Grizzly 20" planer taking chunks out of our wood..

[Kevin Cackler]

So I am new to big boy planers. I have only ever used my small Dewalt benchtop. We recently upgraded to a Grizzly G0454 20" planer (http://www.grizzly.com/products/20-Planer/G0454) and just cannot get this thing to give an even halfway decent finish. It's hard to get a photo of it, but basically we're seeing massive chunks being removed from our wood, no matter which way the grain is facing. This is from trying to remove 1/16". I am attaching a photo of a piece of scribe so that you might be able to see what I'm talking about. I spent 3 hours this afternoon going through everything with a rotocator and trying to get it within spec and that just raised more questions.



The manual (http://cdn2.grizzly.com/manuals/g0454_m.pdf) has the following specs outlined in it.



Dist. Below Knife Edge at BDC (Figure 42)

A. Infeed Roller.......................................0.040"

B. Chip Breaker.......................................0.04"

C. Pressure Bar.......................................0.008"

D. Outfeed Roller .................................... 0.020"

Bed Roller Height Range ..............0.002"-0.020" (We set ours to .010" for a first run adjustment)



1. The instructions in the manual say that to adjust the feed rollers, chip breaker, pressure bar, to set the blade to BDC. This took a lot of effort to find and I think we finally got it there, but I'm not 100% sure. It's hard to tell. Am I missing some secret technique on ensuring I am at absolute BDC on the knife?

2. When I set the Infeed roller to .040" below the tip of the knife, my piece of wood had deep imprints in it from the feed roller (It is a serrated metal roller, not rubber so it left a uniformly distanced line in the stock). It was so low that it was digging in to the wood. I had to raise it up considerably to remove those marks but now I'm way out of spec according to the manual.

3. What piece of the puzzle would most contribute to those chunks missing?

4. After going through and adjusting everything, we greatly reduced the number and severity of chunks missing, but still randomly one would occur in the middle of a board. Why????

5. Any other tips or advice? I'd really like to get this thing in top shape by the weekend as we have a lot of stuff to push through it before next week.



Thanks in advance!

[glenn bradley]

These things come with (or recommend) settings for planing rough stock and are nothing like a finish (lunchbox) planer. To get a finish that is closer to a finish planer I set the bed rollers at or below the surface. I back the tension on the infeed and outfeed rollers off quite a bit to minimize the roller marks (you have already discovered this part).

Tearout with sharp knives is generally figure-direction related. There are also boards that just tearout more than others due to reversing grain or other figure anomalies. If you are getting tearout either direction at the same location on the stock it is probably grain reversal. I use a lot of figured material and this is why I went with the insert cutter head. If you get random tearout on different materials; maple, pine, cherry, then I would suspect worn knives.

[Kevin Cackler]

Thank you for the info! I had considered lowering the bed rollers but I figured hey, I should just do what the manual says.

Regarding the tension on the rollers - So you're saying that I should go ahead and keep that infeed roller at .040" below the knife but that I should just back the tension off?

[Walter Plummer]

For thin stock like that I like to run it through on top of another "slave board". We have a piece of 1" plywood waxed that fits inside the planer with a cleat on the end to catch the table to keep it from running through the planer. The thin stock rides through on that surface eliminating the bed rolls all together. Is this a problem with thicker boards also or just the thin stock?

[Kevin Cackler]

Hey Walter. Thanks for the tip on the slave board. We'll definitely implement that after we get this issue tuned up a little bit. Unfortunately this problem is also happening (And even worse) on our full sized stock.

[Mel Fulks]

The approach Glenn mentioned will work but it isn't always done with lunch box planers. Many mills use two identical ,or comparable sized large machines and have a policy of one being used for rough and the other for finish. The main reason is you get rid of grit before using the "finish" machine. Most new machines are sold new with low grade steel. I've worked in shops where the owners thought the only remedy was to sand off about a 1/16th. That is not true.

