How much HP is too much for a 14" Bandsaw?

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Nova wrote:

Have you checked it with an ammeter?

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--John
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It does. You just don't believe its telling you the truth.
Bob
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snipped-for-privacy@sewanee.edu wrote:

Until it's big enough to break expensive things if something gets hung up bigger is better with motors. Now if you were talking 200 horsepower, which is enough to sling the whole saw through the roof if something goes awry, then I'd say maybe it was too much motor, but 2 should be fine on a 14". If it was one of the little bitty miniature hobbyist jobs I'd be worried about twisting off the drive axle or slipping the pulley, but a 14" unless it's a real piece of garbage should have no trouble with 2 HP.

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--John
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wrote:

Congratulations J. You clearly stated the case in way that anyone will understand and my hat is off to you. While some of us are getting tangled up in engineering design theory, you are came out and said what needs to be said.
Bob
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No problem. 2horspower is still pretty weenie.

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CW wrote:

It depends. Most 14" bandsaw have a problem providing enough tension for a 3/4" blade without the frame flexing. Given a situation where a 2 HP motor would be beneficial, unless the saw was designed to handle that size motor, the frame of the saw would most likely flex, dropping the tension on the blade and result in a barreled cut. Hopefully that's the worse that would happen.
Grizzly's tech support was iffy on a 1.5 HP on my G1019 and had a definite "no" on a 2 HP.
-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)
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The only time you really need the power and tension is when you're resawing, and when you're resawing, there's usually very little material on one side of the blade. So, it seems to me you could solve the frame flexing problem by having a removable strut which could be fitted as a compression member between the upper frame and the table when resawing.
I've never seen such a thing on a bandsaw, but I find it hard to believe nobody else has thought of it before me. Does such a thing exist?
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Roy Smith wrote:

File the patent. This looks like one of those "Why didn't I think of that???" things. ;-)
-- Mark
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I was just thinking of such a thing for my performax 16/32.....
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calmly ranted:

The motor horsepower shouldn't be of any concern (unless too small.) I'd think the size of blade and the resultant tension required would be the limiting factors.

Did they say why? Were they saying no to the combo or to the larger motor? My guess is the former, not the latter.
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Larry Jaques wrote:

Blade friction. When you start resawing lumber where the power is needed a larger motor, say 2 HP will torque the frame. It will still pull the blade through the wood but with the flex the blade will "bunch up" above the drag. A smaller motor will stall before this happens. With my G1019 with the riser i got the distinct impression from Grizzly's tech support it would be risking snapping the frame with a 2 HP motor.

If you mean the combo of the G1019 and a 2 HP motor, yes the saw was designed for a 3/4 HP motor. I don't know if the riser kit figured in, but I imagine it would. The tech says a 1 HP wouldn't be a problem, 1.5 was questionable and 2 HP was out.
-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)
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calmly ranted:

Blade friction?!? The motor drives the lower wheel which drives the blade and the upper wheel goes along for the ride. Whether you have a 0.5 or a 5.0 hp motor should make little difference, since the weight of the blade and upper wheel will be the same mass no matter what motor.

No, I meant the wider blade and higher tension. But did you tell him you'd be using low-tension Suffolk Timberwolfs? (Or were you?) How much difference in mass could the longer/wider blade make? 8 ounces? That slim margin would easily be quintupled by extra tension on the original bandsaw with the original spring. Inertial mass _can't_ be it.
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Larry Jaques wrote:

The blade friction is still there and has to be overcome. Unless the blade slips on the wheels the torque is taken by the frame. Think of it as pushing a rope which is the reason for barreled cuts.

I normally use a 1/2" Timberwolf blade which Suffolk recommended for the saw. I tried there 3/4" and as Suffolk predicted the saw can't handle the tensions produced by the added blade friction of the extra 1/4" blade width while resawing. It is especially noticeable when attempting to saw "green" lumber (i.e. milling short logs into boards) which has more of a tendency to bind the blade.
-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)
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calmly ranted:

I think of it as the wheel pulling the teeth down, into the wood. The majority of the tension on the blade is between the table and the bottom wheel on the downward side. Since the wheels are connected, there may be a very minor amount of "pushing", but the fact that the band is laying on the -outside- of the wheels precludes much of that. Any attempt at pushing would simply make space between the blade and the wheel, and that could come only if there was no tension on the blade at all. No, it is my understanding that barrel cuts are the result of insufficient tension on the blade.

The only part I can see being stressed by having a larger motor would be the lower wheel (major) and its bearing (minor). Startup might be quicker, creating higher initial (and inertial) stress, and it would be able to do more work when making heavy cuts while resawing. The upper wheel and frame are merely used as guides for the band.
I just don't buy that C-frame flex thing at all. Wider bands and the higher tension needed to run them would be the only cause of frame stress that I can see. No, I take that back. The frame may have more stress AT the lower wheel bearing mount during heavy cuts. The wheel being slightly deflected upward up would also result in lower tension on the blade, with the tension spring attempting to take up that slack.
Maybe the guy at Griz could expand on his concerns. I'd be very interested (despite having their old heavy-duty 18" G1012.)

Yeah, and they make resaw blades for both green and dried wood, with different set, hook angles, gullet depth, etc. for each one.
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How about this:
The free-wheeling upper wheel gets ahead of the driven, but loaded lower, causing the blade to bunch into the gap. Doesn't take much difference in speed to start the process, which then increases in effect as the bunched part slows....
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George wrote: ...

The upper wheel isn't free-wheeling, it's driven/pulled by the blade...the blade makes the wheel move, not the other way round...
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On the other hand, the upper wheel has rotational inertia. It's an interesting dynamics problem to figure out exactly what happens if you get the whole system up to speed and then place drag on the downward-moving blade.
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Roy Smith wrote:

Not a tremendous amount, however, as the mass of the wheel isn't all <that> great... But, you're correct, it's a fairly complex dynamical system if one accounts for all effects including blade slip, stretch, ...
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On 24 Dec 2004 13:10:10 -0500, snipped-for-privacy@panix.com (Roy Smith) wrote:

that is exactly what happens every time you cut with the saw. it's what they are designed to do, exactly.
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the upper wheel is an idler and has less mass than the driven lower. just how is it going to get ahead?
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