Accuracy

Accuracies of the Estimators have been checked using a sampling of over 500 assembled clubs built by Dynacraft for their shaft testing program. The following table summarizes the estimated swingweight accuracies of clubs assembled with a wide variety of shaft models, lengths, weights and flexes:

Difference in Swingweight*	Graphite Shafted Clubs		Steel Shafted Clubs
Difference in Swingweight*	Free Estimator	Paid Estimator	Free Estimator	Paid Estimator
0	27%	53%	33%	49%
within + / -1 point	68%	98%	83%	95%
within + / -2 points	95%	100%	100%	100%

* Actual measured swingweight minus estimated swingweight

Clubmakers Calculator is significantly more accurate than the Swingweight Estimatir Basic Free, particularly for graphite shafted clubs. That’s because Clubmakers Calculator takes into consideration shaft balance points, and the actual range in balance points (from low to high) is more dispersed for graphite than for steel. The following example demonstrates the variance in estimated results for different balance points.

Example 1: A driver 45" long with a graphite shaft shows a 4 point spread in swingweight of D1 to D5 for shafts of identical lengths and weights, but with extremes of shaft balance points. The "Low", "Mid" and "High" rows in the table below show the estimated results using three different shaft balance points. Clubmakers Calculator can accommodate actual balance points within the extremes of low to high. The Basic Free version is programmed with an average shaft balance point corresponding to only the mid-range, thus limiting its accuracy.

Shaft Balance Points	Weights			Estimator Results
Shaft Balance Points	Head	Uncut Shaft (46" long)	Grip	Club Balance Point	Swingweight
High	197g	76g	50g	12.2	D1
Mid	197g	76g	50g	11.9	D3
Low	197g	76g	50g	11.5	D5

To achieve the greatest accuracy in estimating swingweights, you must use actual weights of pre-assembled components, preferably weighed with a gram scale. It is important to be aware that specified component weights listed in a catalog are nominal and that actual weights will vary due to manufacturing tolerances. The following example demonstrates how much swingweight can vary with extremes in actual weights.

Example 2: A driver 44.5" long with a graphite shaft shows a 4 point spread in swingweight of C9 to D3 within the tolerances of the catalog’s specified weights. The "Limit 1" row in the following table is with head and shaft weights lower than specified, while the grip weight is higher than specified. "Limit 2" is the opposite extreme.

	Weights			Estimator Results
	Head	Uncut Shaft (45" long)	Grip	Club Balance Point	Swingweight
Limit 1	196g	79g	52	12.2"	C9
Specified	198g	80g	50	12"	D1
Limit 2	200g	81g	48	11.8"	D3

The program is called an "Estimator" because it does just that – it estimates values to give a reasonable approximation of results before assembling clubs. Because of the wide variations in head models and designs, it’s impossible to estimate every pre-assembled club to the exact final swingweight.