Wavy cuts need help please.

[MSTireman]

I've done some searches and checked all the usual stuff so far I think.  We are running a Logmaster LM5 with a 85 hp Cummins and a 2" .055 band.  We got the mill and have had to replace the roller guides. We went with the mega rollers from cooks.  That seemed to help but these bigger logs are giving us problems.  My dad got some big southern yellow pine to cut. After getting squared up it was around 26 inches. We were getting wavy cuts both lengthwise and across the cut. We have a new munks blade installed . We were running ripper 37 and had the same problems just not as pronounced.  It seems that entering the cut we are really close to being straight but across the log into the cut is where problems are happening. I will attach some pics (same place lengthwise just halfway across the log) right now the cant is 22" square. This log was a butt cut and had a big swell 38" to 30" on small end. We've checked blade alignment and adjusted it with no change in how it's cutting. I've changed feed speed, blade tension, and checked tooth set. I have run tension anywhere between 4 and 7k psi. Set is between .020 and . 025 with the bottom side of blade being .020. My roller guides are getting hot to the touch after 4-5 cuts. Never felt them before so really don't know if this is normal. So far no matter what we've tried, no change performance. I know with this mill there is no real tech support so we are just trying to figure out everything our own. Any help and suggestions are welcome. 


 

 

 

 

[DDW_OR]

my thoughts, in no order

speed
pitch build up on blade
dull blade
tooth angle
blade tension

Wood-Mizer can be modified to cut wider.
https://forestryforum.com/board/index.php?topic=84823.msg1297441;topicseen#msg1297441

here are some good links to read


Observations of a New Sawyer in Sawmills and Milling

Useful sawmill mods in Sawmills and Milling

what degree bandsaw blade in Sawmills and Milling

Blade Can in Sawmills and Milling

New Circle mill adventures in Sawmills and Milling

Shifting Large Logs laterally on sawmill in Sawmills and Milling

Stopping Falling Stickers.......Video by 123 Goat in Sawmills and Milling

trees and bees, can it pay to plant cover crops in young forests? in Alternative methods and solutions



this is a really nice looking table
Toddlers cedar picnic table in General Woodworking

[jimbarry]

Are you able to slow the engine speed on the motor? When I have to deal with big flared buts and knotty logs, I slow the engine speed to 2800-3000 rpm. Kinda like driving on driving in slippery conditions, you gotta slow the acceleration in order to control your travel.

20210617 saw milling knotty spruce

[Southside]

Heat says to me you have a friction issue. Big SYP log and the issues you describe say dull band to me. Are you running a debarker? SYP is notorious for trapping sand in the bark. Even if it looks clean it can dull a band quickly, and with big logs everything needs to be right.

Do you have a new band you can try? Myself with SYP as long as you have the HP to pull it I find the Turbo 7 works best overall. I have no experience with the Ripper 7 but sharp it should do fine in clear pine, knots will be the tell. 

[terrifictimbersllc]

Are the blades actually sharp. Hand lens with a 10 X magnification is the most reliable way to check.

Is your drive belt tensioned to what it supposed to be?

The above two items are the most common origin of any wavy cuts that I see on my sawmill. It happens with blades that I thought were sharp, ones I sharpened myself. A quick look with a hand lens and I see rounded outside corners or a glint of light thatI didn't notice in the sharpening/ setting process, That band should have gone around the sharpener again.

Is your blade staying clean? The amount of set that you describe is not a lot for sawing softwood. Any build up and cut quality goes downhill fast, faster with that amount of set.

[jimbarry]

... rounded outside corners or a glint of light thatI didn't notice in the sharpening/ setting process, That band should have gone around the sharpener again.

Is your blade staying clean? The amount of set that you describe is not a lot for sawing softwood. Any build up and cut quality goes downhill fast, faster with that amount of set.

Good point there. That glint is a tell tale sign for sure. 

[Larry]

I have run tension anywhere between 4 and 7k psi.

I assume the 4 to 7k psi is a reading from a gauge on your saw.  That would be something to check right off.  A lot of these gauges are a shot in the dark and the number means nothing.  The tension on your band should be something in the range of 20,000 to 24,000 psi strain.  You can get the exact number from the band manufacture.  To check the tension you need a band tension gauge.  WM and Lenox both sell them as do others.  Once you get the tension correct look at the gauge on the saw and mark it for reference so you don't need to use the band tension gauge except to check calibration.

