Wash board ripple effect, and needing some guidance

[5quarter]

Peter...if you don't know what you're talking about, then I'm really out in the wilderness.  ;) :D

[Cazzhrdwd]

I do not think that any sawmill manufacturer would intentionally use a lower quality item.  They want us up and running sawing all of the time.

I don't know if its intentional or not, I will say I spent thousands on a new moulder and knife grinder and they intentionally dropped that line like a rock, its put me in quite a position. I may have to deal directly with the Chinese to get parts, I'm incredibly angry about it.

It seems the grease in the bearings dries out more, was wondering if any of you noticed that?

[4x4American]

What kind of grease are you using?

[Cazzhrdwd]

The newer bearings are sealed bearings and it seems to be some type of synthetic grease. If I can reuse them I'll do like a previous poster suggested, pull the seal out and add grease to them.

[Kbeitz]

I have a lathe and tried turnin my rollers. A carbide bit won't even scratch them. Had to use a tool post grinder. Those rollers are case hardened, which makes them a bit expensive...

The tool post grinder does not have the accuracy to do a good job on the shoulder of the wheel. [ the grinder where's down, then you have to redress it] What you use is diamond tip carbide turning tool on your lathe. They're only about $400.00 a tip. But if your good with a lathe you can do a lot of wheels.
Be sure to use a water base coolant and keep it on the hair fileing. They will get hot and catch fire.
Easy.

The diamond tip carbide turning tool is not good for interrupted cuts.

[Peter Drouin]

I have a lathe and tried turnin my rollers. A carbide bit won't even scratch them. Had to use a tool post grinder. Those rollers are case hardened, which makes them a bit expensive...

The tool post grinder does not have the accuracy to do a good job on the shoulder of the wheel. [ the grinder where's down, then you have to redress it] What you use is diamond tip carbide turning tool on your lathe. They're only about $400.00 a tip. But if your good with a lathe you can do a lot of wheels.
Be sure to use a water base coolant and keep it on the hair fileing. They will get hot and catch fire.
Easy.

The diamond tip carbide turning tool is not good for interrupted cuts.

I guess I don't know better, Have done 30 or 40 of them. :D :D :D

[Al Miles]

I'm replying to this old post as I am going through a similar problem with Woodmizer rollers.

While doing a complete alignment recently, with a blade on , tensioned, properly positioned on the blade wheels, with new guide rollers and engine off, I was turning the blade wheels by hand. Every time the inner blade guide roller did a revolution the flange would contact the blade. That would only happen for about one third of the blade then the blade would move away from the roller. Once the blade did a revolution the flange would once again start hitting the blade back every time it turned.
After further investigation I discovered two problems. The first being the blade was welded out of square. I put a two foot straight edge across the back of the blade, with both ends of the straight edge touching the blade a space was in the middle near the weld. The space was larger the closer to the weld with a 1/16th inch space at two inches on either side of the weld. After rotating the blade half way around I put the straight edge across the back of the blade and the straight edge rocked on the blade, contacting in the center but not the edges.
I checked four of the box of ten they were all not square. Woodmizer sent me a new box of blades, I've checked and used one and it is welded straight.
The other problem is the flange of the blade guide roller was wobbling as it rotated. Quite easy to see the flange move fore and aft every time i spun the roller. Unfortunately I did not measure the flange out of true or the roller barrel itself. Woodmizer sent me a new roller, it was out of true as well. Woodmizer wanted the roller back to evaluate but I haven't heard what the outcome was as of yet. I did measure the second roller, it wasn't as noticeable as the first roller but was out of true 7 thou on the flange and 8 thou on the barrel. That roller made the blade vibrate so bad I thought the drive belt was loose. I tightened the belt but the noise continued. I ordered a new drive belt, not inexpensive. Thinking it may be the roller and not the belt I took off the new roller and installed an old used one. The noise stopped. So far Woodmizer has sent me four rollers and all four run out of true.
It could be the roller are machined untrue or perhaps the bearing bore is not parallel to the sides of the barrel, or maybe the bearing installation.

I do know one cannot cut straight lumber with a defective roller. Maybe that was the cause of your washboard cuts.

[Cazzhrdwd]

Not sure about your rollers Al, they do come with messed up welds sometimes. I just replace my third potentiometer. First one lasted 18 years, second one year, we shall see about the third. Mike Eichenberger at Woodmizer is very knowledgeable.

As far as washboard, Mike was the one who convinced me to use the 7degree turbos after 20'years using 10degree blades. He said the washboard was typical with them. They are certainly much better blades, too bad I'm so late in using them.

[Cazzhrdwd]

I don't think those marks are from seizing. If the roller is still perfectly concentric, then it is unlikely it ever seized. I don't think any mill manufacturer would knowingly use a low quality part. That is really bad for ones reputation.

It's usually the water side, seems to get in there and foul things up. But the marks are definetly from seizing, Its happened to me several times.

