HP 91/92/97/97s printer spur (idler) gear

[Geoff Quickfall]

Firstly, thanks Katie for the following as I did use this repair on my first 97:

http://www.hpmuseum.org/cgi-sys/cgiwrap/...gi?read=84

Now in know there have been replacements but i am obviously not doing the correct search as I cannot find the recent posts. However, the waiting period has been over a year so here are the specs, thanks Katie! (Reproduced from Katie's article):

- 80 pitch - measured by the pitch diameter method (not the circumferential pitch method)
- 30 teeth
- 1/10" gear face
- 1/4" hub diameter
- 5/64" hub projection
- 3/32" bore
- made of Delrin or nylon

The reason for the post and Katie's specs is that I am too lazy to measure myself, her article has helped me fix four printers but there are no sources for the fear including DAVEHAL2001 who used to sell on EBay.

As a result, I am thinking of a Shapeways product (I need four) available for all to order. I am a newbie and would need help setting up the print with the above specs.

Geoff

[Jlouis]

Thanks for post it, Geoff.

I need 2.

Cheers

JL

[rprosperi]

I believe Adam (aj04062 here on the Forum) had a batch made a year or two ago, and perhaps he still has some available.

[Geoff Quickfall]

Bob,

Thats right Bob, and I have been waiting a year for some. Adam needs a minimum order of, I think, forty. So far not happening, so if I can get Shapeways to make on demand it may simply things.

Cheers, Geoff

No slight against Adam, and that's the posting I could not find, but I want these running :-)

[Katie Wasserman]

It seems to me that Shapeways is a very expensive way to go. Just an idea.... has anyone asked Eric Rechlin if this is something that he'd like to stock on his e-store site? He could order the 40 minimum (or more) and make a profit selling them one or two at a time. I think it would be a pretty popular item once word got out about it.

[Geoff Quickfall]

Thanks Katie,

Everything is cost dependent :-(

Geoff

[Etienne Victoria]

Geoff,

As a fallback if you don't get your gears from Shapeways, I still have 2 753030 gears I ordered from GHW-MODELLBAUVERSAND years ago.



from this site: See Stirnräder aus Messing Modul 0,3 Line 16

They are brass and you would have to drill them for the correct ID as described here.

Etienne

Edited to update vendor name and item reference.

[Geoff Quickfall]

Etienne!

I may take you up on that. Both Shapeways is turning out to be expensive and my other source would need a gear cutter fabricated (expensive).

Give me a little while to see how to sort this out. So far Shapeways modeller has stated 20 dollars a gear just for modelling it to my standards with examples for refinement. Then the Shapeways cost on top of that if I read his posting correctly. Don't know what the Shapeways costs are yet.

Geoff

[Jlouis]

(04-11-2016 05:29 PM)Geoff Quickfall Wrote:  Etienne!

I may take you up on that. Both Shapeways is turning out to be expensive and my other source would need a gear cutter fabricated (expensive).

Give me a little while to see how to sort this out. So far Shapeways modeller has stated 20 dollars a gear just for modelling it to my standards with examples for refinement. Then the Shapeways cost on top of that if I read his posting correctly. Don't know what the Shapeways costs are yet.

Geoff

If you wish, we can share this cost

[Dave Frederickson]

(04-11-2016 05:29 PM)Geoff Quickfall Wrote:  So far Shapeways modeller has stated 20 dollars a gear just for modelling it to my standards with examples for refinement. Then the Shapeways cost on top of that if I read his posting correctly. Don't know what the Shapeways costs are yet.

Shapeways costs are based on machine utilization and material. If you use the HP-41 parts as an example then the gear would probably cost about $5 USD each for the strong and flexible plastic.

If you add a dollar to the cost of each gear to account for the $20 NRE then that's $6 each. I don't think that's "very expensive".

If you can get Egan Ford's daughter, she's a modller at Shapeways, to create the model on the side then maybe you can save the NRE.

Dave

[Geoff Quickfall]

Thanks Dave!

I agree, that is not expensive :-)

I will email Egan and enquiry about his daughter as the modeller. Keep it in house as it were. At that cost I don't think we need to impose for cost cutting, just good modelling!

Geoff

[Katie Wasserman]

(04-11-2016 05:59 PM)Dave Frederickson Wrote:  Shapeways costs are based on machine utilization and material. If you use the HP-41 parts as an example then the gear would probably cost about $5 USD each for the strong and flexible plastic.

