Slate flatness...

[fastone371]

Practically speaking, & thinking as a woodworker i agree.
A wood frame is never going to be perfect over time, but it has some excellent perhaps overlooked benefits in the modern era, including decent stability with changing humidity within typical values in a human living space; and excellent thermal stability across the same.
Slate is quite stable, although it needs support and shimming in the thickness typically used for pool tables. Accepting those 2 materials, there does not seem to be much in terms of "adjuster" systems that would excel shims and levels for leveling.
Plus there are what, a billion legacy tables out there? Playing fine?

Thinking technically, though, Rasson is probably the way things will trend in the future. Commodity level tables with ease of set up, steel tube frames, built in leveling systems at similar cost to Diamond. It is even easy these days to start to imagine an automatic leveling system. Perhaps for only a few $K upcharge.

Slate is probably still the cheapest bed material. Especially as 3 pc slate sets.

OTOH, glass is more or less easy to make flat, weighs less than 2/3 wt of slate, and is somewhat stiffer & stronger (many x stronger for tempered) than most slate. Not thinking of "designer" tables which already include some. Thinking of using materials to build a commodity table, even "barboxes" the way Diamonds are now.

We are probably at a cusp where the old materials vs new are just about a toss up cost wise, but it could flip quickly. Wood sure has gotten expensive lately. And scarcer.

One issue with steel or alloy tube frame is that it is not thermally stable. That may or may not be a factor for tables, in "typical" living spaces.
My sense is that slate is more thermally stable than glass (can't find data" but at those levels probably irrelevent. Rail systems based on extrusions could be engineered with elastomers & wood to play as well as anything, and the esthetics easily tailored as well.

smt

I have always wondered why everything holding the slate up was not made of steel. Undoubtedly its stronger than wood (at least the common available wood) It seems like it would be easier to design and build a simple leveling system for. Although steel is not thermally stable I think it is more stable than wood at normal temps and is not affected by moisture.

 

[fastone371]

Steel is very stable, a way more than aluminium and others material, slates are affected by humidity less or more dependenly where they come from, Italian slates are more dense than some others and less prone to be humidity affected. Just scew and glue 3/16 thick cheap steel flar bar on the wood frame table and it would be very strong and stable, better than any things existing.

If your screwing 3/16" flat stock to wood the wood it is attached to will still move and change the level/squareness of the frame. 3/16" flat stock offers very little strength unless you stand it on edge. Aluminum would also be a fine material to make table frames from, it just needs to be a thicker gauge than steel. Aluminum frames would be slightly tougher to work with, welding is not as simple as with steel but aluminum is much more repairable than steel although I dont see where this applies to table frames. Aluminum is equal size is about a third of the weight of steel, I would consider that a downside, I think heavier tables are more stable.

 

[Ssonerai]

A picture to show what I mean, I made that as lot of time on construction to screw with lag screw, 3/8 x 8 flat bar on header opening at floor level 10 feet wide, wall over and roof truss, and it make a very strong job. When the flat can't twist it is very strong, a 3/16 x 6 or 8 inch screwed and glued on table frame would fix that in the time.

Are you trying to illustrate a flitch plate?
Your pic does not really show what i think you are trying to demonstrate - a wide piece of relatively thin flat steel sandwiched between 2 (or more) 2 x 12's. There is usually a call-out on the plans for the engineered bolt schedule.

Starting in construction myself, and still doing odd jobs, we (my crews) often used flitch plates in garage door headers.
Most of those were 3/8" or 1/2" x 10" plate sandwiched between a couple 2 x 12's (which are only about 11-1/4" wide actual)

For my own work, usually found W sections (wide flange "I-beams") cheaper and easier to use, though it is necessary to go back and block them for finish facing. Which a flitch beam avoids.

When removing bearing walls in people's houses to open up large span free spaces, one of the most effective methods is to go above, remove all the drywall from a near stud wall, block it, hang the joists below from it with steel hangars, and epoxy glue and screw plywood on both sides to form a very deep box beam. This can be done in a single story place, too; if the downstairs center wall was required load bearing, where many legacy homes were rafter framed. (Instead of truss).

