LT40 Yanmar Drive Belt Adjustment

[rmack]

Does anyone have the deflection/tension specs for adjusting the LT40 drive belt with 36HP Yanmar?

I have the adjusting tool, just not sure where to set the initial O-ring or what I'm looking for on the second one.

[rmack]

whoops! it was written in pen on the back side of the instructions...

7/16@18 LBS

[rmack]

something doesn't seem right. I have taken quite a bit of adjustment out of the belt, it is very tight... almost scary tight, and I still have over an inch of deflection at 18 pounds pressure.  :-\



 

[POSTON WIDEHEAD]

I don't know about the Yanmar. But my Kohler 29 only needs 12 pounds.
You're better to run it a little loose than a little tight.

[barbender]

My Lombardini diesel requires similar tension, and if it's not up there it starts to slip just a little, but it's enough to give you fits on wide cuts. Make sure you're measuring it correctly, you don't want to overtighten it and bust you're crankshaft

[ladylake]

When mine starts squealing on the wide cuts most times at the end of the logs in the dried out wood I tighten it a little.   Steve

[terrifictimbersllc]

whoops! it was written in pen on the back side of the instructions...

7/16@18 LBS

These specs the same as mine, that's what to use if it's in your manual.  Not sure what you mean by scary tight if there's an inch of deflection at 18 pounds on your gauge.  It will be pretty tight with clutch engaged, and loose enough almost to be able to pull it off the pulley when clutch not engaged.

[rmack]

I have been running into problems with wide cuts, and entering the log, plus the mill is at 51 hrs and by all accounts due for adjustment.

I took about half an inch out of the bottom rod and another quarter inch out of the turnbuckle, I'll try that and see how it goes. I agree that the minimum tension that will do the job is probably the best. I still see some deflection in the belt with it running without the guard, but the mill runs noticeably smoother than it did before.

[Brucer]

On the 28 HP gas engine it's 7/16 @ 14 pounds, so for your engine 7/16 @ 18 pounds would be about right. Are you using the tool correctly?

Set the deflection O-ring at the 7/16" mark and set the pressure O-ring at zero. Put the point of the tool on the center of the belt half way between the pulleys. Put a straight edge along the surface of the belt as a reference a push on the tool until the deflection O-ring is at the edge of the straight edge. Remove the tool and you can read the pressure by the location of the other O-ring.

I don't seem to have enough hands to hold everything in place so I drew a sight line on the inside of the housing with a permanent marker. Before deflecting the belt I sight across it to the  line and then press the tool until the O-ring lines up with the line. Best done with one eye closed, just like shooting :D.

Too lose and your belt will wear quickly. Your belt could also slip in a heavy cut and then you'd be getting wavy wood. Too tight and you could bend the crankshaft or damage the bearings.

[Will_Johnson]

As I mentioned on a similar thread a week of so ago there are some situations where there's no substitute for calling the company.

This is one of them. Whatever the brand of mill, a drive belt that's too loose or too tight will hurt performance. As mentioned here, a too-tight belt looks snazzy and "ship shape" but it can also ruin your engine.

Call Wood-mizer Service young man!

Will

[rmack]

As I mentioned on a similar thread a week of so ago there are some situations where there's no substitute for calling the company.

This is one of them. Whatever the brand of mill, a drive belt that's too loose or too tight will hurt performance. As mentioned here, a too-tight belt looks snazzy and "ship shape" but it can also ruin your engine.

Call Wood-mizer Service young man!

Will

I did that last week, unfortunately it's a 120 mile trip to Salmon Arm and would take me at least an overnight trip to leave the mill there for a going over. Add to the problem, there is currently no Woodmizer tech during road calls in BC.

I have the belt set for the Cat specs but notice there are no specs for the Yanmar in my book, do you know if they are the same?

[terrifictimbersllc]

Can't tell whether you've been able to get your questions answered by WM tech support or not.  My experience is they will spend whatever time it takes with you on the phone, for free, to resolve a problem.  Is there a problem getting through to a Canada branch?  If so I would send them an email and ask for a phone call.  Or do the same to Indianapolis if you have to.  Maybe get around a long distance phone charge this way, although I would expect you could get an answer by email from them on this as well.

[Brucer]

If the diameter of the motor pulleys is the same, then the specs will be about the same for any given horsepower.

The manual for my 2006 LT40 shows 7/16" deflection for 18 pounds for 33 & 34 HP diesels, and the same tension for 36 HP gas engines. The information was in Chapter 5 (maintenance) of the user's manual, in the Drive Belt Adjustment section.

[Will_Johnson]

Yes Woodmizer should be able to give you the proper belt deflection spec for your specific machine over the phone or via chat or email.

I can tell you that on TK machines these specs vary considerably depending on the specific model and engine, so I would be very leery of using any of the specs above that are not your exact model and engine.

