HP 97 Printer Gear

[RPZ]

Hello All,

I now have several HP 97,s that I am attempting to restore.

Of course they need printer idler gears.

I have tried the sources mentioned in the threads I found and they all seem rather pricey.

This would seem a perfect application for 3D printing but I found nothing on Thingaverse or Shapeways. Has this been tried?

If it did not work I am curious as to the problems encountered.

If it did work, where can I get some?

Regards, Rick

[RPZ]

Most of the gears I found were about $50.

Just found a site selling an aluminum gear for $19.90 and free shipping over $40.

How did I miss this? Seems reasonable.

Was about to order 3 when I noticed it was in the vintage calculator section. What else do they have? Lot's of great stuff. Then I noticed a AAA battery holder for HP classics I just bought some of these from Waterhosko. Someting is not right.

SCAM ALERT ************

The site was registered on 2020-08-22 according to whois.

Mark has confirmed that he has no idea who these people are.

For sure a scam.

Oh well.

By the way, I am very pleased with Mark's aaa battery packs. They now stay in all my classics with lithium Energizer batteries.

Regards, Rick

[RPZ]

SCAM ALERT ***********

Forgot to mention the site bjointup.com. Scam

Found it when I googled hp 97 printer gear.

Gear pictures and everything.

[Dave Frederickson]

A list of HP repair parts and services has been compiled by Sylvain Cote and can be found under Important Threads in the Articles Forum.

Adam Jones was selling gears for $35.95. His current listing is for repair of the paper advance mechanism for $59.99 and he states that he has idler gears for an additional $30.

https://www.ebay.com/itm/HP-91-92-97-or-...2985263032

[RPZ]

Thank you Dave.

I had not seen that list. It is extensive.

I did not contact Adam Jones as he mentions limited supply and I would guess he needs them for his repairs.

Cost with shipping for advance repair with gear and shipping is around $130. This is probably a fair price as I have not yet replaced and advance wheels but looks tricky.

Might have a gear solution. Will post if it works.

Regards, Rick

[RPZ]

Finally. I have successfully 3d printed an HP 97 printer idler gear.

Parameters were found on this wonderful forum, plus some measurements, and some guesswork.

80 pitch
30 teeth
0.180" total width
20 degree pressure angle
3/32" bore

The hub was not used as it is unnecessary and I thought it would be easier to see wear. Also either side of the gear can be used if there are imperfections.

The drawing was created with OpenSCAD version 2015.03-2 and modified public domain gear code.

Gcode for printer was created using Cura version 15.04.6.

Printing was done using a Monoprice Select Mini 3D Printer V2 ($219) and Hatchbox PLA.

Cost is about 2 cents per gear and some time.

I am not cheap, I am thrifty.


To test I ran a short counting loop with a print space and a pause.

Gears were not cleaned or lubricated.

After 24 hours and 43,000 cycles I could not see any wear or any change in sound.

I lubricated the gears with some silicone grease and saw no change. This may not be a good idea as I don't know how the grease may react with pla or HP plastic over time. Might also collect dust and dirt and cause a problem.


I uploaded the stl file to Shapeway.com and got immediate online quotes.

One gear printed with versatile plastic is $5.00 plus a fixed cost of $10.15 for a total of $15.15. 2 gears would be $20.15.

They can print with all kinds of interesting materials.


Versatile plastic is $5.15 + $10.15 for a total for one gear of $15.15.

Fine detail plastic is $7.50 + $10.46 for a total for one gear of $17.96.

Steel is $15.00 + $11.38 for a total for one gear of $26.38.


Now it gets interesting. A gear 20 times as wide is not much more and could be sliced up.


20 x wide gear (3.6")

Versatile plastic is $5.51 + $10.21 divided by 20 is $0.79 per gear.

Fine detail plastic is $9.93 + $10.77 divided by 20 is $1.04 per gear.

Steel is $38.17 + $14.25 divided by 20 is $2.62 per gear.


I don't need that many gears especially since mine seem to work but may order some to check out these other materials and to see what accuracy can be done with a really good printer.


Regards, Rick





---eof

[markhen]

Great work! I have a half dozen 91/92/97s lined up for restoration, I'd love to try your gears! Can we buy from Shapeway?

[RPZ]

Thank You!

I have been at this for weeks off and on.

A real learning experience.

I would be happy to send you some of mine if you would like to try them.

My guess is that Shapeways gears will have a finer resolution than mine.

I plan on placing an order with them as I have never used an outside source.

Attached are some photos and files.

Regards, Rick

[RPZ]

I received HP 97 printer gears from Shapeways on Saturday.

