Ridges In Walnut

Jjoness4 · February 06, 2017, 01:36:03 PM

Just now getting up and running on LT-40 D35. My background is about 4 years sawing with a push it manual, low powered (16HP) mill. My issue is knowing how hard and long to push a blade with the higher powered, more torque diesel. I have cut about 5 logs, three were beams so not a lot of cut passes. With my manual pusher mill I knew when I needed to change blades without any doubt. I am getting the pattern shown below on walnut. Tyler Whitley told me that folks tended to cut too slow with the diesel which can cause a ripple in the cut surface. I am not getting any dipping or waves just the ripples shown in the picture. I just want to make sure I am getting the proper amount of sawing out of a blade without abusing it. The cut smoothes out about a foot into the cut.

Weekend_Sawyer · February 06, 2017, 01:42:11 PM

At first glance it looks like you have a tooth out of alignment.

When I was running my buddy's LT35 he said to enter the cut and bring up the power feed until you hear the engine start to labor. worked good for me on 2000 bdft hardwood.

Jon

MobileSawMilSlo · February 06, 2017, 03:05:06 PM

Hi

By my experience you must listen the sound of the engine and sound of the blade. When you hear, when engine sound dully than you are on the edge. But I have LT20 with Kubota 22 HP engine.

My college had almost the same problem with ripples like yours. First thing to check is the blade, than blade roles if the have movement.

Magicman · February 06, 2017, 07:29:19 PM

Your blade is oscillating before it enters the log. More or less blade tension sometimes will smooth it out. Also, entering the log/cant at sawing speed should cause the blade to settle down quickly and eliminate the ripples.

pineywoods · February 06, 2017, 07:37:46 PM

Classic case of slipping drive belt. You may not hear it squeal..Check the belt tension...

MartyParsons · February 06, 2017, 08:45:55 PM

Hello,
I see this on new owners and I try to show this as part of the training. You can see as you started the cut you went slow as in slow feed rate then you increased feed rate and the wash board went away. At times you see it at each end of the board or cant. I teach to increase feed rate as soon as you see the first sign of saw dust. Determining the feed rate is something you need to learn and remember most sawyers need to increase their feed rate by 50%. Feed rate is determined by many factors, not sure if I need to list them. You need to saw as fast as the engine and the blade will cut without changing the band speed.

I hope this helps.

Marty

YellowHammer · February 06, 2017, 10:28:23 PM

Blade oscillations or resonance due to a sharp band, soft wood, and feeding too slow. You should be able to see the blade vibrations and bounce before you get into the log, and loading the band will dampen it as you increase feed. Also, adjusting band tension will visibly change the resonance.
So, as they say, saw faster ;D

Ljohnsaw · February 06, 2017, 10:47:36 PM

Man I love this site with all the knowledge and expertise! I have not had this problem but reading the above, it all makes sense to me - I will file it away in my gray matter for the future. Hopefully I will be able to find it when I need it! :D

Magicman · February 07, 2017, 07:20:03 AM

Entering the log at sawing speed should eliminate the ridges at the beginning of the cut, but do not overlook what Pineywoods said about the drivebelt tension.

A slipping belt will usually cause the ripples or waves while sawing.

Jjoness4 · February 07, 2017, 03:20:08 PM

Quote from: Magicman on February 07, 2017, 07:20:03 AM
Entering the log at sawing speed should eliminate the ridges at the beginning of the cut, but do not overlook what Pineywoods said about the drivebelt tension.

A slipping belt will usually cause the ripples or waves while sawing.

I will certainly check the drivebelt tension. Since the ripples disappear about a foot or so into the cut would drivebelt tension cause the ripple due to the initial high torque of blade meeting wood, then settle out as the belt gets a grip. Keep in mind that the mill has only 5 or so hours of sawing on it. This will give me a good opportunity to check belt tension for the first time.

Quote from: MartyParsons on February 06, 2017, 08:45:55 PM
Hello,
I see this on new owners and I try to show this as part of the training. You can see as you started the cut you went slow as in slow feed rate then you increased feed rate and the wash board went away. At times you see it at each end of the board or cant. I teach to increase feed rate as soon as you see the first sign of saw dust. Determining the feed rate is something you need to learn and remember most sawyers need to increase their feed rate by 50%. Feed rate is determined by many factors, not sure if I need to list them. You need to saw as fast as the engine and the blade will cut without changing the band speed.

I hope this helps.

Marty

Marty, thanks. As others have suggested slow sawing speed seems to be a very influential factor in creating ripples early in the cut.

Thanks to all for your timely responses. I still need what you guys use as criteria for a blade too dull to continue using. With this diesel I am afraid I might keep going when it is time to switch out.

Ljohnsaw · February 07, 2017, 03:33:26 PM

Quote from: Jjoness4 on February 07, 2017, 03:20:08 PM
I still need what you guys use as criteria for a blade too dull to continue using. With this diesel I am afraid I might keep going when it is time to switch out.

Rule of thumb: If a manual feed mill, when it gets hard to push. This can be elusive as it gradually creeps up. Every mill (generally), when the blade dives (or rarely rises) for no good reason (knots) the blade is dull and/or has lost set on one side.

pineywoods · February 07, 2017, 04:11:31 PM

When to swap blades...watch the blade closely when it exits the end of the log/cant. If it drops below the kerf or rises above, there is trouble a'comin...

terrifictimbersllc · February 07, 2017, 04:59:53 PM

When the cut is not flat. Waves, especially over knots or where grain is irregular, or place a straightedge across the cut on straight grained wood, and see that it is crowned or dipped across the width.

Also, once one knows what it looks like, dullness can be seen looking at the tips of the teeth especially the outside corner of the set teeth, with a 10x hand lens. Roundedness or dulling is seen easily as a glint or shininess, whereas when sharp the tip is nothing other than intersecting planes with no shine or roundedness to the intersection. Whether some observed dulling leads to waviness or not isn't always predictable. Power, well aligned and tensioned blade, certain types of wood, easy grain patterns with no knots, and narrow widths, you get away with dull longer. But at risk of lower blade life and living on the edge of damaging valuable wood with climbing and diving blade.

RPowers · February 07, 2017, 09:43:54 PM

Quote from: Magicman on February 06, 2017, 07:29:19 PM
Your blade is oscillating before it enters the log. More or less blade tension sometimes will smooth it out. Also, entering the log/cant at sawing speed should cause the blade to settle down quickly and eliminate the ripples.

X2 speed your entry up and see if that helps

paul case · February 07, 2017, 09:48:16 PM

Quote from: pineywoods on February 07, 2017, 04:11:31 PM
When to swap blades...watch the blade closely when it exits the end of the log/cant. If it drops below the kerf or rises above, there is trouble a'comin...

Same here.
A little harder with the command control.

PC