Author Topic: LT 300 Upgrade (or was it a down grade?) (Read 2352 times)

smwwoody · « **on:** July 29, 2005, 07:35:59 pm »

Well it was time to have the steel band wheels recrowned agian on the 300. They need to be done every 300 hrs of sawing. When Eddie called to get a new set sent out ( wood mizer does and exchange on them ) they talked him into going with thier new up grade.. The new upgrade is suposed to save money by not recrowning every 3 to 4 months. The up grade is the same wheels with a grove cut in them for a V belt. so in the last 2 weeks the new wheels have cut my production in about half, almost shook the mill apart, upped my band breakage by 10 times, and I cant cut a good board. Wood mizers support is the greatest support out there and they are being very helpful with all the problems. They have totally stopped even the smallest amount of vibration with a simple little vibration damper. and have sent a few differnt sets of belts to try. Next week they are sending a shim for the air bag. I will get into more detail tonight.

Woody

Bibbyman · « **Reply #1 on:** July 29, 2005, 08:08:39 pm »

Were the new wheels sent out for field test? Or did WM think they had a working, tested product?

smwwoody · « **Reply #2 on:** July 29, 2005, 09:08:02 pm »

They are a working tested product . they are what they use on the new 300's

Woody

Tom · « **Reply #3 on:** July 29, 2005, 09:32:12 pm »

I would be interested in the history of Wood Mizer's change from crowned steel to V belts.

Please let us know how the upgrade ends up. It's not much of a step forward if you lose production, is it?

Bibbyman · « **Reply #4 on:** July 29, 2005, 09:52:36 pm »

I’ve never sawn on anything but the Wood-Mizer LT40 with V-belts and not really had much of a problem. Then one time last summer I noticed some vibration and additional noise – kind of like a freight train chugging along.

I didn’t know what was going on until I noted when the blade was about to stop the nettle on the blade tension gauge would wiggle just a little. I got to looking and found a gob of gunk (sawdust/bark?) had built up under the v-belt on the drive side. I cleaned that out and everything smoothed out. I had to do it a couple of times shortly after that and then the problem just went away.

I don’t know why after 11 years of sawing on three mills and many thousands of hours it just decided to gunk up but it did. Now I notice some vibration every once in a while and then it’ll smooth back out.

I’ve also found gunk wedged in the drive pulley. I’ve also found my main drive belt with a 5” chunk ripped off all three “Vs” of the belt at the same place. Changed the belt and that made things run much better.

Are the belts tight on the pulley or are the loose like using the B57 belts on an LT40?

lamar · « **Reply #5 on:** July 29, 2005, 11:21:49 pm »

I noticed a little spot where my tire(v belts tight on 19" wheels) on idler side humped up.This was when I first got it. I took tire off and checked it with a dial ind. it was close +- .005 .What I noticed was (marked bad spot) where my marks were is where they drilled balance holes in the bottom of the v groove.I then dialed the v groove sides and also miked across and apparently what happened was they took finished cuts then drilled holes (a bunch of them about 2+" worth) It seems that the sides closed in(stress relief) which would be ok for what that belt pulley was meant for.I put old (new) belt back on and wrapped a heavy ratchet strap around it with max pressure on hump.Ive been running is about 4yrs. and its ok but its not right $:-\$

gmmills · « **Reply #6 on:** July 29, 2005, 11:27:24 pm »

Woody,

   I have 25" belted wheels on my LT 70. I have no problems with vibration. There is a vibration damping disk mounted between the drive pulley and the driven band wheel. I think if your replacement wheels are patterned after the LT 70's you shouldn't be having these kinds of issues.

   My blade flex life is great with these wheels. I have been running 75 - 80 lbs of pressure in the air bag when tensioned. Had only one blade fail prematurely. Broke at the weld. Most of my blades have been sharpened as many as 15 times and getting too narrow.

   I think you have been sent a pair of wheels that have not been balanced properly or are out of round. If they are out of round the vibration will be transferred directly to the blade. this can cause major blade breakage problems. Take a magnet mounted dial indicator and check the wheels for out of round.

   You should not be having these issues with a work tested upgrade. Maybe they have upgraded a few more parts as a revision on a later model 300 and have neglected to get Ed all the parts needed. Just a thought.
Good luck to you and Ed. This type of frustration none of us need.

Swede · « **Reply #7 on:** July 30, 2005, 05:04:37 am »

My saw mill has 20" V-belt wheels. After sawing for a while and some broken blades I took them tight fiting B-ropes off and put SPB 1600 ropes on. They have a higher profile, they also are longer so they can leave the wheels.
When changing the blade I also take a look at the V-belt and the wheels. If there is any saw dust or other build up on the wheels I take it away.

Bad bearings also makes vibrations and make blades breaking. Have changed from bearings with 2 screws for fastening on the shaft to bearings with conic sleeves. I think that´s the only way to get the shaft good centered.
Can´t remember I´ve had any vibrations after doing my "updates"

And no (Monkey-) blades has broken yet after I made my own guides! Think it has to happen real soon.

Swede.

smwwoody · « **Reply #8 on:** July 30, 2005, 07:24:06 am »

Bibby the belts are loose and I have changed them 4 times trying new ones WM has sent us. no build up under the belts

Tom

They said that this was a more cost effective way to go...

