machine. Don't know if that would have minimized the damage, but it sure would have helped (at least until the carbide bits hit the impeller on the dust collector...)

Think maybe I'll stay out of the shop on future Friday the 13th's... :rolleyes:

Here are a few photos.
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[Ken Fitzgerald]

Oh man......!

I am glad you weren't hurt!

[John Schweikert]

That's terrible. I am amazed at how much damage resulted. Can't say I have ever sent wood through a jointer or planer with grain parallel to the head.

Don't beat yourself up though. Crap happens and we just have to fix things and move on. Take a break and start fresh tomorrow. A clear head always helps.

[Jesse Busenitz]

Oh man, well at least you weren't hurt! That's always a big plus. I had a friend who did about the same thing just with a slice of tree trunk.... blew out several of the carbide teeth and slammed the chunk into his hand. Hope you're able to get it running again, as those things cut so smooth and quiet when you use them right.:-)

[Peter Quinn]

Oh no, that is a nightmare. Sorry for your loss, very glad you weren't injured. Sucks about the planer. Probably clean up fine with a little fine every and some new chips and chip breaker. Did the glue joint let go or did the wood break off?

[Marty Tippin]

Did the glue joint let go or did the wood break off?

No, it broke right in the middle of the last 2" segment. Looking at it now, I see the piece that broke was an end cut from the original board and it seems likely there was some end grain checking that I didn't notice.

[Max Neu]

Wow,that sucks!Tell your wife she owes you a new planer,it's all her fault. J/K :)

[Rod Sheridan]

Glad to hear you are OK, you can always repair machines, people are more difficult..........Rod.

[Randy Red Bemont]

Yes glad you were able to get out of the way safely. Those pictures are painful to look at!!

Red

[Matt Day]

Oh boy! Complete :-(
Hard to look at the pics. Glad you weren't hurt though.

[Earl McLain]

I've heard 1 carbide insert break--it's a scary sound grinding and banging. I can't imagine the sound of 32 going off!! Glad you're okay.
earl

[Dave Zellers]

I will also join the chorus and say I'm glad and it is very good that you weren't hurt. Carbide inserts flying around can't be anything but dangerous. Like bullet dangerous.

The 1/8" cut was the real problem. I know that you already know that.

But I'm not sure the Friday the 13th meme is the story here. You were lucky, not unlucky. Very lucky to escape unharmed.

Been there. I have a shattered plastic dust fitting prominently displayed right behind my radial arm saw as a reminder of my close call.

When you're given a pass like this it's important that you acknowledge it and never forget it. In my incident, I fully expected to look down at my hand and see blood everywhere and 1 or 2 fingers missing. Instead, my fingers were just numb. I mean, completely numb. That's why I expected to see them lying on the table. I actually enjoy looking at that shattered piece- I embrace the second chance I've been given.

I'll be surprised if your planer isn't toast. Save a couple of the mangled carbide inserts and display them close to your new planer so you never forget.

[Rich Riddle]

Sorry to hear about your bad fortune. It's never good when tools get damaged.

[David Delo]

Like everyone else has said, glad you made it out unharmed. Those are some nasty looking pictures.

[James Nugnes]

Thankful nothing came your way. Wondering if you ended up cutting the power at the circuit breaker to avoid getting near the machine while it was manufacturing shrapnel or was there another switch you could get to in order to cut the power?

[Bill Orbine]

Ouch! Ouch! Ouch! That is nasty! Glad you are safe!

Thanks for sharing this with us. There's a lesson learned for you and all of us! The do's and don'ts . However, I wonder......... if this could have been avoided with a back-up board behind the end grained piece to prevent the blow-out?

[Ole Anderson]

Friday the 13th huh? Boy that got ugly in a hurry. Sorry about your loss man.

[Chuck Hart]

Oh man I cringed when I saw the pictures. There is nothing that makes you feel worse than know you coulda, shoulda, woulda...It's a good thing you were not hurt. In that sense you were lucky. A hard lesson I hope it looks worse than it really is and you can fix it easily.

[Wade Lippman]

I've got one of those and share your grief.
Back when I had a dewalt I make an endgrain cutting board, and using the lightest cut nearly tore it apart. I am not surprised 1/8" did. But I am surprised it trashed the machine so badly.

