1 1/4 inch bandsaw vs 1.5 inch bandsaw

Mesquite cutter · January 11, 2022, 06:25:27 PM

Looking for advice. I have a sawmill that can cut up to 38 inches. I use a 1 1/4 blade. When I cut wide logs my blade sometimes leaves a wavy cut. This only happens on really wide logs. If I change to a 1.5 inch blade would that help when I cut wide logs? Would I need to change the roller guides? I am using the roller guides from Cooks Saw.

Thanks

Southside · January 11, 2022, 06:28:33 PM

What mill and engine are you running? Have you checked your drive belt tension? Are you running a debarker and how sharp are your bands?

There are a lot of factors that go into wavy boards and yes, band width is one, but without the others being correct they won't help you.

barbender · January 11, 2022, 06:29:16 PM

1.5" will help and yes you can run them on your guides. To get the full benefit from them you'll need matching 1.5" guides though. Depending on if you have enough horse power to pull it, I'd run a 1.5'x.055" blade for those wide cuts.

Mesquite cutter · January 11, 2022, 08:04:45 PM

My sawmill is a DIY sawmill. I am using a 19 horsepower Kohler engine. I know I need a double pulley for it but for now I am operating it on a single pulley. If I change the blade to a 1.5 inch blade, would my 19 inch wheels still work with these blades? Here is a video of it.

Happy customer - YouTube

Mesquite cutter · January 11, 2022, 09:31:19 PM

I don't use a debarker. Around here mesquite trees are so crooked that a debarker would not work half of the time. I know the wavy patterns will happen with dull blades. My issue is that it sometimes happens on wide logs with new blades. My thinking is that mesquite wood is very hard wood so I may have to go to a wider blade.

Southside · January 11, 2022, 09:42:53 PM

Is your drive belt just a single V belt? If so I suspect that has a lot to do with what is happening, under heavy load the band FPM is dropping as you can't transfer all of the torque from the engine to the band through one belt so it slips, then dives, giving you waves.

Personally, I think a 1.5" band with 19HP isn't a good solution, it will actually take more torque to pull it likely resulting in more waves. Given you are sawing hard and wide wood, I would spend the money on a triple drive belt setup before changing bands.

terrifictimbersllc · January 11, 2022, 09:45:59 PM

Wide cuts are more demanding of sharpness and other sawmill/blade performance than narrow cuts.

Id call your blade supplier and ask for a sample or two to try or just purchase them. See what happens.

Mesquite cutter · January 11, 2022, 10:10:00 PM

I was thinking of going with a double groove belt. Currently I am using a single groove. And yes it does slip. I am ising the blades from woodmizer.

Southside · January 11, 2022, 10:30:22 PM

There is your problem. Normally a double would be fine with 19HP, maybe it would be fine here too, but you are asking a lot of your saw so if it were me I would give it every advantage possible.

Larry · January 11, 2022, 10:44:46 PM

What kind of belt? If a A or B belt changing to a AX or BX will make a lot of difference. Making a 38" wide cut with 19 hp is asking a lot. Once the blade speed drops beyond a certain point you get a wave.

Mesquite cutter · January 12, 2022, 11:17:11 AM

Quote from: Larry on January 11, 2022, 10:44:46 PM
What kind of belt? If a A or B belt changing to a AX or BX will make a lot of difference. Making a 38" wide cut with 19 hp is asking a lot. Once the blade speed drops beyond a certain point you get a wave.

I am using an A belt

Mesquite cutter · January 12, 2022, 12:55:36 PM

For a cutting width of 38 inches, what size engine would you all recommend?

Stephen1 · January 12, 2022, 01:24:28 PM

Quote from: Mesquite cutter on January 12, 2022, 12:55:36 PM
For a cutting width of 38 inches, what size engine would you all recommend?

I cut 34" with a 38 gas and wish I had a diesel. I can do it but I bet the diesel would be better.