[Magicman]

I am loving 7° turbos, but I have to listen to the engine and push the blades to the limit.  I believe that it is the amount of sawdust that they are bringing out that will cause ripples if/when you slow down.  (Just my thought)  I see no way that they could be effectively used with lower HP engines.

[OffGrid973]

Stupid question but unless you are trying to cut too quickly shouldn't the blade not be actively riding against that vertical part of the wheel?

[Al Miles]

Ripple cuts can be a result of feeding the blade too slowly, worse in some wood than others. I know of one case where just switching from a 10 to a 9 degree hook stopped the ripple.

I measured the barrel diameter of one of the defective rollers, it is round to within five ten thousandths of an inch. This roller has run-out of 7 thou on the flange and 8 thou on the barrel.

I can only think  the bearing bore is on a tilted axis, not parallel with the barrel sides, defective bearings or incorrect bearing installation that would cause a round bearing to wobble when it turns.

[bandmiller2]

Maybe its time for manufactures to try different materials for rollers carbide, ceramic, or even Teflon or brass. when I ran the LT-70 WM we had I believe little ceramic pads that were glued in holders. They seemed to work OK but the pads would break bond with their holders but still work because they were in a pocket, no rollers I don't remember any wash board. Frank C.

[Al Miles]

Those ceramic pads are in addition to the rollers, supposed to help prevent the blade from taking a dive or rising, they don't. If a blade is going to dive it will it just bend down from the pads. I took all that off my mill as every once in a while some sawdust or chunk of wood would get caught between the blade and the pad which would cause the outer blade guide arm to slam against the log/cant and cutting would come to an abrupt stop.

As for Cazzhrwd's question about cheap roller bearings, the last couple of rollers I got from Woodmizer has China written right on the bearings.

[Cazzhrdwd]

As for Cazzhrwd's question about cheap roller bearings, the last couple of rollers I got from Woodmizer has China written right on the bearings.

Yep, that's been my experience. I didn't replace my first set for years after my mill was new, now it's just about every other year. Funny how people think they would never do that, they do have a reputation to keep up.   :

I don't blame them though they do have to compete with all the other mill companies out there. I'm just wondering when there is going to be enough mills around me. I'm glad my business is established after 20 years. Helps me to charge confiscatory rates that I wouldn't be able to do if I was begging people to let me Saw for them. Sorry for the rant.

[drobertson]

I've seen it happen with new blades, alignments correct.  Logs, SOG ect...can cause funny things, this said, oscillations can cause it, set screw on top between the wheels.  Discussions on the rollers totally different ball game.  I've trued mine up in the past. Precision grinding, they had wear, smaller on the outside, bigger towards the flange.  I also had the marks on the flange till the day I sold the mill. It showed no signs of wavy marks or signs of oscillations, a good feed rate should be bumping the flange, not riding on it. I would be close to betting a dollar to a dime its the band blades.   

[Al Miles]

You are not the only one ranting. Woodmizer makes a good product but then cheaps out on things that make you shake your head. I talked to a rep about that a couple of days ago and even he is amazed at that tendency. Another rep I knew a couple of years back told me Woodmizer makes a Cadillac of a mill then puts mickey mouse parts on. With the volume of bearings they buy they must be able to buy North American made for a good price. Or buy local and add the extra $0.50 to the price of the part.
There are about 20 sawmilles on the Island I live on, five of them are woodmizers, I have heard from three of the other four owners complain about Woodmizer lowering their standards once a product gets accepted in the industry.

[esteadle]

What I think is happening is that your feed speed is high enough and your blade dull enough that you are pushing the band back into the roller bearing edge and when the mutilated bearing rolls around, it forces the back of the blade up and down, and that creates a blade flutter which creates the ripples. When it was on the "entry" side of the wood, it was probably worse, but you switched it and it probably moved to the other side of the cant.

You probably changed blades too, and changed the sharpness so may have not had as much pushback on the blade, thus masking the problem which was still there, but not evident when you weren't getting blade pushback. But as the blade dulls in the cuts you make, it starts to get pushback and then you get ripples.

Sound about right?

I think you need a pair of brand new roller bearings and your problem goes away. Bite the bullet and get new, vs. trying to figure out if the machining skills you apply to cutting the old bearings are good enough to solve the problem.

In the meantime, you can try to adjust the spacing and give yourself a little more room before you hit the back edge. On my mill (Timber Harvester), I set both guides to 1/8" spacing off the back of the roller. (I get why yours might be 1/16" on the entry side, and 1/8" on the exit side. If the exit roller side is moveable, then it's on a cantilevered arm of some type and that will move a bit no matter how tight the attachment bolts are. They entry side is typically fixed, so it wont' move that way).

You can also try slowing the feed speed down, especially in wide cuts, and as your blade gets duller. That will prevent the blade from pushing back into the edge of the roller.

Good luck to you!

P.S. I just went to Cooks Saw and see that they are selling roller bearings 10% off. http://store.cookssaw.com/