With the heavy bands your using and your horsepower something has to be terribly bad to get the waves your getting.

[slider]

After what you have done i would look at drive belt tension .

[MSTireman]

Thanks for all the replies. To answer a few questions, I can control engine speed but the mill is all hydraulic including the blade drive.  The mill behaves better at wide open as far as control of carriage etc.  I think my blade speed is way too high but according to ed@ Logmaster I can't change it unless I change the gears in the hydraulic motor.  Maybe someone can weigh in on this point also.  According to the formula from cooks, my blade speed is around 9420 sfpm. (2x3.14x15=\12)x1200rpm at wheels .  Maybe someone can tell me if I'm doing that wrong.  We did make some progress in readjusting the roller guides as far as downward tension and pitch of blade. We have the guides 1/4 inch down and have the blade pitched up 1/16 right now in the front. Gonna readjust and try for 1/8 to 3/16 up this weekend. It looked like when we are coming out of the cut the rear of the blade is higher than the tooth side so that's why we are adjusting the front side up. The heat factor on the roller guides is still there but they seem to be close to the same. The blade is cool to the touch.  We are not having a pitch problem since we switched to diesel/trans fluid for the lube.  Our mill does not have a debarker so I may have some dulling issues with sand/dirt but it has been constant with several blades so far.  Guys I appreciate all the replies and hope to some day be able to repay the forum members back with some knowledge myself. 

[JoshNZ]

If your wheel radius is 15" at 1200rpm then yep 9425fpm, that's awfully quick alright.

[Southside]

FWIW my Super 70 band speed is 5400 FPM.  

[customsawyer]

If you have .025 set on the top teeth and .020 set on the bottom teeth then the blade is going to do what it is doing in the picture. Check if the flange on the blade guides are to close to the back of the blade.

[Peter Drouin]

The blade is not level with the bed front to back.

[duffdav]

We have the guides 1/4 inch down and have the blade pitched up 1/16 right now in the front

From my experience this may be your problem.

I had a homemade resaw with a 24 inch belt. For years I ran 1 ½ wide blades with no problem as long as I kept a sharp blade with good set. I thought I would give some 2 inch wide/one inch spacing .055 Munksforsagers a try. Sawed about 18 inches..  the blade was shooting for the sky...nearly an inch rise. Tried two more new ones same thing. Put my normal 1 ½ back on and sawed fine.

Months later I go the 2 inchers back out again. I put a six foot level across the top of the band. Way out of parallel with the belt. About  six inches difference between the height at the ends of the level. I adjusted things until the height was the same at both ends then they sawed fine.

It is logical considering the geometry of things that the wider the blade the less forgiving they are. The wider the blade the more pronounced the back end will be when out of parallel kicking the back end up or down more than a narrower blade not being able to clear the gap the set creates.

The back end takes control and acts like a rudder guiding the path causing friction and overheating things.

I sharpen blades for others with BMS500/8 inch CBN wheel.

Have a guy with a big mill using two inch blades. I sharpened a round and they cut fine. The next batch he complained did very poorly. I said bring them back for a redo. The blades had a heavy ridge on the backside from running too tight against the guide. The back of the blade too wide to clear the kerf gap and took control. Expensive blades to the junkpile.

[KenMac]

Thanks for all the replies. To answer a few questions, I can control engine speed but the mill is all hydraulic including the blade drive.  The mill behaves better at wide open as far as control of carriage etc.  I think my blade speed is way too high but according to ed@ Logmaster I can't change it unless I change the gears in the hydraulic motor.  Maybe someone can weigh in on this point also.  According to the formula from cooks, my blade speed is around 9420 sfpm. (2x3.14x15=\12)x1200rpm at wheels .  Maybe someone can tell me if I'm doing that wrong.  We did make some progress in readjusting the roller guides as far as downward tension and pitch of blade. We have the guides 1/4 inch down and have the blade pitched up 1/16 right now in the front. Gonna readjust and try for 1/8 to 3/16 up this weekend. It looked like when we are coming out of the cut the rear of the blade is higher than the tooth side so that's why we are adjusting the front side up. The heat factor on the roller guides is still there but they seem to be close to the same. The blade is cool to the touch.  We are not having a pitch problem since we switched to diesel/trans fluid for the lube.  Our mill does not have a debarker so I may have some dulling issues with sand/dirt but it has been constant with several blades so far.  Guys I appreciate all the replies and hope to some day be able to repay the forum members back with some knowledge myself.

