Calculating XL 037 belt lengths

My Skill 1400H1 belt sander gave up on me today - unreasonable really as I only bought it 14/01/1982 (yes I have the receipt!!!!). The drive belt has disintegrated leaving only a fraction of shredded material that measures as an "XL 037" (3/8 wide 0.2" pitch) Cannot trace original spares but it has a '14 notch' and a '28 notch' wheel mounted on 98mm centres. How do I calculate how many teeth on the belt ?

TIA

AWEM

Reply to
Andrew Mawson
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60 me old sparrow.

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Reply to
john

In article , Andrew Mawson writes

Hi Andrew,

I don't have the same sander, but I looked at mine (an Elu MHB 157/02, belt is a SuperTorque 57924626)) and it measured thusly:

Wheels 110.5 mm between centres. Small wheel 20mm across teeth, ~17mm across core; large wheel 38mm across teeth, didn't measure across core.

Belt 70 teeth, pretty 4.5 mm pitch (measured across 10 teeth).

Playing around with the numbers, I can approach a good match by assuming that the belt goes exactly half way round each wheel, the outer diameter of the wheel is the effective diameter, and the straight bit each side is equal to wheel spacing*, thus:

Belt measurements 70 x 4.5 mm = 315 mm

Estimate (20+58) x pi/2 = 91.1, plus 2 x 110.5 =221, i.e. 312.1 mm

Error could be slight inaccuracies in measurements, more likely to be because the use of the outer diameter of wheels to get wrap-around is slightly too small - the continuous part of the belt sits *outside* the teeth of the wheel. Adding 1.0 mm to the diameters (i.e. 0.5 mm per side, looks about right) comes out very close - 315.2 mm. You should check this addendum looks about right for your belt/wheels.

Hope this helps (but if you end up with the wrong size, you get no more than your money back!). You will have to do the maths yourself as you didn't state the diameter of the wheels.

*I know it isn't quite right, but the errors seem to cancel out quite well, at least for mine.

Regards,

David

Reply to
David Littlewood

material

Thanks John & David,

That calculator what just what the doctor ordered. I'd guesstimated 60 two ways. a/ the 'tape round the pullies' method and b/ the approximation David suggests but it would be easy to be a tooth out and there is no tensioner or centre distance adjustment.

Off to buy a 60 tooth belt!!!

AWEM

Reply to
Andrew Mawson

In article , Andrew Mawson writes

Yes, the calculator looks good - if it suits. However, if I have understood it correctly, it seems to restrict the belt tooth pitch to a set of stock sizes, which as it happens does not include my 4.5mm pitch! Glad it worked for you though.

David

Reply to
David Littlewood

That's because a 4.5mm belt isn't a standard size.

John S.

Reply to
john

In article , snipped-for-privacy@stevenson-engineers.co.uk writes

Pity no-one told the makers of my sander (Elu) then. Wonder where they got it from.

David

Reply to
David Littlewood

David, You said " measured over 10 teeth" ie 9 gaps/pitches Is it possible you measured over 9 tooth pitches and divided by 10? Just a thought I can't imagine why Elu would not use standard parts. Bob

Reply to
Bob Minchin

Well, that's a very sensible question, Bob, but no, I measured over 10 teeth and 10 gaps. Just to make sure (I didn't think I had made such an error, but it never hurts to check*) and it is definitely 4.5 mm pitch. Machine is at least 20 years old, maybe a sign that times were different then, or the fact that the maker was (IIRC) Swiss (later I think bought out by Black & Decker).

*Well, I say it never hurts, but this time one of the brushes popped out, took several minutes of fiddling to get it back....

David

Reply to
David Littlewood

different

I've fallen foul of non standard length belts before now but not odd pitches. My coin counter uses an inverted toothed belt as transport for coins, and is a 'special' only available from the makers in Japan - 51 tooth iirc with no length adjustment.

AWEM

Reply to
Andrew Mawson

If I did not know why you might count enough coins to wear out a coin counter belt, I might be tempted to visualise you as a miser! LOL (instead of the generous chap you really are!) Bob

Reply to
Bob Minchin

,

transport

Yes I never thought that counting money could be boring, but believe me it is. Particularly when you know that the majority is destined for the gas man, the electric company and the landlord !

AWEM

Reply to
Andrew Mawson

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