Contents copyright Herb Johnson 2010, except quoted material. Last update April 8 2010. Quoted material is copyright by the respective authors of that material and used with permission. YOu can email me via this Web link. Corrections are appreciated.
For more technical information about floppy drives, check this Web page. This page is linked to other discussion of drive belts.
In Jan 2010, user "Lorne" at the Vintage Computer Forum alerted me to the discussion he had in that vintage computing discussion group. The text below is in part from that discussion, and in part follow-up correspondence with me.
The bottom line is this: drive belts for floppy drives are rubberized fabric belts, not rubber belts. A company which made them in the past no longer offers them in 2010 except as custom belts made to your measurements. Jump to the end of the page for details.
See the full discussion at vintage-computer.com under "forums", in the "general vintage computer discussions" on the subject "Floppy disk drive belts". The following is copied below with Lorne's permission. - Herb Johnson, Jan 6th 2010
I’ve read numerous posts about drive belts and their sources, but after doing a search, couldn’t find the info I was looking for (not easily anyway – there are tons of posts).
Thankfully, I’d bookmarked the following two sites that others had referenced previously
http://www.mcmaster.com/#drive-belts
http://www.beltcorp.com/
I’m hoping with this thread and its title, to get enough replies and prior experience from those “in the know”, that this info will be easier for others to find. While I’m specifically looking for belts for two different types of drives (an 8” Shugart 800 or 801, and a 5 ¼” Tandon TM100), I think this [discussion group] would be a good place to deposit any info and experience you have had in obtaining /replacing drive belts.
Questions:
[There were suggestions by others to use McMaster-Carr belts, NOT to use vinyl record turntable belts. Another person got an 8" IBM drive belt from Ken's Electronics ] - Herb
With much help from [others], we now have much more information regarding disk drive belts.
The belts used on Tandon and Shugart drives (and probably others) aren’t rubber, they’re a flat rubberized fabric belt. Forget about the 10% stretch (that’s for rubber belts) – these belts are not meant to stretch. Grab one of your existing drive belts, and you’ll see what I mean. Turntable belts appear to be rubber.
The rubberized fabric belts appear to be used in VCRs, disk drives and projectors (all of which can now be considered vintage). These rubberized fabric belts are manufactured by PRB Line [Projector Rubber Belt] and can still be obtained through Russell Industries (who purchased PRB Line).
The Shugart 800/801 belts are a model # FRF22.8
Their internal circumference is 22.8” and their width is 0.193”
The Tandon 100 belts are a model # FRFX12.5
Their internal circumference is 12.5” and their width is 0.127”
Russell Industries provides a cross reference document which lists belts for Atari, Chinon, Commodore, Control Data, Digital Equipment, IBM, NEC, Shugart, Tandon and Texas Instruments.
Finding the cross reference can be a bit convoluted, so to get to the cross reference document, go to Russell industries website at www.russellind.com, click on Download, click on Cross Reference Software, then on PRB Belt Cross Reference, and then either do a search for Shugart, Tandon, etc or go to page 127 where Computers are listed.
Now for the kicker - these belts aren’t cheap. You’ll see pricing on the PRB Line site that may shock you.
A Shugart 800 belt is listed as $ 45.32 and a Tandon belt is listed as $ 37.97, and that’s “each”. However, there’s a [recent] seller on Ebay....[information under review]
And if the belt cost $ 8.00 in 1980, it would be $ 20 now @ 3%/yr anyway.
There’s also page 26 in [the Russell catalog PDF at this Web link].
And then there’s also [this PDF list of belts in that catalog. which tells you that FRF is flat rubber fabric, FF is flat fabric, and FR is flat rubber.
- Lorne
Note: Russel has a number of belting catalogs on their Web site. Caution, most are for RUBBER belts, which won't work on floppy drives. You need RUBBERIZED FABRIC belts. - Herb
On Jan 7 2010 Lorne wrote me with the following:
Update: I just had a telephone call returned (from a few days ago) by PRB Line. PRB Line is no longer making the rubberized fabric belts, other than one belt with a 7.6" dia circumference. It seems there's no demand for these types of belts.
As the PRB rep put it - "gone are the days that these belts are needed - no one is using the projectors and equipment that these belts were made for anymore, and the cost to keep them in the manufacturing process outweighs the demand for the belts". And the PRB rep said he doesn't know of anyone else who still makes fabric belts. - Lorne
...and in April I got an update:
The guy who used to make the belts for Shugart 800's (Edward at BPB Inc 831-449-5086) doesn't know if he still has the drawings/specs, and doesn't want to go looking for them.
He'll make the belts any size you want, but there's a $ 125 minimum.
The BPB Inc guy said the belts would cost about $ 16 each. But again there's
his $125 minimum order to cover for set up costs. So, you could order 8
belts for roughly $16 each, or pay $125 for one belt.
Note: Lorne also described that the belts are cut from wider materials, and of course
they must be cut to length and spliced. These all go to "setup costs".- Herb
I'm supposed to have two belts coming from the Ebay seller
"isellprojectorbelts", but haven't heard from him in a few weeks. I've sent
him another email, and hope to hear back in a day or two.
As best as I can figure, the [Shugart 800] belts are flat rubberized plastic and are
23.25" long X 0.193" wide, and that's what the Ebay seller is supposed to be
sending me. I can't be dead certain on the size until I get them, but I'm
99.9% sure they're the ones I need. - Lorne
Some days later, Lorne wrote:
I received the belts from the Ebay seller "isellprojectorbelts".
They're the correct size (23.25" long x 0.193" wide) as far as I'm concerned
- they fit nice, and have a little less slack the old ones that were on the
drive, which were measured as 23.375" long. They are new belts, not old stock. In his business, he must have all the
right "connections" because he [said he] had these belts made special. - Lorne
Copyright © 2010 Herb Johnson
Herb Johnson
New Jersey, USA
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