Why do pool tables have slate?

[OTLB]

Coefficients of expansion of plate glass and slate are similar. See http://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html

Mass-produced float glass has outstanding flatness as a natural result of the manufacturing process (read "cheap", no need for milling). It's flatter than the vast majority of milled surfaces. The main problem with all these materials (including slate, glass, and steel) is that they sag. This problem has been solved by telescope makers who use "flotation cells" for their large mirrors. Passive flotation cells could also be designed to make an extremely flat surface for a pool table surface as a unit. The only remaining task would be to level the surface as a whole, a much simpler thing to do.

The cheap way to make a table feel solid is to make it very heavy using cheap materials. That's how most tables are made today. An alternative is to engineer a very stiff, low-vibration (dampened) structure of much lower weight and bolt it to the floor. That would cost more, so people don't make them for mass market.

You could also go the other way, and make a good pool table frame/bed out of reinforced concrete, pre-cast or poured and finished on-site using molds. I think the concrete guys could easily compete with Diamond and Brunswick for pool room tables, if they are looking at 4k-5k a table.

Neat thoughts.

 

[ChopStick]

I see that your profile says Orlando.
Is that where you owned the two Diamonds?
If so, do you feel that 'higher than average' humidity could have been an issue in the area where you kept the table(s)?

Not that humidity alone would wrench your slate so quickly, but humidity swelling wood could.

My first one, I bought in Tampa and moved to Orlando. It was a Professional. My second was a ProAm that I had in Orlando. Both of them had an upward curl at the end of the slate that I was never able to totally get out.

 

[ChopStick]

You should first try finding someone that knows how to level a pool table correctly

I have read everything you have ever written on the subject. I had it printed out on the table when I was working on them. I spoke to Brian Miller about having you come out but he said you only work out west. I was using a 12 inch Starrett on both of them. I was adjusting the ProAm over a period of two years. Well beyond the period it needs to settle. It always developed a bulge or sag that wasn't there before.

At the IPT tournament in Orlando, the ProAm Mike Sigel and Efren Reyes played the final on had a bad corner pocket. I was sitting in the front row lined up with the side rail. I saw Efren miss a ball because it rolled off. What was cool is a little while later he had the same shot and he shot it wrong and let it curve in.

Now if you can't even get a level table, from the factory, with factory mechanics, for a $200,000 match, what chance does a regular guy have? I know from experience that slate moves around over time. I was just thinking about some alternative material that does not do this. This isn't just about Diamond. I have seen other tables do it too.

 

[ChopStick]

why not granite? you could get 1 piece cut with cutouts for the pockets and holes for the rail and attachment. It's much harder than slate and doesn't bend as much.

That fellow ceebee that invented the BreakRak told me he had one. I talked to a guy who installed granite counter tops. He told me granite will sag over time just like slate.

 

[Mr. Bond]

My first one, I bought in Tampa and moved to Orlando. It was a Professional. My second was a ProAm that I had in Orlando. Both of them had an upward curl at the end of the slate that I was never able to totally get out.

I'm assuming that you got a good look at the 'curled' areas....

I'm really curios, did the slate look any different there?

 

[derangedhermit]

I talked to a guy who installed granite counter tops. He told me granite will sag over time just like slate.

I know glass doesn't sag over time, and I very much doubt slate or granite do either. Glass sags immediately, and unless something changes, it keeps that amount of sag - for decades, or centuries. I believe slate and granite do the same.

 

[The Turk]

I know glass doesn't sag over time, and I very much doubt slate or granite do either. Glass sags immediately, and unless something changes, it keeps that amount of sag - for decades, or centuries. I believe slate and granite do the same.

Actually glass does sag over time. It is classified as an aqueous solid. Means very stiff liquid. I own a 102 year old home and was fascinated to see the windows were thicker at the bottom. Glass laid flat will form a miniscus. The thicker the faster.

 

[brain]

Glass is a super cooled liquid, and it does not flow (Google it). The panes in old windows are thicker at the bottom because tradesmen knew to install them that way (glass manufacture wasn't as advanced back then).

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