Thread: Calculating the cutting speed through a block of material on a horizontal band saw

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Originally Posted by MattiJ
I would start at the 1 cubic inch per hp material removed. Should give you ballpark fiqure upper limit on this sort of sawing op.
you're not going to get any more than that, but there are a number of other walls you hit on bandsaw first....like width of blade that can bridge 9" with enough down pressure to make a chip across 9"

you might do the job faster by figuring out the width you can cut given what with and down force a 3/4" blade can handle and starting there. If the blade is cutting for say 2" across 9, all the other 7 inches of the travel is doing is rubbing. ie 3 tpi with a 3" wide stack sort of thing might be faster overall.

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Thanks MattiJ, I hadn't heard of that rule of thumb before. What is the time frame for that rule? 1cu/hp/min?

Tim

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Originally Posted by tmc_31
Thanks MattiJ, I hadn't heard of that rule of thumb before. What is the time frame for that rule? 1cu/hp/min?

Tim
yeah, sorry i forgot, its per minute. And like mr. Anderson said there can be other limiting factors also. But atleast it will give you ballpark figure.

Edit: mostly this rule of thumb is used for milling and turning.

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?? is that you agent Smith

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Mcgyver, as these kinds of threads go, I am revising my method as the thread progresses. At this point I have settled on a 6X6 bundle (36 pieces per cut) and turning the bundle so that the upper and lower faces are as square to the blade throughout the cut as possible.

How would you determine what width (length?) of cut a 3/4" blade could bridge and still make a chip. The down pressure on the blade is recommended by the saw manufacturer if I remember correctly. I seem to remember hanging the saw arm from a hanging scale and adjusting the spring to provide the recommended down pressure when I set up the saw.

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Originally Posted by Mcgyver
?? is that you agent Smith
Dammit, I knew that "mr." there sounded wrong for this guy:

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Without a specialty blade I think you're still going to be "over the top" with a 6x6 pattern. Although if you can cut that 3 inch round in about 5 min per cut that's pretty good. What I'm thinking is maybe a 3x6 or 4x6 grid sitting vertically. That way the blade gullets hopefully don't fill up and lift the blade and you'll still get through the cut in roughly 10 minutes. And even with 18 pieces per pass that's only 6 runs to get your 100 pcs. If you can do that in 10 minutes per pass plus 2 or 3 more to stack the materials you'll be done in around 1.5 hours.

You may also want to take the time to watch this video if you have not seen it already. It might also answer some of your questions about blade suitability and width of cut and the risk of clogging the gullets.

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Thanks BCRider, Joe bundling idea is pretty good. He doesn't say much about blade suitability or cut width in this video though.

Tim

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Originally Posted by MattiJ
Dammit, I knew that "mr." there sounded wrong for this guy:
geez, I like Mr Anderson.....i was going to go put on a black trench coat

call me anything but don't call me late for dinner. My handle is a nickname given years ago by some friends, but not wanting to associate too directly with a mullet sporting TV type, I spell it as its spelled in a painting in my sons room - Mcgyers Bait and Tackle

How would you determine what width (length?) of cut a 3/4" blade could bridge and still make a chip.
You'll have to go back to the text book perhaps, there are not doubt formulas, but off hand I'd say you'd want 10-15 teeth in the work, so if its a 3tpi, you're good up 4-5 inches. 5 inches or so is probably about the maximum bridge. Not sure how coarse a blade you can get for 3/4"...if less than 3 consider adjusting to a smaller bridge. Then weight it down until it doesn't cut straight - I don't have a formula, bigger saws have a feed rate.

When I say max bridge, I mean while maintaining max feed.....you can certainly bridge longer than that and get a straight cut, just not while trying maximize the chip load
Last edited by Mcgyver; 08-12-2017 at 05:58 PM.

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Originally Posted by tmc_31
Thanks BCRider, Joe bundling idea is pretty good. He doesn't say much about blade suitability or cut width in this video though.

Tim
Well, he cut what you saw (seen? ) in the video with the saw you saw. So at least to that amount it is possible and practical

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