band saw resawing - Page 2 - Woodworking Talk - Woodworkers Forum
Old 12-28-2016, 08:06 AM Thread Starter
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[QUOTE=falbergsawco;1538897]I still don't understand why woodworkers use the term psi to measure spring load when only a corporate bureaucrat can conjure up enough double-talk to explain the tenuous relationship between the two. QUOTE]

probably because psi is the "tension scale" provided to us by the blade manufacturers.
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Old 12-29-2016, 03:26 AM
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My saws have about a 1" range of tensioning slot between the slack end (enough to change a blade) and the fully tensioned end. You should be able to pull a fully tensioned blade sideways, like drawing an archer's bow, through the length of that range without feeling much increase in the "pull". You' d have to factor in the leverage of 10" wheels and a 110" blade to calculate a spring rate equivalent. Doing it like that, you get a "feel" for what constitutes "enough" tension. Turn it on. Cut some wood. Did it cut straight and fast? That's the right tension then. Are we woodworkers here or are we engineers? Put away the toys then and make a table or something!
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Old 12-29-2016, 04:22 AM
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Originally Posted by falbergsawco View Post
Doing it like that, you get a "feel" for what constitutes "enough" tension. Turn it on. Cut some wood. Did it cut straight and fast? That's the right tension then. Are we woodworkers here or are we engineers? Put away the toys then and make a table or something!
First, do you realize how funny it is that someone engineering and building a bandsaw for commercial sale thinks using an accurate and repeatable method for setting tension is too nerdy? I suppose you don't bother using the highly engineering approach of using a air pressure gauge on your car tires, if the car goes straight and fast then you have the correct pressure.

Bandsaw blades are designed to work at their optimum when they are tensioned within a specific range. Using them outside that range increases wear and changes the harmonics. Low tension can also lead to barrelling in the cut. The marks you suggest are due to tensioning "flap" are mostly a result of hesitation marks from hand feeding and harmonics in the blade. All bandsaw blades will exhibit harmonics, lower tension results in lower frequency and higher amplitude harmonics so the marks will be further apart and deeper higher tension reduces the amplitude and increases the frequency so the marks are more shallow and closer together.

Also how can you call something an industrial veneer mill with only 2hp, that is less than half the hp for decent speed cutting of 15"+ veneer in domestic hardwoods and 20% of the horsepower and industrial bandsaw manufacturer would put on any saw being called a resaw. With 16-20" resaws in hardwood I have to run my power feeder at near the bottom of its speed range and I have 250% more horsepower and that is with a thin kerf carbide blade (I could run faster with a very thin impulse hardened spring steel blade but it would dull quickly). I just find it near ROFL funny that you tag a 2hp bandsaw with the word industrial, any industrial setting cutting veneer will be using a rotary mill or a high speed carriage bandmill for flitch cutting with 10-20 times the horsepower. For the price you have listed on your veneer mill you could get a 9 horsepower 32" Minimax and a medium power feeder that would have the efficiency to at least work in a light commercial setting cutting veneer.
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Old 12-29-2016, 04:12 PM
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Originally Posted by falbergsawco View Post
My saws have about a 1" range of tensioning slot between the slack end (enough to change a blade) and the fully tensioned end. You should be able to pull a fully tensioned blade sideways, like drawing an archer's bow, through the length of that range without feeling much increase in the "pull". You' d have to factor in the leverage of 10" wheels and a 110" blade to calculate a spring rate equivalent. Doing it like that, you get a "feel" for what constitutes "enough" tension. Turn it on. Cut some wood. Did it cut straight and fast? That's the right tension then. Are we woodworkers here or are we engineers? Put away the toys then and make a table or something!
I don't know about you, but yes - I am an engineer. and stuff like "leverage of 10" wheels..." left the track from the start. there's very little mysticism left in mechanics. I'd "call a friend" with a mechanical engineering background and trade some beer for a review of "how things work" in your design.
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Old 12-30-2016, 03:09 AM
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Tom, let's pretend I just handed you a frosty beer of your choice . How do things work in my design? Why is it so easy to pull the blade sideways like drawing a bow when there is obviously more spring force being applied? What would a real engineer say about that. How should I have described that? Just don't tell me I need a half ton more steel and more HP than "cutting like butter" gets me. ("Cutting like butter" is a designer term for 2HP, or "sufficient" . Engineers, being more tradition-oriented, use the word "industrial" to describe over-powered bandsaws that have to compensate for the inefficiencies inherent in the two-wheel design.
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Old 12-30-2016, 03:19 AM
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Huxly: " do you realize how funny it is that someone engineering and building a bandsaw for commercial sale thinks using an accurate and repeatable method for setting tension is too nerdy?" Yes
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Old 12-30-2016, 04:11 AM
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there are 2 sides to this discussion ....

