Interchangeable thumbs

[Ryster]

I have heard of cores separating due to age of a ball and related use [years of use], temperature extremes, or just general failure of materials/poor curing. Have never heard that hammering in thumb slugs would cause a core to separate. When you think of the abuse a bowling ball goes through, getting a thumb slug hammered in to it would seem pretty tame.

[Phonetek]

True but also the slug goes down inside pretty deep. I assume the drill penetrates the core. Therefore the vibration from the pounding is directly on the core itself.

Like the 6th grade science experiment where we had to find a way to drop eggs off the roof without them breaking. I cut open a Nerf football and placed it inside. My egg did not break. Now pound something directing into the ball. Splat! What I'm saying is most of the abuse is absorbed by the cover. (Aside from aging & temp)

[Ryster]

Right, but the slug doesn't touch the core until it hits the bottom of the thumbhole. The hammering is displacing the air pressure in the space between the bottom of the slug and the bottom of the thumbhole as it is going in through the filler material. I guess displacing that pressure could put forces on the core, but it is still hard to believe it would be enough to separate the core itself.

[Phonetek]

When you say "separate" do you mean the core separating from the filter material (hence rattling around) or do you mean the core itself physically breaking?

[Phonetek]

This brings up another question. What if you bowl with a ball like this? As far as performance, is it just going to hit like a marshmallow or is going to do some whacky stuff down the lane? Or neither, it's just at higher risk of cracking?

[Ryster]

Core separating from the filler is what I think of when I hear "core separation".

I have seen people throw balls where this has happened. They sound like a 6lb house ball when they hit the pins. Some balls will actually wobble going down the lane.

[Phonetek]

Core separating from the filler is what I think of when I hear "core separation".

I have seen people throw balls where this has happened. They sound like a 6lb house ball when they hit the pins. Some balls will actually wobble going down the lane.

Hmm... Interesting. The ball my PSO was talking about still works just fine for now. Well when I threw it last anyway. It's been about 6 months since I've thrown it though. I'll have to give it a try one of these days and pay close attention. It's a 16# so it may be a while before I try it.

[classygranny]

I have the interchangeable thumbs. I have two in each size...normal, smaller (winter) and a larger. I like to have one in my spare ball so I don't have to change between shots. I think this cuts down on the wear factor. I've lost 1 in the back that was never found, 1 was found within the week, and 1 was found immediately, and 1 came out going down the lane. All at the same house. If I lose one, I always ask immediately for it to be looked for. I've used them for over 6 years. I now try and check that it is in tight before every shot - made it part of my pre-shot routine. If they get to loose, you can put a piece of tape in the thumbhole and it will tighten the IT - most people don't realize this, and that might be a reason for loss. None of mine have broken. I've seen some break when they are dropped on the floor.

[Phonetek]

Ah okay, now we're getting somewhere. So the loosen up? It's it the snap lock thing on the insert itself that wears out or what it locks on to inside the hole?

[classygranny]

Ah okay, now we're getting somewhere. So the loosen up? It's it the snap lock thing on the insert itself that wears out or what it locks on to inside the hole?

It just get looser in the hole. When you first get them they are really tight to twist in the hole - there's even a tool to take them in and out, if needed. As time goes by and you insert them many times a week for weeks and weeks or years, they are easier to twist. Then sometimes they just work themselves loose from throwing the ball. Thus, my "checking" for tightness each time. My spare ball has become very loose and probably need a piece of tape added. I have not had the locking inserts break or wear down, but I guess they could wear a bit and make it loose as well.