Bad Gear Design, Shapeways would not print it.

[landcrush]

I designed this gear using the spur gear script in Fusion 360. The specifications from the practical machinists forum were used as follows:

The original gears are 16 DP, 14.5 PA, 5/8 bore, 1/2 face width. 

I then added an ansi standard keyway for this diameter hole

This is what I got. The keyway is too close to the root diameter of the gear and could not be printed.

 

Trying hard to understand what I'm missing here. File attached.

[laughingcreek]

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@landcrush wrote:

...I then added an ansi standard keyway for this diameter hole...

did the original have that keyway?

the gear was made exactly per your input, but it's to thin at that keyway for shipways to print properly.   .6mm is really thin for 3dpriting.

[landcrush]

Okay, I've re-measured the keyway and redone this model with the most exacting of measurements. The keyway is .180 wide and .08 deep. This gives me a distance of .035294 ( 8.964676 mm for you metric heads ) from the bottom of the keyway to the edge of the root radius. I wonder if this will print.

 

[etfrench]

The gear may be available from Boston Gear.  It would probably be higher quality than one 3d printed.

[landcrush]

Hello again my friend. I've had a quote request in with their local distributor in Albany, OR for over a week. Can't seem to get a response. I even called them and the CSR gave me a different email to send the quote request into, said she'd follow through and make sure it got read. NOTHING.

[billbedford]

What material are you attempting to print this from? and did you check the minimum wall thickness on the material's design page?

For instance, the minimum wall for their binder jetted steel is 1mm, and for the stainless steel it's 0.8mm

[landcrush]

Stainless

[billbedford]

Your calculation is out. 

0.035294in * 25.4 = 0.8964676mm

So I can see why Shapeways would be leery of accepting this file for printing

[landcrush]

There was never a calculation, there was only a measurement with a micrometer. Don’t have  clue where you fabricated that 25.4 number from, but the conversion from imperial to metric was done with the conversion function on a scientific calculator, and if you had bothered to read the entire thread, you would know that this current measurement of 8.964676 is different from the original one that was rejected. So what was the point of your reply anyway? Was there anything helpful or useful there?

[TheCADWhisperer]

I tried to get this information earlier, let me try again -

Can you post an image of the shaft where that gear is to be mounted (as close as possible and still in focus and looking right down the axis (so that it appears circular))?

I am then going to request one more photo, but let’s get this one first.

[billbedford]

I Inch = 2.54 centimetres = 25.4 millimetres

So 0.035294 inches, as per your drawing above, = 0.8964676 millimetres and so was close to the minimum wall thickness that Shapeways specified. 

[TheCADWhisperer]

@landcrush 

Did you ever figure this out?

I was expecting to see something more like this... (exaggerated for illustration).

[landcrush]

This is what the change gears look like. This is every one except the missing one.

This is where the missing 16 tooth gear is supposed to go. The threaded end is only there to hold the gear on once it's been installed.

The gear picture below is the 32 tooth version of the gear I need. Imagine this one half the size with 16 teeth. That is what I need.

[etfrench]

Do you need the 16 tooth gear for a specific project?  A change gear calculator may be able to find a different combination that works.

[landcrush]

If you take a look at the change gear chart below, you can see that the 16 tooth gear is needed as a stud gear for all 22, 24, 26, 28, 30, 32, 36, and 40 pitch threads and also as a thread gear for 64 pitch threads. It is necessary.

[TheCADWhisperer]

Is that a removable collar with a welded key on the threaded shaft?

Can you rotate the shaft up 90 deg at take another photo?

From that angle the thread appears to disappear into a collar rather than having lead off.

Even the key way appears to be cut into the thread which wouldn’t be needed unless that is a removable collar.

[etfrench]

None of the above.  It's a simple shaft with a keyway. More likely a collar with a keyway. My Logan 400 is nearly identical.

[TheCADWhisperer]

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@etfrench wrote:

 My Logan 400 is nearly identical.

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Show picture of same spec 16t gear with hole and key way the given size.

The only way I can see this possible is if that is a removable collar permitting the 16t gear to have a smaller hole than what the OP has specified.

[TheCADWhisperer]

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@TheCADWhisperer wrote:

Is that a removable collar with a welded key…

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I realized I wrote this in an awkward way.

The key (pun intended) information I am trying to ascertain is that a removable collar I see on the mounting shaft?

[TheCADWhisperer]

@landcrush 

Where did you go?

Logically you cannot physically have a gear with those specs with a hole and keyway that large - so something is missing in this problem description.

It appears to me that if that is a collar that can be removed you could have a 16T gear with a smaller hole diameter.