Point being, wood or steel, used appropriately, either can carry the structure.
I doubt a composite wood/steel arrangement for pool table framing would be efficient in any sense (cost, ease, weight, etc).
OTOH good legacy wood systems are, but the materials are getting expensive and wood had inconveniences mentioned in posts above.
Steel tube also should be. If added mass is desired, use polymer concrete for damping, selectively.

smt

 

[trentfromtoledo]

Do you know how a pool table frame is made... main frame and cross member, the cross member keep the main member right they can't twist, reinforce the main member with flat bar well fixed and the main member will be 3 time stronger, you can think what you want, I know what I tell about.

Why are you on here telling us how it should be done ?? If you really know build a table , then show us. I work on some of the best tables made and none of this is relevant to anything IMO.

TFT

 

[Ssonerai]

Do you know how a pool table frame is made... main frame and cross member, the cross member keep the main member right they can't twist, reinforce the main member with flat bar well fixed and the main member will be 3 time stronger, you can think what you want, I know what I tell about.

I am not a tech and don't know how to set a table up, especially don't know anything about the rails, really.

That said, to answer your question, a small time table builder & table dealer sought me out during the early 1980's to make parts & tools for him. My regret, often expressed on here, is that i did not pay close attention, since i figured "John will always be around if i need to know that" I did notice structures for various tables that were in the top of the manufacturers lines, the products John built, John often pointed out why he thought a structural option was "better" in various frames. I've posted on this forum the project of restoring the frame for my wife's 1920's 9' BBC. I was familiar with slate from the quarry on out, at that tiime. I am conversant with typical construction structural solutions for residential and light commercial buildings and building re-purposing projects.

There is not a lot of evidence that the better products of quality billiard table manufacturers are deficient in wood framing, though some can be improved. The way Brunswick shortened the long supports on some models of GC, for instance. But that was a geometry/engineering defect probably at the behest of bean-counters, not a problem with the (wood) material strength.

Some frames (many old worn frames?) can benefit from having the cross-members or supports brought up flush, and the entire top flattened.
Wood makes that easy.

Again, steel tube frames might eventually be even better.

Historical note: BBC advertised a steel frame high end table sometime in the late 19teens or early 1920's (would have to search)
I've seen the catalog pictures, but none really show the framing. Wonder if anyone has ever seen or worked on one? What was the defect that caused them to not be more widely accepted at the time? There have been other manufactured steel frame tables over the years that were "successful" as pool tables, but failed to be widely adopted.

No need to get belligerent when you post something in public, and the public tries to figure it out.

Your ideas are certainly interesting.
I think many of us would like to see your surface gage be successful & cost effective.
OTOH, why are your proposed projects more likely to be successful that past efforts?

My personal feeling, expressed elsewhere above, is that steel frame, (& possibly glass bed) will eventually be cheap enough and engineered as a total package to make inroads on traditional design, for which the materials get more expensive every year. Right now, slate is cheap. Wood is getting less so. The manufacturing issues (cost) with wood framing are probably more expensive in a production setting, than steel is.

smt

 

[trentfromtoledo]

I spoke about reinforcing old table not build new ones, if you not followed the thread it's not my problem

I see you wanna be a smart ass, ok, I will play. LETS SEE YOUR WORK OR SIMPLY MOVE ON. If you can't show us all, I ask you stop bull shitting me. How does that work for you?

TFT

 

[trentfromtoledo]

You can stay jammed for always in time with your method I don't care, 20 years ago people worked with 4 feet construction level, today with machinist level... if the tables would have 20 feet long how many times you would need to report your small level to reach each end and how accurate at each end, impossible to know, with long bar always very accurate. I have not started this thread to speak about this system and be sure when it will built never I will show that to you. The discussion is ended.

Says the guy who usually produces nothing. Have a great day!

TFT

 

[kid]

No offense but with the tool you designed, you can only see if it’s leveled between the four points touching the slates. If the center slate is sagging you’d never know... slates are grounded to 0.005 on 6’’ and a 12’’ starret is at 0.010 which makes it the perfect tool to accurately level the surface without detecting the imperfections that are within tolerances.. i only use one and it doesn’t take long to level a table.


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[bradsh98]

No offense but with the tool you designed, you can only see if it’s leveled between the four points touching the slates. If the center slate is sagging you’d never know... slates are grounded to 0.005 on 6’’ and a 12’’ starret is at 0.010 which makes it the perfect tool to accurately level the surface without detecting the imperfections that are within tolerances.. i only use one and it doesn’t take long to level a table.


