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Thread: Advice on Cutting Aluminum?

  1. #1
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    In a thread contemplating repairing the shrunken back on my '21 A, it was suggested I make some Bench Clamps ala Frank Ford. I've taken a good look at his articles on their use, He cut them from 1/2" Aluminum plate, and they look like the right tool for the job. I would like to make something similar, but I've never worked with aluminum. They're a pretty custom job, and the aluminum alone would run me near $50 I think, plus the tapping tools.

    I've done some research, and apparently it's possible on a wood-cutting bandsaw, however it's suggested by some that the blade runs far too fast. This Guy modified his band saw to slow the blade. I've got an old craftsman bandsaw, and could do this if necessary, but am wondering if there are cheaper less-extensive options.

    What suggestions could you all offer on creating bench clamps in a small shop 'on the cheap'?
    - Any tips on cutting aluminum?
    - Could similar usable clamps be made of wood, or are the stresses too great.
    - How about stock aluminum angle, cut w/ my cheap miter saw, and with a hardwood triangular insert between the legs?

    (Frank, as I assume you might read this, I thought about writing you directly but figured this would be better than bugging you with a series of emails on how to mod your tool --- I sure appreciate all the info you provide at frets.com)

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    (1) You can buy a metal-cutting blade for your bandsaw.

    (2) You should be able to change the sheaves - motor, lower wheel shaft, or both - to achieve a ratio that will gove you a slower cutting speed.

    When you are done, and ready to go back to wood cutting, re-install the old sheaves, and be sure to thoroughly clean the tires.

  3. #3
    Registered User sunburst's Avatar
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    Two things:

    See if there is someone (machine shop, fabricator) around with a metal cutting bandsaw to cut them for you.

    It might have been me that suggested some sort of rim shaping jig like Franks.
    I have a jig that works similarly, but is much different. I made it quickly and roughly from scrap wood to do one job, but it worked so well that I kept it and have used it for several mandolins since. It started out just for an A, but at some time I cut away part of it to use if for an F. I just have square drive wood screws through there. I ground the ends blunt, and I but little scraps of mandolin sides in between the screws and the mandolin sides when I use the jig. There is cork gasket material in the bottom part. Once I get the rim pushed into shape, I can clamp the back on right in the jig, and set the whole thing aside, out of the way, for the glue to dry.
    It ain't purty, but it works...
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    Registered User sunburst's Avatar
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    BTW, I made that jig before I read about Franks method, and if I had known people were going to look at, I might have made something that looked better, but, like I said, it worked, so I kept it.
    Someday I might make something like this, but with aluminum angles like Frank uses, only smaller, so that I still have the portability, but more adjustability.
    I made another one of these for mandola.

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    Registered User Frank Ford's Avatar
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    About 25 years ago I scored a metal cutting Rockwell 14" bandsaw at a garage sale, so I have two, one set up for metal speeds and one for wood.

    I cut brass, steel, etc. on the metal saw. Aluminum doesn't do too well on it. I always cut aluminum on the wood saw at full speed, and with the same blades I use for wood. Generally, I'm a bit of a cheapskate on blades, so I buy regular skip tooth or hook tooth, both of which are fully hard enough for the job. In fact, I doubt it would be easy to find a bandsaw blade that's not hard enough to cut aluminum.

    Aluminum tends to glue itself to the teeth of any saw, so from time to time, I stop the saw, move the blade by hand and use a file card (you know, the metal file brush) to knock the chips off. It's easy to tell by the feel and sound when it's time to clean the teeth.

    That's it. I've been cutting alumium that way since I first heard it cuts at wood speed.

    Now, if you want a thrill ride, you can also cut aluminum on a table saw. . .

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    Hey, thanks all

    Frank, I think your solution is very elegant, and if I find the need to do multiple repairs would be something I'd be willing to invest in. I know from reading on your site that they have a multitude of uses. I really appreciate the info on cutting aluminum, I'll definately have uses for that and not be scared to ruin my old saw from now on.

    But, John, I think your jig is more w/in my budget and I can build it mostly from scraps I have on hand. I can see how w/ that config the wood would have enough substance to resist the stresses, my original thought of wood bench clamps might not. Thanks a bunch for posting it, it's more than purty enough for this guy.

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    coprolite mandroid's Avatar
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    A machine shop cuts in a stream of cooling and lubricating cutting oil/fluid. then again if you are not doing production work and time to slow down to the speed faking it requires is oK then thats fine.
    I offerthere is a particular type of hand file, made for aluminum shaping in the Nicholson catalog is 'vixen' a series of rows of curved plane like teeth with lots of room for chips in between.
    They seem to work well for wood shaping as well, leave a somewhat smooth surface.
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