HP 97 replacement printer cog?

[Dave Britten]

I just got an HP 97 that seems to be in good working condition electronically, but it's got a couple issues that I was expecting to have to fix. Obviously, the card reader wheel is gummy, and I've got replacement o-rings on the way, but the middle of the three printer cogs has some stripped teeth and needs to be replaced. Anybody know where to get a replacement for this cog?

[Dave Frederickson]

Maybe this will help.
https://www.hpmuseum.org/cgi-sys/cgiwrap...gi?read=84

[Dave Britten]

(06-10-2020 04:09 PM)Dave Frederickson Wrote:  Maybe this will help.
https://www.hpmuseum.org/cgi-sys/cgiwrap...gi?read=84

Interesting ideas there. I wonder if those suppliers are still selling the parts listed in that 20-year-old article.

I'm considering checking out the local hobby shop to see if any of the RC car or model train gears might be a match.

[Moggul]

Hello Dave.

You can check my old post about replacing the cog:

https://www.hpmuseum.org/forum/thread-13...22726.html

There you have the details regarding the exact model train wheel and the bore diameter to help you in your search.

[Dave Britten]

(06-10-2020 06:29 PM)Moggul Wrote:  Hello Dave.

You can check my old post about replacing the cog:

https://www.hpmuseum.org/forum/thread-13...22726.html

There you have the details regarding the exact model train wheel and the bore diameter to help you in your search.

Thanks! At the very least, that ought to help my search at the local hobby shop. I've got some 3/32" drill bits in case I need to widen the bore slightly.

[teenix]

(06-10-2020 05:12 PM)Dave Britten Wrote:  

(06-10-2020 04:09 PM)Dave Frederickson Wrote:  Maybe this will help.
https://www.hpmuseum.org/cgi-sys/cgiwrap...gi?read=84

Interesting ideas there. I wonder if those suppliers are still selling the parts listed in that 20-year-old article.

I'm considering checking out the local hobby shop to see if any of the RC car or model train gears might be a match.

I found these at PIC design. There are a few gear types of similar sizes. The bore sizes for 80 pitch/30 teeth are all 1/8" so will need to be drilled

https://www.pic-designcatalog.com/gears/...rs/?page=9

They don't list prices, just request for quote.

Ive seen other similar items around but they all seem expensive

cheers

Tony

[GreyUser]

I have some homemade gears and while they’re not perfect, they work and are not as noisy as the pic aluminum gears (which require a fair amount of work unless you have a micro lathe). Also have replacement card reader wheels that are (IMO) better than regular o-rings and no, it’s not silicone tubing, which I found to be very problematic unless you you hit the jackpot with a piece of tubing that was perfectly concentric. Most are far from it. Medical grade tubing would be but it is prohibitively expensive.

Would be happy to send you you a kit if you want. PM me and we’ll work it out.

[Dave Britten]

(06-11-2020 03:42 AM)GreyUser Wrote:  I have some homemade gears and while they’re not perfect, they work and are not as noisy as the pic aluminum gears (which require a fair amount of work unless you have a micro lathe). Also have replacement card reader wheels that are (IMO) better than regular o-rings and no, it’s not silicone tubing, which I found to be very problematic unless you you hit the jackpot with a piece of tubing that was perfectly concentric. Most are far from it. Medical grade tubing would be but it is prohibitively expensive.

Would be happy to send you you a kit if you want. PM me and we’ll work it out.

Neat! Are they 3D-printed gears?

I have some o-rings en-route for the card reader, so I'm good there. Funny enough, I actually have lots of IV tubing, but it's fairly small gauge stuff (less than 2 mm inner diameter, I'd guess), and probably wouldn't fit.