Woodmizer should also be able to send you the tool needed to properly measure the belt deflection.

If this becomes an issue call or email me and I'll send you one -- you can either buy it from us (about $60.00) or I'll do for you what we do for TK customers and loan it to you so long as you promise to send it back!

Best,

Will

[rmack]

Yes Woodmizer should be able to give you the proper belt deflection spec for your specific machine over the phone or via chat or email.

I can tell you that on TK machines these specs vary considerably depending on the specific model and engine, so I would be very leery of using any of the specs above that are not your exact model and engine.

Woodmizer should also be able to send you the tool needed to properly measure the belt deflection.

If this becomes an issue call or email me and I'll send you one -- you can either buy it from us (about $60.00) or I'll do for you what we do for TK customers and loan it to you so long as you promise to send it back!

Best,

Will

There is nothing in the Woodmizer literature that refers to my engine, in fact, that section of the manual refers me to the engine manual for specs. needless to say, there are none there that I can find.

I already have the adjusting tool, got it with the mill, the 7/16@18lbs is written in pen on the back of the instructions.

Far as advise from Woodmizer, I talked to the guy who sold me the mill about constant problems with out of square cants and he said to adjust the mast true to the horizontal rod on the dual plane clamp. before doing that I checked and found that rod was 1/4" out of square with the frame of the mill. mind you the frame cross members varied up to 3/32 along the length of the mill. all things considered though, the mast was already relatively square to the frame.

I rechecked all the bed rails and found they were between a 1/32 and 1/16 low at the outside edge, still no explanation for what's causing the 3/8" across 24" cant out of square that I am often experiencing.

It's a good thing I double checked before truing the mast to something that was out of whack to begin with.

I have been trying to get some piano wire to set a straight line from one end of the mill to the other to find out if the outside edge of the blade runs true to a straight line the length of the mill, just curious I guess.

Does Woodmizer have a specific number for the Yanmar 36 belt tension?

[jcbrotz]

I have been in your shoes and your best bet would be to go through and do a complete alignment by the book. If you change one thing then you directly affect another adjustment. Unfortunaly it is not as easy as adjusting when out of square because if you lift or lower the outer guide to make the cant square then you have just put on or removed the down pressure of the roller and you will experience may issues including thinking your blades are dull due to no/little down pressure when the problem is not the blade. Even at such low hours you should go through a complete alignment due to this being a piece of equiptment that does get jarred and banged around with logs and sometime other pieces of equiptment and in my case our lovely Pennsylvania highways that the gasholes have destroyed. Take a few hours and do an alignment and your problems will go away. OH and call indy and aks for the speck for the Yanmar, Or just PM one of them on here either sparks or mooney will help. but for the record my Kubota is 7/16 at 18lbs also.

[Will_Johnson]

Sorry I didn't mean to confuse -- I won't have the Woodmizer specs but was just saying that you should contact Woodmizer directly for the proper specs for your specific mill model and engine. As I said in a post last week there are certain things for which you really need to go to the manufacturer directly and this is definitely one of them. Usually there are some WM factory guys here on the forum -- maybe someone could point them to this string? I am always glad to pitch in on customer service but am unaccustomed to doing Woodmizer customer service.   :D

[Bandmill Bandit]

Does Woodmizer have a specific number for the Yanmar 36 belt tension?
[/quote]

The Cariboo Plateau is very beautiful region to live and work in. Your dealer is a good one as it is the same dealer I work with. I wont mention names BUT I can tell you that there is a chart at the shop for the belt tension gauge that you have, which is likely the same one most of the rest of us have, that has the proper specs for your Mill that the service people will have written on the  bottom or back of your instruction sheet that comes with the gauge. I know you can trust t hat number PROVIDING that every thing else is in sink and set correctly. My mill is a LT40HDG28 and I love the tension gauge. Makes  setting very simple.

[Brucer]

I rechecked all the bed rails and found they were between a 1/32 and 1/16 low at the outside edge, still no explanation for what's causing the 3/8" across 24" cant out of square that I am often experiencing.

I'm assuming you have the manual for your mill. Read through the section called "Complete Alignment". If you imagine doing each step, you'll get a pretty good idea of how it's set up.

In general (and leaving out a lot of the details), the mill is set up with no deflection on the guide rollers and the mast tilted so the blade is parallel to some fixed part of the frame (that's just a reference). The bed rails are set at the same height and exactly parallel to the blade. Then the guide rollers are adjusted to deflect the blade downwards 1/4". Once the blade is adjusted the entire mast is tilted slightly so the outside end of the blade is 1/16" higher than the inside end of the blade. When the saw enters a cant, the sideways pull of the blade takes out any slack in the various bearings and the blade ends up running exactly parallel to the bed.

