SwingWeight

[saevel25]

An interesting topic i think. I was trying to figure out a way to measure the swing weight of my clubs, with out a meter. Being from an engineering background. A swingweight meter is just a measurement of weight on the butt end of the club when the club is not balanced at a 14" (or 12") focal point.

D-0 is basically when there is no weight measurement reading, or when its balanced.

so using math and physics, i found that if you measure the focal point of the club, balance point. You now have were all the weight of club acts upon in on location. Knowing this, you can simplify the equation, not having to measure any of the club components. Its nearly impossible to measure clubhead weight when its stuck on a club :p

Lets go with measuring weight in ounces, and focal point in inches.

Wt = total weight of club

Fp = distance from butt end to balance point

Swing Weight = ( Wt x (Fp - 14) - 213.25 ) / 1.75

So all you need to do is measure the balance point, which i do with a engineering ruler (its a three prong ruler, so it can be multitasked to measure length and act as a fulcrum)

The tricky part is, ok, so now what do you do when you want to add weight to the club. This gets tricky because the balance point shifts. But its still a nice math problem. Taking the moment around the new focal point, assuming that the weight is added to the clubhead.

Wc = Weight added

Fd = distance from butt of club the weight was added.

Change in Swing Weight = Wc x (Fd) - (Wc x 14) = 1.75 * ▲SW

or

1.75 x ▲SW = Wc x (Fd - 14)

Which makes sense. If you put weight at the butt end, Fd = 0, so all that weight acts on the scale at 14" from the focal point.

Of course the math works the same for a 12" scale

1.75 x ▲SW = Wc x (Fd - 12)

People might wonder, what about club length, that is taken care of in the total weight of the club. Since the original weight is a constant, and cancels out, the only thing that matters is the weight added and were at on the club.

So the process would be,

Lets say you take a 35.5" club, Weights 16.5 oz club, Fp = 27.24", that means its roughly a swing weight of 3

Lets say you want to take it up to a swing weight of 6

so that's a change 3, lets say you want to add it all to the clubhead, with some lead tape. That will be roughly 35.25" from the butt of the club.

So

1.75 x (3) = Wc x (35.25 - 14)

Means, the weight you need to add to the end of the club will be 0.245 ounces, or 7 grams of lead tape.

[dbwood]

There's an easier way.

http://www.tutelman.com/golf/design/swingwt4.php#sw_scale

It's quite accurate.

[saevel25]

Its basically the method i said,

Quote:

Having covered that caveat, here's the method. ( My thanks to Rich G. Ciccotti for pointing out this method from Ralph Maltby's book. )

1. Measure the distance of the balance point of the club from the end of the grip (in inches).
2. Subtract 14" from the result, and multiply it by the club's total weight in ounces or grams.
3. The result is the torque (in inch-grams or inch-ounces) about an axis 14" from the butt, the base definition of swingweight.
4. Use the following table to convert to the swingweight point scale:

SW = Wt x (Fp - 14)

D-0 = 213.5 (i messed up with 213.25, typo