H19, H88, H89, Z90 Detachable Hinge

[Kenneth L. Owen]

Hi All,

 

More than once, the topic of replacements for the plastic hinge used on the cabinet top for H-19, H-88, H-89 and Z-90 computer has been on SEBHC.  I, too, have some units with broken hinges.  I decided to see what could be done.

 

First, I worked out a simple metal hinge replacement and took it to my machinist.  He told me this was a good candidate for 3D Printing.  Norberto’s son, Hector, is taking a course on 3D printing and he developed the model file.  The print he made fit and worked but was not a polished part and there was some reservation about strength and durability.  Mr. Gene Buckle felt that a properly printed part should work just fine.  We sent him the model file, he printed two sets of hinges and sent them to me for evaluation.  They arrived this morning.

 

I installed a set of hinges, no problem – perfect fit.  The top installed and operated just like with the original hinge.  Now I am ready to evaluate the durability, but HOW short of breaking it.

 

Attached is a PDF picture of the hinges and the 2D drawing from which the model was made.

 

Comments and suggestions will be appreciated.

 

If any need new hinges and want to get a set for evaluation, please contact Mr. Gene Buckle who can give a price for a set

 

-- ken

[Glenn Roberts]

Well the engineering approach here would involve:

 

1. Analyze the hinge to determine the weakest point (examples of ones that have previously broken would be useful for this)
2. Analyze what likely would cause (or in the case of actual broken pieces what caused) the piece to break.
3. Print some extra parts for “destructive testing”
4. Try doing step 2 until you can break the part, then see where/why it broke
5. Make changes to improve, e.g. maybe make part of the hinge thicker, or try a different kind of plastic…

 

It would be hard to truly test the hinge without breaking a few… (but they cost next to nothing to print!)

 

• Glenn

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[Kenneth L. Owen]

Hi Glenn,

 

Yes, that is basically the way I am going at it.

 

So far as the study of the currently broken parts, I believe that they probably broke when some wiring in the power supply area was improperly dressed so it was between the lower case and the cabinet top when the cabinet top was fully closed (and latched).  Another possible scenario is that the top was removed for access to the internals and the hinges were broken by dropping the top or some other application of force in the storage area.

 

-- ken

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/029b01d3b88b%2417c381d0%24474a8570%24%40gmail.com.

[Norberto Collado]

Cool!

 

Ken,

 

I’m having a co-worker reviewing my son’s 3D drawings to improve the design. I should have new parts next week to test them out.

 

Thanks,

Norberto

 

From: "se...@googlegroups.com" <se...@googlegroups.com> on behalf of "Kenneth L. Owen" <tx83...@bellsouth.net>
Reply-To: "se...@googlegroups.com" <se...@googlegroups.com>
Date: Saturday, March 10, 2018 at 7:20 AM
To: "se...@googlegroups.com" <se...@googlegroups.com>
Subject: [sebhc] H19, H88, H89, Z90 Detachable Hinge

 

Hi All,

--

[Glenn Roberts]

Awesome!  At least one of those tests is repeatable (the cable thing).  Not sure you want to toss the lid on the floor though…!

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/F20D6A8C338C4FA0867600897F8E4C27%40KenPSPC.

[geneb]

On Sat, 10 Mar 2018, Kenneth L. Owen wrote:

> If any need new hinges and want to get a set for evaluation, please
> contact Mr. Gene Buckle who can give a price for a set

I'll print anyone a set or two for the price of mailing them - $4ish if
memory serves.

g.

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[walter]

Any chance of posting an .STL file for the hinge?

 

..walt 

[geneb]

On Sat, 10 Mar 2018, Norberto Collado wrote:

> I’m having a co-worker reviewing my son’s 3D drawings to improve the
> design. I should have new parts next week to test them out.

Norberto, your son did an excellent job on the design. He just needs to
make sure he uses metric next time - all the slicing software for 3D
printers use metric. It will avoid any potential scaling issues. ;)

[geneb]

On Sat, 10 Mar 2018, walter wrote:

>
>>
>> Any chance of posting an .STL file for the hinge?
>>
>

I think Norberto did that early last week.

[Norberto Collado]

Thanks, and I will him know.

Norberto

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[Norberto Collado]

Ken,

My co-worker brought a new hinge and it is very strong. Attached is the latest picture. 

Thanks,

Norberto

-------- Original Message --------
Subject: Re: [sebhc] H19, H88, H89, Z90 Detachable Hinge

From: Norberto Collado <norberto...@koyado.com>
Date: Sat, March 10, 2018 3:06 pm
To: "se...@googlegroups.com" <se...@googlegroups.com>

Cool!

