Yes you are correct
How level is "level" for pool tables?
- Thread starter jviss
- Start date
Yes you are correct
I agree with you wholeheartedly.
And it doesn't take hours to roll balls. It takes seconds.
The Diamond single-piece-slate tables that are taken to tournaments are leveled using 18 levels and 18 adjusting screws. The levelling is done with the rails on. The process takes about 20 minutes. I think it usually gets the practical result I noted about: you can make a thin hit with a slow-rolling full-table shot.
As for the Earth's curvature being a factor, unless I dropped a decimal point a perfectly flat table will be sway-backed relative to the Earth's curvature by 5/1,000,000 of an inch. I think that's actually possible to measure since telescope mirrors can be checked to much better than that, but it's not done with a machinist's level. I don't think any table is that smooth, though, and I doubt that any cloth is uniform in thickness to that level. It's at the level of your opponent sitting on one side of the table or the other changing both the local gravitational field and the sag of the floor.
As for the Earth's curvature being a factor, unless I dropped a decimal point a perfectly flat table will be sway-backed relative to the Earth's curvature by 5/1,000,000 of an inch. I think that's actually possible to measure since telescope mirrors can be checked to much better than that, but it's not done with a machinist's level. I don't think any table is that smooth, though, and I doubt that any cloth is uniform in thickness to that level. It's at the level of your opponent sitting on one side of the table or the other changing both the local gravitational field and the sag of the floor.
If you can get a 12" Starrett machinist level to read no more than 1 slash off of dead center (5/1000 of an inch) for all locations on the table, that may be about as good as you can reasonably expect to get it. Obviously if it reads consistently one slash off in the same direction from one end to the other or one side to the other, that should be easy to make adjustments to get to read near perfect, but as is often the case, you're just splitting the difference to try to get all the measurements on the table as close to level as possible.
I always shoot for as close to perfect as possible. My experience has shown me just how close I can get, based on the particular table that I'm working on. Some tables will NEVER be perfect.
If you can place a 98-12 anywhere on the table, and have the bubble between the first set of lines, you've done pretty well. However, temperature will play a factor in that as well. The warmer the temperature, the bigger the bubble will be. Conversely, in colder temperatures, your bubble will be smaller, making your tolerance window larger..
I would love to tell you that it is certainly possible to get every set of slate within the first set of lines on the vial. However, that is certainly not the case. Sometimes, I have to be ok with leaving an area out 2 lines. I try to never do that, but it depends on the table. How much time do I want to spend, and what is it worth to the customer? I can adjust the table, such that the impact is minimized. But, some tables only offer so much adjustment.
Let's say that you have a Brunswick Gold Crown I, with a Brunstone playing surface. Even if the table were set up properly, from the day that it came out of the factory, I would hazard a guess that there is a fair amount of sag across those 'slates'. You can shim the outside edges, and along the center support, but you can only go so far. You need to place shims between the slate liners and frame, from underneath the table. But even that will only do so much. Sometimes, you have to live with low spots across the surface, simply because there is no support in the low areas.
Not only that, when these tables were made, the machining tolerance was quite a bit more open. With the slower cloth of decades ago, the required surface finish, flatness, and level, were not of as much importance as they are with today's cloth.
Thanks again. Very useful and interesting information.
I have a Gold Crown I, how do I know if I have Brunstone?
The easiest way to tell is by the color. Brunstone is more of a brownish gray color. On the bottom side, you may even see it marked with "BS". Slate is more of a bluish gray color.
Still unsure? You can take a razor blade, and attempt to scrape the surface (preferably outside of the play area). Slate will scrape very easily, forming a fine powder. Brunstone will just dull your razor blade.
Pay no mind to what some say about the pocket radius telling the story about which is which. That is complete B.S. (pardon the pun). You may also hear that Gold Crown I's were only built with Brunstone... That is also B.S... I have installed almost just as many Gold Crown I tables with a slate surface, as I have with a Brunstone surface.
Slate also has milling marks. Brunstone doesn't.
Hmmmm...if rolling the balls on bare slate is the best way to check for level, what do you do about the curved grinding mark's on the surface of the slate, as they WILL have ridges on them??? Cloth fills in the lows and covers the grinding marks over to create a uniform surface for the balls to roll on. In 38 years of ACTUALLY working on pool tables, I've NEVER rolled the balls on the bare slate to check for level....that's what my machinists levels are for.
Last edited:
What regulation table measures 54" across....I'm curious?
No, not quite, if that were the case, mechanics wouldn't have to level the slates once mounted....but I can tell you 100% for sure, I've had to level EVERY slate I've ever installed on a pool table.
Just wondering, how big is that laser beam, an 1/8"?Good evening, everyone.
The best method for me is to use a laser level. I place five steel measuring rules on the baize, one at each corner pocket and one in the centre of the table. I like the way this then allows tiny adjustments to be made until all five laser beams give an identical reading.
Best wishes,
RC.
I only use 8" because the 12" create to long of a bridge for my liking. Theonger the level, the less you see the valleys on the slate because they bridge over them, but it's easier to use a 12" rather than an 8".....because the 8" requires more precision leveling, but a 6" is way to hard to level slates with, because they're TO sensitive the the slightest movement of the slate, floor, and walking around the table.
Ya think? Now you know why you didn't get a response to your question in the mechanics forum, because the simple answers don't satisfy you, and long drawn out debates are a waste of everyone's time.
Go to any bar, there EVERYWHERE....and yes, everyone of them have to have the slate lifted out in order to install the cloth.
Horrible recovery job!!
Does that method tell you if the slate is swayback, or crowned?