Both sides can be right. You have the engineering side and the seat of your pants, build it until it works side. The performance is what matters. If the Falberg saw can resaw 15" with little variation in thickness, then what ever he's doing is working. His saw weighs under 300 lbs or so, I can't remember. That's a long way from 800 lbs of a cast iron or welded steel version, if weight is a factor. It sounds like the parts are made in small lots or one at a time which accounts for the high cost, which may be a factor for a small operation.

Anyone sawing 15" thick material will have to deal with supporting the weight of the piece OR move the saw like a band mill. Either will require a serious structure to support the weight. If the piece is shorter than 36" and just for veneer, then the Falberg saw may have an advantage.

Personally, anything I've resawn in my home shop was 4 ft long at the most. I've used either a 1/2" blade or 3/4" blade from Timberwolf and have no experience with other brands. I have no interest in spending more than \$40.00 per blade, but I may be just ignorant in that regard. I have sharpened my own 131" blade with a Dremel with fairly worthwhile results. ... Again it's a home shop.
not an industrial setting where production is more important than time. My saw is a 18" Min max S45, a fairly nice welded frame saw with a 3 HP motor. It has enough power for a 10" resaw with a sharp blade.

http://www.woodworkingtalk.com/f2/re...bandsaw-58708/

Bugman, in the thread above, has a great small shop resaw setting using rollers in and out and a 25" Grizzly saw in the center.

The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
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Old 12-30-2016, 09:41 AM
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Old Delta 14" with riser here. I just tighten the blade until I get a good cut. I use my "seat of the pants" meter to be sure I don't over tension. Unfortunately for some, you can't buy that meter.
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Old 12-30-2016, 10:32 AM
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I'd wager over time there have been more and better designs created 'by the seat of the pants' than by degreed engineers.... being 'an engineer' is nothing more than a person with the aptitude - the paper is superfluous; for most of history 'the paper says I'm an engineer' did not exist.

why do you not detect a lot of pull distance deflecting the blade? because the force required to deflect it is a very very small fraction of the force holding it in tension. the deflection force can be accurately measured and you will see the difference - but by "feel" detecting the _difference_ between blade tension force, not so much.
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Old 12-30-2016, 03:00 PM
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Old 12-30-2016, 05:33 PM
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Originally Posted by falbergsawco View Post
The width of a blade is not directly responsible for the speed at which it can cut. The important factor is the swarf clearing ability and that is a result of the gullet size and to some extent the gullet shape. This is more or less governed by the TPI of the blade, as generally the lower the TPI the larger the gullet. There are several factors impacting the maximum feed rate of a band through a given piece of wood. The tooth profile is the first. TCG grinds tend to have more side clearance and produce less friction but don't leave the best finish on the wood. The sharpness of the teeth is a big factor, which carbide is used in most serious resawing it also has the dullest teeth (due to the grain structure) but they last far longer than the alternatives. Gullet size is one of the biggest factors, large gullets result in quicker chip clearance and thus quicker feed rates. Kerf can also be a significant factor. Kerf is also a factor and can run from .016 to .085 in resaw blade made for vertical saws. Potentially the biggest factor is blade speed. 65 mph (mph really?) is a middling speed for resawing (about 5700 fpm for those used to standard machine conventions) and about half what a serious vertical resaw will run. Most if not all the bandsaws that run at these speeds will be DMD to reduce drivetrain vibration. 2hp is not nearly the "limit" of a 1" Lenox Woodmaster CT even at 4000 fpm but they certainly aren't a direct relationship since you might well run out of chip clearing in a softwood but horsepower in dense hardwood.

While it appears your testing of the Woodmaster CT in aluminum was just for curiosity avoid much aluminum cutting with that blade the shear surfaces on the teeth will give up fast in aluminum, if you want a multi-material blade get the Trimaster instead, the TCG is right at home in everything from wood to titanium alloys.