 

Ken,

 

I’m having a co-worker reviewing my son’s 3D drawings to improve the design. I should have new parts next week to test them out.

 

Thanks,

Norberto

 

From: "se...@googlegroups.com" <se...@googlegroups.com> on behalf of "Kenneth L. Owen" <tx83...@bellsouth.net>

Reply-To: "se...@googlegroups.com" <se...@googlegroups.com>
Date: Saturday, March 10, 2018 at 7:20 AM

To: "se...@googlegroups.com" <se...@googlegroups.com>
Subject: [sebhc] H19, H88, H89, Z90 Detachable Hinge

Hi All,

 

More than once, the topic of replacements for the plastic hinge used on the cabinet top for H-19, H-88, H-89 and Z-90 computer has been on SEBHC.  I, too, have some units with broken hinges.  I decided to see what could be done.

 

First, I worked out a simple metal hinge replacement and took it to my machinist.  He told me this was a good candidate for 3D Printing.  Norberto’s son, Hector, is taking a course on 3D printing and he developed the model file.  The print he made fit and worked but was not a polished part and there was some reservation about strength and durability.  Mr. Gene Buckle felt that a properly printed part should work just fine.  We sent him the model file, he printed two sets of hinges and sent them to me for evaluation.  They arrived this morning.

 

I installed a set of hinges, no problem – perfect fit.  The top installed and operated just like with the original hinge.  Now I am ready to evaluate the durability, but HOW short of breaking it.

 

Attached is a PDF picture of the hinges and the 2D drawing from which the model was made.

 

Comments and suggestions will be appreciated.

 

If any need new hinges and want to get a set for evaluation, please contact Mr. Gene Buckle who can give a price for a set

 

-- ken

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[Kenneth L. Owen]

Hi Norberto,

 

We now have hinges made from different sources and materials.

 

To gain an objective analysis, we need to do a number of things:

 

Since all were made using the same model file from Hector:

 

    1.    List the material used to make the hinge.

    2.    List the model of printer.

    3.    Break the hinges of each type using some quantitative process to determine the strongest hinge.

 

I have been thinking about how to do this and propose something similar to the attached.

 

-- ken

 

From: Norberto Collado

Sent: Monday, March 12, 2018 1:02 AM

To: se...@googlegroups.com

Subject: RE: [sebhc] H19, H88, H89, Z90 Detachable Hinge

Ken,

 

My co-worker brought a new hinge and it is very strong. Attached is the latest picture.

 

Thanks,

Norberto

 

-------- Original Message --------
Subject: Re: [sebhc] H19, H88, H89, Z90 Detachable Hinge
From: Norberto Collado <norberto...@koyado.com>
Date: Sat, March 10, 2018 3:06 pm
To: "se...@googlegroups.com" <se...@googlegroups.com>

Cool!

 

Ken,

 

I’m having a co-worker reviewing my son’s 3D drawings to improve the design. I should have new parts next week to test them out.

 

Thanks,

Norberto

 

From: "se...@googlegroups.com" <se...@googlegroups.com> on behalf of "Kenneth L. Owen" <mailto:tx83...@bellsouth.net>
Reply-To: "se...@googlegroups.com" <se...@googlegroups.com>
Date: Saturday, March 10, 2018 at 7:20 AM
To: "se...@googlegroups.com" <se...@googlegroups.com>
Subject: [sebhc] H19, H88, H89, Z90 Detachable Hinge

 

Hi All,

 

More than once, the topic of replacements for the plastic hinge used on the cabinet top for H-19, H-88, H-89 and Z-90 computer has been on SEBHC.  I, too, have some units with broken hinges.  I decided to see what could be done.

 

First, I worked out a simple metal hinge replacement and took it to my machinist.  He told me this was a good candidate for 3D Printing.  Norberto’s son, Hector, is taking a course on 3D printing and he developed the model file.  The print he made fit and worked but was not a polished part and there was some reservation about strength and durability.  Mr. Gene Buckle felt that a properly printed part should work just fine.  We sent him the model file, he printed two sets of hinges and sent them to me for evaluation.  They arrived this morning.

 

I installed a set of hinges, no problem – perfect fit.  The top installed and operated just like with the original hinge  Now I am ready to evaluate the durability, but HOW short of breaking it.

 

Attached is a PDF picture of the hinges and the 2D drawing from which the model was made.

 

Comments and suggestions will be appreciated.

 

If any need new hinges and want to get a set for evaluation, please contact Mr. Gene Buckle who can give a price for a set

 

-- ken

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[Norberto Collado]

Hello Ken,

I hope to get more hinges next week and will send then to you to evaluate. At least now, we do have a simple solution to replace them. This is due to your efforts in putting together the 2-D CAD diagram and I thank you for such.

