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 ?
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!!!
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.
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....
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.
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 !
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 "1, 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.
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