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Is this possible on a lathe?

Discussion in 'Modding' started by Weekly_Estimate, 19 Jul 2018.

  1. Weekly_Estimate

    Weekly_Estimate Gives credit where its due

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    I'm trying to figure out if the outside gear with the inner teeth would be possible on a lathe before i purchase one, the small gears are obviously easy but inside? (o.0) I know gears are possible on a cnc machine but these are going to be very small about 8mm each so cutting would be complicated compared to a lathe. Also at this size for the torque plastic gears are out of the question =/ else it would be a breeze with a 3d printer lol

    [​IMG]
     
    Last edited: 19 Jul 2018
  2. Canon

    Canon Reformed

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    See the flat spot at the end of each tooth is going to be quite important and I would imagine that being tricky on the lathe?

    Personally I've always left the machining down to the criminals that enjoy that kind of work so can't be sure but at a glance I would go with CNC. Just going to be less chance of a mistake and you can always just pay for what you need.
     
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  3. Cheapskate

    Cheapskate Insane? or just stupid?

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    It would be similar to keyway broaching. You would just need a big enough lathe that you could fit that big of a ring.
     
  4. cobalt6700

    cobalt6700 Active Member

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    I've never heard of gear cutting on a manual lathe - how do you get the indexing right? I've used a horizontal mill to do external gear cutting, a vertical to do internal cutting and internal broaching, but each time used a dividing head to ensure accurate gear placement.

    Without being to index and then hold the chuck I think you will really struggle. You could index the outside of the chuck and then find a way to hold it dead still? I think that's about the best you can get.

    I'm not saying its right, wrong, the best way etc, but this may be of some insight

     
  5. Weekly_Estimate

    Weekly_Estimate Gives credit where its due

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    Thanks for the suggestions, apparently to get this custom made it would be around £93 for the gear alone… which would be fine if it was for a tool but to go inside an idea it just isn’t liable so i’d like to make every component myself from materials. Considering it's just aluminium i’d rather just mass produce the part myself for £2 in material and the cost of the setup.

    He’s managed to do it using a lathe but it seems to the lathe would have to have lots of force behind it



    Hold on, i think i figured it out the part has to around 28mm on the outside, i could use my drill press to cut the inner hole, buy a 10/50 ton hydraulic press, get a toolmaker to make up something which could be pushed down in 1 go to create the teeth, thoughts? Oh the parts going to be a aluminium so it is a soft metal.

    If anyone could offer ideas on why the hydraulic press route wouldn't work it seems cobalts way is the only way this is going to work :)
     
    Last edited: 19 Jul 2018
  6. cobalt6700

    cobalt6700 Active Member

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    How many are you looking to make?

    The press idea may work - Something like a stepped broach. It’s not a techniquie I’m aware of though.

    I feel you may have more luck / much better suggestions posting on a machinists forum :) Broaching is quite a neiche thing.
     
  7. Nexxo

    Nexxo Queue Jumper

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    Cheapskate and cobalt6700 are right: this is something that would have to be done with a bespoke cutting broach. You could use a stepped broach and push straight down, or use a wobbling cutting broach holder (which are pricey), which requires less force. You'd look at about £500,-- for the tooling.

    I'd look for off-the-shelf gears.
     
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  8. Weekly_Estimate

    Weekly_Estimate Gives credit where its due

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    ugh this crap is so frustrating, I'm eating, sleeping, and crapping gears (addictive personality)

    Anyone understand this better then me? I'm rather solid

    I get lost at the 950-teeth gear axle and multi-step approach lol

    edit: I think i might of found a supplier (fingers crossed)

    I guess i could buy a 3d printer modify this to be 100:1
    [​IMG]
    by using the gears from this which is 100:1

    [​IMG]

    Then i could replace the gears with metal gears and be done with it. The problem with just printing out the 100:1 one is the gears are curved which are more difficult to make in metal, and because their plastic if you try and reverse this thing they'll snap under the pressure straight gears f t w
     
    Last edited: 21 Jul 2018
  9. Nexxo

    Nexxo Queue Jumper

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    Gear cutting is usually done on a mill with an indexer chuck.

    Internal gears need to be done on a rotary table with a special broach cutting machine. That sort of stuff is a bit beyond home hobby metalwork.
     
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