Turning Nose Cone without a Lathe?

Discussion in 'Techniques' started by gna, Feb 8, 2020.

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  1. Feb 8, 2020 #1

    gna

    gna

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    I need a pointed nose cone for a design I would like to build. I can't find one the right size, or close, but I did find a balsa ogive cone. I bought it, and I'm wondering if I can glue a dowel in the base, chuck it in a drill, and sand it/file it down. Will this work? Anyone done it? Or am I wasting time and balsa?
     
  2. Feb 8, 2020 #2

    lakeroadster

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    Yep.. you can do it... just be patient. Do some searches on the site here for some tips. Here's a couple:

    Sandman was the wiz at this... he hasn't posted though since Dec 2018 :(

    https://www.rocketryforum.com/threads/turning-balsa-cones.116177/
    https://www.rocketryforum.com/threads/turning-balsa.64477/
    https://www.rocketryforum.com/threads/turning-nose-cones.80136/
     
    Last edited: Feb 8, 2020
  3. Feb 8, 2020 #3

    neil_w

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    He's active over at YORF.
     
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  4. Feb 8, 2020 #4

    jlabrasca

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    The trickiest part of what you are proposing is work holding. The nosecone will only be supported at one end so you are liable to push out the center.

    There are a mess of YouTube videos on how to build a tailstock and ways for a hand-drill-powered lathe. I've made similar jigs a couple of times -- but my need is infrequent, so I have never made a nice enough set-up that it would be worth the space it would take up between uses. So they always end up back in the scrap pile.

    Grizzly sells a "hobby lathe" that does all of that for you -- but it is really not worth ~$100 if you are handy enough to kludge something together out of scrap wood.

    Good luck.
     
  5. Feb 8, 2020 #5

    prfesser

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    It can be done but it will be quite difficult to get the dowel centered perfectly and aligned with the axis of the nose cone.
    If you have a nose cone that is larger in diameter than needed, it could be turned down much more easily.
    Or start with a balsa block.

    Best -- Terry
     
  6. Feb 8, 2020 #6

    jlabrasca

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    Since the OP writes

    I'd guess that the nose cone already has a hole from where it was mounted on the lathe when it was turned the first time.

    I've used this hole to do pretty much exactly what the OP is suggesting when I've had to turn down the shoulder on balsa cones to fit into a thick-walled body tube. In my most successful attempts, I've used a piece of threaded rod with a t-nut -- so that the points of t-nut are driven into the balsa wood to keep it turning with the drill. A drop or two of CA under the nut helps too.

    [​IMG]
    [​IMG]

    Where the removal is close to the base of the cone, it is a fairly easy to keep the cone from wobbling off-center.

    Removing material from closer to the tip of the cone -- especially for a cone with a taller aspect ratio -- is harder to manage. If the OP doesn't want to fabricate some kind of tail-stock to hold the tip of the cone, it might help to drill the original hole deeper -- so that it runs through most of the height of the cone -- and glue a dowel into the hole to provide a rigid support.

    Also, I do not recommend doing it hand-held as I did in the pictures above. I don't have a picture of it, but I ended up clamping the drill down to the bench so that I could use both hands on the work-piece.
     
  7. Feb 8, 2020 #7

    gna

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    I bought an ogive cone from BMS; it's a small, BT50 nosecone. Yes, the cone has a hole centered, and it runs fairly deep. I glued a 1/4 dowel in. I'll clamp my drill in a vise and try to sand it down. I'm visiting my parents tonight and my dad has a benchtop drill press, so I suppose I could bring it out there and try that, too.

    If I ruin it I can order another one--I may want to order a new transition from BMS anyway, as I stupidly glued a tube on a bit crooked last night. It will probably be fine, but it bugs me...
     
  8. Feb 8, 2020 #8

    gna

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    Thanks everyone. Much easier than I thought:

    2AA68BB7-BC6C-48B9-9CEC-90CCF5803C44.jpeg 7257C0C3-E35F-478C-99A0-7041DDD2D504.jpeg 692EB656-7CB9-4DC2-A0FD-197EF577579B.jpeg BA4772DD-66BF-43CF-86ED-DB9CC05ED989.jpeg

    I started with 100 grit on a woodblock, went to 400, then 600. Now it’s wood filler time.
    Vanguard 1 on its way. I’m sure to have questions about clear fins before I’m done.
     
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  9. Feb 8, 2020 #9

    ThreeJsDad

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    I do this all the time on my drill press. I normally use wood rasps. I really miss having a wood lathe in the shop.
     
  10. Feb 13, 2020 #10

    jqavins

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    It looks like you didn't use your dad's drill press. If I weren't late to the party I'd have strongly recommended using the drill press. I'm glad it worked out.
     
  11. Feb 15, 2020 at 5:08 AM #11

    o1d_dude

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    Where is Captain Low 'n' Slow when we need him?

    He's turned any number of nose cones and transitions on his lathe.
     
  12. Feb 15, 2020 at 5:28 AM #12

    rharshberger

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    Turning on a drill press really only works okay with balsa without some major prep and jigs. I used to use a drill press but due to the run out caused by sideloading the bearings it was too easy to get out of round nosecones. The best method for balsa I found was to make a jig with a circular wooden base plate and a metal mandrel (mandrel goes in drill chuck) then a wooden dowel of .75" to 1" about 2" long (all along a common center). I drilled a .75 to 1" matching hole in the end of the balsa block and inserted the wood dowel in the block and glue the block only around the edge of where the nc would finish at (no glue on wood dowel). Shape using whatever tools that you have to work with. After final shaping and sanding I used a pull saw to separate the base of the nc from the circular wooden base, it should slip off the dowel at that point.
    Sorry I dont have pictures of the process any longer since I have been using a lathe for the last several years. Lathe chisels work for roughing out balsa blocks but unless the density of the block is pretty high balsa tends to tear out too much, so sandpaper blocks and files and rasps become tools of choice as the nc gets closer to final shape.
     
  13. Feb 15, 2020 at 7:22 AM #13

    GlenP

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    To help maintain the lip you could have put a short piece of body tube on the nose cone shoulder when on the drill. That might help to not sand down to any smaller than the O.D. of the body tube you plan to use.
     
  14. Feb 15, 2020 at 5:12 PM #14

    Alan15578

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    When I turn a nose cone or transition on a real lathe, I usually add in a short ring of body tube and turn to fit.
     
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  15. Feb 15, 2020 at 6:26 PM #15

    gna

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    I was messing around, chucking the nosecone in the drill and put it in my vise, and I gave it a quick try. It seemed straightforward. Next time I'll probably find my old cord drill that I can lock the trigger down.

    I did go a bit too far on one side. Fit and finish helped cover it up. I'll remember that tip next time.
     
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  16. Feb 16, 2020 at 2:16 AM #16

    prfesser

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    I seem to recall someone making a nose cone by holding the balsa block in a vise, sanding with a long strip of sandpaper (like a shoeshine would do your shoes) and rotating it in the vise every now and then. Never tried it since I have both a lathe and a drill press.
     
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  17. Feb 16, 2020 at 2:53 AM #17

    GlenP

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    I used that technique to shape a Cub Scout Rain Gutter Regatta boat keel, the older single hulls, not the new tri-marans. Also, for the Pinewood Derby cars, you put the nail/axles in a drill and use a strip of sandpaper after filing to smooth out the tool crimp marks to reduce friction where the wheels spin on the nails.
     
    Last edited: Feb 16, 2020 at 3:00 AM
  18. Feb 16, 2020 at 4:27 AM #18

    dhbarr

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    Dremel collet works really well for the axles.
     
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