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MMD > Archives > January 1997 > 1997.01.01 > 05Prev  Next


Measured Widths of Music Rolls
By John Phillips

A few days before Christmas I described my new roll-repair table. I didn't mention a disastrous discovery I made just before it was completed.

The disaster involved the take-up spool, which came out of an old spool- box salvaged by a friend from our local garbage tip. I was very pleased to have acquired this ready-made, thinking of all the workshop time I had thereby saved. All I had to do was add a couple of collars to the shaft and put crank handles on the ends.

When I designed my repair table I spent quite a while measuring the dia- meters of rolls and their spool ends to make sure I could accommodate the largest rolls at the supply and take-up ends of the table. I measured everything except the width between the flanges of the take-up spool. Well, everyone knows that a take-up spool is always a bit wider than the standard eleven and a quarter inch width for 88n rolls, don't they?

On finishing the table I put on an 88n roll I had taken into the mechani- cal workshop at work and wound it back and forth, demonstrating to the guys there how clever I was. Then I took the table home, to start on the huge back-up of rolls needing attention.

The first roll I tried was a UK Aeolian roll and to my surprise it didn't quite fit between the flanges of the take-up spool. To my dismay neither did a second similar roll. To my absolute horror, neither did a third.

At this stage I decided it might be a good idea to measure the width of the take-up spool. It was 11.30" (28.7 cm). This was greater than 11.25" (28.58 cm), so what was the trouble, I wondered? I also measured the spool widths of the four upright players casually scattered around our house and got these results:

Steck 11.42" (29.00 cm)
Foster 11.36" (28.85 cm)
Stroud 11.38" (28.90 cm)
Gulbransen 11.34" (28.80 cm)
So all the players I had been playing rolls on with no trouble had take-up spools wider than my salvaged one, although the Gulbransen came close.

I decided I would bolt the stable door after the horse had bolted and do a survey of 88n roll widths. I would say that this pastime is less interesting than watching racing snails but it beats watching cricket.

The mean widths follow. The number in brackets after each roll type is the number of rolls in the sample. I worked out the standard deviation of each sample, which is a measure of the scatter in the results, but nobody wants to know about that, except that it was small, less than 0.05" in all cases.

[ A low value of standard deviation is a good indication of a valid
[ experiment. -- Robbie

UK Aeolian TL series (100) 11.31" (28.72 cm)
US Aeolian TM (43) 11.30" (28.71 cm)
QRS Recordo (old) (50) 11.29" (28.69 cm)
Hupfeld & Animatic (56) 11.30" (28.70 cm)
Remember that the nominal width of 88n rolls is supposed to be 11.25 inch or 28.58 cm. So all these rolls are noticeably over-width.

Wondering if the paper had swelled due to humidity, I started a project of measuring the widths of a few selected rolls at various humidities. This hasn't gone very well, because it's hard to keep the temperature in a room constant while changing the humidity, and I think it is necessary to keep the temperature constant if the results are to mean anything. All I can say so far is that I don't think humidity has anything to do with these oversize rolls. I'll report more when I can.

So it was back to the workshop for the take-up spool, so that it could be widened. This was painful in the extreme but it got done.

What worries me most in all this is that the salvaged spool box had a Themodist tracker bar in it, so it was designed to play all those over- width Aeolian and Hupfeld rolls. I wonder how many it has chewed up over the years. When I mentioned this to my daughter she said "Why do you think it was on the tip in the first place, Dad?"

A nice comeback, but why did the roll companies make over-width rolls?

John Phillips (Hobart, Tasmania)

[ "...on the tip..."? Is this like the American expression,
[ "on the Fritz"?! (Poor Uncle Fritz, he gets blamed for everything
[ that quits working!)
[
[ I've seen several take-up spools without flanges, and they seem
[ to work just fine. I wonder why flanges are needed?
[
[ -- Robbie

(Message sent Thu 2 Jan 1997, 02:38:11 GMT, from time zone GMT+1100.)

Key Words in Subject:  Measured, Music, Rolls, Widths

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