Center of Gravity for a Shopsmith

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dusty
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Center of Gravity for a Shopsmith

Post by dusty »

I can't do this right now because I am not near a standard Shopsmith but

as you raise a fully configured Shopsmith from horizontal to vertical is there a point (60,70,80 degrees)where gravity steps in and assists that transition (ie: completes the rotation)?
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garys
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Re: Center of Gravity for a Shopsmith

Post by garys »

Probably not because the headstock never reaches 90 degrees and the tipping point.
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Re: Center of Gravity for a Shopsmith

Post by chapmanruss »

Other than getting easier to lift as it gets closer to 90 degrees, gravity will want to pull it back down.
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BuckeyeDennis
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Re: Center of Gravity for a Shopsmith

Post by BuckeyeDennis »

For my model 520, with the table in drill-press position, the answer to Dusty's question is "yes". My machine will remain in the vertical position (with reasonable tipping stability) even if I don't engage the conical tilt-lock screw. Ergo, it had to have reached "neutral" tipping-stability at some point before it became fully vertical, after which point gravity helps complete the rotation.

I do, however, always try to remember to engage the tilt-lock screw.

Note that I do not have the double-tilt base.
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Re: Center of Gravity for a Shopsmith

Post by RFGuy »

dusty wrote: Mon Sep 13, 2021 10:56 am as you raise a fully configured Shopsmith from horizontal to vertical is there a point (60,70,80 degrees)where gravity steps in and assists that transition (ie: completes the rotation)?
Yes. On the center of gravity, when I tried this morning, at about 73° is where the center of gravity took over for my Mark V when raising to vertical causing it to tip over the rest of the way into fully vertical drill press mode. Of course, I had my main table extended (for drill press mode), so I am sure this angle is dependent on where the headstock is locked down as well as the carriage and main table positions. FYI...I don't have the double-tilt base.
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dusty
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Re: Center of Gravity for a Shopsmith

Post by dusty »

chapmanruss wrote: Mon Sep 13, 2021 11:07 am Other than getting easier to lift as it gets closer to 90 degrees, gravity will want to pull it back down.
Not once you reach the center of mass (aka: Center of Gravity). Where that will be is totally dependent of the mass. If this was not true, placing the Mark V in drill press mode would be hazardous and I doubt that that lock mechanism would hold it vertical.
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Re: Center of Gravity for a Shopsmith

Post by JPG »

One does not 'reach a center of mass'. A center of mass reaches some point in space when moved. A tipping point is when the mass tending to alter an angle from a hinge providing support reverses direction of that tendency.

Regardless the tipping point for a SS is 15° or more away from the drill press raised location.

I wonder what that angle is for a 'reversed shorty' assembly?
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Re: Center of Gravity for a Shopsmith

Post by jsburger »

JPG wrote: Mon Sep 13, 2021 1:32 pm One does not 'reach a center of mass'. A center of mass reaches some point in space when moved. A tipping point is when the mass tending to alter an angle from a hinge providing support reverses direction of that tendency.

Regardless the tipping point for a SS is 15° or more away from the drill press raised location.

I wonder what that angle is for a 'reversed shorty' assembly?
The way tubes are offset from the pivot point by what, about 3". In the conventional mode the center of mass is farther away from the pivot point by that amount whatever it actually is. In the reversed shorty the center of mass is closer to the pivot point by that amount. Would that not make the angle in question less?
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dusty
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Re: Center of Gravity for a Shopsmith

Post by dusty »

jsburger wrote: Mon Sep 13, 2021 4:06 pm
JPG wrote: Mon Sep 13, 2021 1:32 pm One does not 'reach a center of mass'. A center of mass reaches some point in space when moved. A tipping point is when the mass tending to alter an angle from a hinge providing support reverses direction of that tendency.

Regardless the tipping point for a SS is 15° or more away from the drill press raised location.

I wonder what that angle is for a 'reversed shorty' assembly?
The way tubes are offset from the pivot point by what, about 3". In the conventional mode the center of mass is farther away from the pivot point by that amount whatever it actually is. In the reversed shorty the center of mass is closer to the pivot point by that amount. Would that not make the angle in question less?
I would have to go back to the books to make a hard statement on that BUT I think no. Where the center of mass is would not effect the angle of rotation. It would play a part in determining the Center of Gravity.

From the center of the pivot pin to the center line of the Way Tubes is 5".
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Re: Center of Gravity for a Shopsmith

Post by JPG »

The reason it is different is the headstock and table are mounted reversed. I would expect tip angle to be less than 15° from 'vertical".
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