Re: [Emc-users] Printer working, need involute gear designer

[Gene Heskett]

On Thursday 18 June 2020 17:31:52 marcus.bow...@visible.eclipse.co.uk 
wrote:

> Gene,
>
> Have you looked at www.gearotic.com
> or did someone mention that already?
>
> Marcus

No. I downloaded it, but its a winders.exe and I don't have a huge choice 
of winderz stuff installed.  So whats it need in addition to a licence 
file I haven't purchased yet. That can always be a showstopper.  That, 
and winders stuff seems to give me a rash...

So thank you Marcus.


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Gene Heskett]

On Thursday 18 June 2020 17:24:56 N wrote:

> If remember correctly something about involute gear used in a gear
> pump, you need the equation for the geometry?
Not at the moment Nick.  I think I solved that problem with a teeny peristaltic 
pump and a couple of timers rigged to be variable excitation for a mister.

Now I'm in the plotting stage of motorizing a BS-1 clone. Mounting a motor on 
the rear with a belt drive to the center of the tilt axis, then a gear from 
there to the worm.  And I don't even have the idler shaft for the middle of the 
tilt axis made yet, nor have I drilled and tapped that hole in the side of it 
yet.  Waiting on more ats-667's, which I got today.

But with the woof in the shop, I need to organize getting her 401-k 
disbursement going to pay the shop bill till whenever...  End stage COPD. And 
I'm running on a 31% pump so I'm not as fast as you younger whippersnappers.  
Darn it.
.
> > Greeting all;
> >
> > 3d Printer is working and actually making solid parts, now I need to
> > make a couple gears. with enough muscle to drive this BS-1 clone.
> >
> > There's a parametric gear thing I have but its a sample of many gear
> > styles and I don't know how to cut it apart and use just the
> > external spur piece of it. I need something that openscad can
> > handle.  But there must be 1000 or more. Most proprietary so are
> > non-starters.
> >
> > Thanks all.
> >
> > Cheers, Gene Heskett
> > --
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author)
> > If we desire respect for the law, we must first make the law
> > respectable. - Louis D. Brandeis
> > Genes Web page 
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 

___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[marcus . bowman]

Gene,

Have you looked at www.gearotic.com
or did someone mention that already?

Marcus


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[N]

If remember correctly something about involute gear used in a gear pump, you 
need the equation for the geometry?

> Greeting all;
> 
> 3d Printer is working and actually making solid parts, now I need to make 
> a couple gears. with enough muscle to drive this BS-1 clone.
> 
> There's a parametric gear thing I have but its a sample of many gear 
> styles and I don't know how to cut it apart and use just the external 
> spur piece of it. I need something that openscad can handle.  But there 
> must be 1000 or more. Most proprietary so are non-starters.
> 
> Thanks all.
> 
> Cheers, Gene Heskett
> -- 
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[andy pugh]

On Thu, 18 Jun 2020 at 06:43, Gregg Eshelman via Emc-users
 wrote:
>
>  It's Metric gearing's version of 14 DP, for which you don't want to have to 
> come up with replacement gears.

I can make 14DP gears.  (https://youtu.be/xdE46yvckbM)

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[andy pugh]

On Thu, 18 Jun 2020 at 07:35, Chris Albertson  wrote:
>
> In the US, the traditional system uses teeth per inch.

The Inch version of Module is not circular pitch, it is DP, Diametral Pitch.

And the calculations are just as easy in that system, you just divide
rather than multiply.

In your example, if you had two 30T gears at 4DP then the centre to
centre distance is 30T / 4in, ie 7.5in.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Gene Heskett]

On Thursday 18 June 2020 02:32:24 Chris Albertson wrote:

> In the US, the traditional system uses teeth per inch. but the problem
> with this system is "where do you place the tape measure?"  The answer
> is NOT around the outside of the gear.   You need to place the tape
> such that it runs inside the teeth. this is hard to do.  Also here is
> a quiz:You have two gears both 4 "pitch" both are 30 teeth, what
> is the center to center distance?   Can you figure this out in your
> head quickly? I bet not.
>
> Outside the US everyone uses a simple system.  They define "diameter"
> as if the gear were a smooth roller.  So two gears with 40mm diameter
> would have a 40mm center to center distance.  Then they define
> "module" as teeth size that mesh.  so any mod 1.0 gear meshes with any
> mod 1.0 gear.  A mod 0.2 gear meshes with other mod 0.2 gears.
>
> Then and here is the key... "module is the diameter divided by the
> number of teeth"
>
> Example
> (1)   A 40 tooth 40mm diameter gear is module 1.0  it meshes with a
> 20T 20mm diameter gear and the center to center is obviously 20+10=30
> (2) I just printed a Mod. 2.0 gear with 100 teeth. How big is it?  
> Well, some algebra:  2.0 = D/100  So D=200.  It is about 200mm across.
> it is HUGE and covers up most of the build plate on my printer.  The
> mating gear is 25T and you can easily work out the shaft distances
> without the need of a table.
>
> In real life most designs use even number modules like 0.5, 1 or 2.0
> so there are only a handfull of sizes and you learn to identify them
> by sight.
>
> So what is the "pitch" of a mod 1.0 gear?  assume 10T and 10mm
> diameter. The circumstance is 10*pi = 31.4159 mm with 10 teeth the
> pitch is "Pi millimeters" for Mod one.   For mod 2 the pitch is two Pi
> mm and so on.
>
> You don't need a calculator to design stuff with metric gears.
>
> Today there exist countless US standard gears but I can't imagine
> anyone using them in new designs.  Even in the US, the industry is so
> globalized that everyone has switched over.
>
>
>
>
> On Wed, Jun 17, 2020 at 10:43 PM Gregg Eshelman via Emc-users <
>
> emc-users@lists.sourceforge.net> wrote:
> > Module is the Metric version of gear pitch. A google for module gear
> > chart will tell you everything you need to know. There are also
> > module <> diametral pitch converters online in case you're using
> > gear design software that only does Mod or DP but does allow input
> > of arbitrary numbers.
> >
> > My you never ever encounter metric machinery with Mod 2.5 gears.
> > It's Metric gearing's version of 14 DP, for which you don't want to
> > have to come up with replacement gears.

Excellent tut. Makes perfect sense.  Thank you Chris.  

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Chris Albertson]

In the US, the traditional system uses teeth per inch. but the problem with
this system is "where do you place the tape measure?"  The answer is NOT
around the outside of the gear.   You need to place the tape such that it
runs inside the teeth. this is hard to do.  Also here is a quiz:You
have two gears both 4 "pitch" both are 30 teeth, what is the center to
center distance?   Can you figure this out in your head quickly? I bet not.

Outside the US everyone uses a simple system.  They define "diameter" as if
the gear were a smooth roller.  So two gears with 40mm diameter would have
a 40mm center to center distance.  Then they define "module" as teeth
size that mesh.  so any mod 1.0 gear meshes with any mod 1.0 gear.  A mod
0.2 gear meshes with other mod 0.2 gears.

Then and here is the key... "module is the diameter divided by the number
of teeth"

Example
(1)   A 40 tooth 40mm diameter gear is module 1.0  it meshes with a 20T
20mm diameter gear and the center to center is obviously 20+10=30
(2) I just printed a Mod. 2.0 gear with 100 teeth. How big is it?   Well,
some algebra:  2.0 = D/100  So D=200.  It is about 200mm across. it is HUGE
and covers up most of the build plate on my printer.  The mating gear is
25T and you can easily work out the shaft distances without the need of a
table.

In real life most designs use even number modules like 0.5, 1 or 2.0 so
there are only a handfull of sizes and you learn to identify them by sight.

So what is the "pitch" of a mod 1.0 gear?  assume 10T and 10mm diameter.
The circumstance is 10*pi = 31.4159 mm with 10 teeth the pitch is "Pi
millimeters" for Mod one.   For mod 2 the pitch is two Pi mm and so on.

You don't need a calculator to design stuff with metric gears.

Today there exist countless US standard gears but I can't imagine
anyone using them in new designs.  Even in the US, the industry is so
globalized that everyone has switched over.