Mesquite cutter · January 12, 2022, 02:12:28 PM

What horsepower diesel would you use?

Southside · January 12, 2022, 04:03:26 PM

One thing to keep in mind is a diesel is going to weigh more than your gas engine, and if the mill can't handle the weight or strain of the torque then you will find the next weak link in your mill.

What degree band are you running?

Mesquite cutter · January 12, 2022, 04:32:52 PM

Quote from: Southside on January 12, 2022, 04:03:26 PM
One thing to keep in mind is a diesel is going to weigh more than your gas engine, and if the mill can't handle the weight or strain of the torque then you will find the next weak link in your mill.

What degree band are you running?

I am using a 7 degree blade. I am thinking of going with a 25 or 30 hp gas engine.

Southside · January 12, 2022, 06:57:41 PM

Try 4 degree bands, they are much better in hard wood, lower HP situations. Honestly, get your drive belt situation resolved before going to a bigger engine. Your belt slip and resulting wave will increase with a bigger engine if that isn't addressed.

JoshNZ · January 12, 2022, 07:17:39 PM

A single "A" belt doesn't stand a chance in hell of dragging 19hp and for sure not through a 38" log, I'd bet you'd get waves even in a 38" cedar log. Neither does a single B. Even a double B at times is a headache unless belt tension is correct.

That definitely needs fixing first but simple answer to original question is a 1.5" band will help - if your bearings and beam are up to tensioning them fully, that's the only other consideration. I've got 1.5" pillow bearings on my mill and they won't handle the force required for a 1.5" band.

fluidpowerpro · January 12, 2022, 07:36:16 PM

Quote from: Southside on January 11, 2022, 09:42:53 PM
Is your drive belt just a single V belt? If so I suspect that has a lot to do with what is happening, under heavy load the band FPM is dropping as you can't transfer all of the torque from the engine to the band through one belt so it slips, then dives, giving you waves.

Still learning here so forgive me if this is a dumb question...
Why does the blade slowing down cause waves.
Why wouldnt the blade still cut straight? The set of each tooth hasnt changed. I would think that you would just have to slow down your feed speed to account for the reduced RPM.

Southside · January 12, 2022, 08:10:00 PM

In theory you are correct, but in reality the slipping drive belt causes the band FPM to fluctuate, so unless you could adjust the feed speed precisely in line with the fluctuations then you begin to either over run the band forcing it down, or it overfills the gullet with chips causing friction and changing band performance, even forcing the band to flex. Something is going to give and in the case of a narrow kerf bandmill the band itself is very weak in terms of vertical resistance, even when properly tensioned, so it waves to find a path of least resistance.

Belt tension is one of the most common overlooked maintenance items and always results in reduced band performance.

fluidpowerpro · January 12, 2022, 08:12:42 PM

Thank you.
At least I learned one thing today!

Skipper11A · January 13, 2022, 01:45:43 PM

I went through the same issues (in the same region) and here's how I solved it.

I reground my blades to 4° , I increased blade tension, I lubricate with diesel/bar oil on both sides of the blade, and I change to a new blade at the first hint that my blade is losing its sharpness. I also feed very slowly so that I don't overfeed the blade and give it time to clear the sawdust out of the log. I actually feed too slowly, but anything faster than that and the blade will dive.

I feel like I've optimized the conditions for my blade and I can achieve acceptable results but the bottom line is that you and I are pushing what an 1-1/4" blade is capable of because the wood is just too hard.

I haven't tried 1-1/2" blades, but that would be the next thing I would try to increase performance, again 4°.

GARose · January 13, 2022, 11:53:35 PM

Quote from: Mesquite cutter on January 11, 2022, 08:04:45 PM
My sawmill is a DIY sawmill. I am using a 19 horsepower Kohler engine. I know I need a double pulley for it but for now I am operating it on a single pulley. If I change the blade to a 1.5 inch blade, would my 19 inch wheels still work with these blades? Here is a video of it.

Happy customer - YouTube

Do it and find out.