Cutting out airframe tubes - whats the best saw blades?

Discussion in 'Workshop Tips and Secrets / Tools' started by Zoomzoooie, Feb 14, 2018.

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  1. Feb 14, 2018 #1

    Zoomzoooie

    Zoomzoooie

    Zoomzoooie

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    It's been a a while since I've been back here. I've been planning modifications to my airframe.

    I have to cut out some of the 5/8" 4130 tubes for the modifications. I had already cut a few 3/3" tubes with a hacksaw and this took forever and wore the blades out very fast.

    I would like to know which hacksaw and reciprocating blades you would recommend for the 4130 in the airframe.

    ZZ
     
  2. Feb 14, 2018 #2

    BJC

    BJC

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    I still have some (apparently no longer available) Heller Tool Co High Speed Max Hard Edge with Start-A-Cut teeth over the first three inches. I use 32 TPI for tubing. They were expensive back in the 1970’s, but well worth the cost.


    BJC
     
  3. Feb 14, 2018 #3

    rv6ejguy

    rv6ejguy

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    Sandvik makes pretty good blades.
     
  4. Feb 14, 2018 #4

    dcstrng

    dcstrng

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    I find an inexpensive angle grinder with a cutting wheel will go through almost anything, fast -- flapper wheel to finish...
     
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  5. Feb 14, 2018 #5

    Zoomzoooie

    Zoomzoooie

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    I am weary to use a cutoff wheel, one slip or cut too close and another tube needs replacing. I will have to use a grinder with a flapper to finish off the excess.

    I came across these blades and they look like that would do the trick: http://www.diablotools.com/products/product/DS0908CF
    I watched some youtube videos and they look pretty good cutting through some thick hard metals including a file. A bit expensive, but they look like they last much longer.
    Anyone have experience with these?

    ZZ
     
  6. Feb 14, 2018 #6

    dcstrng

    dcstrng

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    Not familiar with that blade, but I've had good performance with that brand...

    On the other hand, if I can position myself comfortably/steadily enough to TIG weld (I'm a weekend hack), then I'm positioned solidly enough for the cutoff wheel (not to say it can't get away from me... mostly making sure the rotation doesn't suck me in where I don't want to go... )
     
  7. Feb 14, 2018 #7

    Pops

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    Very good.
    Use the smallest dia wheel so the wheel will have less leverage if it gets caught. For close spaces, I buy a thin, 1/32" x 4" dia wheels and drill a center 3/32" hole and cut small 1 1/2" or so wheels out with an aviation snips to use on my Dremel. Last many times longer and cut better the the small Dremel cut-off wheels.
     
  8. Feb 14, 2018 #8

    TFF

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    Cut off wheel for gross cuts. Harbor freight mini high speed grinder with carbide or diamond dremel flame or cylindrical bit to wipe away welds. Come up with some armor for hands and arms as the shards are painful. Face shield of course.
     
  9. Feb 14, 2018 #9

    Hephaestus

    Hephaestus

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    Cold cut saw would technically be the proper way...

    But I have never seen one in a hangar truth be told. But no tempering issues microfractures etc.
     
  10. Apr 26, 2018 #10

    TejasNW

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    What is the best way to 'cope' or 'fish mouth' tubing? My engine mount calls for 5/8" .060 wall tube and has joints at non right angles, of course. I have been debating a 2 flute 5/8th end mill or a 5/8th hole saw on the drill press. If I could get your opinion on best hole saw blade in that small a size; or if their is better way; I would be grateful to hear your experience.
     
  11. Apr 26, 2018 #11

    pictsidhe

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    For an engine mount and not many joints, you may be quicker just doing two cuts with a saw then touching up with a file or an angle grinder if you want to tighten the fit. Once you have the hang of it it can be done pretty quickly.
     
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  12. Apr 26, 2018 #12

    Pops

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    True, and buy 1/2 round files the same dia as each tube size that you will be using, helps make it quick and easy. Like you say, after you do a few and get the hang of it, takes about 10 minutes to do a 1/2"- 7/8" dia tube, larger tubes a little longer.
    When doing several of the same cuts in larger tubes I make a marking tube from the next size tube at .058 wall thickness. Picture of a Bearhawk landing gear jig with marking tubes for the larger LG tubes.
    Use this to cut the tubing. Also will need a vice to hold the tubing while cutting and filing.
    https://www.harborfreight.com/3-in-heavy-duty-electric-cut-off-tool-68523.html


    http://dogfeatherdesign.com/ttn_js/


     

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    Last edited: Apr 26, 2018
  13. Apr 26, 2018 #13

    BBerson

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    Yeah, just hacksaw or chop saw the end angles (rough cut about 1/8 long) Put it in position then grind off high spots till it fits. Might take four trips to and from the jig to the grinder. Both ends need to be fitted more or less together in stages till it fits in place.
     
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  14. Apr 26, 2018 #14

    TejasNW

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    Gentlemen, Thank you for the responses and resources. The template creator I will have to spend some time playing with.

    I have seen saddle cuts on larger pipe, but did not think the smaller diameter would allow. I have some practicing to do. Again, thank you for the guidance.
     
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  15. Apr 26, 2018 #15

    Little Scrapper

    Little Scrapper

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    I made these videos about 5 years ago. Good luck.

    [video=youtube_share;CCqKmRu4Z94]https://youtu.be/CCqKmRu4Z94[/video]
     
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  16. Apr 26, 2018 #16

    Little Scrapper

    Little Scrapper

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    And video 23.

    [video=youtube_share;Db1TlB6VRYU]https://youtu.be/Db1TlB6VRYU[/video]
     
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  17. Apr 27, 2018 #17

    TejasNW

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    Nice video series, Mike. You are helping a lot of folks overcome the 'unknown' factor; and helping them get into building. Kudos, Sir.
     
  18. May 14, 2018 #18

    Armilite

    Armilite

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    Here are some different Tools from Harbor Freight.
     

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  19. Jun 27, 2018 #19

    wanttobuild

    wanttobuild

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    A small Rigid tubing cutter, Black, Red and Green handled tin snips and a medium grit Scotchbrite wheel.
    Have Fun!
    Ben
    H-Minus
     

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