Testing Cues for Straightness

I recommend it for other people!

John,

I think rolling it on a rail or in the rollers is a great move when you are considering buying a cue. It is a good way to negotiate price downwards as it will show imperfections as tiny as the finish being a little thicker on one side than the other. Likewise I can put a cue that spins perfectly true in my lathe one time in there again and make it spin twenty-thousands out or basically as much as I want it to. If I am not trying to shark somebody about their cue or negotiate a lower price I'll eyeball down the length of it or give it a quick roll on a clean table. If it seems reasonably true like this it is plenty true enough to play with.

I'll bet that anyone that wants to can bring me their $3000 up pool cue including those made by the masters and I can "prove" it isn't true both on a set of rollers and in my lathe. Any takers willing to bet pretty big?

There comes a time to consider what a cue is and what it's function is. I have three shafts in my case. By August every one will be warped pretty badly. By late November every one of them will be as straight as the eye can detect again.

Hu

John Biddle said:

I participated in Ftgokie’s Cuemakers Buildoff that will be finishing up soon. It was a unique learning experience and I thank him, the (still unidentified) cuemakers who donated their work, John Barton, who donated a case to hold them while they made their way across America, and all the AZers who participated in the project. It was great fun and I’m glad I got to participate. This kind of thing is one of many that set AZB apart from all the others.

One important thing I noticed when I got the cues was that only 1 was perfectly straight and a second was very nearly so. The other 5 were noticeably off. There was limited commentary on the thread about this, which initially surprised me. And this was after one shaft had been replaced for being warped.

During the evaluation process, 14 of my pool friends, almost all APA 6 & 7 equivalents, looked at the cues and provided their feedback. One of the criteria on the evaluation sheet I gave them to use was straightness.
I was surprised to see the technique many of these guys used to check for straightness and would like to point out a couple things.

Rolling the cue flat on the table is a poor method of detecting a straightness problem. If you get your eyes right down on the cloth and watch the gap between the shaft and the cloth as you roll the stick you can learn useful info, but looking down on the cue while standing over it won’t tell you much that isn't immediately obvious by just looking at the cue.

A much better technique is to put the butt end of the cue in the center of the table and lay the front end of the forearm on the rail. The joint should be beyond the cloth of the rail. Now when you roll the cue and watch the ferule for wobbles you can detect smaller problems with no extra effort. You can see warpage, but also will see the problem if the pin isn't straight or isn't perfectly centered.

One of the evaluators is a well known cuemaker (did not have a cue in the build-off) and another is a big cue collector. Each had a set of rollers mounted to blocks on which they could roll the cues and easily see imperfections. The rolling on the rail method is not quite as good as this, but almost, and I highly recommend it.

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In the interest of fairness, John, I think the people doing the 'build-off' evaluating should have access to the devices you describe. Rolling a butt, or a shaft on a pool table can be acceptable, but only marginally so because of the variables involved. Either that or have them drag around a cue lathe, which of course would be impractical.

The roller method is by far the best method to use. I used to work at Sterling, and we checked every cue before it went out. We had a long (about 6.5 feet) shelf on the wall, and a product that I think was called Pocket Lathe, which was a pair of small plastic bases with two hard rubber wheels on top. When you lay a cue across the rollers, and roll the cue, any problem with straightness becomes immediately obvious.

Steve

(If I'm wrong on that product name, someone please correct me...at my age, my memory isn't what it used to be! )

ShootingArts said:

I have three shafts in my case. By August every one will be warped pretty badly. By late November every one of them will be as straight as the eye can detect again.
Hu

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Wood does move. We all know what wood rifle stocks will do to accuracy if not properly inletted/bedded don't we Hu? What's straight today may be a total trainwreck by next week !!!

Maniac

pooltchr said:

(If I'm wrong on that product name, someone please correct me...at my age, my memory isn't what it used to be! )

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At least YOU can still remember your age :thumbup:!!!

Maniac

Maniac said:

At least YOU can still remember your age :thumbup:!!!

Maniac

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Apparently, I still have moments of clarity. I found this site that actually sells the product.

http://www.cuesight.com/ncsmpl.html

Steve

all in the testing

John,

I do expect a nice cue to roll reasonably well on a well made set of rollers providing they are spaced a reasonable distance apart. As you see there are a lot of subjective words in my statement. A set of precision rollers will cost far more than most people are willing to pay so first we have run out on the rollers themselves to consider. Then if they are placed six inches apart at the butt we can magnify any run out roughly ten times. Even rolling a cue on a rail is magnifying the run out. I use 10X magnification to examine the chambers and bores of my rifle barrels. Some of the best custom rifle barrels in the world don't fair too well when magnifying their flaws ten times and they are built on far more precision equipment than most cues and the material itself isn't subject to moves due to climate such as a cue is.

When examining cues there is a fine line between reasonable expectations and being ridiculous. It's very tough to measure run out on a shaft for example if you simply screw it into a fixture you may be measuring joint run out or the run out between your measuring fixture and the lathe chuck. If you have one-thousandths angular run out one inch from the chuck then you have thirty thousandths run out at the end of a thirty inch shaft. Since you see that thirty thousandths in both directions, you see a horrible sixty-thousandths wobble at the end of the shaft!!