From order to delivery was 11 days. Not bad.

No modifications were made except to open the hole with a 3/32" drill.

Checked them by fitting to a printer and feeling by hand for binding or slop.

Some photos are attached.


HP Gear, Light brown

We all know what this is like.


My Gear, PLA, Yellow

Slightly rounded teeth, nice fit.


Shapeways, Versatile Plastic, White

Slightly rounded teeth, nice fit.


Shapeways, Fine Detail, Clear

Well formed teeth, nice fit, almost perfect.
Description says brittle but I think they mean in relation to other choices as
it drilled easily and I threw onto my tile floor with no damage.


Shapeways, Steel, Silver

Very rounded teeth, oversize and would not fit, magnetic, very hard to drill
because of the added bronze. Did not plan to use anyway, but so many possibilities.


I plan to use my PLA gears that were tested for 40,000 print cycles but the
Shapeways gear from fine detail plastic is really nice and I think the best 3D print.


Regards, Rick

[Alevin]

Hi.

After a couple of bad experiences with brass gears, I would like to tell you later, I go for the plastic replacement.

An 3d printed alternative is offered in

https://www.ebay.es/itm/294930335704?has...Sw3cRiAPTN

But aspect seems not very attractive (see pic attached)

I am planing to use RPZ publishsed 3D files to order to shapeways (or the RPZ kidnle offered home made units if still avaible). But some questions arises at this point.

After some years of experience form the last post? Is still the shapeways the fine plastic option the best one,

Has the shapeways 3d model a centered bore hole to drill to the proper size 2/32" or is a solid gear? If solid,the drill can cause a not centered bore hole. Furthermore the EU metric units in drills can also cause some fitting problems. I had to strugle with these issues in the bronze gears.

The 20" wide gear to cut in proper size may be attractive, but is it possible to simple use a XACTO blade to perform the cutting? or some specilized mini saw?

Thanks in advance for your clarifications

[Jeff_Birt]

This gear on eBay is not well made. It looks to be resin printed with a low resolution, or a poor mode, or both. The teeth are pointed, not a proper gear tooth shape.

I have had good luck printing some very small gears in resin with very good detail. I have ordered a proper macro lens for my camera so I can take good pictures to show the detail.

[Alevin]

Hi

I have made a couple of fixing of the printer idle gear. I want to share the experience.


I have experiment with bronze metal gears, and plastic ·3d printed public model (printed at Shapeways), documented above, from RPZ (many thanks for your generous work).

The bronze gears from Germany used, are documented in a 2014 original post:

https://www.hpmuseum.org/forum/thread-11...97+printer

The supplier web:

http://www.modellbauershop.de

part number 753030

In respect the Shapeways materials options, nowadays they have avalaible a more ample set of options than in the date of the thread opening in 2020.

https://www.shapeways.com/materials

Finally I ordered gears in MJF Plastic PA12,

https://www.shapeways.com/materials/mult...usion-pa12

MJF Plastic PA12 seemed the most resilient and less brittle for mechanical operation involving dynamic forces and wear. It can be read in the technical description:

“Multi Jet Fusion (MJF) Plastic PA12 is HP’s nylon plastic with excellent mechanical properties and a slightly grainy finish. Is an ideal choice for a wide range of applications from industrial parts to durable end-use goods. Its strength, durability and stiffness make it great for functional parts, such RC car parts and mounts. Is printed using HP’s Multi Jet Fusion technology and supports very complex geometries and thin features”

The grainy finish could not be avoided ordering the smooth glossy option, as it was not available for the size of the gear teeth. This grainy finish was more rough than I expected.

Case A.

In the first Hp-97, the bronze metal gear did not work well to me. It is required to open the bore hole to the axe proper size, done by a Dremel drilling. At first trial the bore hole got not well centered, and quarter of the circumference did not gear at all with pinon. At a second trial with another gear, the hole was better centered, but it was a bit too much (may be because of metric drills?). Then it had tendency to wobble, and move back an forth over the axe, as the gear width is smaller than the original and the circaclip is well away from the outmost external face. This caused some time to get stuck in diagonal in between the motor pinon and the printer gear. May be the motor axe an pinon were sightly deformed. Finally, it was really noisy.
Pics attached show this gear.

Then I went for the nylon printed Multi Jet Fusion (MJF) Plastic PA12 by Shapeways.

Increasing the size of the bore hole, was made turning by hand with 2.25, 2. 5 mm drills, so the inner diameter was better controlled.