But then again I wasn't aware it was Friday the thirteenth. I don't believe in such things, but if I did, it would explain a lot. I had a terrible day. Not as bad as yours, except for getting injured or a letter from the IRS, there aren't many days worse than yours. Matter of fact I did get a letter from the NY Tax Department. Apparently my town charged over the legal limit and NY refunded $432. Of course I still have to pay tax on it, but it is still a pleasant unexpected thing. So I guess the day wasn't all bad.

[Mike Schuch]

Was the 1/8" cut the problem?

I have a very similar planer, the exact same design with blades instead of the spiral cutter head. I have occasionally, inadvertently tried to take too big of a bite out of something I was planing and the stock simply will not feed through my planer.

I have never heard of running stock through a planer with the grain parallel to the cutter head instead of perpendicular to the cutter head... but it is still just wood. Is this really that much different than some really wavy funky grain that the spiral cutter heads are supposed to be so good at. Is this even as bad as hitting an inadvertent knot?

I really wonder if the root cause of the incident was a loose cutter? If a cutter was loose and worked its out enough that the cutter finally broke I could see the broken piece breaking a chunk of the stock off as it flew around and contacted the stock?

Yes the bite was too big and I am not sure about the grain direction but I would really expect the planer to be able to plow through the thick cut without grenading. I wouldn't expect the planer to let a user feed stock and take a bigger bite than the planer can safely handle. I know my planer won't. I also can't visualize how running the grain in the wrong direction would cause this issue. My hunch is this incident was due to a loose cutter. To me I can see how a loose cutter could manifest itself exactly as described.

How old is the planer? How many hours do you have on it? Have you made any adjustments to the cutters recently? Have you ever checked the torque on the bolts retaining the cutters? Is checking the torque on the cutters even a recommended maintenance step? I wonder if there are many more incidents like this one.

P.S. I am glad to hear you walked away without any harm.

[Matt Day]

Mike,
I think the error was grain direction and glue joints on a small piece. Including a deep cut equalled kaboom.

It hurts to see such a destroyed cutter head, especially when I want one so bad!

Hopefully it can be fixed with "just" a new chip deflector and cutter head.

[Kevin Jenness]

I would agree that running the workpiece in that orientation caused the problem. A safer approach would be to reduce the thickness at the table or bandsaw. It could have been a real disaster rather than an expensive mishap. Good luck with repairing the machine.

[Phil Thien]

Sorry for your misfortune, glad you're okay!

[glenn bradley]

Glad you weren't hurt. I agree that you were lucky versus unlucky although I am sure it doesn't feel that way ;-( Although a whole new cutterhead is $1000 less than a new planer, it is still no minor thing. I hope any additional damage is insignificant.

If I am reading right, this was one strip of segments from the strips being prepared for a "checkerboard" type cutting board. Although glued in a strip like train cars, the individual pieces lack a lot of structural support and can be delicate. I have had pieces break as you discuss simply by tossing them towards the scrap bin and hitting the floor instead. They don't break at the glue line, they break along the grain.

[Raymond Fries]

Ouch! :eek:

Glad you are OK and I hope it can be repaired.

[Brian Holcombe]

Was the 1/8" cut the problem?

I have a very similar planer, the exact same design with blades instead of the spiral cutter head. I have occasionally, inadvertently tried to take too big of a bite out of something I was planing and the stock simply will not feed through my planer.

I have never heard of running stock through a planer with the grain parallel to the cutter head instead of perpendicular to the cutter head... but it is still just wood. Is this really that much different than some really wavy funky grain that the spiral cutter heads are supposed to be so good at. Is this even as bad as hitting an inadvertent knot?

I really wonder if the root cause of the incident was a loose cutter? If a cutter was loose and worked its out enough that the cutter finally broke I could see the broken piece breaking a chunk of the stock off as it flew around and contacted the stock?

Yes the bite was too big and I am not sure about the grain direction but I would really expect the planer to be able to plow through the thick cut without grenading. I wouldn't expect the planer to let a user feed stock and take a bigger bite than the planer can safely handle. I know my planer won't. I also can't visualize how running the grain in the wrong direction would cause this issue. My hunch is this incident was due to a loose cutter. To me I can see how a loose cutter could manifest itself exactly as described.

How old is the planer? How many hours do you have on it? Have you made any adjustments to the cutters recently? Have you ever checked the torque on the bolts retaining the cutters? Is checking the torque on the cutters even a recommended maintenance step? I wonder if there are many more incidents like this one.

P.S. I am glad to hear you walked away without any harm.