One of the most popular cue lathes has the spindle assembled with methods and components that give .003", three-thousandths, tolerance at the spindle. This spindle uses scroll chucks which are not precision chucks and subject to their own errors. Assume a perfect interface between the fixture and the scroll chuck and assume someone that knows what they are doing has just trued the chuck and we can still get .180 wobble at the tip of a perfectly straight shaft. That is a huge 3/16" wobble to convert to fractions people are more familiar with. Put pressure on a shaft holding it at both ends and again the run out can be huge simply from bowing the shaft under pressure.

I'm not trying to cover for poorly made cues, they deserve to be hammered. However most of the test methods used to check the straightness of cues are subject to as much or more error than the cues themselves and cues that appear to be straight when playing with them are straight for all practical purposes. If somebody truly wants a cue tested for straightness they should be prepared to pay for several hours of shop time. Then only a small percentage of machinists truly know enough to separate the straightness of the cue from other factors. Anyone testing anything for straightness before verifying the trueness of his test fixture immediately before testing be it precision lathe, cue lathe, rollers, or table and rail is very suspect as far as accuracy of the test.

Sorry to write a book on this but many people have unreasonable expectations and many more don't understand the problems with their test methods. Accurate testing is very difficult and less than accurate testing can lead to cue builders being wrongly hammered.

Hu

John Biddle said:

@Pooltchr, the Nivecraft Pocket Lathe is a fancier version of what I was talking about. I believe the two I saw were DIY products.

@Tramp Steamer, most of the evaluators were regular players, who are unlikely to need, or want, such a device. My point was about a way to test straightness that yields an accurate result without needing the rollers.

@ShootingArts, I don't know what to say. No one was trying to make anything look bad, only get at how straight the cues were, along with many other characteristics. I'm also surprised at how much you think cues change in a very short amount of time. While I agree that abuse will give bad results, reasonable care should not affect a well made cue.

I will readily admit that some of the not straight cues hit and played well and I don't have a good feel for how far off a cue would have to be before it affected one's performance.

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ShootingArts said:

John,

I do expect a nice cue to roll reasonably well on a well made set of rollers providing they are spaced a reasonable distance apart. As you see there are a lot of subjective words in my statement. A set of precision rollers will cost far more than most people are willing to pay so first we have run out on the rollers themselves to consider. Then if they are placed six inches apart at the butt we can magnify any run out roughly ten times. Even rolling a cue on a rail is magnifying the run out. I use 10X magnification to examine the chambers and bores of my rifle barrels. Some of the best custom rifle barrels in the world don't fair too well when magnifying their flaws ten times and they are built on far more precision equipment than most cues and the material itself isn't subject to moves due to climate such as a cue is.

When examining cues there is a fine line between reasonable expectations and being ridiculous. It's very tough to measure run out on a shaft for example if you simply screw it into a fixture you may be measuring joint run out or the run out between your measuring fixture and the lathe chuck. If you have one-thousandths angular run out one inch from the chuck then you have thirty thousandths run out at the end of a thirty inch shaft. Since you see that thirty thousandths in both directions, you see a horrible sixty-thousandths wobble at the end of the shaft!!

One of the most popular cue lathes has the spindle assembled with methods and components that give .003", three-thousandths, tolerance at the spindle. This spindle uses scroll chucks which are not precision chucks and subject to their own errors. Assume a perfect interface between the fixture and the scroll chuck and assume someone that knows what they are doing has just trued the chuck and we can still get .180 wobble at the tip of a perfectly straight shaft. That is a huge 3/16" wobble to convert to fractions people are more familiar with. Put pressure on a shaft holding it at both ends and again the run out can be huge simply from bowing the shaft under pressure.

I'm not trying to cover for poorly made cues, they deserve to be hammered. However most of the test methods used to check the straightness of cues are subject to as much or more error than the cues themselves and cues that appear to be straight when playing with them are straight for all practical purposes. If somebody truly wants a cue tested for straightness they should be prepared to pay for several hours of shop time. Then only a small percentage of machinists truly know enough to separate the straightness of the cue from other factors. Anyone testing anything for straightness before verifying the trueness of his test fixture immediately before testing be it precision lathe, cue lathe, rollers, or table and rail is very suspect as far as accuracy of the test.

Sorry to write a book on this but many people have unreasonable expectations and many more don't understand the problems with their test methods. Accurate testing is very difficult and less than accurate testing can lead to cue builders being wrongly hammered.

Hu

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Very informative--thanks. I've got a small collection of cues (12), and I play with all of them. I've noticed that all but two of them appear to have noticeable, but not dramatic, straightness issues, based on the usual rolling-on-a-table test. They all play just fine, though, and none of the straightness deviations are noticeable in play. I've concluded that absolute straightness is a) very difficult to evaluate, and b) not terribly important to the function of the cue. Your detailed explanation helped me understand why that is the case.