D._Frederick · « **Reply #9 on:** July 30, 2005, 10:57:54 am »

Its been a couple years ago at a show that I noticed that WM on the LT 300 had changed from a solid band wheel to a Vee belt pulley. When I ask why was told that the "crowns" were wearing off and was causing to much down time. Said the Vee belts were a better field fix than sending the solid wheel to be re-crowned.

smwwoody · « **Reply #10 on:** July 30, 2005, 12:44:19 pm »

D

That is the same reason they gave us. They are not useing a v belt pulley. It is the same steel band wheel that had the crown but they have had a v groove cut into it .

Woody

VA-Sawyer · « **Reply #11 on:** July 30, 2005, 02:22:44 pm »

Have they replaced the wheels yet ? If all the problems started with the 'new' wheels and you haven't been able to correct it with new belts, then I would insist on a different set of wheels. Have them send you a 'known good' set for testing purposes.

Buzz-sawyer · « **Reply #12 on:** July 30, 2005, 02:30:28 pm »

Hi Woody
Seems simple to me the old way was LOTS better...get your wheel
s back.............

gmmills · « **Reply #13 on:** July 30, 2005, 11:52:12 pm »

What style of blade guides does your 300 have? The earlier mills a guide system that consisted of sandwich style guide blocks and roller bearing mounted horizontally that acted as a roller guide for the back edge of the blade. The mill I looked at had steel crowned wheels. This system used no downward deflection of the blade through the guide system. The blade depended on the crown of the wheels to run stable in the cut with the sandwich guide blocks helping control blade deviation.

My LT 70's wheels run a inserted belt. The blade guides on the 70 are similar to the earlier 300's guides,but not the same. The Lt 70 guides use a WM blade guide roller to deflect the blade downward 1/4" prior to the blade going through the sandwich style guide blocks on the blade guide arm side. On the drive wheel side the blade passes through the guide blocks and then another roller guide. With this system the blade is stabilized buy the guide roller and not the belted wheel. If you are using a belted blade wheel with out any downward deflection at the guides,in my opinion, your cut quality will suffer.

smwwoody · « **Reply #14 on:** July 31, 2005, 03:28:54 pm »

GM

We upgraded to the new guides when we put the belted wheels on. I really think it is time to go back to the steel wheels and old style guides. In the 15 or so years that I have been messing with small band, band mills I have never seen a belted wheel that can compair to the quality Of a true crowned steel band wheel. Cut for cut I would put that LT 300 (with steel wheels on it) Up agianst any small band, band mill on the market. With the belted wheels on it it is just another band mill. on average I saw 32000bf of mixed hard wood per week on it. the 32000 feet is not a freek thing it would do it week in and week out. We are giving wood mizer a few more days to to correct the problem then it is back to the real thing. This problem is not only dipping into eddies pocket real hard (which I dont like because if eddie isnt makeing money I don't have a job), but it is dipping into my pocket too. Usually every week I have an extra tractor trailer load of red oak cut that I deliver to West Virginia over the wekend. this makes for a nice little extra in the check. this week the load wasnt there...

Woody

smwwoody · « **Reply #15 on:** August 01, 2005, 10:26:14 pm »

I have to say this agian Wood Mizer has the greatest support I have ever worked with bar non. they are next day airing us parts to try to solve our problem. today we got shims to put under the band tension air bag. It was a good try. I realy thought it might help. but they made no differance... our problem really seems like a band tension problem but nothing we do is helping.

do any of you that are running v belt wheels have problems with sawdust build up- under the belts? If so how do you deal with it?

Woody

Tom · « **Reply #16 on:** August 01, 2005, 10:55:33 pm »

Yep, I occasionly had problems with certain species. Cypress was bad about getting sawdust under the belt on the power wheel. It was usually a softer wood that contained a lot of moisture that caused th problem. It would pack under there like "beaver board".

I couldn't stop it because it was so intermittant. I had to take my knife out and clean the wheel when I "heard the roar". (look on the knowledge base 'hear that bandmill roar')

Percy · « **Reply #17 on:** August 02, 2005, 10:02:00 am »

Heya SMwoody.
If the problem is sawdust/crap getting under your V belts, try a tight one. I had to do that with my 70 as it seemed to have the same problem as you when I first got it. If your wheels are the same size as mine, a B72 fits snugly enuff to keep the crap from building up under it yet loose enuff that you dont learn a bunch of new words, putting them on

Jason_WI · « **Reply #18 on:** August 02, 2005, 10:15:03 am »

If these wheels were machined to have the Vee groove in them maybe they are not machined to the center of the hub and are out of round. A dial indicator with a magnetic mount would determine this. If the machinest used a 3 jaw chuck to turn these this could be your problem. 3 jaw chucks are not 100% center. Only way to get it 100% on center is using a 4 jaw chuck.

IF your sawing 32k feet a week you dont have time to fart around with this "upgrade". I would heve kept my old wheels and had them send out the new wheels as demo only. Hindsight is 20/20....... $:-\$

Jason

GF · « **Reply #19 on:** August 02, 2005, 02:19:28 pm »

I would check with a dial indicator first for true roundness at several points.

My next question would be what the hardness of the metal is they are using in the band wheels, recrowning them every 3-4 months seems a little extreme to me. Also when the metal blade is running around the metal band wheel it would also be interesting to see if there is some heat buildup causing the wheel to get out of round.

Might try running the saw for awhile getting the band wheels heated up somewhat and then check them for roundness with a dial indicator. I would also be curious to see what the hardness of the metal in the bandwheel is. Just some ideas.

News:

Author Topic: LT 300 Upgrade (or was it a down grade?) (Read 2352 times)