Cheap planer lesson/sore thumbs...

[Ed Ditto]

Had a near miss this morning while making a batch of the ubiquitous walnut/cherry/maple end grain Xmas cutting boards...and thought I'd share the lesson learned, as well as a solution.

I was doing the initial thickness planing with my Makita 2012NB, being careful to take tiny little bites so the planer wouldn't bog down. But the fourth board I fed through had a vertically-oriented "slice" that stood a hair taller than the others, and as luck would have it, it was second from the front in the direction I was feeding.

So picture it: the rollers accept the first lower "slice" and carry the board into the planer. The lead blade abruptly come into contact with the second higher "slice." It shatters. The second blade slaps the face of the slice but doesn't shatter, thereby propelling the board back toward me at Mach 9...jamming the hell out of both my thumbs in the process. Worse than any basketball ever did, and both of them at once.

I dance around the shop cursing Santa Claus until sanity resumes and I think to shut the planer and dust collector off. Now I'm typing an accident report and every time I hit the space bar I wince. Fun, fun. Lucky not to have two broken thumbs, or a cutting board embedded in my abdomen.

So here's the solution I thought of. First, before thickness planing an end-grain glue-up it's worth taking a few passes over the board with a hand planer to reduce the board to close to uniform thickness. And 2nd, when thickness planing an end-grain glue-up that's close to the width of the planer, it's a good idea to use a push stick from off to one side.

Anybody see any other ways to make this a safer operation?

I'll share one other cutting board tip with you, since 'tis the season and all. If you're passing end-grain glue-ups through a thickness planer you have to deal with tearout on the trailing edge.

You could go ahead and add a sacrificial piece to the trailing edge...but I've found that if you go ahead and round over the trailing edge, this has the effect of making that edge fall away from the planer blade before the very end. And that prevents tearout. Then you re-round that edge during your final finishing.

OK...now I gotta go find some ice...and order some new planer blades.

Ed

[Keith Beck]

First off, no fair using big words like "ubiquitous" on us!

As for the cutting board vs. planer, BTDT! Luckily I wasn't standing behind the planer at the time and no serious damage to the planer. But, it did result in a cutting board that had to end up several inches short than planned.

I've learned my lesson, no more end grain cutting boards through the planer. I've now got a Jet drum sander, so I use that instead. If I didn't, I'd resort to a belt sander and handplane.

Keith

[Art Mann]

Thickness planers were not designed to cut across the grain. Some people do it and get away with it for a while, but kick-back and knife damage (at least) is often the result. If I were building end grain cutting boards, I would take them to a cabinet shop and have them smoothed on a drum sander.

[Mike Marcade]

I have heard a few stories on the creek about surface planing end grain glue-ups. The one thing they all have in common is a bad kick-back at the end of the story.

I concur with Art.

[Gary Keedwell]

I have heard a few stories on the creek about surface planing end grain glue-ups. The one thing they all have in common is a bad kick-back at the end of the story.

I concur with Art.

That is absolutely false. I have done end grain cutting boards without incident and have heard from numerous people who, also, have not had any problems.
I have also watched at least 2 videos from reputable woodworkers who have done many end-grain cutting boards without incident.
Gary

[Mike Marcade]

That is absolutely false. I have done end grain cutting boards without incident and have heard from numerous people who, also, have not had any problems.
I have also watched at least 2 videos from reputable woodworkers who have done many end-grain cutting boards without incident.
Gary

All I said was about the few stories I have heard personally. I guess you have heard some different ones. Thats all good, but it doesn't make mine false does it?