I realize this in your case

John Biddle said:

@Hu, I take all your points. The degree of precision is important. Absolute perfection isn't the issue, and neither is intentionally discrediting anyone's product.

In both instances where the roller technique was used, the rollers were not close together. In one case, roller #1 was on the butt sleeve, the other on the forearm at the end near the joint but not right next to the joint. in the other the butt sleeve roller was the same but the other roller was just outside the wrap area, IIRC.

These distances seems quite fair to me, and approximate what can be had with a little less precision rolling the cue on the rail. Cues that wobble visibly in this situation are not ready for prime time, IMHO.

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John,

I'm well aware that your intentions were above board and didn't mean to hint at anything else. Looking at a ferrule isn't a very good way to judge the straightness of the butt and the trueness of the joint face however. Shafts that have been played with for awhile are likely to show as much about how they have been treated as how straight they were to begin with. I don't consider it abuse for the tip of the cue to contact the table solidly at the end of most follow-throughs or for it to be bowed a bit on the break. Never-the-less wood has a memory and will show the effects of this over time.

My shafts show the effects of indexing the cue most of the time and sweating by the gallon in New Orleans summer heat. Test the roll out of my cues as you describe doing in August or September and you would say that they are badly crooked. Test again after the shafts are dried out in late November through January or so and you might find the cues and shafts to be perfectly straight. The butt and joint face were perfect summer and winter, the difference was in the conditions the shafts were subjected to.

I strongly believe that the trueness of butts and shafts should be tested separately in evaluations. One thing I much want to know is how well centered the pin is. No way to know when a cue is assembled with the shaft that came with it. The cheapest production cues usually start life dead straight because no matter how crooked everything is a final pass is made on the outside of the cue from end to end with it assembled. The pin could be coming out one side of the cue and it would still be straight at the moment. Some custom builders "cheat" the joint in a similar manner if the pin or insert is off. Nothing more annoying than building a straight and well centered shaft for an existing butt and then finding that you either have to give it to the customer with it hanging out on one side and in on the other or you have to cut the collar off center to match a poorly placed pin.

Hu

ShootingArts said:

John,


My shafts show the effects of indexing the cue most of the time and sweating by the gallon in New Orleans summer heat. Test the roll out of my cues as you describe doing in August or September and you would say that they are badly crooked. Test again after the shafts are dried out in late November through January or so and you might find the cues and shafts to be perfectly straight. The butt and joint face were perfect summer and winter, the difference was in the conditions the shafts were subjected to.


Hu

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I played with a Schick cue that done the same thing. During the Summer months, one of the shafts would get a small bow and then it would straighten back out that winter. I thought it was odd, but for some reason that shaft just preferred the winter months. I miss that cue.

the book does us in every time

John Biddle said:

@Hu & Sliprock, Man you guys need to try out this new fangled technology called air conditioning. It's the cat's whiskers.:wink:

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John,

One of the major annoyances down here, air conditioning is usually installed according to the cooling capacity off of a specification sheet. Unfortunately I have found that you need at least a third more capacity to actually cool and dehumidify the air. Both of my shops have several times the cooling capacity that is supposedly needed and they are heavily insulated besides. The doors stay closed most of the time and it works well. Pool halls with adequate air conditioning are as rare as hen's teeth, especially when there is a big tournament with crowds of people and the doors hanging open most of the time. If a building was originally built as a pool hall by a pool shooter it might have adequate cooling. If it was built as commercial space . . .

Hu

This is all fine and dandy but this thread is turning into a technical page for one of the other forums. Most people here don't have the wherewithall to make incremental measurements of straightness.

For all intents and purposes, rolling on a table is good enough for the average player looking at a cue in a poolroom.

John Biddle said:

I respectfully disagree. If you're going to grab a stick off the wall to play with for an hour, OK, but if you're going to be buying it I think you want it straight. Rolling it the way I suggested, butt on the slate, top end of the forearm on the rail, is no more difficult than rolling it on the slate, but much more revealing.

More accurate than that is probably overkill, but I'm not sure. Clearly a badly warped stick will affect play, and straighter ones will do so less and less all the way to straight. How close is close enough I don't know, but would like to.

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Okay, John., I'll play along

Explain to me how rolling the cue as you say is MORE revelatory than simply rolling on the table and watching the space change. Personally, I think they're equally valid in the sense that a warp is a warp is a warp, but table rolling is my preferred choice because the warp is more graphically identifiable when you can see the space between the cue and table change. Table rolling magnifies the less perceptable warp(2x in fact), making it easier to see.

If the pin is bent or if the butt is warped(slightly let's hope), how is that manifested in your demo that makes it easy to distinguish from a simple warped shaft. And for all practical purposes, does it really matter? If there's a warp but you don't know why, does it matter why? You either buy the cue or send it in for repair and say"it's warped", and let the cuemaker figure it out.

Rolling it on the rail, table or floor, you it should be understood that most any piece of wood will have some runout. What you should learn to agree on is what is an acceptable amount of runout.

If you roll it on the table, and it appears to be straight, that is straight enough.