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Rough machining with a bandsaw?

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  • Rough machining with a bandsaw?

    Does it make any sense to rough shape a work piece by making intersecting slits with a horizontal bandsaw?

    I'm thinking of setting the bandsaw to stop at an angle short of its normal, horizontal cut off position, and making a jig to hold a rectangular steel bar at that angle and at an appropriate height so that I can cut a slot of desired depth. Then rotate the piece 90* to make a slot intersecting the first one to remove a small rectangular bar from the work piece.

    I'm sure this would be a joke in a production shop - just hog the metal out on the mill. But for the home shop, where time is not $, it would save wear on milling cutters, and even yield material for other possible uses instead of chips.


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  • #2
    yup, jist remember which side of the line you're working on. Seems whenever I do this trick I manage to eat metal on the wrong side of the line, and get to start all over on a fresh piece. Murphy likes me a little too much, I think.
    I'm here hoping to advancify my smartitude.

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    • #3
      roughing out material on the bandsaw is not uncommon in a shop. I do it all the time , lets face it, with the right saw and the right blade teeth you can saw out material faster than milling it out, plus I would rather clean my saw than the huge pile of chips the mill would make with coolant mixedin with the chips.

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      • #4
        I roughed out two pieces that way week before last. I thought it made sense. Mike

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        • #5
          Sawwing and drilling are the two fastest ways of metal removal.

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          • #6
            I work in the aviation field and we use that method a lot, for one time parts.

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            • #7
              According to "Standard and Emergency Shop Methods" by Colvin And Stanley, roughing out on a bandsaw was done extensivly During WWII.
              It usually makes sense to cut out a section rather than make it all into chips.

              When boring large holes in plate, rough out with a hole saw or treppanning tool.
              For non round holes sawing or chain drilling, or even (not for the squeemish)flame cutting out a good portion of the waste, then grinding or machining to finish dim.

              It usually saves time and materials, especially for one offs, and saves wear on precision machines.

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              • #8
                I like roughing out with a saw it saves tons of time, as does drilling. At least in wood working they tell you to use a bandsaw for this type work before other machining operations. It really does make sense.

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                • #9
                  I used the band saw to cut out the 4 crank disk for my steam engine crank shaft. Sure saved a lot of time as the disk was about 7 inches in diameter.
                  Charlie
                  Don\'t ask me to do a dam thing, I\'m retired.
                  http://home.earthlink.net/~kcprecision/

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                  • #10
                    Herb
                    This was done all the time at one point. These days it depends. One shop owner I know that makes fittings for Nuclear and petrochemical use they don't even bother. Tney would just a soon drop a 20" hastalloy slug in the mill and just chew the inside out. This is much faster that the old method of drilling the blank, threading the blade, welding blade, cutting blank. It takes the High Horspower CNC machines much less time - and time is the most precious commodity in his shop, cost is not an object. He still feels the end justifies the means. I thnk it is a terrible waste of extremely expensive stock when all he wants is the outer 1/2" of that blank.

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                    • #11
                      Why would it be better to waste extremely expensive time than to waste extremely expensive stock? You quote the man as saying time is the most precious commodity in his shop. Do you not believe him?

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                      • #12
                        Regardless of the relative value of time vs material, it's still a waste of material.
                        That's always been a fault of mine: I cannot bring myself to use material frivously. I know that I waste lots of time needlessly planning and calculating and analyzing to make the most efficient use of material (both metal and wood). I hate myself for it at times, but I just can't help myself. I can't even force myself to clean out and throw away the chips from my lathe's chip pan. Even sanding dust... there's gotta be some use for it!

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                        • #13
                          lynnl, I believe you're on to something! A composition board made of metal chips and sawdust! A little resin, some pressure, a bit of coloring..... countertops with sparkle! Throw in a few magnesium chips and mold into a log form, and voila! fireplace logs with character!

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                          • #14
                            Lynn,

                            I can help with the sawdust. You can discard sawdust with a clear conscience because every pound of sawdust that ends up in the landfill is just that much more carbon that will never become carbon dioxide and contribute to global warming.

                            This is why we should also immediately stop recycling paper. The faster we can get that carbon out of circulation, the better off we're all going to be.

                            If you've been turning aluminum, you can make thermite with the chips. Then you can use the thermite to melt all your ferrous scrap.

                            [This message has been edited by Uncle Dunc (edited 01-21-2003).]

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                            • #15
                              I've tried the thermite thing, and haven't been able to get it to work. Do you have a recipe? Is there some optimum or threshold size for the aluminum particles?

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