If, in fact, the blade is that much overspeed, that would account for some extra heat in the guide roller bearings. I think on my AC36 they run about 13k rpm already at normal factory speed. Good luck with finding the solution.

[BtoVin83]

Methinks your formula is off, I come up with ~4700 fpm

[btulloh]

You're right.  4700 +/-  

The mistake is in the formula, which as written shows c=2piD. It should be c=2piR or c=piD, which makes the computed fpm shown above twice the actual speed. 

Wavy cut causes are pretty much covered in the previous posts, so it's a matter of checking all the possibilities. I always suspect a dull blade first. 

[MSTireman]

Sorry I thought I put in previous post that I have 30" band wheels.  That's where I got the 15 from.  Sorry for the missing info.

[JoshNZ]

You're right.  4700 +/-  

The mistake is in the formula, which as written shows c=2piD. It should be c=2piR or c=piD, which makes the computed fpm shown above twice the actual speed.

Wavy cut causes are pretty much covered in the previous posts, so it's a matter of checking all the possibilities. I always suspect a dull blade first.

How are you arriving at 4700, with 30" wheels doing 1200rpm?

[btulloh]

I thought the diameter was 15", although that would be mighty small. I picked that up from someone else's post though, which appears to be inaccurate. So the original figure is correct. 

[bannerd]

I'm going to second the issue is with the blade.  Not sharp/ set right, not well lubricated and either moving too fast or not tension enough.  The one picture where there is a dip but level at both ends happen to me once, blade stretched.

[jrsloan1]

A lot of good information has been provided. 

Did you get it corrected? 

I like to run my blades dead flat with my deck/bunks.  My mill seems to saw better.  I find it almost impossible to check the blade flatness without something attached to the blade then a 4' level and a good tape.  It will surprise you what the difference will show up. 

I find loose drive belts cause chatter marks on the lumber.  I did not see any in the pics.

[Chuck White]

Thanks for all the replies. To answer a few questions, I can control engine speed but the mill is all hydraulic including the blade drive.  The mill behaves better at wide open as far as control of carriage etc.  I think my blade speed is way too high but according to ed@ Logmaster I can't change it unless I change the gears in the hydraulic motor.  Maybe someone can weigh in on this point also.  According to the formula from cooks, my blade speed is around 9420 sfpm. (2x3.14x15=\12)x1200rpm at wheels .  Maybe someone can tell me if I'm doing that wrong.  We did make some progress in readjusting the roller guides as far as downward tension and pitch of blade. We have the guides 1/4 inch down and have the blade pitched up 1/16 right now in the front. Gonna readjust and try for 1/8 to 3/16 up this weekend. It looked like when we are coming out of the cut the rear of the blade is higher than the tooth side so that's why we are adjusting the front side up. The heat factor on the roller guides is still there but they seem to be close to the same. The blade is cool to the touch.  We are not having a pitch problem since we switched to diesel/trans fluid for the lube.  Our mill does not have a debarker so I may have some dulling issues with sand/dirt but it has been constant with several blades so far.  Guys I appreciate all the replies and hope to some day be able to repay the forum members back with some knowledge myself.

In most cases the teeth on your blade are NOT supposed to be tipped up, or down!
Your blade "in most cases" should be LEVEL with the deck, bunk, etc, whatever your manual calls the part(s) your log sits on while sawing!

[DDW_OR]

Thanks for all the replies. To answer a few questions, I can control engine speed but the mill is all hydraulic including the blade drive.  The mill behaves better at wide open as far as control of carriage etc.  I think my blade speed is way too high but according to ed@ Logmaster I can't change it unless I change the gears in the hydraulic motor.

my fully hydraulic timberking 2000 has a variable valve that i rotate to change carriage rate.
you should have something like that

more photos of your mill please.




 

[ladylake]

 If your running 30" wheels at 1200 rpm that is 9420 fpm. You need to get that down to at least 5000 fpm or less what ever it takes.  That high speed wont saw straight, break bands way sooner, wear out bearings.  I run my mill quite a bit less fpm than factory and it saws straighter.   Steve

[MSTireman]

Appreciate all the responses. So far we have put a 5 foot level across the band and used it instead of a 12" straight edge to get level with the bed. The cuts are much better with a 1/16 or less of wave. I can control carriage speed with no difference in cut quality. My next step is to figure out how to slow the hydraulic motor that runs the blades. I got mfg info off the valve that controls the motor and am gonna call Monday to see if they have any info on adjusting it. It looks to have an adjustment on it, I just don't know if it's for pressure or flow.  From what I've read and been told, I need to reduce flow to slow my blade speed. 

