Thinner / Deeper ? The change in the 70's was from the kind with the round head screw studs or pegs to lock it down to the flat spades that stick out about 2 inches or more. The change was most likely along with the change from the small door to the taller "recessed" door (the one with the framing).

So, last Game Lucky Strike, first game Spirit of 76

http://www.ipdb.org/showpic.pl?id=2293&picno=4943

But I could be wrong about the other things changing at the same time (door, lock down bar, lock down slide assembly, shorter legs)

Maybe he means the early 70's style with the welded end caps, vs. the all formed in one piece style? I think that was around late 72, or early 73......

Wild Life was the last game with the welded end cap/squared off style. Jack in the Box was the first one with the smooth style.

As for the nubs versus the shark fin it came some time after they went to the larger coin door because Spirit of 76/Pioneer and Royal Flush/Card Whiz still had the nubs with the new coin door. Maybe the shark fin came in about the same time as the new flipper design which was shortly after.

I think the early 'large door' games (~1976, like Buccaneer) still had the button-style lockdowns, and not the later 'shark fin' style. But I don't have any '76 games on hand at the moment to check. The '77 games have the shark fin. Or my memory is just bad.

But stashy is right - there were three styles used in the 70's, including the '67-'72 welded end cap style, then the one piece with button pegs, then the one piece with shark fins.

I think it was earlier. He means the narrow lockdown bar on the early '70s games to the wider one (which are interchangeable) which started in 1973. The "sharkfin" bars, which look identical to the previous wide type from the top, started sometime during the deep cabinet/ large coin door era.

My beloved Volley has buttons and a big door. I'm too lazy to look at my Ship Ahoy now, and it really wouldn't prove anything at this point.

Some of these games came with an insert/extra page that would list the new parts on that particular game. That way an operator would know if they needed to order different/newer style parts. That is probably the best way to check all these trivia facts.......

If "Volley" still has the studs, then so does "Ship Ahoy". I don't know when they started with the "shark fin" tabs for locking the bar in, but it's apparently well into the run of the large door/ deep cabinet games.

http://www.pinrepair.com/gtb/

The only thing Clay didn't put in this was when the lockdown bar changed. Too bad. It's got everything else.

I sure wish the model in the middle was readily available to replace the older style. The old style really hurts my hands after a while.

Might be a fluke, my Jumping Jack had the welded endcap bar. Then my recently aquired Top Card has one as well.

El Dorado has the round threaded pegs on the bar.

That's probably my fault . I hate the square welded end caps version so I dump them on any game I sell off.

I even converted my El Dorado to the "shark fin" style just to see what it would take since the peg versions are getting so hard (and expensive) to come by. But there are plenty of System 1 and even System 3 games still getting junked for parts.

To the OP: sorry I didn't think of the square one as being "thicker" but instead "uncomfortable". I always figured that was a 60's bar. But you are right, its on plenty of really early 70's games too.

Pinball resource has the years listed for the different styles used.
http://www.pbresource.com/lockdb.html

I have no idea why Steve Young won't get these back in stock. It's such a high demand item. Has to be much more in demand than some of the coin doors and other stuff that seems to be in stock all the time.

Yeah, but it says "from about Target Alpha", so it's not certain when the transition took place. So anyone with deep cabinet EM Gottliebs, pull off the bar and let's try to determine when exactly the tabs were introduced. "Golden Arrow" has the tabbed bar, but that's getting close to the end of the EM run. I would imagine all the System 1 games had the tabbed bar.
He also says that the one piece wider bar is an exact reproduction for "Astro" up to "Surfer", but that doesn't seem correct. "Astro" and several games afterwards would still use the narrower "welded end cap" bar, and games after "Surfer" even into the deep cabinet era, still used the wider single piece bar with the screw studs.

i have wedges from '74 to '79 i think

what differences are we looking for exactly?? i never noticed but will have to check now?

I believe the main one in question is exactly when the switch was made from the Peg style lock down bar to the shark fin. So far, we have determined it didn't exactly coincide with the change to the deeper cabinet and taller recessed door. The other thing to note would be when the new style flipper assembly appeared (the ones all self contained on a bracket with that large greenish white nylon block on the end of the plunger)

Clay's website http://www.pinrepair.com/gtb/ says Surf Champ was the first game with the new flipper design.

The Gottlieb lockdown bars on some machines become extremely tight I assume from the accumulation of dust and grime between the frame and the slider which are factory riveted. What is the best approach to free up the mechanism pls and has anyone actually disassembled the mechanism?

I have used several solvent types to free up a sticky slide mech. Rust may also be present as all those liquids just sitting in there will obviously degrade with time. I would take it off the cabinet to really work on it. 6-8 wood screws and soooo much easier to deal with. I haven't found a great way to shine up the zinc-plated type (just hand polishing) , but I don't have an electric buffing wheel like other folks may.

There is always a good chance that the product gumming it up is soda (sugar based) or Beer. So, I would start by removing it and running it under hot water possibly with a bit of mild soap. I have found that sometimes, the hot water does a better job breaking it up than any cleaning agent. Then, blow it dry with compressed air and lightly lubricate and metal on metal portions.

That is funny, I have four different types of lockbar and not three. One must be from a Chicago Coin or something and somehow migrated to my Flip a Card.

In the metal rail era, there were actually six different Gottlieb lockdown bar types. Post a photo of the one on your game.