How do club fitters know how much to adjust the angle of your clubs?

I've got one local shop, but I think the guys their are morons and don't trust them as far as I can throw them. I was wondering if there was a way to tell how much I need my club angle adjusted so I can just go in and tell the guy what I want. I know they need to have the end of the club angled up through looking at the dirt line across the face of the club, just not sure how much.

thanks

Usually, they put some impact "tape" on the bottom edge of your 8 iron and then have you hit a ball off of a plastic lie board. The marks made when the taped bottom edge of your club hits the plastic board indicates what part of the sole is hitting. They should do this a few times until your impact mark is in the center of the sole of your club.

You will know whether or not they are doing this well or not.  It is a very simple process.

If you really wanted to do it yourself, you should be able to purchase the tape and board, but I can't think that it would really be worth it.

If the only thing that they do is look at the dirt line on your clubface, I wouldn't let them proceed.

The adjustment should be a precise response to your swing plane.

The general rule of thumb for most irons when using impact or electrical tape on the sole of the club is 1° of lie adjustment for every 1/4" the mark is off from the center of the face, as measured from the center of the mark itself.  Clubs with very curved soles can be 1/4" = 1-1/2° or more, and on clubs with very flat soles 1/4" = less than 1°.  (Golf Club Fitting and Performance, pg. 206)

EACH club should be checked and adjusted, not just checking one club and adjusting the rest of the set accordingly.  There is a (very loose) industry standard of +/- 1° tolerance in lie angles, and adjusting the entire set based off of one club can still throw the rest of the set off.

Example:

Club  -  Advertised lie (+/-1°)  -  Actual lie

5  -       61.0°  -                          61.0°  (+/-0°)

6  -       61.5°  -                          62.5°  (+1.0°)  1.5° more than the previous club

7  -       62.0°  -                          61.0°  (-1.0°)  1.5° less than the previous club

8  -       62.5°  -                          62.5°  (+1.0°)  1.5° more than the previous club

9  -       63.0°  -                          63.5°  (+0.5°)  1.0° more than the previous club

^^^ Easy to see why each club should be adjusted individually and not the entire set adjusted based on one club.

Fitting a given length club for lie angle seems pretty mechanical.  What seems to me to be more challenging is trading off between lie angle and length.  For example, in Ping G10 clubs the Silver code 7 iron at 1 inch over has the same lie angle and length as the White code 6 iron at 1/2 inch over and the same lie angle and length as the Maroon code 5 iron at standard length.  The swingweghts will be different, about D6 for the 1 inch over, D3 for the 1/2 inch over and D0 for the standard length (excluding wedges).  What makes one combination better than another?

Swingweights will be different due to the added length of the club, and no correction made to the weight of the heads.

Length and lie are directly related, and when fitting the order should be length first, then lie.  Given the same posture and hand position, lengthening or shortening the cub will change the the lie angle as the golfer hold the club.  "Typical" (and I use that term loosely) clubs are built in 1/2" length increments, and .5° lie increments.  Some sets are built in 1/2" length increments and 1° lie increments, and some have no rhyme or reason as to the increments they choose (Taylormade, I'm looking at you!).

So, the longer the club, the flatter the lie must be to fit the golfer.  Consequently, the shorter the club, the more upright the lie must be to fit the golfer.

I can't speak to Ping's color coding, as I have never looked at it or know what color means what.

Ping's color chart is found here:

http://www.ping.com/uploadedFiles/Custom_Fitting/PING_Color_Code_Chart.pdf

The color codes are .75 degrees apart.

Ping's irons are 1/2 inch apart and .75 degrees apart in lie:

G15® Iron Specifications

My clubs are 3* upright, White code, and 1 inch extra in length.  The swingweight is D6.  I probably could also fit clubs 3.75* upright and 1/2 inch extra length, or 4.5* upright and standard length.  The swingweight would change, but I would have some clubs with the same length and lie in each set.  My 7 iron would match, in length and lie, the 6 iron in the hypothetical Silver code set and the 5 iron in the hypothetical Maroon code set,  The swingweight would probably be D3 in the Silver code set and D0 in the Maroon code set.  The question I have is how does the fitter get the length right in choosing among the alternatives?

Your skill level will be the first determining factor, that being your ability to hit the same spot on the club face consistently.  Wrist-to-floor measurements are just used as a starting point to pick a shaft length to start the fitting, but certainly cannot be used as the sole basis for length (everyone has a different stance, a different posture, arms/legs/upper torso ratios will almost never be the same).  From there, placing impact decals on the club face and hitting balls with different length shafts and watching where on the club face you are making impact.  When you are making impact consistently on the center of the face, you have pretty much found your ideal length.  From there it is a matter of building/adjusting the length up and down the set from that iron.