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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc. |
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5th Oct 2019, 1:12 pm | #1 |
Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 564
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Measuring tape recorder belts
Can any one please tell me how do I measure a tape belt if it hasn't broken please do I. Bend it in half and then double it etc mm doubled or something else
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5th Oct 2019, 4:22 pm | #2 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,783
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Re: Measuring tape recorder belts
Lay it flat and measure the length. Double the measured length to get the circumference. A bit of algebra gets you the radius, which doubled gives you the diameter. Belts are normally sold by circumference or diameter.
https://en.wikipedia.org/wiki/Circumference |
5th Oct 2019, 10:55 pm | #3 |
Banned
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
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Re: Measuring tape recorder belts
Its exactly as Paul has explained. Here is an Australian catalogue page showing exactly that in pictures. I have not cropped the scan to show some of the belts available. There are three such pages in the catalogue, so many belts are still available.
Joe |
6th Oct 2019, 12:30 am | #4 |
Hexode
Join Date: Jun 2018
Location: Buckinghamshire, UK.
Posts: 381
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Re: Measuring tape recorder belts
With thicker belts or o-rings the doubling up method can be difficult to do accurately.
An alternative method is to place two coins inside the belt on a flat surface, pull the coins apart to tighten the belt to the required tension, and measure the distance between the coins. If the diameter of the coins is 'D' and the clear distance between coins is 'H', then the inside circumference of the belt is made up of two straight sections, each (D/2 + H + D/2) = (H+D) long, plus two half circle sections of diameter 'D', each (pi*D/2). So the circumference = 2*(D+H) + pi*D The inside diameter of the belt is then (circumference/pi) Cheers |
6th Oct 2019, 4:22 pm | #5 |
Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 564
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Re: Measuring tape recorder belts
Thank you everyone most grateful
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6th Oct 2019, 5:35 pm | #6 |
Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 5,263
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Re: Measuring tape recorder belts
make sure you dont order a belt that has the same circumference as the old stretched one, or you'll just end up with two the same!
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Kevin |
10th Oct 2019, 5:06 pm | #7 |
Pentode
Join Date: Jan 2013
Location: Powell River, British Columbia, Canada.
Posts: 217
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Re: Measuring tape recorder belts
Back in the days of VCR repair, I purchased a device made of
cardboard which measured belts. It is like a slide rule, with two posts, which held the belt under slight tension. There were other measuring means for thickness as well. It came from the parts house I was using in the 90s. It was fine for most belts, but useless for the long belt in the Philips vacuum tube recorders.
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Steve Dow VE7ASO |
10th Oct 2019, 5:34 pm | #8 | |
Nonode
Join Date: Jun 2004
Location: Norwich, Norfolk, UK.
Posts: 2,543
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Re: Measuring tape recorder belts
Quote:
David
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10th Oct 2019, 5:56 pm | #9 |
Heptode
Join Date: Jul 2008
Location: Hereford, UK.
Posts: 719
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Re: Measuring tape recorder belts
I was going to say the same as above, but 10% seems too much, I do about 3%
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1st Dec 2019, 12:51 pm | #10 |
Heptode
Join Date: Nov 2018
Location: Staffordshire Moorlands, UK.
Posts: 595
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Re: Measuring tape recorder belts
I agree with last post, I calculated about 5%.
Anyway, I had no success supergluing the belt/cord material that I purchased, so ended up buying new belts for my Philips N4308, which incidentally were so much more expensive than listed by our Australian friend, joebog1 in the attached pdf. |