[barbender]

To adjust your blade to the bed precisely, you need to make sure the level isn't resting on one of the set teeth- it needs to be flat on the body of the blade.
  

[ladylake]

Appreciate all the responses. So far we have put a 5 foot level across the band and used it instead of a 12" straight edge to get level with the bed. The cuts are much better with a 1/16 or less of wave. I can control carriage speed with no difference in cut quality. My next step is to figure out how to slow the hydraulic motor that runs the blades. I got mfg info off the valve that controls the motor and am gonna call Monday to see if they have any info on adjusting it. It looks to have an adjustment on it, I just don't know if it's for pressure or flow.  From what I've read and been told, I need to reduce flow to slow my blade speed.
 

Maybe thats a flow divider valve that just need adjusting, if not they make flow divider valves.  Steve

[Peter Drouin]

Wood Mizer has a tool to level the blade to the bed.

[Magicman]

 

 
Correct barbender and Peter Drouin. 

Use the proper tool that will not contact and teeth

[tacks Y]

MSTireman, The Logmaster manual I had was pretty weak. Like the others say, good advice. My Baker says with a 12" scale on blade level or 1/32" up lead. So the teeth side can be slightly up. Is your hyd drive direct? No belts to slip and slow blade?  

[MSTireman]

MSTireman, The Logmaster manual I had was pretty weak. Like the others say, good advice. My Baker says with a 12" scale on blade level or 1/32" up lead. So the teeth side can be slightly up. Is your hyd drive direct? No belts to slip and slow blade?  

Yes sir my blade drive is direct hydraulic. 

[JoshNZ]

As a bit of an off topic hi-jack, why do some mills specify a slightly off blade alignment like that?

You want less flow going through the drive motor to slow it down. Divider would work but to slow it down that much you may consider swapping out the motor. Seems bizarre a factory made unit would be so far out, makes me wonder if we're missing something

[MSTireman]

As a bit of an off topic hi-jack, why do some mills specify a slightly off blade alignment like that?

You want less flow going through the drive motor to slow it down. Divider would work but to slow it down that much you may consider swapping out the motor. Seems bizarre a factory made unit would be so far out, makes me wonder if we're missing something

Thanks josh, I've thought about missing something on this mill also.  I've searched the internet and even though the company is not making mills like this anymore, I can't find any info on a LM5. You can find old brochures on almost any other mill they made.  I still haven't been able to get an owners manual from them either. Hope to get to fool with it again this weekend after work. 

[JoshNZ]

The hydraulic motor (or pump for that matter) could have been replaced with one of incorrect capacity. I was playing around with a casappa pump/drive on a press I built recently and ended up needing to pull it apart for whatever reason. The housing is the same for about 60 different pumps of the series, but by lengthening the gear sets inside (capacity) and giving up space on the end blocks that secure them they can quite drastically change the flow rates/torques etc. So if your drive is anything like that you might be able to consider that too but probably more trouble than it's worth.

Are you sure your engine isn't over revving? Is the hydraulic pump pulley driven? Pulley ratios haven't been tampered with?

Could there once have been a flow divider that fed another feature of the mill that has been deleted or something?

Are you sure it's 1200rpm on the band wheels? Borrow/buy a cheap laser tacho and confirm?

Does the mill have any other components sucking on the hydraulic circuit? How is the blade stopped? Just being nosey now XD any photos haha?

Ive forgotten what's been said in the these already sorry if I'm repeating questions

[tacks Y]

I find it hard to believe there is a major problem. I have see a couple of the LM5s in the last couple years, none in person. I would think leaving the plant it ran fine, so what is diffferent or wrong?  How many hours on the mill? I had the same results once on my mill, rpms to slow and clutch slipped. Look for the simple.