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This is inaccurate.

While his tool only contacts 4 points, it has indicators spanning the entire area of the apparatus. The indicators will inform the flatness of the plane, without regard to the 4 locations where the "feet" rest on the slate. The design is quite simple, yet brilliant in the same regard. Though, I do think that it would be better with more indicator points.

 

[kid]

Where is this pool hall located?


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[trentfromtoledo]

This picture was last year before covid and also just before a big provincial tourney, I placed the 4 supports on table at the same place that the table feet on the ground because the table feet are pivot points and it more easy and faster for leveling. When I will straighten the slates the supports will be at the slate extremity. I will do tables one by one at changing felt, I do that for my pleasure first.

SERIOUSLY?? I am not trying to be mean, but, 4 points?? even on a one piece slate, that is ridiculous.

TFT

 

[kid]

Heriot? They need the cushions to be changed for k-55...some of the tables there have both k-66 and k-55 from at least 3 different sources...
Also, it’s on the second floor and when people walk by the tables you can see the bubble move on a starret.
Good luck in your project


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[trentfromtoledo]

Heriot? They need the cushions to be changed for k-55...some of the tables there have both k-66 and k-55 from at least 3 different sources...
Also, it’s on the second floor and when people walk by the tables you can see the bubble move on a starret.
Good luck in your project


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I think its neat he is trying to do stuffs, but, that aint where pool tables are broken: Its many of the people setting them up and not knowing how....It is a constant learning process and I love the chase.

TFT

 

[kid]

I’ve been working for canada billiard for the last 21 years...
Installed over 10 000 tables of all kinds...every 4 or 5 years the owner of the hériot calls us to fix what other people do to his room...


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[kid]

I hope you plan on taking the bed cloths off because you will probably break the seams... please don’t use bondo as last time i had to scrape off three layers of it that was as thick as 2 knife blades!!!!


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[fastone371]

A picture to show what I mean, I made that as lot of time on construction to screw with lag screw, 3/8 x 8 flat bar on header opening at floor level 10 feet wide, wall over and roof truss, and it make a very strong job. When the flat can't twist it is very strong, a 3/16 x 6 or 8 inch screwed and glued on table frame would fix that in the time.

So you are talking about using the shear strength of the steel flat stock?? Steel is very strong when stressed in shear, so much so that 3/16" thick flat stock or plate would be overkill. Think of a firewall in a car, a large flat surface that is only .028"-.032 thick yet it offers incredible shear strength. If you push on it it is very weak and easy to distort or dent but extremely strong mounted in shear. I could see this working on a pool table frame but it doesnt remove the issue of expansion/contraction due to moisture. Thats the real reason I could see the benefit of steel tube frames for pool tables, completely eliminate wood holding up the slate. also, if you are steel mounted in shear alongside of the wood frame if the wood bows at all it eliminates the advantage of the steel. The steel only remains strong in shear if it is straight.

 

[Ssonerai]

As per my note further up, based on his description, i believe he is referencing flitch beams.

Flitch beam - Wikipedia

en.wikipedia.org

We used them in garages in tract homes.
For many construction problems, they are neither cheaper nor easier, except that most carpenters can relate to them, and they require no blocking to add (nail, screw) face materials such as siding or drywall etc. I believe they are considered slightly more fire-proof than bare steel I beam. (Getting ever further off the rails, so to speak -In a fire, bare steel structure often fails from plastic deformation before heavy wood beams are compromised)

Usually, a steel W section ("I" beam) for the same span & loads is cheaper not only in materials, but it saves a lot of somewhat close fabbing time.

For pool tables, i think it would offer the worst of both worlds at extra cost.

But the OP may have a point for repair work in a commercial setting.
Would be interesting to see photos.

smt

 

[kid]

That’s nice and all but you need to know what happens to those pool table when someone thinks it’s out of level and tries to fix it by lifting it by the aprons to turn the ajustable feet. Then either the blocks fastening the slates to the frame will slide up a little or the slate screws pop off..i have to fix those everytime i go there... adding steel to the frame (which is strong enough) is not going to prevent any of that.


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[kid]

Oh and please keep in mind that at some point, pool tables have to be taken apart. Use removable bolts if you think you have to add anything, no epoxy


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