GearHeads Corner

Kirk:

Yes, thats one of my issues, a 3d printed worm would wear otu pretty quick Id think.. or wouldnt print very well.. And that woudl leave us with another
issue like bevels, but worse. We can print a working bevel, Ive printed several, but cncing them is much more difficult.. worms are also hard to machine and also hard to
print, which makes them questionable as to if time should be invested in them..
  Bevels I intend to cure with an engraving module, more of a 3d waterline type of cut..worms cant even easily be solved that way..

But Ill ruminate on them while Im on my hiatus...

Art

I'd be ok with generating a hobbing tool for now.

You can only add so much...

Kirk

Please accept my vote for worms also.....

Hi Guys:

It is near the top of my list for types of gears..

Art

Perhaps there could be tools for designing, machining, and printing worm wheels that work with standard threaded rods and maybe standard acme screws. Print the wheel, buy the worm.

--Justin

Jerry:

Depending on the worm you have that now, many worms use a normal spur gear as the wheel,
the worm is just a single gear tooth wrapped on a cylinder. Fully enveloped would have the spur
gear turned down a bit on its tooth center, but still very simular..

Art

JustinO wrote: Perhaps there could be tools for designing, machining, and printing worm wheels that work with standard threaded rods and maybe standard acme screws. Print the wheel, buy the worm.

I did try to model some worm gears for acme screws a while ago.  They weren't mechanically great. (http://www.thingiverse.com/thing:270309)

If you know the thread form of the drive screw, and you have a lathe it should be relatively easy to use the same thread form to make a primitive hobbing set up like this: https://www.youtube.com/watch?v=J0o3W4_LRBw

Hi,

Just looking if there is the possibility to make worm wheels wit Gearotic, as I see at the moment not.
Art say that is must maybe a 5 axis job, but in this article they do it with the 4th axis, I think with a form cutter (40 degrees?)


http://blog.cnccookbook.com/2013/04/08/ ... roduction/

Rien Netherlands.

Hi Rien:

  That mating gear to a worm I suspect can be done, its the longitudinal worm thats harder.. but I do think a form cutter could
do it. Just a matter of making the Gcode for the cutter.. I see that as a kind of threading operation using the 4th axis..

Art

Hi Art,

I think it is no problem for the most of us to make the Worm in the lathe, dimensions from Gearotic.
And the Wormwheel in the 4t axis with code from Gearotic.

regards,  Rien.

MJBoluijt wrote: ...
I think it is no problem for the most of us to make the Worm in the lathe, dimensions from Gearotic.
And the Wormwheel in the 4t axis with code from Gearotic.
...

If you have a lathe and a mill it may be easier and faster to build a hobbing jig for making worm gears.

https://www.youtube.com/watch?v=J0o3W4_LRBw

brilliant..

Only problem with this method is, as the tap starts it's running on the OD and it will generate OD*Pi / pitch of tap which will be totally different from the Pitch circle * Pi / pitch of tap.
Many people using this method say it's a toss up on how many teeth you finish up with. Many pre gash the number of teeth they want with a slitting saw to ensure they get the correct number they need.

I used to hob worm wheels on a hobbing machine, full enveloping wheels, 40 T or 60 T and the odd time I forgot to fully tighten the blank it finished up being driven by the hob and not the machines with 42 or 43 teeth of incorrect form being cut.  Wasn't bad on a 60T wheel as it could be saved and made into a 40T but a I really wanted a market for 30T wheels to use up the scrap 40's :-)

John:

  Interesting..  So really to do the pinion would only require the current tangential code for a normal spur, with an added radius of the arc of the envelopment of the worm itself put into the Z, so the arc bottom is center of the spur.. ?

  That at least sounds do-able, but the worm itself, short of a shaped tool I don't think is possible.. Am I wrong in that thought?
(Yours being the opinion on such things I would at all times take to the bank...)  :-)

Art