Table Test Machine

[Island Drive]

In your experiments, did you notice any significant cue ball bounce when it exits the ramp and lands on the table? I was thinking it might be nice if the surface of the ramp were concave so that its bottom would be almost horizontal and lead to a more graceful exit of the cueball. However, if bounce is not a problem with a straight ramp, then it would obviously be simpler to make if its straight.

I was also thinking that the ramp should be such that the cue ball would only travel about 3 feet. This way you could test both directions on a table without hitting the cushion. The reason for this is because if the ball hits the cushion, a new variable is introduced, and we would be testing more than just the bed cloth speed.

I also believe firmly that we need an apparatus to measure the cushions of the table. But I'm not sure its a good idea to incorporate the bed speed and the cushion rebound in the same test.

I have a design in my head and a few sketches of a way to test the cushion using a cueball mounted to the end of a pendulum. The pendulum would be raised to a fixed hight and then released. It would bounce into the cushion and then rebound to a new maximum height. The height before the release can be compared to the height after the release to obtain a numerical value (coefficient of restitution) that can be used to compare different cushions, different installation techniques, different amounts of rail bolt torque, different brands of cushion, etc. This is something I'd like to build and ship to different AZ members, especially the mechanics who could test the installation variables that the rest of us can't. This would be more complicated to build, so it is something I think I would just make one of, and we could share it and ship it to each other on AZ.

Why not at least take a look at the Stimph (sp?) meter they use in golf to see what they have done?

 

[JoeW]

In my test runs there was not that much of a bounce when the ball hit the table. It was of course smoother with the angled cut. I think a device could be made without the cut angle on the base. The angle on the bottom makes it similar to the stimpmeter (which I did read about for those who asked). I am ambivelent about this cut angle thing. Easier to make with no angled cut on the base. A little more professional looking with one and very unlikely to cut the cloth with an angle. The cut angle also provides more stability when corner molding is used. What will people accept?

I am not sure but it seems that a longer run than across table would be more satisfactory. I think that something like a lag shot would seem "right" for most people (including me). In Bob Jewett's discussion of table speed he uses the time of the return from the foot rail to assess table speed so in a sense I was trying to conform to what people are used to.

A compromise position would be to have two or three stops. One stop would go across the table, another stop for one length of the table (not testing rails), a third stop would go two lengths for the lag test.

I understand the advantage of assessing only one thing at a time and think that this would be the preferred approach. However, I also think that a portable device that yields much information is also important for wide spread acceptance. Hence, the compromise might be more acceptable to many people and only requires additional stop slots.

 

[JoeW]

It turns out that is was extremely easy to make a pool table Stimpmeter. I bought a piece of "Sprung Core" 1 5/8" cove molding from Home Depot for $6.00. It is white and appears to be made of some type of plastic.

Cut the molding 16" long. Place on the rail so that the end of the molding piece lines up with the first diamond down from the long rail. Draw a red line on the molding where the molding intersects the rail and the cloth on the head rail. This is a reference point for setting the meter in the same place each time on any rail.

Hold the pool ball with both hands so the edge of the pool ball lines up with the edge of the cushion and let go. The ball rolls eight diamonds to the foot rail and returns one diamond. This is the basic reference point for my table which has brand new Simonis 860 (installed the day before). This procedure was used for 10 different balls and from different places at the head of the table. Unless I made some silly mistake such as not setting the ball exactly on the edge of the cushion, the balls return within 1/2" of each other. This means the meter is reliable for this type of measurement. The molding is marked at this position with the number "8" meaning eight diamonds expected return.

In the next phase I found the place on the ramp where the ball would roll up to but not touch the bottom rail. This was marked with the number "7" meaning seven diamonds expected roll.

In the last phase the meter was placed on the side rail and I found the reference points for "3" and "4" diamonds that will allow me to check cloth and rail return from the side of the table.

If anyone is interested I can give the exact measurement I have. From what I have learned my table is competition speed (using Bob Jewett's method). However, a simple meter like this calibrated by a table manufacturer or a professional organization would be the better approach.

I have photos of the whole process but recently learned that I can no longer use the free Photobucket service to reference photos. Does anyone have a suggestion for another service like Photobucket had in the past?

 

[Andrew Manning]

Unless I made some silly mistake such as not setting the ball exactly on the edge of the cushion, the balls return within 1/2" of each other. This means the meter is reliable for this type of measurement. The molding is marked at this position with the number "8" meaning eight diamonds expected return.