[MSTireman]

I don't think we have a major problem or at least I hope we don't.  The mill had 290 hours when we purchased and is showing 360 as of last weekend. The biggest problem with the mill is probably the dummies running it so far.  I think it was manufactured around 04-05 according to the date code on the engine. I've never sawn before so the learning curve is steep as everyone on here knows. It doesn't help matters that I'm a weekend warrior either.  Most of the info I'm gaining is from this forum and videos on the net.  One thing that has been consistent as far as info is blade speed. I have checked the band wheel speed with 2 different photo tacs and both agree to within 30 rpm.  I think that once we get it slowed down just a little everything will fall into place. 

And to answer a question for josh
The hydraulic pump is direct drive off of crankshaft so no pulley ratio to worry about there. The engine is rated for 85 hp at 2400 rpm. We usually run around 2200. I can't see where anything has been taken off the mill as far as valving. It looks to have the main pump dedicated to the blade drive/hydraulic functions of the mill then. Smaller pump run off the timing cover for the controls.  I'll do my best to get some pictures this weekend. 

Once again, I appreciate all the responses. 

[fluidpowerpro]

If you do determine that its a blade speed issue, instead of adding a flow control to slow the motor down, from an efficiency standpoint, you would be better off sizing your pump and motor to get the correct blade RPM (based on a given engine RPM). If you add a flow divider/flow control in that circuit, it will likely create a lot of heat, and your hydraulic oil temp will get too high. 
I can help you size these if you like. Just send me a PM.

[JoshNZ]

No chance the pumps been put on the band wheel and the drives been put on the engine hah..?

There probably is something else going on, with alignment/wear/tension etc but a modern mill coming off factory with a band running twice as fast as it should seems more odd than anything else to me. And should be on the list of things to fix, whatever else is going on aside

[ladylake]

If you do determine that its a blade speed issue, instead of adding a flow control to slow the motor down, from an efficiency standpoint, you would be better off sizing your pump and motor to get the correct blade RPM (based on a given engine RPM). If you add a flow divider/flow control in that circuit, it will likely create a lot of heat, and your hydraulic oil temp will get too high.
I can help you size these if you like. Just send me a PM.

I can see where a flow control  valve would create heat by blocking off part of the flow. Does a divider valve where part of the flow is sent to the motor and the rest sent to  other hydraulics create heat too.  Could be this mill has  one and the previous owner adjusted it thinking more band speed would be better.  Steve

[tacks Y]

Ed or Herman give any idea of rpm to run? Try running at 1800 rpm maybe or 2k? Take a look at a hp and torque curve chart for your motor, I would think the engine would do good at a slower speed. Your hyd oil is good right? No foaming while running or milky? You checked your wheel speed on the drive wheel?

[tacks Y]

Another thought, ck blade flat to mill at both rollers. Possible one roller is off?

[fluidpowerpro]

If you do determine that its a blade speed issue, instead of adding a flow control to slow the motor down, from an efficiency standpoint, you would be better off sizing your pump and motor to get the correct blade RPM (based on a given engine RPM). If you add a flow divider/flow control in that circuit, it will likely create a lot of heat, and your hydraulic oil temp will get too high.
I can help you size these if you like. Just send me a PM.

I can see where a flow control  valve would create heat by blocking off part of the flow. Does a divider valve where part of the flow is sent to the motor and the rest sent to  other hydraulics create heat too.  Could be this mill has  one and the previous owner adjusted it thinking more band speed would be better.  Steve

It all depends on the pressure in each side of the circuit. If the pressures were equal, then theoretically no heat will be created. If however one side is at high pressure and the other is low, then yes, a lot of heat is generated.
I would speculate that the side not feeding the saw motor is feeding a set of open center directional valves to run the cylinder functions. When your not using those functions, the oil on that side is at low pressure because it is going to tank. 

[fluidpowerpro]

And to answer a question for josh
The hydraulic pump is direct drive off of crankshaft so no pulley ratio to worry about there. The engine is rated for 85 hp at 2400 rpm. We usually run around 2200. I can't see where anything has been taken off the mill as far as valving. It looks to have the main pump dedicated to the blade drive/hydraulic functions of the mill then. Smaller pump run off the timing cover for the controls.  I'll do my best to get some pictures this weekend.

Once again, I appreciate all the responses.

Based on the above, it makes total sense to have 2 pumps. One dedicated to the blade and the other for the cylinder functions. This minimizes heat. In an ideal world, the blade motor takes all of the flow that the pump is putting out and you have no need to regulate flow. (no heat/wasted energy)
Unless something has been changed from the factory, I think its haphazard to re-engineer anything at this point. I sure would think LM knows what is needed to make their saw work....
Tom

[barbender]

It being twice as fast as it should be, seems like a mistake somewhere along the line. I've never heard of a blade being driven that fast.

