Sorry, I didn't think of this until I had posted previous...
Think of it this way as an approximation...the extra force when the blade hits an additional obstruction is essentially same as suddenly grabbing a hold of the blade and yanking downward---if the motor is over-sized, it won't stall but will just keep on pulling until something gives...given the moment arm of the upper axle around the support column, that could well be the place.
I was just thinking of such a thing for my performax 16/32.....
but given that it's the same blade running at the same speed on the same wheels, there is *no* difference.
now if you use that bigger motor as an excuse to jamb bigger pieces of wood faster through a duller blade, yes you will be loading up the frame. it'd be like putting a big block on a gocart. no problem at idle, but floor it and the motor will tear itself free.
the upper wheel is an idler and has less mass than the driven lower. just how is it going to get ahead?
if your saw is *that* underbuilt just throw it away and buy a real saw....
that is exactly what happens every time you cut with the saw. it's what they are designed to do, exactly.
Larry Jaques notes:
Me, too. But you've got to realize that Grizz is the one that still recommends using a 20 amp fuse for an 18 amp machine because a 30 amp fuse might allow damage to the motor. IIRC, and I'm not sure of this and can't find what I did with the manual on the jointer, they try to make this a warranty issue. This one wouldn't stand up anywhere, IMO.
Charlie Self "Political language... is designed to make lies sound truthful and murder respectable, and to give an appearance of solidity to pure wind." George Orwell
I don't agree, all that extra tourque is dilivered to the wood being cut, the upper wheel don't see a thing. All the frame and upper wheel sees is blade tension. I don't see the problem with a bgger motor, 'cept that Grizzly has to put a limit somewhere! Greg
It continues to rotate at its original speed for a few msec after the load slows the lower. Within the limit of blade/frame flex, it crams.
It's rotational inertia that counts.
One wonders if Grizzly even has an engineering staff. I suspect that the real engineers are not employed by Grizzly and speak little if any English and have never been within 5000 miles of the US.
On Fri, 24 Dec 2004 14:26:16 -0700, snipped-for-privacy@all.costs calmly ranted:
Yes, but only that portion of the frame which supports the driven wheel bearing.
P.S: Jambs are for doors, not jammin' wood.
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1) this is a tiny force in the context of a bandsaw. 2) putting a bigger motor on it doesn't change the upper wheel configuration a bit.
I wouldn't put money on that "speak little if any English". My wife stoped a pair of random young people in Nan Ning, CN and asked them in English to take our picture. They both spoke English quite well.
bridger responds:
You are right, as I see it. I think a smarter question would involve something like what is the maximum useful HP for a replacement motor on a 14" bandsaw. That would probably run up on 2 horses. There's simply not a lot of point in running that blade off a 5 HP motor unless you do constant resawing of ipe or something similar...and I doubt even then.
Charlie Self "Political language... is designed to make lies sound truthful and murder respectable, and to give an appearance of solidity to pure wind." George Orwell
My explanation was how the blade begins to flex. You may charge any windmills you care to without changing the basic dynamic equation which anyone who owns the standard 14" bandsaw knows by the sound of the blade slapping on the left - push a rope syndrome - or the right, where the blade slows and flexes at the top of the cut - even under tiny force. It's differential which counts, and in a dynamic system with four sources of built-in-flex - the blade, the frame, the spring and the tires, in conjunction with differential friction on a driven and free-wheel, there's a bit more of that than necessary at times.
As to HP limits, my initial in this thread summed up my opinion - wouldn't hurt, but there are better uses for 2 HP, if it is 2HP @ 115, motors than for bandsaws, which are belt and blade limited in their use of torque. Now that I know it's a Grizz we're talking about, my experience with breakage in a number of their castings makes me side with the phone tech.
Actually, I was thinking that a two or three horsepower three phase motor might be useful if you power it with an inverter. As I understand it, the torque would stay the same while you'd be able to vary the speed of the blade.
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How does the torque get delivered to the wood being cut???
The blade is being *pulled* down through by the lower wheel, held fast by friction to the rubber around the wheel. The upper wheel is freewheeling. An old sawmill at Upper Canada Village in Ontario Canada uses a straight blade that cuts on the way down, being pulled by the rotating jointed mechanism at the base. That way the wood is also held fast to the table during the cut. Japanese hand saws cut on the pull stroke. It makes sense.
[It's not strictly "torque", which is a turning force, at the wood surface, where the blade is being pulled down with sharp edges into the wood, ripping [tiny] chunks out of it.]Merry Christmas.
I think you missed the (semi) sarcasm mode...
I'd think 2 horse would be fine. probably more than you'll actually draw with that saw, but a little extra horsie never hurt anybody.
I think that way before you snapped the arm the saw would give you all kinds of warnings- it'd be throwing bands and slipping belts and tearing up tires all over the place.
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