On Wed, Jun 17, 2020 at 10:43 PM Gregg Eshelman via Emc-users <
emc-users@lists.sourceforge.net> wrote:

> Module is the Metric version of gear pitch. A google for module gear chart
> will tell you everything you need to know. There are also module <>
> diametral pitch converters online in case you're using gear design software
> that only does Mod or DP but does allow input of arbitrary numbers.
>
> My you never ever encounter metric machinery with Mod 2.5 gears. It's
> Metric gearing's version of 14 DP, for which you don't want to have to come
> up with replacement gears.
>
> On Wednesday, June 17, 2020, 9:45:33 PM MDT, Gene Heskett <
> ghesk...@shentel.net> wrote:
>  On Wednesday 17 June 2020 22:23:23 Chris Albertson wrote:
>
>
> > About printed gears.  One thing, just don't try for smaller than
> > about module 1.0.  Yes, 0.5 will mesh but the error in shape is high
> > as they get smaller.
>
> Module is a term I've never met in that context. Where can I find a
> tutorial on it as applied to gears?
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Gregg Eshelman via Emc-users]

Module is the Metric version of gear pitch. A google for module gear chart will 
tell you everything you need to know. There are also module <> diametral pitch 
converters online in case you're using gear design software that only does Mod 
or DP but does allow input of arbitrary numbers.
 
My you never ever encounter metric machinery with Mod 2.5 gears. It's Metric 
gearing's version of 14 DP, for which you don't want to have to come up with 
replacement gears.

On Wednesday, June 17, 2020, 9:45:33 PM MDT, Gene Heskett 
 wrote:  
 On Wednesday 17 June 2020 22:23:23 Chris Albertson wrote:


> About printed gears.  One thing, just don't try for smaller than
> about module 1.0.  Yes, 0.5 will mesh but the error in shape is high
> as they get smaller.

Module is a term I've never met in that context. Where can I find a 
tutorial on it as applied to gears?  
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Bruce Layne]

I still say you guys need to print gears on an MSLA resin printer using
a dense high durometer polyurethane structural resin.  They'd not only
look like high quality injection molded parts, they'd be as strong as
injection molded parts.  Email me an STL and a USPS mailing address and
I'll see what I can do.

I finally learned how to engrave text in FreeCAD tonight, so I could put
your name on your gear for you.   :-)




On 6/18/20 1:09 AM, Chris Albertson wrote:
> The theory with printed gears is that with helical gears there is more
> material in contact so the stress on the teeth is reduced and that for
> plastic we need this extra strength.   But what I found is that teeth never
> fail.  The hubs fail first.
>
> The better reason for helical gears is that they are quieter.  But if they
> move slow, all gears are quiet.
>
> Try breaking stuff, it's fun.  especially if the material cost only 2 cents
> per gram.  If you have parts that did not come out as you like.  Try
> crushing them in a vice, whacking with a hammer or screw it to a shaft and
> see what it takes to break the set screw.
>
> On Wed, Jun 17, 2020 at 9:03 PM Gene Heskett  wrote:
>
>> On Wednesday 17 June 2020 22:28:22 andy pugh wrote:
>>
>>> On Thu, 18 Jun 2020 at 03:04, Gene Heskett 
>> wrote:
> Note, these are a daft idea. But I have actually seen a 9 foot
> diameter triple helical in my dad's old workplace. He did need to
> explain to me why it was silly, and why they refused to replace it
> and specced a double instead.
 That's easy, the teeth in the middle were carrying twice the thrust
 load.
>>> It isn't that it is that it is kinematically redundant, one of the
>>> sets of teeth will see no load at all.
>> Or, given manufacturing tolerances it could even dance from one set of
>> teeth to the other. I was assuming a perfect make, where the outside
>> rows of teeth would be carrying half the thrust load per side that the
>> middle row was carrying by itself.  But it never got a chance to wear in
>> and achieve even that.
>>
>>> (Though possibly, over time, they might wear to share equally)
>>
>> Cheers, Gene Heskett
>> --
>> "There are four boxes to be used in defense of liberty:
>>  soap, ballot, jury, and ammo. Please use in that order."
>> -Ed Howdershelt (Author)
>> If we desire respect for the law, we must first make the law respectable.
>>  - Louis D. Brandeis
>> Genes Web page 
>>
>>
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Chris Albertson]

The theory with printed gears is that with helical gears there is more
material in contact so the stress on the teeth is reduced and that for
plastic we need this extra strength.   But what I found is that teeth never
fail.  The hubs fail first.

