Grizzly planer and jointer spiral cutter head bolts

[glenn bradley]

Big question, why are they breaking off? This is unacceptable. I'm thinking of buying a new planer with a spiral head, but if I have to pull out a broken bolt every time I need to replace or rotate a cutter...........

Everyone/anyone else have this problem with Grizzly?

I haven't had any issues on my G0490X.

I believe this is just a case of someone wanting to be prepared. I have rotated the 40 inserts on my jointer a couple of times and the 70-odd on my planer once. Never broke a bolt or an insert. There was a wave of bad Byrd head QA reports that I think boiled down to folks not following procedure when rotating. The machines come with a few extra bolts and inserts but, the drive bits they come with are cheap-o's.

Get a good torx bit (I bought a couple Milwaukees made for impact use) and torque wrench, clean everything well and seat to spec and you should be trouble free. If you try to wing it, I could see trouble. The torque amount is pretty low and one could easily exceed the spec. The current manual asks for 48 - 50 inch pounds. The older manual spec'd 55 inch pounds which is what I used without issue.

insert%20rotation%20002.jpg

I do it like so . . .

• Unplug jointer
• Remove guard
• Use wedge and a light tap from the hammer to lock the head in position
• Loosen screw with small torx #20 and handle
• Back out screw with magnetic tip so as not to become unhappy
• Remove insert and wipe the bulk of the crud off of it
• Drop insert into cleaner
• Use nylon brush to scrub seat area on the head with cleaner
• Blow seat area clean with compressed air
• Scrub insert clean and then dry with paper towel
• Inspect insert to assure no foreign matter is anywhere (X-Acto knife helps if you find anything stubborn)
• Seat insert
• Apply small drop of 3-in-1 to threads of screw
• Insert screw with magnetic tip and finger tighten
• Apply 50 - 55 inch pounds with torque wrench <=== double check the spec for your machine
• Rinse and Repeat

[Rod Sheridan]

Hard to imagine that you could break a bolt with 50 inch pounds of torque, as that's approximately 4 foot-pounds.

I have a torque screwdriver that is in that range, it's used for electrical fittings like household size circuit breakers.................Rod.

[Mark Furjanic]

Still working on it. I sent the pic in this thread to our metric supplier and my office spoke to our rep this afternoon. From what I was hearing from my girl they were looking at a standard flat head screw which this one isn't. I dug around in my box of tricks and found what I might call a maintenance pack that came with my Grizzly jointer (previously sold due to space constraints but seemingly I never gave the buyer the pack of extras) I have a few cutters, a pair of screws, and a couple drivers in the pack. I'll get actual dimensions of the head off the screws I have and get back to our supplier.

I did take a good look at the relationship between the screw and insert and I see no reason for an undercut. There's plenty of room for a fully threaded screw to securely hold the insert to the drum and the undercut would only potentially weaken the screw.
More to come as I have it.

[Van Huskey]

Could it be the undercut is designed to have the screw fail prior to the insert, they are cheaper than the inserts? That said I find it hard to fathom how 50 or so inch pounds are breaking the bolts unless they are seriously compromised. Either the bolts are made from extremely poor steel or the torque wrench is out of spec, by a good amount.

[Ronald Blue]

Could it be the undercut is designed to have the screw fail prior to the insert, they are cheaper than the inserts? That said I find it hard to fathom how 50 or so inch pounds are breaking the bolts unless they are seriously compromised. Either the bolts are made from extremely poor steel or the torque wrench is out of spec, by a good amount.

Van you might be on to something there. Dan what brand is your torque wrench? I am thinking a decent quality one might be warranted here. Is it 1/4" drive?

[David Kumm]

I've never heard of a fastener on a rotating cylinder spec'd to fail so there can be two projectiles to duck from. Sounds to me like a bad batch of screws. If you can easily break them with low torque, they certainly could fail if the insert hits a knot. I'd find out the scoop from Grizzly. They should be explaining what is wrong and sending replacements. Dave

[Van Huskey]

I've never heard of a fastener on a rotating cylinder spec'd to fail so there can be two projectiles to duck from. Sounds to me like a bad batch of screws. If you can easily break them with low torque, they certainly could fail if the insert hits a knot. I'd find out the scoop from Grizzly. They should be explaining what is wrong and sending replacements. Dave

That is a good point, I was thinking that if it didn't fail tightening it that it wouldn't fail which upon some thought makes no sense because the forces on the screw would probably be much higher than a small amount of over torque. My first point only makes sense in a static environment which this is far from.

So, either REALLY bad screws or a torque wrench far out of spec.

FWIW I use a Park TW5 torque wrench for this range (26-132 inch pounds), it is a bicycle tool company but it is pretty accurate (within 4%) and it does double duty in my household since I am a cyclist. They run about $100. You should be able to get a set torque driver for less money and even more accurate.

