Trying to make a ring pulley

[tomb18]

Hi,
I need to make a ring pulley.  In other words I am making an XL pulley with 90 teeth.  The outside diameter is around 5.5 inches and it has a "shaft diameter" of 5".
So this is a ring.
I would like to place three holes in this ring which will be used for screws to mount it on another piece of material.
Is it possible to do?
I have tired to export a DXF and bring it into Fusion 360.  This works but there seems to be no way to make the hole in the pulley there without waiting hours, or having many many crashes.
Any help would be appreciated.
Thanks, Tom

[ArtF]

Hi Tom:

Are you making this from a 2d dxf output? I cant undertsand why youd have to wait seconds let alone hours or why anything would crash..
Is this just Fusion 360 refusing the dxf load?

Art

[tomb18]

Well, Fusion 360 is so full of bugs....I guess that's why its now only $25 a year.
Importing a 90 tooth pulley as a DXF results in really long delays, crashes, and many other issues.
So is it possible to make arbitrary holes in a gear in gearotic? (My pulley is 90 teeth, and I want three circles in the body).
Thanks

[ArtF]

Sorry, but it isnt. I havent added any real free form cad ability to it. But you should be able to find one program
or another that would allow a dxf to have 3 circles added to it. Gearotics DXF's are a common flavour and most programs
seem to load them.  I dont use Solid Fusion, is that how you intend to generate the Gcode? Or is this being cut with Gcode?

Art

[tomb18]

Hi,
On the advice of someone on the shapeoko forums I tried out LibreCad software and it allowed me to place the holes without an issue.
Thanks

[ArtF]

Cool, there is always a way. :)

Art

[tomb18]

Well again I spoke too soon.
I am beginning to think that the issue arises from Gearotic and not the other applications.
In Fusion 360, any attempts to modify my gear fail with either crashes or any modifications never appearing when it is brought into MeshCam.
In LibreCad, I can add the holes to the pulley but then importing them into MeshCam results in the size of the gear being miniscule AND the holes are not there either.
I now suspect that there is an error somewhere in the Gearotic gear when it gets this large.
I'm stuck. I've spent ,money, tons of time, and still can't produce what I need no matter whose package I try.
Any suggestions?

[ArtF]

tomb:

Send me the DXF of the gear involved, and if you can explain where the holes need to be, tell me that too, Ill see if I can add
them here. Ive used some pretty large dxf outputs though, havent sen any issue. Your problems with size woudl seem to be metric vs
imperial conversions.. but adding to a dxf really shouldnt be that difficult. Send me the dxf your using so I can check it out ,
and Ill send you one back with holes in it..

Art
(Just send to support @ gearotic.com ) zip it up or it may not transfer..

[tomb18]

Hi,
I'm still working through all of this.  This is what I have found:

Gearotic -> Fusion 360 .....can't add holes.  Fusion 360 crashes or won't allow modification of the gear
Gearotic -> LibreCad -> MeshCam ...meshcam doesn't pick up dimensions and holes are missing.
Gearotic -> LibreCad -> EstlCam ...success.  In every way this one works well.

So it seems that the issue just might be Fusion 360 (for sure...that's why the price dropped to $25 a year lol) and MeshCam.

So so far so good!
Just for reference this is the kind of thing I want except that the outside has the XL teeth.
http://www.stage3motorsports.com/CR0004 ... -Ring.html

Thanks, Tom

[ArtF]

Hi Tom:

  Well, Im glad its working for you at any rate. Welcome to the wonderful world of DXF,
the loosest standard out there. Youll find its a common thing to select your favorite programs
for dealing with dxf's from dealing with the problems on various software. I use vectric, pretty much
bulletproof in my experience..but we all have our favorite..

Art

[tomb18]

Hi,
Well the author of Meshcam looked at the pulley I made and he suggested "no splines" or "convert splines to polylines" or the equivalent.  Apparently lots of software has issues with splines?
He also pointed out that the central 5" hole (shaft ) in my pulley is composed of polylines and is not just a plain circle. Again he suggests a circle would be better.
Thanks, Tom

[ArtF]

Hi Tom:

  Gearotics DXF's are kept purposely simple , they use no splines or arcs typically.
Some do use circles for centers, others use polylines. I purposely try to stay away
from anything other than lines. Rob at Meshcam probably finds the same type of things
as I do with various dxf's... Havent spoken to him for awhile, but Ive known him a long
time. :)

Art