[GreenKeys] 28 ASR Typing Reperforator Print Hammer Replacement

[Nick England]

I’ve tried vinyl tubing, shaving the sides of the round tubing, etc.
no luck so far.

On Thu, Jan 2, 2020 at 6:36 PM Nick England <navy.radio at gmail.com> wrote:

> 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
>
-- 
Nick England K4NYW
www.navy-radio.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20200102/69770ea9/attachment.html>