Thanks,

Norberto

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/E83760C3EC4C4F03A8820A09D87A3600%40KenPSPC.

[Alan Hampson]

Ken & Norberto,

Just to weigh in (pun definitely intended :) ), does it really matter? If we have hinges that fit, work, seem to hold their own under normal use and can be printed as needed, does it matter in the long run which is strongest?

I can be just as curious as this, but I wonder if you are putting too much concern into which hinge is the strongest when actually any of them would do?

BTW, I think the blue color is awesome and I do appreciate the effort everyone is putting into this!

Just my two cents,

    alan

[Glenn Roberts]

I think you’re right Alan.  We can learn from “practical testing” if these are strong enough.  I’d say install and use them and see how they work…

 

From: se...@googlegroups.com <se...@googlegroups.com> On Behalf Of Alan Hampson
Sent: Monday, March 12, 2018 10:12 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] H19, H88, H89, Z90 Detachable Hinge

 

Ken & Norberto,

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[Norberto Collado]

I agree! :) 

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/000701d3baae%24e4851880%24ad8f4980%24%40gmail.com.

[Kenneth L. Owen]

I don’t have a problem with not testing except that Gene Buckle asked me to test the PLA versus the ABS to see which was better.

 

The one that I mounted for fit and initial operational test was the PLA.  I will test the two types so I can give Gene some feedback.

 

-- ken

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/20180313124344.1321cca37f09b4ab87c5049afdc8ceaa.c4a2b90e69.wbe%40email09.godaddy.com.

[Glenn Roberts]

This will be an interesting experiment Ken.  I believe conventional logic suggests that the ABS should be stronger.  I’ll be interested to see what you find!

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/7FC385EB1E7A4949867CFF921D1ED39C%40KenPSPC.

[Lee Hart]

Glenn Roberts wrote:
> This will be an interesting experiment Ken. I believe conventional logic
> suggests that the ABS should be stronger. I’ll be interested to see what you find!

Besides, breaking things is always fun. You too could have an exciting career in
QC testing. :-)

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something, build a new model that makes the existing model obsolete.
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[geneb]

On Tue, 13 Mar 2018, Kenneth L. Owen wrote:

> I don’t have a problem with not testing except that Gene Buckle asked me
> to test the PLA versus the ABS to see which was better.
>
> The one that I mounted for fit and initial operational test was the PLA.
> I will test the two types so I can give Gene some feedback.

Both materials may work equally well - PLA is just easier to print for
less experienced users. ABS can be a black art at times. :)

[dwight]

There was a youtube video of using different 3D printed materials to replace a broken prop on an outboard motor. ABS is more ridged but that also usually means it is more brittle. As I recall, almost all failed at the spline that didn't have the blades crack first.

You might try to track that video down.

Dwight

---

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of geneb <ge...@deltasoft.com>
Sent: Wednesday, March 14, 2018 7:18:17 AM
To: se...@googlegroups.com

Subject: Re: [sebhc] H19, H88, H89, Z90 Detachable Hinge

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[geneb]

On Wed, 14 Mar 2018, dwight wrote:

> There was a youtube video of using different 3D printed materials to
> replace a broken prop on an outboard motor. ABS is more ridged but that
> also usually means it is more brittle. As I recall, almost all failed at
> the spline that didn't have the blades crack first.
>

PLA is more brittle than ABS is. ABS will bend before it breaks. PLA
will snap.

[Bob Groh]

There are also some exotic drafting packages out there (well beyond most of us mortals) that will do stress analysis of the 3D structures.  Perhaps someone knows someone who knows someone who has access to something like that and they can 'tune' up the design if needed.  

BOb Groh

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[geneb]

On Sun, 11 Mar 2018, Norberto Collado wrote:

> Ken,
>
> My co-worker brought a new hinge and it is very strong. Attached is the
> latest picture. 

I finally had a chance to look at the photo.

The part is printed with the layer lines in parallel with the application
of force (if I understand how the hinge works). This means that the part
is prone to failure due to layer separation. The hinges I printed have
the layers perpendicular to the application of force. The difference
being that the force is being applied against the material strength
instead of the inter-layer bonding strengh.

[Kenneth L. Owen]

Hi Gene,

I believed you to be a smart man. Now, it is confirmed.

-- ken

-----Original Message-----
From: geneb
Sent: Wednesday, March 14, 2018 12:22 PM
To: se...@googlegroups.com

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[geneb]

On Wed, 14 Mar 2018, Kenneth L. Owen wrote:

> Hi Gene,
>
> I believed you to be a smart man. Now, it is confirmed.
>

Thanks Ken. I've been accused of the opposite enough times. *laughs*