The roughness of the Plastic PA12 finish, and some slight oversize may created a too much resistance, so the motor could not move the gear chain. After a patient turning the pipno idle assembly for 30 minutes or so by hand, the gear and pinon got some attrition, enough to make possible to the motor torque turn the gear chain. Finally, it got to spin smooth. Even though it is a nylon piece, the noise was also loud, no as much as in the bronze idle gear case, but similar, what surprised me.

Pics attached show this gear installed

Case B.

Given the previous experience, I started with the printed nylon Plastic PA12. Surprisingly, in this case the idle gear had more tight engage than the previous HP-97, case A. After applying the same manual procedure spinning the gears to create the wear enough to make the system turn freely, It was still stuck.

So, I went to the bronze idle gear. In this case, the idle gear did not show wobble, and stayed in place. The printer noise was louder, but not so much as in the first Hp-97 with the metal gear.

So I kept in this case the bronze one on the printer. I will try to add some spacer to keep the gear on place.

May be tolerances of the plastic idle gear or the different condition of printer components made the difference.


I conclude that, apparat from the gear material and larger tolerances in the printed gear, may be Hp-97 unit printer condition may influence in the result and the most convenient option in each case.


To end up, I ask for you guys some advice,

I have found a reference for the advance wheels substitution, a guide in a slide show format created by Ignazio Cara (Italy), cited in this old forum thread.


https://www.hpmuseum.org/cgi-sys/cgiwrap...ead=216173

But the link is not working,.... Is there some other site where the slide show can be found? Some one kept it and can uplodad it or send it to me by mail?

Thanks a lot

[dmh]

I need one of these and am looking at 3D printing as international shipping is so expensive these days.

How does the following compare to the the RPZ version? The file sizes are different so I assume they were developed independently.

Anyone tried both and if so, which is better?

I notice the one below was updated last year.

https://www.thingiverse.com/thing:6168680

[Hiwi]

Hi,
the 3D printed gears do not work very well. The gears flanks are sometimes too flat.
I tried with my prusa printer, shapeways and even a very high tech 3D printer in our company.

The modellbauershop has 2 versions of the appropriate pitch, one is wider, costs 5 times of the smaller one, but works perfect. The samller one costs only 3 Euro and works good with a washer.

The bore should be 2.4mm. The shop has very high quality drills on stock. I took some from 2.1 up to 2.4mm and drilled in four passes on a high precision drill press from proxxon.

Do not try to bore in one pass with a 2.4mm or 2.5mm drill.

This fits perfect on the axle and runs smoothly.

A bit of silicon grease (or mos2) and the printer works like new. (Minor louder)

The modellbauershop offers a service to make custom gears, so you can get gears with 2.4mm bore from there, i suppose.

I won't buy the 3D printed gears on ebay. They are racketeering in my mind. :-)

There is a seller on ebay in germany who offers a metall gear for 29 euros. Give him a try.
He is a HP specialist. I am not related to him.

Ralf

[tangdfx]

I have a lot of nylon gear for HP97.

It is come from off-the-shelf parts.

[teenix]

(04-23-2024 01:53 PM)tangdfx Wrote:  I have a lot of nylon gear for HP97.

It is come from off-the-shelf parts.

That's interesting, do you provide them or are you able to share a source that others may use?

cheers

Tony

[dmh]

Do you have a link for the specific parts and this shop?

Thanks

(04-23-2024 11:18 AM)Hiwi Wrote:  The modellbauershop has 2 versions of the appropriate pitch, one is wider, costs 5 times of the smaller one, but works perfect. The samller one costs only 3 Euro and works good with a washer.

The bore should be 2.4mm. The shop has very high quality drills on stock. I took some from 2.1 up to 2.4mm and drilled in four passes on a high precision drill press from proxxon.

Do not try to bore in one pass with a 2.4mm or 2.5mm drill.

This fits perfect on the axle and runs smoothly.

A bit of silicon grease (or mos2) and the printer works like new. (Minor louder)

The modellbauershop offers a service to make custom gears, so you can get gears with 2.4mm bore from there, i suppose.

I won't buy the 3D printed gears on ebay. They are racketeering in my mind. :-)

There is a seller on ebay in germany who offers a metall gear for 29 euros. Give him a try.
He is a HP specialist. I am not related to him.

Ralf

[Hiwi]

drills:

https://ghw-modellbau.de/Spiralbohrer-Sa...S-21-30-mm

gears Pitch0.3 30t:
https://ghw-modellbau.de/Stirnrad-Messin...-03-30-Z_1

https://ghw-modellbau.de/Stirnrad-Messing-Modul-03-30-Z