Broaching press

  1. BelgiqueB Member

    Messages:
    156
    Location:
    Belgium
    Am getting pretty tired of broaching keyways with my manual Chinese press, thinking of making a bracket for a double action hydraulic cylinder which I'll power of the hydraulic pump of my 4 post lift.

    I have a 70mm cylinder which will roughly press about 5.6 ton at 200 bar, will this be enough to broach 12mm keyways, I assume it is but am not sure.

    Any remarks about the design below? All made out of 20mm steel plate, it's basically a bracket that holds the piston that hooks onto the 2 existing U channels from the Chinese press.

    Thanks Christof.

    Type of press:

    Schermafbeelding 2020-11-06 om 14.08.30.png

    'Design'

    Schermafbeelding 2020-11-06 om 14.10.02.png
     
  2. Munkul

    Munkul Jack of some trades, Master of none

    Messages:
    3,170
    Location:
    Cumbria
    Tuppence:
    Our machinists will never use the hydraulic press in our workshop, they got me to buy a new Marlco flypress for hand broaching when our old one gave up to to historic abuse. You get better feel for it, especially if you're faffing with a blunt cutter and abused spacers. You can also get some speed out of the job.
    Having said that, we got our cutters sharpened and a whole load of new T shaped spacers, and since then, broaching appears to be a breeze (if not, they'd have been twining at me about it again!)

    I guess hydraulic will work, but I'd say you want a pressure gauge in line so you can visually see if there are any snags etc.
     
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  3. mike os

    mike os just a little insane.....

    Messages:
    7,010
    Location:
    North Wales
    Hate broaching with hydraulics just no feel
     
    roofman, 8ob and fizzy like this.
  4. Brad93

    Brad93 M J B Engineering

    Messages:
    10,398
    Location:
    Essex
    Saw a nice jones and shipman one on an auction.
     
  5. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    2,899
    essex england
    Depends on width material and length of keyway. Sometimes you gotta use hydraulic
     
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  6. mtt.tr

    mtt.tr Member

    Messages:
    4,095
    Essex England
    If i were making a broaching press id build the pulling type
     
  7. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    2,899
    essex england
    Different broaches
    Very very expensive
     
    northwest likes this.
  8. mtt.tr

    mtt.tr Member

    Messages:
    4,095
    Essex England
    i know, but i would build to be able to do both

    i think its bizarre that pull through broaches are not more common place, come on china its your calling
     
  9. roofman

    roofman Purveyor of fine English buckets and mops

    Messages:
    7,835
    Location:
    North West
    You will become too greedy with the cuts and start going through cutters too much...manual press you can feel the work;)
     
    nickk likes this.
  10. BelgiqueB Member

    Messages:
    156
    Location:
    Belgium
    Stuff to think about :D, I'm just a one guy side business 'shop' no budget and room for a dedicated press. So will probably go against advice and try it with the hydraulic piston.

    Would 6T of pressure be enough to broach a 12mm keyway in mild steel or stainless?
     
  11. Agroshield Member

    Messages:
    1,390
    What size press do you currently use? And for what size broach? And what is the biggest broach the current press will press? Write down some numbers and try to derive a relationship between broach width and force. It may be linear (6mm takes twice the force of 3mm); it may be exponential (6mm takes four times force of 3mm). It will surely vary with material.

    Have you perused any broach manufacturers' sites to see if they have anything to say on the issue? DuMont in USA is a major manufacturer.

    Put 'broaching force calculator' into Google and follow some links. Try these two (first one would not display on my browser but looks promising)

    https://www.brighthubengineering.com/manufacturing-technology/47630-cutting-forces-on-broaching/
    http://www.an-engineering.co.uk/broaching-forces/
     
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  12. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    2,899
    essex england
    I had a job in back in 2012
    60 hubs. Keyway was 12mm keyway length 100 material en16

    Wouldn’t fit on my 4” slotter as by tradition slotters don’t have enough room for the job, tool and underside clearance on max stroke.
    My then hydraulic press was manual so too slow.
    I used my marlco broaching press, anyone under 18stone couldn’t pull it round.

    I was still suffering arm pain two years later!
     
    Milkybars likes this.
  13. optima21 Forum Supporter

    Messages:
    3,087
    Location:
    halifax, England
    or there is the colin furze version of modified hydraulic press

     
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  14. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    2,899
    essex england
    Cost young man, I had a pull broach machine. It was perfect for production and splines but tooling was scary
    Convenience no special equipment with push broaches required
    Space
     
  15. BelgiqueB Member

    Messages:
    156
    Location:
    Belgium
    Got it all up and running, works perfectly, I can broach a 12mm keyway in half a minute now :laughing::laughing:, already broached a dozen gears and no broken cutters yet. There is indeed no 'feeling' when broaching, but as suggested I mounted a gauge so I can monitor the pressure, which so far seems to work ok.

    As for my own question how much pressure do you need for broaching a 12mm keyway, that would be 60 bar max on my setup. I have a 60mm piston which if my calcumulations are correct (probably not :laughing:) equals to about 1695 kg of force on the broach @ 60 bar.

    20201217_060905.jpg
     
  16. BelgiqueB Member

    Messages:
    156
    Location:
    Belgium
    Missed this post :laughing:, did basically exactly the same thing, only using my 4 post lift power pack as the power source instead of buying a separate one.
     
    optima21 likes this.
  17. Agroshield Member

    Messages:
    1,390
    Correct.

    Did you follow the links in post #11 above? I think they will answer your question.
     
  18. James1979 Forum Supporter

    Messages:
    1,608
    Location:
    Orkney
    @BelgiqueB nice looking workshop you’ve got there.
     
  19. BelgiqueB Member

    Messages:
    156
    Location:
    Belgium
    I did have a look at them, but seems like you need 'specific resistance' of the cutter which i have no idea what it is ? So I did what we probably all do in this occasion, I fitted the biggest hydraulic ram that fit inbetween the frame rails :-).
     
    daleyd likes this.
  20. BelgiqueB Member

    Messages:
    156
    Location:
    Belgium
    Can't complain :laughing::laughing:
     
    James1979 likes this.
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