The better reason for helical gears is that they are quieter.  But if they
move slow, all gears are quiet.

Try breaking stuff, it's fun.  especially if the material cost only 2 cents
per gram.  If you have parts that did not come out as you like.  Try
crushing them in a vice, whacking with a hammer or screw it to a shaft and
see what it takes to break the set screw.

On Wed, Jun 17, 2020 at 9:03 PM Gene Heskett  wrote:

> On Wednesday 17 June 2020 22:28:22 andy pugh wrote:
>
> > On Thu, 18 Jun 2020 at 03:04, Gene Heskett 
> wrote:
> > > > Note, these are a daft idea. But I have actually seen a 9 foot
> > > > diameter triple helical in my dad's old workplace. He did need to
> > > > explain to me why it was silly, and why they refused to replace it
> > > > and specced a double instead.
> > >
> > > That's easy, the teeth in the middle were carrying twice the thrust
> > > load.
> >
> > It isn't that it is that it is kinematically redundant, one of the
> > sets of teeth will see no load at all.
>
> Or, given manufacturing tolerances it could even dance from one set of
> teeth to the other. I was assuming a perfect make, where the outside
> rows of teeth would be carrying half the thrust load per side that the
> middle row was carrying by itself.  But it never got a chance to wear in
> and achieve even that.
>
> > (Though possibly, over time, they might wear to share equally)
>
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Gene Heskett]

On Wednesday 17 June 2020 22:28:22 andy pugh wrote:

> On Thu, 18 Jun 2020 at 03:04, Gene Heskett  
wrote:
> > > Note, these are a daft idea. But I have actually seen a 9 foot
> > > diameter triple helical in my dad's old workplace. He did need to
> > > explain to me why it was silly, and why they refused to replace it
> > > and specced a double instead.
> >
> > That's easy, the teeth in the middle were carrying twice the thrust
> > load.
>
> It isn't that it is that it is kinematically redundant, one of the
> sets of teeth will see no load at all.

Or, given manufacturing tolerances it could even dance from one set of 
teeth to the other. I was assuming a perfect make, where the outside 
rows of teeth would be carrying half the thrust load per side that the 
middle row was carrying by itself.  But it never got a chance to wear in 
and achieve even that.

> (Though possibly, over time, they might wear to share equally)


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Gene Heskett]

On Wednesday 17 June 2020 22:10:02 Chris Albertson wrote:

> Go to McMaster Carr and find a stock gear you like.  If they don't
> have one you like then Grainger, SPD/SI or Boston Gear will
>
> All those sites allow you to download a CAD file of the stock gear. 
> Of the CAD file types "step" (or ".stp") is the most universal.
>
> Then you use your CAD software to modify it.  Use OpenSCAD if you like
> but OpenSCAD has the steepest learning curve by far of anything you
> will find. It is not for casual users.

Yet its script like language allowed me to modify it with a reasonable 
expectation that it will work.  It took me about 10 minutes to convert a 
sprocket with a hub and flanges, to make it into the printable half 
sprocket with one flange I could make a much stronger alu hub and other 
edge flange for.  I'm totally lost in freecad long before ten minutes is 
up.

