Scroll saw: 7/8", 1 3/32" , or 1 3/16" stroke length?

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paulrussell
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Scroll saw: 7/8", 1 3/32" , or 1 3/16" stroke length?

Post by paulrussell »

There is a post by JSBurger describing his "Teal" scroll saw as having almost no vibration: viewtopic.php?p=222280#p222280
Try as I might, while I have been able to greatly improve the smoothness of my scroll saw, above about 3/4 speed there is noticable vibration.
Then I saw conflicting information regarding stroke length in Shopsmith documentation. The Teal scroll saw is specified as having a 7/8" stroke, while the Shopsmith Academy page (with pictures of the grey scroll saw) lists a stroke of 1 3/32".
My saw, which I believe to be one of the earliest made due to its "ball end" tensioning rod, measures a stroke of 1 3/16".
A quick review of modern scroll saws shows the vast majority having a stroke of 3/4 or 7/8". This leads me to conclude that Shopsmith tweaked the stroke length over the years until they reached the sweet spot. And it makes sense that a shorter stroke would produce less vibration.
Can anyone with a Teal or later grey scroll saw verify these numbers?
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paulrussell
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Re: Scroll saw: 7/8", 1 3/32" , or 1 3/16" stroke length?

Post by paulrussell »

Some possibly supporting data: The part number for the weighted cam, which determines the stroke, changed between the grey and teal versions.
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Re: Scroll saw: 7/8", 1 3/32" , or 1 3/16" stroke length?

Post by JPG »

Is it possible the shorter stroke emerged with the self powered model? (requires less HP)
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paulrussell
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Re: Scroll saw: 7/8", 1 3/32" , or 1 3/16" stroke length?

Post by paulrussell »

JPG wrote: Sun Apr 04, 2021 12:11 pm Is it possible the shorter stroke emerged with the self powered model? (requires less HP)
Mine is the self-powered 555272 and the stroke is the 1 3/16" in the photos above. (I suspect mine is supposed to be 1 3/32" and the extra 3/32" is due to manufacturing tolerances)

Also, the manual for my saw has parts lists for both stand-alone and Shopsmith mounted. The part numbers for the relavent parts are identical.

And the 7/8" stroke is specifed for the Shopsmith-mounted teal model. https://www.shopsmith.com/ownersite/cat ... ollsaw.htm
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paulrussell
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Re: Scroll saw: 7/8", 1 3/32" , or 1 3/16" stroke length?

Post by paulrussell »

i toyed with buying a cam and shaft from a Teal model just to see how if it would work in my older saw, but it appears the part is significantly different, and the chances that it would balance with the other weights is slim -- and buying both is richer than I'm willing to go. By my measurements and calculations the functional difference would be the pivot hole being approximately 0.09" closer to center than on the grey models.
Teal saw, counterweight/cam:
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