[glenn bradley]

Thank you for the info! I had considered lowering the bed rollers but I figured hey, I should just do what the manual says.

Regarding the tension on the rollers - So you're saying that I should go ahead and keep that infeed roller at .040" below the knife but that I should just back the tension off?

My machine is the G0453Z so, a 15" and it has no pressure bar. Other than that the mechanisms are very similar. I left the feed rollers at factory height but, backed the tension off. The manual states something like the adjuster should protrude about 1/8" above the casting. Mine are . . . . twice that (just went to check). Cap screw #4 protrudes more as described in the manual.

This yields no roller marks on all but the softest woods as long as I take at least 1/32" minimum per pass. It may be that I was just paranoid about backing the cap screws off so far but, I put a dot of hot glue on each one. I'm not a big hot-glue guy but, I put it on there 7 years ago and its still there despite spilling oil on it now and again when lubricating the feed roller bushings.

Speaking of lubrication, remember to be sure your gearbox is full before running the machine. It ships only partially full. Also, remember to change your gear oil after the first 20 hours or whatever it is. After that I have only topped mine off as it still runs pretty clear when I check it.

[Bill Dufour]

Are you sure those measurements are inch or metric?
Bill D

I like the following link because the example used is my Parks 12" planer same make and model. I do not think they changed anything over the life of the run. Just the cover of the gearbox became Aluminum instead of cast iron.
Bill

http://wiki.vintagemachinery.org/Getting%20Peak%20Planer%20Performance.ashx

[Kevin Cackler]

It's directlyl from the Grizzly manual and it says .040" so I'm assuming it's inches...

[J.R. Rutter]

Have you checked / reset the knives?

I had the Shop Fox version of that planers and did a couple of things to get it cutting better:

Made a full width bed of 1/4" hardboard and laminate with a cleat underneath the front edge to hold it in place. Easy to remove and wax as needed. Takes the bed rollers out of the equation with no worries about stock catching on the edges of the slots where they sit below the table.

Have your sharpener put a slight "back bevel" on the flat face of the knives. This helps in hardwoods, including figured wood, but isn't as good for softwoods.

Ultimately, I put a Byrd head in it.

[Wayne Lomman]

The tear out and the ripples are separate issues. Tear out is cranky grain. The uneven ripples are insufficient pressure on the feed rollers.

Finding bdc is just a measurement. Set your table at 4" or whatever and set your rollers at the specified which would be 3.960" for the infeed and so on with the other components.

Your infeed roller is going to make pressure marks that are then planed off. This type of infeed roller always does. If it doesn't, it's not gripping. It means that there is a minimum cut you must take in order to clean up the face.

Getting it right will take a bit more tuning. I hope you bought it second hand, because a new machine supplied like that is unforgivable. Cheers

[Geoff Crimmins]

The feed rollers, pressure bar, and chip breaker need to be adjusted correctly to ensure proper feed and planing. As another poster said, if the imprint from the infeed roller is a problem then you can back off on the roller pressure rather than its height. I have a Grizzly 15" planer and find that as long as I raise the bed at least a 1/4 turn of the handle between passes then the marks from the infeed roller are planed off. The outfeed roller is smooth so it doesn't mark the wood. The higher the bed rollers, the better the planer is able to feed rough stock, but the more snipe you will get. I don't believe that lowering the bed rollers below the bed with improve the quality of the cut, it will just reduce the amount of snipe. I've never seen a planer do what yours is, but clearly something is wrong. My first guess would be that the knives are extremely dull, especially if you bought the planer used. Having the knives sharpened or buying a new set would be a good place to start. Using the slower feed speed might also help, but the problem is bigger than that. You might also check to ensure that the knives are all set to the same height. I'm not sure what would happen is one knife was cutting deeper than the others, but it certainly wouldn't help. You also might send that photo to the technical support people at Grizzly; they are usually pretty good about helping to trouble-shoot problems.

--Geoff