> One of the direct modeling 
> systems works pretty much like you would in the shop where you think
> in terms of drilling holes and making cuts, not in terms of
> programming to create geometry.
>
> On Wed, Jun 17, 2020 at 6:23 PM Gene Heskett  
wrote:
> > Greeting all;
> >
> > 3d Printer is working and actually making solid parts, now I need to
> > make a couple gears. with enough muscle to drive this BS-1 clone.
> >
> > There's a parametric gear thing I have but its a sample of many gear
> > styles and I don't know how to cut it apart and use just the
> > external spur piece of it. I need something that openscad can
> > handle.  But there must be 1000 or more. Most proprietary so are
> > non-starters.
> >
Thanks all.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Gene Heskett]

On Wednesday 17 June 2020 22:23:23 Chris Albertson wrote:

> You can make a double-helical by downloading a left and a right
> helical and sticking them together.  You do not even need to know what
> "involute" means as you just cut and past from McMaster Carr. Just
> keep faith that they know how to design exotic stuff like spiral
> bevels, they do.
>
> Designing gears got so much easier when I found that all the gear
> resellers give away their designs.
>
> One other big advantage yo downloading a stock gear is that later when
> you need a metal version of thegear, you know you can get one.
>
> In theory, you should be able to mill these exotic gears on a mill if
> only you had a small enough ball end mill.  It makes take a week.
>
> About printed gears.   One thing, just don't try for smaller than
> about module 1.0.  Yes, 0.5 will mesh but the error in shape is high
> as they get smaller.

Module is a term I've never met in that context. Where can I find a 
tutorial on it as applied to gears?

> On Wed, Jun 17, 2020 at 6:44 PM andy pugh  wrote:
> > On Thu, 18 Jun 2020 at 02:23, Gene Heskett  
wrote:
> > > There's a parametric gear thing I have but its a sample of many
> > > gear styles and I don't know how to cut it apart and use just the
> > > external spur piece of it. I need something that openscad can
> > > handle.
> >
> > You could take OpensCAD out of the loop, I suspect, and print the
> > gears from the stock part models from (for example) McMaster Carr
> >
> > Or you could tell me the centres, tooth size and PCD you need and I
> > can send back a model from Inventor in not much time.
> >
> > But why use spur gears? One thing that 3D printing is good at is
> > double helicals.
> >
> > Or even triple, or quad. But those are stupid:
> > https://images.app.goo.gl/ZbZBVWoBEnRbPL469
> >
> > Note, these are a daft idea. But I have actually seen a 9 foot
> > diameter triple helical in my dad's old workplace. He did need to
> > explain to me why it was silly, and why they refused to replace it
> > and specced a double instead.
> > --
> > atp
> > "A motorcycle is a bicycle with a pandemonium attachment and is
> > designed for the especial use of mechanical geniuses, daredevils and
> > lunatics."
> > — George Fitch, Atlanta Constitution Newspaper, 1912
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[andy pugh]

On Thu, 18 Jun 2020 at 03:04, Gene Heskett  wrote:

> > Note, these are a daft idea. But I have actually seen a 9 foot
> > diameter triple helical in my dad's old workplace. He did need to
> > explain to me why it was silly, and why they refused to replace it and
> > specced a double instead.
>
> That's easy, the teeth in the middle were carrying twice the thrust load.

It isn't that it is that it is kinematically redundant, one of the
sets of teeth will see no load at all.
(Though possibly, over time, they might wear to share equally)

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Chris Albertson]

You can make a double-helical by downloading a left and a right helical and
sticking them together.  You do not even need to know what "involute" means
as you just cut and past from McMaster Carr. Just keep faith that they know
how to design exotic stuff like spiral bevels, they do.

Designing gears got so much easier when I found that all the gear
resellers give away their designs.

One other big advantage yo downloading a stock gear is that later when you
need a metal version of thegear, you know you can get one.

In theory, you should be able to mill these exotic gears on a mill if only
you had a small enough ball end mill.  It makes take a week.

About printed gears.   One thing, just don't try for smaller than about
module 1.0.  Yes, 0.5 will mesh but the error in shape is high as they get
smaller.



