Re: Patching TPU innertube

On 1/22/2025 8:49 AM, Ted Heise wrote:

On Tue, 21 Jan 2025 22:23:27 -0500,
   Joy Beeson <jbeeson@invalid.net.invalid> wrote:

  On Sat, 18 Jan 2025 22:37:20 -0500, Joy Beeson
<jbeeson@invalid.net.invalid> wrote:
>

The forecast is for very cold and dangerously windy.  We had
the January Thaw today, so there may be puddles of ice when I
walk tomorrow.

>
  There was.  I let Lou Cook drive me home -- the streets were
  clean, but our driveway was (and still is) glare ice.  I may
  have trouble fending her off next Sunday; most people are
  aghast at the thought of walking more than a few feet, and I
  really *need* that walk now that it's hard to get time to ride
  a bike.

 I can relate. We're not all that far from you, so have very
similar weather.  And the physical activity seems increasingly
necessary as I age (in my last 60s year now).
 I don't go out on the bike when it's below 30 F, or if there is
chance of icy patches.  Instead I ride a set of Kreittler rollers
in my garage (which has itself been damn could with the recent sub
zero outdoor temps).
 Speaking of the rollers, I wanted some resistance when I got
them (25 years ago?) but wasn't that interested in the fan options
offered by Kreitler,  So I cobbled the mag resistance unit of my
previous junky set of rollers onto the new ones.
 Part of the flange on one side of the pulley on that unit has
broken off.  I glued it together, but it broke of again.  This
time I found a washer about the size of the outer side of the
flange, and glued it against the side of the pulley with JB Weld.
 Seems likely to be pretty durable, but I've been trying (with no
luck) to get a replacment from McMaster-Carr as a backup.  It
seems the shaft is a hair over 3/8" so the pulleys with 3/8" bore
won't slide onto the shaft.  I tried drilling out the bore hole,
but don't have a drill press so the wider bore wasn't perfectly
straight (seems the pulley wobbles a bit when turning).
 Is there such a thing as 1 cm bore pulleys?  I'm not finding
anything that's clearly along those lines.
 The next largest U.S. spec pulley is a 1/2" bore, which would be
too big.  I suppose I could look for tubing that would fill the
gap between the shaft and a 1/2" bore pulley, but that seems like
a long shot (and maybe hard to track down).
 Any other ideas from the brain trust?
 

  And typing with the key board on a table is a royal pain, even
  with Dave's chair on its highest setting and two pillows on it.
>
  Which is happening because I've got Agent on the new computer
  and it worked right off!  Had a terrible time copying it to the
  Sneakernet drive -- Sneakernet had to be scanned and formatted,
  and Explorer is really, really rotten at that sort of thing.
>
  But I hope to shut off Vista tomorrow, and move this computer
  onto my own desk.  First I have to download my three Web sites
  and my LETTERS folder.

 Good luck, hope it goes well, Joy!
 

The Minoura mag unit is the most prevalent so I'll assume it's that or rebranded Minoura. Just measured one and yes shaft is 10mm.  Yes, 10mm shaft pulleys do exist, less common in USA. Here's the first result in a search for "10mm shaft V belt belt pulley"
https://www.ebay.com/itm/166027767983?itmmeta=01JJ7AA3FF2XYFAEBFF678FJ8Y&hash=item26a806b0af:g:gzwAAOSwluNkNQ9L&itmprp=enc%3AAQAJAAAA4CodCO1vSDjg2xNOt8By6oBgR14HEvUANdveTIGUdj6NMd1fACLg%2BRCzbf6L91sTNHKYOrljqUaZp5RMRFVzGjGxIFKbuRpr5ZQfoefrhVRzDAUWxReRP8ijDHyQx4svlv7EkC11oUYDkfmelh7oipr6ABeXf%2FDo1NgxSfXecUuKQVumqPo%2Bt6L04aSVKHAX65q%2B7LF5DDnONpjOWBUpCWA4T218i19rkSnTeTojywjUWgAXPZwUQai609rJCciheafJjhAz3e542GwEEWQQMAJ3djLtjgh2f2FCQD%2FpEOaO%7Ctkp%3ABk9SR_S3qOqRZQ&var=465531361750
Which is for a round band, same size as your Kreitler drive belt, not a V belt.
https://cdn.road.cc/sites/default/files/styles/main_width/public/2021-kreitler-rollers-and-fly-wheel.jpg
Poly bands are easily shortened and spliced if you have a worn spare handy. Light both ends and press together firmly. I have a section of Kreitler roller band on my sewing machine for example.
Most 10mm belt pulleys seem to be splined for notched belts:
https://www.precisionwormgear.com/photo/pc21405533-aluminium_internal_and_external_splines_timing_belt_pulley_rohs_approved.jpg
which are probably not helpful.
Arbor adapters are common and cheap (we have a lot of those here) in myriad diameters but I could not find any between metric shaft and SAE bore in a quick search.
The simplest solution would have been a 10mm bit or reamer in a drill press. Too bad that didn't work out. The next would probably be another 3/8" shaft V pulley (cheap) and someone else's drill press.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971