Wavy cuts need help please.

[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.