Mike, wood splits along the grain. If you have ever used a hand plane to cut across the grain you'll notice the shavings break into small slivers and often times the end of the cut will split off.

The wood very likely began to split apart in this cut and some of the split pieces likely changed direction jamming between the cutter and another part.

[Marty Tippin]

I managed to pull the cutter head today and checked all the seats for the cutter inserts. Used a small grinder bit in the Dremel to knock down any burrs that would interfere with the mating between the head and insert (and there were dozens of them) and think I'll be ok once I get some new inserts. Grizzly, of course, doesn't have any and won't have them until May so I'm checking a few other leads and hoping I can find some that are an exact match.

Also got the chip breaker out and was amazed at how mangled it was. New one is about $17 from Grizzly. I'll also have to order 30 new torx screws as the existing ones were badly mangled by all the shrapnel.

Also found that the bed below the cutter is badly pitted from all the flying debris. Should be able to clean that up with a little Emory cloth.

Hopefully I'll be back in business in a week or two.

[Matt Day]

I'm sure you could find a very cheap used standard knife head if you really had too, or someone here who upgraded would probably lend you one if you needed it.
Glad to hear you're making some progress.

[ian maybury]

Scary just how much damage the bits of carbide did - you might imagine that they would have been spit out. Maybe a block of wood broke free (a cross grain break as here would take very little force), and maybe it then jammed between an insert and something solid like the end of the table. Perhaps the resulting broken insert(s) then did something similar. Carbide is clearly pretty brittle/prone to shattering under high energy high speed impacts.....

[Peter Kelly]

Time to switch to a Tersa head :)

[Larry Edgerton]

Time to switch to a Tersa head :)

Thats what I have now. I had a similar experiance on a Powermatic 180 with a conventional head. I was planing Jatoba and all of a sudden all heck broke loose. Near as I can tell it shattered a bearing, which allowed the cutter head to flop around, snapping the shaft at the outboard bearing and letting the still running cutterhead flop around till I made it to the panel. Planer was a total loss.

But on the bright side it gave me a reason to buy my SCM with a Tersa, and life got a little better with that purchase.

Is your head a Byrd or a knockoff? If it is a Byrd I would send it in to have it checked, not sure what you could do with a knockoff.

Hey, if it makes you feel better my pressure switch[outside] froze today and my basement flooded when the WH pressure relief blew, and with a high of -2 today fixing the switch outside will be real fun. See, its not so bad.......

[julian abram]

Thanks for sharing this lesson, glad you were not hurt. No trip to ER is a good day!

[Thomas O Jones Jr]

Don't know if this helps; as the result of a problem with my planer, I put on/off switches just above both my 220 and 120 receptacles where my equipment is plugged in.

[John Sanford]

Glad you weren't hurt. I must admit, I kinda would like to have a GoPro in there to catch your reaction. Duck and cover when machinery decides to discombobulate can be amusing to watch. When nobody gets hurt.

I really wasn't aware of this particular risk with planers, although it makes sense. I'm eventually going to be making some end grain cutting boards, I'll be sure to do some more extensive research on the machining aspects before I embark. So, I thank you for sharing your mishap with the rest of us. I'm a big fan of second hand wisdom, i.e. learning from someone else's mistakes.

[Chris Hachet]

So glad you were not hurt!

[Marty Tippin]

As a final update, I wanted to report that I was able to get the planet back together, with the help of a new chip breaker, 32 new carbide insert knives and 30 new Torx head screws. I rotated all the unbroken inserts to a fresh edge while I had it all apart and after going through and setting everything up, my initial impression is that the planet is cutting better than it did previously with what were apparently some dull blades.

I ended up buying the replacement carbide inserts from Oella Saw and Tool www.oellasawandtool.com , as they were the only company I could find that sold exact replacements for the non-standard cutters on the Grizzly spiral head. For some stupid reason, Gizzly chose to use inserts that are 14.17mm square rather than the standard 14mm square.

In the final analysis, I think it was both the depth of cut and not having the dust collection running that caused the meltdown to get so out of control - with dust collection, I think more carbide knife shards souls have been sucked out before they did as much damage.

[Frank Martin]

So glad you were not hurt. If you have not already you may want to replace all of the carbide inserts not just those that were obviously damaged in case there are some damaged ones without visible signs.

[Dave Zellers]

For fixing the planet, I'd say you got off pretty cheaply.

And THANK YOU by the way...;)