[Dan Letkeman]

Van you might be on to something there. Dan what brand is your torque wrench? I am thinking a decent quality one might be warranted here. Is it 1/4" drive?

I highly doubt I was over titening the bolts with the torque wrench set the way I did. I honestly could have snapped them off with a straight driver. I'm guessing the bolts are bad, especially since others did have the same problem.

[Dan Letkeman]

I've never heard of a fastener on a rotating cylinder spec'd to fail so there can be two projectiles to duck from. Sounds to me like a bad batch of screws. If you can easily break them with low torque, they certainly could fail if the insert hits a knot. I'd find out the scoop from Grizzly. They should be explaining what is wrong and sending replacements. Dave

I think I might give this a try. Doesn't hurt to ask.

[Dan Letkeman]

Still working on it. I sent the pic in this thread to our metric supplier and my office spoke to our rep this afternoon. From what I was hearing from my girl they were looking at a standard flat head screw which this one isn't. I dug around in my box of tricks and found what I might call a maintenance pack that came with my Grizzly jointer (previously sold due to space constraints but seemingly I never gave the buyer the pack of extras) I have a few cutters, a pair of screws, and a couple drivers in the pack. I'll get actual dimensions of the head off the screws I have and get back to our supplier.

I did take a good look at the relationship between the screw and insert and I see no reason for an undercut. There's plenty of room for a fully threaded screw to securely hold the insert to the drum and the undercut would only potentially weaken the screw.
More to come as I have it.

Looking forward too it.

[Scott DelPorte]

One time I was rotating inserts on my Grizzly planer, and was using a small impact driver to spin out the torx screws. I have a torque driver to put them back in, but the impact one is much faster when removing them. I took a break, and when i came back, inadvertently tightened one with the impact driver instead of loosening it. I then proceeded to break several bits trying to spin it back out again. The bits would shear off inside the torx head because the screw was so tight. After breaking about 3 bits, it finally came loose, but the screw was plenty strong to handle the over torque and didn't seem damaged. i replaced the screw as a precaution and have had no ill effects from the mishap.

I wonder if they intentionally use weaker screws on your planer so they would break in an over torque situation as a way to protect the threads on the cutter head.

[Cary Falk]

I have taken out the screws on the Grizzly and the Byrd with an impact driver and reinstalled them with a torque wrench. 50 in/lbs is not that much. I could probably put more than that with a screw driver. The torque wrench would have to be way out of cal or the screws are bad. Maybe they were screwed in too tight at the factory and compromised. I was getting non flat results on my byrd and had to remove every cutter. I had 3 inserts fall apart once I removed the screw. I use the HF 1/4" drive torque wrench and don't have any issues.

[Mark Furjanic]

Finally got word back from our 5th metric wholesaler. All 5 are of the opinion that it's not a standard screw (not much surprise). None of the 5 can find anything in their systems for such a screw and said that the machine manufacturers must have them made special for their applications.
Sorry I couldn't help.

[Dan Letkeman]

Finally got word back from our 5th metric wholesaler. All 5 are of the opinion that it's not a standard screw (not much surprise). None of the 5 can find anything in their systems for such a screw and said that the machine manufacturers must have them made special for their applications.
Sorry I couldn't help.

No problem, thanks for trying. I landed up buying a few from Grizzly for spares. I am going to try turning all of the cutters on my G0490x jointer now. I am curious if those are going to break when using the same torque wrench. If not then I know for sure that the bolts were bad in my planer.

Thanks,
Dan.

[Ken Fitzgerald]

Dan,

I am going to ask something and then make a statement. Please understand, I am not trying to insult you in any way.

Have you ever had formal training on using a torque wrench?

Before I retired, I installed and maintained CT scanners for 34 years and MR scanners for 23 years. The new CT scanners spin a frame that weighs over a ton. The frame is spun sub-second. To image the heart the frame with a 350 lb. x-ray tube spins 360º in 0.3 seconds. All the bolts and screws, everything on that rotating frame has to be torqued to very specific values, to hold them in place and to prevent them from breaking during removal. So, over-torqueing and under-torqueing is an issue. Patient safety and downtime due to broken screws/bolts were potential issues. Our torque wrenches were sent to a calibration lab annually and recalibrated. We had to take a class on using a torque wrench.

The proper way to torque something to say, 20 inch pounds is to set the torque wrench to 10 inch pounds, slowly torque the bolt/screw to 10 inch pounds. You want to ease into the value. Then adjust the torque wrench for 20 inch pounds and torque the screw to 20 inch pounds while easing it into that value.

DO NOT GO BACK to recheck the value when you reach the desired value, in the example I made, 20 inch pounds. Often, it's in the rechecking where the over-torqueing occurs.

They demonstrated in the class how easily a bolt or screw's torque value could be exceeded by too casually reefing on the torque wrench. It's very easy to do.

Again, I don't mean to insult you in any way.

BTW, I have a G0490X and have had no problems with breaking the cutters or screws.

Good luck!