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HP 97 Printer Gear - Printable Version

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HP 97 Printer Gear - RPZ - 09-23-2020 05:39 PM

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

RE: HP 97 Printer Gear - RPZ - 09-24-2020 02:34 PM

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

RE: HP 97 Printer Gear - RPZ - 09-24-2020 02:39 PM

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

Forgot to mention the site bjointup.com. Scam

Found it when I googled hp 97 printer gear.

Gear pictures and everything.

RE: HP 97 Printer Gear - Dave Frederickson - 09-24-2020 04:15 PM

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.


RE: HP 97 Printer Gear - RPZ - 09-27-2020 03:16 PM

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

RE: HP 97 Printer Gear - RPZ - 10-05-2020 10:27 PM

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


RE: HP 97 Printer Gear - markhen - 10-06-2020 05:39 PM

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?

RE: HP 97 Printer Gear - RPZ - 10-06-2020 06:58 PM

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

RE: HP 97 Printer Gear - RPZ - 10-20-2020 08:39 PM

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