What is the actual effect of a 'penny mark' strike mark on an iron?

Basically quite a few of my irons have got some pretty visible strike marks on them, pictured is the worst affected club my 8 iron.  I am just wandering if anyone knows if the effect is purely aesthetic and how much (if any) effect it has on the ball flight, spin rates etc. If anyone could put forward what they know, even evidence to show what happens that would be great. I am pretty sure someone must have done some research on it.

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Good question. I would imagine the grooves are worn in that impact area, so you could be loosing a bit of spin. If those were my clubs i would be replacing them (if the budget allowed). Then again, the rust in the sweet spot could be acting a like sand paper and putting more spin on the ball than one might think?

Thats my .02

I think it looks awesome and until your shots stopped doing what you want them to do and you lose control of them I'd keep gaming them til they tell you that they are ready to be retired!

Yeah thankyou :) both of your guys points have crossed my mind, its pretty tough to tell if it is just aesthetic or whether or not the grooves are going to be badly affected. I am thinking a new set is probably in order but I was just curious to see if anyone could possibly provide me with evidence that it is a justified expense :D

Support the economy, buy new clubs!

Can't you take them to a shop to measure and assess the grooves? I took my wedges in and the guy told me they looked worse than they were and that they were fine as it was finish related. I bought new wedges anyway! Lol.

I have a friend that shows up with a 20 year old bag, no head covers, and mismatched clubs, but it's that mark on his 8 iron that says he is a shark!  Point being, I don't get into money games with people with that wear pattern unless I am getting my fair share of strokes. I wish my clubs looked so good.

OMG! I think we have covered this 1000+ times on this forum. Rust does not add spin! We must stamp out this fallacy.

To the OP, as long as the grooves are not worn the club should perform just fine. If that area becomes smooth you could lose spin.

I could possibly try going to my local pro shop and getting a further opinion but so far anybody I've spoken to seems to be unsure of the effect.

Damn, can I buy that club? I would put it in my bag making sure it sticking out for people to see everywhere I go...

There is really no effect unless the grooves have been damaged. It's almost impossible to tell by looking at a picture. You need a club guy to check them out.