BTW carbide tipped bandsaw blades have no "set angle" (normally just called set). Set is the amount alternating teeth are bent away from the backer which produces a wider kerf in stamped blade bodies. Impulse hardened spring steel blades (Woodslicer, Bladerunner and Kerfmaster) have near zero set while blades favored by turners for cutting wet blanks have large amounts of set. Kerf and blade width together determine how tight of a radius a blade can cut. The body of a carbide bandsaw blade has no set and the width of the brazed on teeth are the sole determination of the kerf width.
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Old 12-30-2016, 06:39 PM
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I run a 3/4" Timberwolf 105" in the 14"Jet for resaw and it cuts like butter! 1200lf and counting
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Old 12-30-2016, 06:49 PM
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Hux, I don't know where to start with you. You're mostly wrong and I think deliberately adding more confusion than enlightenment. But go on, I'm sure somebody understands and cares. FYI: You never heard of set angle because I originated it and unless you read my book you didn't read the chapter wherein I described what it does and why I found it necessary to the understanding of band saw behavior (specifically to calculate turn radius of a blade). You should read it; it has many quotations from the prestigious engineers who helped me write it. It's called 'Your Band Saw" You'll love it. It's very technical. It bored the hell out of me despite my efforts to keep it entertaining. The only theory that I had to backtrack on Slicer was the idea I could tune the drive wheel to line up with a parallel fence . I'm experimenting with rail and sled systems now, having much better results. Otherwise; that's my story and I'm sticking to it.
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Old 12-30-2016, 07:34 PM
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Hux, I don't know where to start with you. You're mostly wrong and I think deliberately adding more confusion than enlightenment. But go on, I'm sure somebody understands and cares. FYI: You never heard of set angle because I originated it and unless you read my book you didn't read the chapter wherein I described what it does and why I found it necessary to the understanding of band saw behavior (specifically to calculate turn radius of a blade). You should read it; it has many quotations from the prestigious engineers who helped me write it. It's called 'Your Band Saw" You'll love it. It's very technical. It bored the hell out of me despite my efforts to keep it entertaining. The only theory that I had to backtrack on Slicer was the idea I could tune the drive wheel to line up with a parallel fence . I'm experimenting with rail and sled systems now, having much better results. Otherwise; that's my story and I'm sticking to it.
Well, if you want to call me wrong bother to show me where I am wrong. So you coined a new term of art BUT just happened to use the same term that has been used in saw manufacturing for a couple of hundred years but you are attempting to give it a different meaning and you suggest I am adding to the confusion here.

I am not against innovation but not simply for innovation sake but you use terms that are not common to the industry and your refusal to use normal conventions when discussing the issue just look like an attempt to obfuscate the issues. Nobody in the industry talks about tooling speed in miles per hour. Effective resawing is relatively easy and is extremely well understood. I just don't see where the quantum leap is and if there is one then there is a huge market in the high speed bandmill industry (cutting all that flooring every homeowner wants) but I don't see the problem you are fixing as being well defined.

If you feel like it point out where I am wrong, if not I can will continue to assume I am correct.
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Old 12-30-2016, 08:17 PM
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We resaw with 1.25" Lenox blades, tension springs are very stout. We don't get any blade flutter. Band wheels are solid steel, blade runs directly on the steel. Feedworks is hydraulically variable speed pinching the work between the conveyor and the powered feed wheel. Feed rate is usually set based on the length of the work, I. E. as fast as the in & out feed men can handle. This is the smaller of the Baker saws and only has 20hp. We use it to rip tapered molder blanks (feedworks can be tilted) and veneers for curved, laminated work.
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Old 12-30-2016, 10:43 PM
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This is the smaller of the Baker saws and only has 20hp. We use it to rip tapered molder blanks (feedworks can be tilted) and veneers for curved, laminated work.
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Old 12-31-2016, 09:05 PM
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It is just a single head. bought it used for \$7,000. The original owner used it very little. A very nice saw. Quick and easy to set up for either straight or bevel sawing. I think this is their smallest saw with tilting feed works.
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Old 01-02-2017, 01:23 AM
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Old 08-31-2017, 07:02 PM
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Old 09-01-2017, 01:48 PM
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Huxley: Now you've got me fine-tuning how much tension to apply based on when the tires come off, as they did when I first fired up the Slicer. I could glue the tires on, I suppose, but that's such a hassle to get it on and a nightmare trying to scrape off. It just seems wrong. Also, if tension can erase blade set on the inboard side, I don't want it. Tension also puts more strain on the motor. Plus: I think there's some vibration dampening going on with urethane tires. With the 2 HP on 1" CT blade setup with a rail/sled feed I could push hard and bog down the motor but the blade would deflect and ruin the cut. Why put a bigger motor on that. To go faster I need a 2" blade THEN I want a 3or4 HP motor. For that kind of ripping you want the SAW on a rail and forget the tires because now we're talking LUMBER MILL. Slicer wants to bridge that gap between lumber mill and home shop veneer master. Did you ever put "set" and "angle" together to calculate the "set angle" of a band saw blade? Being an engineer you should love that kind of thing. It took me a month to come up with the formula, I checked it out with my brother, who is literally a rocket scientist, and he assured me it was correct. I'm not intimidated by titles. And my English is right up (or down) there with the average engineer; so if I don't exactly qualify, Do I get some points?

Last edited by falbergsawco; 09-01-2017 at 02:01 PM.
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