[GreenKeys] 28 ASR Typing Reperforator Print Hammer Replacement

[Nick England]

173979 specs
federal stock no 5815-00-084-5008
Overall height - 0.141 inches nominal
Overall length - 0.391 inches nominal
Overall width - 0.250 inches nominal
Material - Plastic
Special features - One slot, 0.047 in. w by 0.188 in. lg

I have a drawing somewhere.

On Thu, Jan 2, 2020 at 3:43 PM Paul Heller <paul0926 at comcast.net> wrote:

> Oh how I wish someone would be able to figure this out.
>
> George Hutchison got close. He may have made an engineering drawing of
> the thing. I believe he had a mold fabricated and was experimenting with
> different materials and hardeners. He was struggling with air bubbles in
> the finished product and was trying vacuum and pressure as a means to solve
> that problem. I understood that he had someone helping him who one day up
> and disappeared (as best I can recall). That person supposedly had a lot of
> knowledge of this kind of thing.
>
> In addition to finding/selecting the proper material to use, there is also
> the issue of how it slips on and stays on the metal hammer.
>
> Dave Tumey, who was a good friend of greenkeys and used to be quite active
> on this list at one time, engineering and had the 33/35 print hammers
> made.  Maybe he has some ideas.
>
> I’d be happy to contribute $$ towards a solution, but not for any wild
> goose chases...
>
> Paul
>
>
> On Jan 2, 2020, at 12:44 PM, Mark J. Blair <nf6x at nf6x.net> wrote:
>
> Oh, I was hoping that this was already a solved problem. Old rubber is a
> headache. It's also a problem in my vintage computing hobby, where it
> affects things like capstan rollers in tape drives. Out of curiosity, I've
> done some minimal study (i.e., looking at YouTube videos) about how rubber
> products like capstan rollers and platens are manufactured and refurbished.
> The process is understandable, but I have a sinking feeling that trying to
> procure a tiny amount of uncured rubber might be akin to calling up the
> regional water district and asking for a quotation for a cup of water.
>
> Maybe it's time for me to try out elastomeric filament in my 3D printer.
> My best guess about the shape and dimensions of a 28 ASR reperf typing
> hammer seem like something that might lend itself to 3D printing, assuming
> that the available elastomeric filaments have suitable mechanical
> properties for this use. I know of at least one computer collector who has
> had some success in 3D printing replacement belts for small tape and
> diskette drives. But I don't know yet about the hardness of available
> filaments, or how well they would hold up in impact service like this.
>
> If that won't work well, then I guess the next thing to try would be to
> get a chunk of suitable rubber and try grinding it to shape.
>
> --
> Mark J. Blair, NF6X <nf6x at nf6x.net>
> http://www.nf6x.net/
>
> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
>
> 2002-to-present greenkeys archive:
> http://mailman.qth.net/pipermail/greenkeys/
> 1998-to-2001 greenkeys archive:
> http://mailman.qth.net/archive/greenkeys/greenkeys.html
> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
> http://comcents.com/tty/greenkeyssearch.html
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to paul0926 at comcast.net
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
>
> 2002-to-present greenkeys archive:
> http://mailman.qth.net/pipermail/greenkeys/
> 1998-to-2001 <http://mailman.qth.net/pipermail/greenkeys/1998-to-2001>
> greenkeys archive: http://mailman.qth.net/archive/greenkeys/greenkeys.html
> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
> http://comcents.com/tty/greenkeyssearch.html
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to navy.radio at gmail.com

-- 
Nick England K4NYW
www.navy-radio.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20200102/6c616d4d/attachment.html>