On Wed, Jun 17, 2020 at 6:44 PM andy pugh  wrote:

> On Thu, 18 Jun 2020 at 02:23, Gene Heskett  wrote:
>
> > There's a parametric gear thing I have but its a sample of many gear
> > styles and I don't know how to cut it apart and use just the external
> > spur piece of it. I need something that openscad can handle.
>
> You could take OpensCAD out of the loop, I suspect, and print the
> gears from the stock part models from (for example) McMaster Carr
>
> Or you could tell me the centres, tooth size and PCD you need and I
> can send back a model from Inventor in not much time.
>
> But why use spur gears? One thing that 3D printing is good at is
> double helicals.
>
> Or even triple, or quad. But those are stupid:
> https://images.app.goo.gl/ZbZBVWoBEnRbPL469
>
> Note, these are a daft idea. But I have actually seen a 9 foot
> diameter triple helical in my dad's old workplace. He did need to
> explain to me why it was silly, and why they refused to replace it and
> specced a double instead.
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Chris Albertson]

Go to McMaster Carr and find a stock gear you like.  If they don't have one
you like then Grainger, SPD/SI or Boston Gear will

All those sites allow you to download a CAD file of the stock gear.  Of the
CAD file types "step" (or ".stp") is the most universal.

Then you use your CAD software to modify it.  Use OpenSCAD if you like but
OpenSCAD has the steepest learning curve by far of anything you will find.
It is not for casual users.   One of the direct modeling systems works
pretty much like you would in the shop where you think in terms of drilling
holes and making cuts, not in terms of programming to create geometry.

On Wed, Jun 17, 2020 at 6:23 PM Gene Heskett  wrote:

> Greeting all;
>
> 3d Printer is working and actually making solid parts, now I need to make
> a couple gears. with enough muscle to drive this BS-1 clone.
>
> There's a parametric gear thing I have but its a sample of many gear
> styles and I don't know how to cut it apart and use just the external
> spur piece of it. I need something that openscad can handle.  But there
> must be 1000 or more. Most proprietary so are non-starters.
>
> Thanks all.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[Gene Heskett]

On Wednesday 17 June 2020 21:41:07 andy pugh wrote:

> On Thu, 18 Jun 2020 at 02:23, Gene Heskett  
wrote:
> > There's a parametric gear thing I have but its a sample of many gear
> > styles and I don't know how to cut it apart and use just the
> > external spur piece of it. I need something that openscad can
> > handle.
>
> You could take OpensCAD out of the loop, I suspect, and print the
> gears from the stock part models from (for example) McMaster Carr
>
> Or you could tell me the centres, tooth size and PCD you need and I
> can send back a model from Inventor in not much time.
>
That (centres) I don't know yet, and won't until I can get the 
intermediate idler shaft made & installed.

> But why use spur gears? One thing that 3D printing is good at is
> double helicals.

That thought crossed my mind also.  Seems to me the thrust would nicely 
balance making it self center, and the rotational accuracy would be 
improved over a straight spur gear. But for any of them I need the 
center distances, hard to measure in its present state.  And I'm stuck 
waiting on Digi-key to mail me a 10 pack of ATS-667's ATM.

> Or even triple, or quad. But those are stupid:
> https://images.app.goo.gl/ZbZBVWoBEnRbPL469
>
> Note, these are a daft idea. But I have actually seen a 9 foot
> diameter triple helical in my dad's old workplace. He did need to
> explain to me why it was silly, and why they refused to replace it and
> specced a double instead.

That's easy, the teeth in the middle were carrying twice the thrust load.

Thanks Andy.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Printer working, need involute gear designer

[andy pugh]

On Thu, 18 Jun 2020 at 02:23, Gene Heskett  wrote:

> There's a parametric gear thing I have but its a sample of many gear
> styles and I don't know how to cut it apart and use just the external
> spur piece of it. I need something that openscad can handle.

You could take OpensCAD out of the loop, I suspect, and print the
gears from the stock part models from (for example) McMaster Carr

Or you could tell me the centres, tooth size and PCD you need and I
can send back a model from Inventor in not much time.

But why use spur gears? One thing that 3D printing is good at is
double helicals.

Or even triple, or quad. But those are stupid:
https://images.app.goo.gl/ZbZBVWoBEnRbPL469

Note, these are a daft idea. But I have actually seen a 9 foot
diameter triple helical in my dad's old workplace. He did need to
explain to me why it was silly, and why they refused to replace it and
specced a double instead.
-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users