I would suggest that the rails are more important than the cloth in determining how hard I need to stroke most shots in order to achieve the desired speed control. In this test, you're only getting a little tiny rail bounce, meaning you're really not measuring the rail speed much, you're measuring the roll speed of the cloth.

To me, the best test of a table's speed is to play a little 5-ball rotation pool on it. I throw out 5 balls randomly, and take ball in hand and run out. Do that 2 or 3 times, and I have a good sense of the speed of the table under a good variety of shooting circumstances. I use 5 rather than a larger number to avoid any traffic on the table, because I want to be able to move the CB around unimpeded.

-Andrew

 

[PlynSets]

OK. So there are some people using a ramp to test speed. But it seems they are either home made or custom made. Why don't we agree to a standard. THat way we can have results that are comparable.

I would be willing to help. I'm and engineer and can make drawings that I would share freely of the ramp. I can also machine a ramp on a CNC. If someone has a ramp design they suggest we use, I would be willing to draw it up. Or I can come up with my own design, and machine a few samples out of a durable material.

The ramp would be the only way to go to consistently get repeatable results (cost effectively). I have a pretty simplistic design in my head..

If you guys really want to "standardize' this it wouldn't be that hard. Make 50 - 100 of them and give them to the people that'd know. I.E. A couple to olhausen, brunswick, diamond, other major table mfg's / cloth mfg's.

They get it for free and began using a universal measurement system, next thing ya know everyone uses the measurement system based on the new "standardized" ramp.

The rest you sell to joe Q public at a mark up to offset initial costs. I don't think you'd make 10 cents on the product, but at the end of the day it would certainly "level the playing field." (pun intended)

The key to the ramp would be at the top of it. It'd have to have a less of an incline (near flat, but not quite) and a stop at the top. You hold the ball against the stop (ensures no forward movement). Release the ball, it slowly rolls forward, and then begins it's run down a steeper incline and eventually transitions again smoothly onto the table. All very easy to do.

DJ

 

[JoeW]

I would suggest that the rails are more important than the cloth in determining how hard I need to stroke most shots in order to achieve the desired speed control. In this test, you're only getting a little tiny rail bounce, meaning you're really not measuring the rail speed much, you're measuring the roll speed of the cloth.

-Andrew

Setting the ramp as described on 1 piece of chalk yields 9 diamonds return. Two pieces of chalk yields 10.5 diamonds, and three pieces of chalk yield 11.9 diamonds. After that the pieces of chalk are probably too unstable.

A small bounce off of the rail does not necessarily tell if the rail is "dead" because the back of the rail is not used for the bounce. However, a small bounce should give some idea of the rails' capabilities and consistencies.

I just checked and found that when the ramp is set to check across the short side of the table and the "8" position is used for the drop the ball does travel 8 diamonds. Interestingly I get the same amount of travel from the long and from the side rails.

The advantage to this particular ramp is that it is extremely easy to make: Cut a piece of cove molding that is readily available.

The use of the ramp is more about comparing the table's performance today versus yesterday including the effects of temperature, humidity, dirty balls, etc. One guy says the table plays fast anthor guy says "no it doesn't." Who is right?

With regard to design, I have already made one for about $1.00 and it takes five minutes to make with a hand saw. Setting the reference points may take 30 minutes to an hour and one has a way to measure table speed, cloth speed and rail bounce. Note that my earlier posts indicates that this very cheap device is quite reliable (within about .5 inch) which should be sufficient for pool players.

I have been wondering if one of the bar tables I play on is as fast or faster than my home table. I have been playing on each for about one year. Now I have a way to find out. The distance between diamonds is probably different on the two tables but I can easily make this conversion.

 

[Dartman]

There is a ramp on the market to roll the cue ball down. This was discussed in the table mechanics section a few weeks ago. The impression I got after reading that thread is that the table mechanics thought it was a joke, and the seller of the product was ripping them off.

That is a good example of a device that could be standardized across the board that will give numerical results of a table's speed. But the people in the business, at least on this forum, don't seem to see its value.

And the numerical value for the speed of a specific table tells you what - hit the cue harder or easier?
I think most players can figure it out with some practice shots - just like bowlers adjust to lane oil.
A ramp to determine speed is a joke but perfect to test accuracy of cushions.

Here is a schematic of a ramp used by a mfg to test cushion accuracy - http://forums.azbilliards.com/gallery/data/500/medium/cushionaccuracytest.jpg

 

[tjlmbklr]

Table speed is important .................snip

I remember my dad had a golf putting ball return thing when I was young. Ibet the mechanism in that could be used to accurately hit a ball.

 

[oldroller]

Time

Some of you guys got too much of it