[fluidpowerpro]

I suppose we cant rule it out. Maybe LM uses different size pumps and motors on different mills and somehow the wrong one got installed at the factory.
I just dont want to get ahead of ourselves. 
Idea...
Get the P/N off of the pump and motor and then call the factory to confirm that they are correct...

[barbender]

The problem is that Logmaster has been out of business for some time, iirc.

[fluidpowerpro]

I guess that kind of rules out that plan....My bad...
It still may be of value to get the P/N of the pump and motor, I can do some detective work and likely figure out what their displacements are. With that we can calculate the theoretical output of the pump and resultant motor RPM.

[tacks Y]

Another thought.... just because most mills here run slower what about larger mills? Or is there an ideal blade speed?

[MSTireman]

I guess that kind of rules out that plan....My bad...
It still may be of value to get the P/N of the pump and motor, I can do some detective work and likely figure out what their displacements are. With that we can calculate the theoretical output of the pump and resultant motor RPM.

Top four pics are the valve assy on top of motor with electric solenoid to engage the blade drive. On the top pic of valve is part number of what I think to be pressure relief valve from my research but why does it have two? Next, from top to bottom are part number for the hydraulic valve assy, motor for saw, and finally hydraulic pump.  I appreciate you taking time to help me try and figure this out.

 

 

 

 
 

 
 

[Stephen1]

I can not help much but it sure is interesting following along  

[Larry]

I doubt your saw is running as fast as you think.  In any case I would verify the speed.  You can do this by going to Walmart and getting a bicycle speedometer for $15.  This will tell you the speed its running.  Its also a useful diagnostic tool.  Watch it as you saw.  If the speed starts dropping drastically, you may have a loose drive belt, bad pump, or motor.  When the speed drops too much, a wave results.

[JoshNZ]

He did use two different photo tachs. You didn't put two reflectors on or have some barcode stuck to the wheel opposite the reflector haha?

You can put your phone into high-speed frame mode (slow motion) and film it, then open the video in vlc, count how many times the wheels rotated in a seconds worth of frames (fps will be in file details)

[ladylake]

 He should count the rpm under load, if the pump or motor was bad it could be way less than free wheeling.  Steve

[MSTireman]

Thanks ladylake, i did check the rpm under load but forgot to include that in the post.  To the best of my memory it was 1020 rpm under load in a 18" cant.

[ladylake]

 That's still 9608 fpm, way to fast.  On the valve in your pic the adjuster rah121s50 is a pressure relief .  I'd try turning one or both of the other 2 in or out and see if the makes the speed of the motor change.  You can always put them back where they were .   Steve

[MSTireman]

Sorry tacks, I thought I replied earlier. Herman/Ed really didn't have any answers on blade speed except to change gears in pump. They never said what speed to run engine and I did pose the question. Ive been looking for a hp/ torque curve and haven't found anything on this old of an engine but that is a great idea that. I never thought about. Appreciate it. And come to think of it I checked the idle wheel, I'll check the drive side this weekend. I think a lot of our problem was a dull blade.  We're gonna saw some more this weekend and check it again.

[JoshNZ]

One easy thing to check is that your guides are angled into the incoming blade slightly (i.e so the contact point between the guide wheel flange and blade is on the upcoming side rather than dropping side. Put a steel ruler across the top of your flange and sight down it, looking at the incoming side of blade, make sure the ruler points to behind the blade rather than in front of it.

I know from experience you'll get waves for sure if it's the other way. You've probably checked it but easy to mention and easy to check, if you haven't.

[tacks Y]

MSTireman, Is your engine a 4B3.3 turbo? 85hp? I found a curve showing max torque 215 @1600rpm, max hp 84 @ 2600rpm.

Not sure what this means as the best rpm to run.

[MSTireman]

Tacks, on the engine data plate, it is 2004 model B3.3.  I don't see the 4 anywhere on it.  The only curve I found was on a newer year model engine with direct injection.  Which do you think would be more important torque or hp?

[Southside]

On a sawmill HP will determine how fast your band is turning when you strike the solid metal log backstop. Torque will determine just how much of that backstop you saw through after all the teeth are broken off the band. 