That's not expensive at all. I was assuming that it would have to be an aluminum gear becasue nylon is not available and I don't think that PLA or ABS will be strong enough for this application. Also, I doubt that Shapeways can create a gear with enough precision with PLA or ABS. They seem to be able to do aluminum to withing 0.2mm, which still might not be good enough. The tip of each tooth on this gear is about 0.4mm.

[Dave Frederickson]

(04-12-2016 12:57 AM)Katie Wasserman Wrote:  

(04-11-2016 05:59 PM)Dave Frederickson Wrote:  Shapeways costs are based on machine utilization and material. If you use the HP-41 parts as an example then the gear would probably cost about $5 USD each for the strong and flexible plastic.

That's not expensive at all. I was assuming that it would have to be an aluminum gear becasue nylon is not available and I don't think that PLA or ABS will be strong enough for this application. Also, I doubt that Shapeways can create a gear with enough precision with PLA or ABS. They seem to be able to do aluminum to withing 0.2mm, which still might not be good enough. The tip of each tooth on this gear is about 0.4mm.

I don't think the plastic is strong enough, either, and an aluminum part would be about $45. Shapeways did offer Black Nylon 11 as a material but removed it because it didn't meet their standards.

I think CNC'd aluminum is the best bet. There's a guy on eBay that repairs 97's. I wonder where he gets his gears?

Dave

[Katie Wasserman]

(04-12-2016 04:27 AM)Dave Frederickson Wrote:  I think CNC'd aluminum is the best bet. There's a guy on eBay that repairs 97's. I wonder where he gets his gears?

Although the picture on ebay is poor, this gear looks like the ones I got from PIC years ago. There's no hub projection, it looks to have a wider face and there seems to be some sort of bore insert.

Quite some time ago someone stated on this forum that the G46-30 gear was no longer available from PIC Design but I see that they do still sell it for $23.61 (quantity 2 on hand as of 04:55 UTC on 2016-04-12).

[Geoff Quickfall]

Thanks Katie,

They still remembered my account after all these years. Qty now 0!

But I will continue exploring the Shapeways and milled in brass/aluminum.

The original gear was the rubber hybrid used for the pinch roller and dampening couple of the card reader families. So why would a hardened (excuse my ignorance on Shapeways plastics) plastic not function similarly to the original.

Cheers, Geoff

[Katie Wasserman]

(04-12-2016 07:57 PM)Geoff Quickfall Wrote:  The original gear was the rubber hybrid used for the pinch roller and dampening couple of the card reader families.

Is that right, I'm surprised. The good ones I've seen look to be made of nylon or delrin and seem very hard. I've never seen a brand new one however. Did it start out as a much softer material that hardened over time?

When they fail they do seem pretty soft.

[Geoff Quickfall]

Actually I have three with the goopy gear syndrome which I repaired using your article. And found one cello printer assembly wrapped by HP as a replacement with a hard nylon/Delrin composition. I think the hard ones were later replacements.

The softer ones were quieter but over time decomposed. I am assuming (ass-u-me) the hard ones were later in the production. I guess we would know if we matched serial numbers or perhaps production sites; Indonesia, USA ... This is why I thought the plastic at Shapeways would work. I have seen cassette deck gear assemblies made using Shapeways printed plastic fully functional.

It will be nice to get the 92 and 97S fully functional but I would still like to see a 10$ replacement for the gear.

[Katie Wasserman]

(04-13-2016 02:01 AM)Geoff Quickfall Wrote:  Actually I have three with the goopy gear syndrome which I repaired using your article. And found one cello printer assembly wrapped by HP as a replacement with a hard nylon/Delrin composition. I think the hard ones were later replacements.

The softer ones were quieter but over time decomposed. I am assuming (ass-u-me) the hard ones were later in the production.

... and I assumed that the "goopy" ones had started out like the nylon/Delrin ones but due to environmental issues (like ambient ozone -- it's really bad for nylon) turned "goopy".

[aj04062]

I just noticed this thread. I'm open to buying from the source I got from before.

40 isn't a min, it just helps spread the setup costs more. In fact, I have pricing for 25 & 50.

What is a "good price"? $15 or $25 each?

[Geoff Quickfall]

To get the machine running with your own labor and $25 I would do it. If we can get the price down fine.

Fo me, I just paid $40 for two that need me to modify them.

Geoff