Fw: [Steam-engine] Belting question?

Bob Smith bobsmith5 at verizon.net
Sat Jun 4 09:06:10 PDT 2005


This is a resend because my original response seems to have fallen into the
'bit-bucket'.

My apologies to those that receive duplicates.

    Bob Smith

Bob Smith wrote:
> I always called it "SWAG",  Systematic Wild A..... Guess
>
> but, seriously - - -
>
> There _are_ systematic methods of arriving a an estimate of the
> length of a rolled belt -
>
>
> METHOD 1  --
> ---------------------
>
> A roll of belting usually takes the form of an annulus i.e., a circle
> with a hole in the center (like a donut);
>
> To determine the length of the rolled belting:
>
> 1.  Find the area of the annulus.
>
> 2.  Divide the area of the annulus by the area per unit length of a
> sample of the belt.
>
> For example, I have a roll of belting with an O.D. of  22" and an
> I.D. of 5".
>
> The area of the annulus formed by the roll is - -  (3.1416 * (22 /
> 2)^2 ) - (3.1416 * (5 / 2)^2 ) = 380.133 - 19.635 = 360.50 in sq.
>
> Now the next step depends on determining the _effective_ thickness of
> the belt to a reasonable degree of accuracy which, in turn, (as Andy
> noted) depends on how tight the belt is rolled, its uniformity, etc.,
> etc., etc.  . . . .  A reasonable estimate can be made by a) laying
> the roll on its side and b) counting the number layers of belting
> between the I.D. and the O.D. Now compute the average thickness per
> layer of belting by dividing the thickness of the annulus by the
> number of layers.
>
> In the above example the thickness of the annulus (T) = (O.D - I.D.)
> / 2 =
> 8.5 " and I counted 34 layers of belting between the Inside and
> Outside of the annulus therefore, the average effective thickness of
> this belt (t) =
> 8.5" / 34 = 0.25 "
>
> Finally, I want my result in feet of belting, so  --
>
> The effective area of a foot of belting is length  * thickness = 12 "
> * 0.25 " = 3 " sq.
>
> So we now have 360.50  " sq.  divided by 3 " sq. giving a length of
> 120.167 feet or  120' - 2"
>
> Working carefully this method will general produce a result accurate
> to +/- 10% or better.
>
>
> METHOD 2 --
> -------------------
>
> 1.  Cut off a unit length piece of the belting and weigh it
> accurately.
>
> 2.  Weigh the roll of belting.
>
> Now --- weight of the roll divided by the weight of the piece gives a
> fair estimate of the total length.
>
> This method over comes errors due to sloppy rolling or poor
> measurements but, is more difficult to implement in the field.
>
>
>     Happy steaming,
>
>         Bob Smith
>
>
>
> Andy glines wrote:
>> Are you trying to figure out how long a belt is while
>> it is still rolled up?  Sounds pretty iffy to me.
>> There are variables here.  Belt thickness, how tightly
>> its rolled, I.D. , O.D..... You probably better
>> stretch it out then measure.   Or, you could use the
>> WAG method.
>>
>> --- Mike Rohrer <wmrohrer at myactv.net> wrote:
>>
>>> What is the calculation to figure the length of flat
>>> belting rolled up?
>>>
>>> Thanks
>>>
>>> Mike
>>>
>>> Mike Rohrer
>>>
>>> Smithsburg, Maryland USA
>>>
>>> Collector of Antique Farm Literature
>>>
>>> Homepage - http://members.myactv.net/~wmrohrer/
>>>
>>>
>> -------------------------------------------------------------------------
-
>>> ------------------------------
>>>
>>> If "ifs" and "buts" were candy and nuts oh what a
>>> Christmas we'd have!
>>>
>>> Willie Rohrer 1917-2000
>>>
>>>
>>
>
____________________________________________________________________________
>>> ____
>>>
>>>
>>>
>>> _______________________________________________
>>> Steam-engine mailing list
>>>
>> http://www.stationary-engine.com/mailman/listinfo/steam-engine
>>>
>>
>>
>> Andy Glines
>> Evansville, IN
>>
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>
> ---   Avoid computer viruses, Practice safe hex  ---
>
> -- Specializing in small, cost effective
>     embedded control systems --
>
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>
>
> Robert L. (Bob) Smith
> Smith Machine Works, Inc.
> 9900 Lumlay Road
> Richmond, VA 23236   804/745-2608
>
>   bobsmith5 at verizon.net

---   Avoid computer viruses, Practice safe hex  ---

-- Specializing in small, cost effective
    embedded control systems --

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Robert L. (Bob) Smith
Smith Machine Works, Inc.
9900 Lumlay Road
Richmond, VA 23236   804/745-2608

  bobsmith5 at verizon.net





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