[Brian Weick]

I have planed several top grain projects through my planer and have had absolutely no problem - it treats it like it was cake going through there- Although I have a Jet 15" planer - that machine eats wood- It may be your planer that can't handle the cross grain planning, sorry to say. I have a Ridged 13"planer as well and that does not like cross grain planing - I did it a few times, smaller projects - fine, but a few larger diameter projects- dulls the blades- and it completed it but it was straining just to finish the plane. It is great for planing "with the grain" but I wouldn't do to much cross grain on it- that goes to the 220v 15" Jet.
My 2 cents
Brian

[Keith Beck]

That is absolutely false. I have done end grain cutting boards without incident and have heard from numerous people who, also, have not had any problems.
I have also watched at least 2 videos from reputable woodworkers who have done many end-grain cutting boards without incident.
Gary

Gary,

I too had made several end-grain boards without incident before I had one "blow up" on me. I think it's more a matter of "when" it's going to happen instead of "if" it's going to happen. With the amount of damage an exploding cutting board can do to your planer, I figure why take the risk?

Keith

[Gary Herrmann]

Out of curiousity, were the incidents planing cutting boards in lunchbox planers or all kinds of models? I'm just wondering if the floor models can grunt through it. Altho I may just pull out a handplane when I get around to making one.

[Eddie Darby]

Belt sander, or Neanderthal it with a real good Bevel Up Low Angle Smoothing hand plane.

[Ed Ditto]

This was a lunchbox planer, a 12" capacity one.

[Art Mann]

That is absolutely false. I have done end grain cutting boards without incident and have heard from numerous people who, also, have not had any problems.
I have also watched at least 2 videos from reputable woodworkers who have done many end-grain cutting boards without incident.
Gary

Read through some owner's manuals of various planers and see what they have to say. Just because you have used a planer in this way without incident doesn't mean it is the right thing to do. There have been entirely too many reports on this board and Woodnet of kick-backs and broken blades doing this very thing to just pass it off as a fluke.

[Walt Caza]

Sorry about your thumbs Ed,
All lessons cost, some more than others...thanks for sharing your
experience. Maybe someone else can learn the lesson that you payed for?

There has been no response to the question of larger planers handling
endgrain better than lunchbox models. Anyone care to weigh in on that?

Also, I have a fresh 15" planer, 3hp 240volt with Byrd carbide head.
(stealth gloat I guess) (I know...no pic, didn't happen)
Now I am wondering if the Shelix can handle a little endgrain?
One of the major benefits they flaunt is less tear-out...
does that suggest the inserts might do ok with endgrain cutting boards?!?

Inquiring minds wanna know....(but I am chicken to hurt my new machine!)
anyone care to share?
Walt

[Ed Ditto]

Here's an update: I got the new planer blades via overnight DHL and installed them, and damned if I didn't have another kickback inside of ten minutes.

I was crafty this time...stood off to one side and used a push stick, and good thing too...the board shot across my shop like a checkerboard cannonball. BAM! Gone.

Sez I: "This ain't right." I unplugged the beast and tore into it to check the works. Turns out what I originally thought was going on wasn't the problem at all...or at least, wasn't the whole explanation.

I found on close inspection that one of the set plates was warped. The Makita 2012B has these little six-screw set plates about an inch by twelve inches that lock the planer blades into the drum, and one of them had maybe two degrees of arc in it for a length of an inch and a half.

What that was doing was allowing the blade to flex slightly, thereby scooping wood fibers out of the top of the workpiece and trapping them between the blade and the drum. Those fibers served to shim the blade out far enough to create a bulge of about 1/32nd or so, which was PLENTY enough to bat the workpiece back out of the machine.

I got this unit three months ago and I've run a couple of hundred board feet face-grain and edge-grain through it, no trouble. So I figure planing end-grain somehow warped the set plate...unless it's possible that the warped set plate was a manufacturing defect that needed vertically-oriented wood fibers to reveal itself.

Search me what the answer is...I can see arguments both ways. At any rate, I'll be asking Makita tech support those questions first thing in the morning.

Ed

[Greg Peterson]

Well, whether or not end grain cutting boards can go through a planer can be argued till the cows come home.

Apparently some folks have no problem using the thickness planer for this process. Were I so fortunate to live such a charmed life I to might throw caution to the wind and engage in said activity. However, with other methods available that lack the potential for injury or equipment damage, I see little reason to tempt the wood gods, capricious as they appear to be.