HP is important, but torque is KING.

[JoshNZ]

HP and torque is something I really never understood. A horsepower is a horse's ability to turn a crank at a given distance from it, stemming from when they used to walk them around in circles driving a crank, for a grain mill or whatever, and a Newton metre is the ability of a Newton of force at 1m on the crank... Isn't it like saying which is better miles or kilometres lol.

Anyway. Torque. You want staying power for milling not acceleration or top end, like they seem to measure with HP.

Maybe you're problem is as simple as that you're supposed to be running it down in the late teens.

[ladylake]

 You could sure run your engine around 2000 RPM  but the blade  speed is still going to be way too high.  Steve

[tacks Y]

Tacks, on the engine data plate, it is 2004 model B3.3.  I don't see the 4 anywhere on it.  The only curve I found was on a newer year model engine with direct injection.  Which do you think would be more important torque or hp?

I think the 4 was just a cly count, some show it but most just say B3.3. This is the motor I have but non turbo.  The sheet I am looking at is a 2007, mechanical injection so should be yours. 

[Machinebuilder]

HP and torque is something I really never understood. A horsepower is a horse's ability to turn a crank at a given distance from it, stemming from when they used to walk them around in circles driving a crank, for a grain mill or whatever, and a Newton metre is the ability of a Newton of force at 1m on the crank... Isn't it like saying which is better miles or kilometres lol.

Anyway. Torque. You want staying power for milling not acceleration or top end, like they seem to measure with HP.

Maybe you're problem is as simple as that you're supposed to be running it down in the late teens.


Horse power = torque X RPM / 5252

the way I look at it is

If you have an engine that develops a lot of torque at a low RPM the horsepower comes in early (ex. a turbocharged Diesel)

If you have an engine that develops a lot of horse power at a high RPM the low RPm torque is usually low. ( small displacement naturally aspirated gas)

This is why an electric motor has a lot of advantages, the torque curve starts out at a low RPM and they are usually designed to run at a fixed RPM which also is low. A DC series wound motor (Starter motor) is a good example, its max torque is 0 RPM but that is also 0 HP because its not turning.

If you need to have the horsepower to maintain your RPM. That's why a bigger engine can run the mill faster.

on my LT15 with the 15hp Kohler, it barely drops engine speed with a 6" red oak cant, when I'm trying to cut 20" I'll lose 200-400engine RPM because there isn't enough HP for the load.

[ladylake]

 
 Did you ever get the blade speed slowed down to where it should be.  Steve

[kelLOGg]

There hasn't been much said about band tension. In the opening post the tension is stated to be:
"I have run tension anywhere between 4 and 7k psi"

Is this the tension on the actual band or a hydraulic gauge reading? My Kasco bands are 0.045" thick and 1.25" wide and according to the manufacturer I should have a tension of 20,000 psi on the actual band and I set it according to this. (0.045" x 1.25" x  20,000psi = 1125 lbs of force on the band itself.) If you are tensioning the band from 4 to 7K psi you are way under tensioned. 

[doc henderson]

timberking is tensioned on the hydraulic gauge to 1200 to 1500 psi.

[Rhodemont]

Completely trashed most of a nice EWP log on Friday afternoon with wavy boards. Kept at it longer than I should have thinking it would self correct.  Saturday morning went out put a new band and band belts on the mill, adjusted the band tension and used my pressure pen to adjust the drive belt tension.  Amazing what proper set up will do, everything ran as nice as can be.

[MSTireman]

Thanks for all the info guys.  Turned out the majority of my problems were dull blades.  My dad and I haven't been at this long and didn't know the difference between a dull and sharp blade.  We have tried 3 brands and so far the munks blades are doing a good job.  I cut a little with a cooks blade saturday and it did ok but had a tooth that was set wrong or got damaged during shipping.  It was some of the roughest finish on any boards we have cut so far and did have some wave in them also. So far, the munks blades have had no wave at all.  I/ve got 5 more of the cooks and munks and will cut some more next weekend and see which ones do the best.  I have a cooks sharpener and setter coming also and this will be the next thing we have to learn is how to correctly sharpen out blades.  I've been in touch with a forum member and he has a tension meter and is gonna bring it one day to see what the tension vs hydraulic gauge is so I know ballpark how much pressure to apply to my bands. Thanks again for the time and replies.