HP 97 Printer gear - again

[Dreato]

I see there's still activity trying to find replacement gears for the HP97 printer idler gear. I'd like to refer you to a post by member RPZ (link below). He developed the files to 3D print this gear. I printed these, and they work like a charm. There may be some advantages to using a plastic gear, like HP originally did.

The original drive train for the printer used 3 gears: The steel gear on the motor, a softer plastic gear for an idler, and a harder Delrin plastic gear for the print head shaft.

If we replace the soft plastic idler gear with a steel or brass gear, we run the risk of wearing out the plastic Delrin gear. The machined gears may have small burrs, or sharp edges etc. You don't want to try to find a replacement for that Delrin gear!

The 3D printed gears using RPZ's models can be made from softer PLA plastic, which will protect the Delrin gear. He tested his idler gear made from PLA plastic for 40,000 cycles, with little wear. If you print one yourself, you'll need to de-burr the plastic as usual, and drill out the hole to 3/32". If you don't have a 3D printer, you can order a gear from Shapeways. Gear cost is low, but shipping will be high. Better order a few.

https://www.hpmuseum.org/forum/thread-15625.html

Anyhow, that's my 2 cents.

Best Regards,
Dave

[vassilisprevelakis]

Hi Dave,

I think that you are absolutely right. Nevertheless, I have been using a 97 printer for about 10 years without any problems and, given the low use of these machines nowadays, I would not rush to replace any metal gear already installed.

For new repairs, the 3-D printed gear is a viable option.

Best Regards

Vassilis

http://www.series80.org