So, once the mill is properly aligned, if you measure from the blade to the bed rails, you'll find the outside of the rails appears to be 1/16" lower.

The "Routine Alignment" is much simpler but it's always a good idea to go back to square one and do the Compete Alignment from scratch every once in a while. That's especially true if you've got an annoying alignment issue that you just can't seem to fix.

[rmack]

I rechecked all the bed rails and found they were between a 1/32 and 1/16 low at the outside edge, still no explanation for what's causing the 3/8" across 24" cant out of square that I am often experiencing.

I'm assuming you have the manual for your mill. Read through the section called "Complete Alignment". If you imagine doing each step, you'll get a pretty good idea of how it's set up.

In general (and leaving out a lot of the details), the mill is set up with no deflection on the guide rollers and the mast tilted so the blade is parallel to some fixed part of the frame (that's just a reference). The bed rails are set at the same height and exactly parallel to the blade. Then the guide rollers are adjusted to deflect the blade downwards 1/4". Once the blade is adjusted the entire mast is tilted slightly so the outside end of the blade is 1/16" higher than the inside end of the blade. When the saw enters a cant, the sideways pull of the blade takes out any slack in the various bearings and the blade ends up running exactly parallel to the bed.

So, once the mill is properly aligned, if you measure from the blade to the bed rails, you'll find the outside of the rails appears to be 1/16" lower.

The "Routine Alignment" is much simpler but it's always a good idea to go back to square one and do the Compete Alignment from scratch every once in a while. That's especially true if you've got an annoying alignment issue that you just can't seem to fix.

Thanks Bruce, I have decided to just walk away from this for a few days, on top of other unresolved issues the mill has now developed an intermittent bearing howl that I have no idea how to begin narrowing down. I was thinking of putting a video of it on youtube to see if someone recognizes it. I think the main problem is my frustration level at not being able to readily deal with these emerging issues, no doubt the experience will be good to have though.

I have winterizing to do around the property and that will give me a good opportunity to put some distance between myself and these problems. Will probably get back to dealing with these issues next week. I have some 1 1/2 x .050 13* blades to try out but that would mean changing the guide rollers so I will read up on the particulars of adjustment for those. I realize it's no big deal to swap them out but other than the cushion distance between the blade and roller shoulder and the orientation of the roller shoulder to back of blade I haven't really checked for adjustment as far as height goes. I do suspect that my mill is capable of producing straight (waveless) cuts through this fir at a much higher feed rate than is currently possible though.

Again, these compound problems are probably overwhelming simply because of my inexperience, I appreciate the members patience in trying to walk me through some of this stuff.

btw, I was told by Woodmizer rep that the only way to deal with the blade rising as it enters the wood issue on dry douglas fir is to turn the log around and saw from the small end toward the butt. Given the size of the logs I have that really isn't an option as chopping/chainsawing for clearance is a regular issue. Have you ever tried this technique?

[Bandmill Bandit]

Take the blade off and run the mill with the clutch engaged. If you still hear the howl it be in the main bearing although this is highly un likely. If you don't hear the howl 99 chances out of a 100 you have a guide roller bearing going and likely the stationary one.  Not hard to change and  available at NAPA. 6304s I think. I keep a couple on hand.

One thing with out of square cants that I have found I do is over aggressive clamping and actually lifting the log off the bed rails slightly when I open the second face. You throw that cut out in relation to the first cut and you are out for the whole log. I have found that the second face is the to most critical to get right and I find it much easier to over clamp since I added the second hydraulic pump. The little picks I added to my clamp have helped a lot.

[Dave Shepard]

What order are you opening the log when trying to get a square cant? The best bet is to open your first face, then flip 180° and make sure that flat face is touching the bed evenly and then open the top. Now you can flip the cant up against the backstops and use a good framing square to make sure the cant is square to the bed. Don't worry about if if's square to the backstops for now. After take a slab off the third face, you should have two square corners on the top. If not, the first thing I would check is if you do have that 1/16" on the outside of the bed rails. If you do, then check to make sure that the outer guide roller is moving parallel to the band. If that is wonky, then it might be time to do the complete alignment according to the directions. I had to make adjustments to my mill after it got a few hours on it and it settled in. Like brucer said, going through the complete alignment will help you understand how changing one thing affects can throw off something else.

[Brucer]

I always saw from the top to the butt. It's the most productive way to saw in my particular operation.

It's hard to get a straight cut in wide, dry softwoods. I found that 1-1/2" 7° blades do it very well.

[Nomad]

     Rmack, you can use 1 1/2" bands with 1 1/4" rollers.  You still need to adjust the ride on the tires and the blade roller adjustment, but you don't have to replace the rollers.

[Brucer]

In fact, I ran 1-1/2" bands exclusively on my old 1-1/4" rollers for 3 years with no problems. Mainly because I didn't know you could get 1-1/2" rollers.