You're thinking too much into it. Don't believe a word you read on this forum. Reference it only for ideas that you can investigate for yourself. You're going to experiment with every material you listed, and will learn by your own experience which ones are legit. Take the time to review this thread and reference who suggested what. Pretty quickly you'll realize just how many posters are completely full of sh!t, and which ones are genuinely helpful.
Shaft plug materials?
- Thread starter Kim Bye
- Start date
If you must know, my name is Vincent Bizon, I have been fooling around with cues since the 90's and started building cues over ten years ago. I am not here to sell cues so I don't promote my cue here on AZ. This is the reason I stay somewhat anonymous, but you don't have to be Sherlock to figure out who I am and that I build cues. I am also Machinist in a research shop as a full time profession so I am confident in saying I understand how parts should fit.
Now having said all that IMO the type of material chosen is directly related to the specifics of your joint. I never said wood joints don't work and are no good. I am simply saying that in close tolerance joint configuration such as in the case of the 3/8" pin with flat root. Wood may not be the best choice of material because of the fact that wood moves too much. Now having said that if Dave or whomever has devised a way of treating there threads to minimize movement so as to maintain a consistent fit through all the seasons then it is all good. It is however my deduction from what I have seen that you can't eliminate wood movement entirely and the only way to compensate for this movement is to have a large enough tolerance on your thread fit to allow for it. So it is only logical to choose a different material which is more stable if you wish to have a joint with a tight fit and I will qualify that statement with saying a clearance fit of +0.001" to a max of 0.002". The whole point of the flat rooted thread is that the minor dia of the pin pilots the joint in order to maintain concentricity, as well I believe you have a better feeling hit when the two surfaces are intimate. I think we have to remember when discussing this subject that one has to be specific in all the elements of the particular joint we are debating. One particular material may be better suited for a particular joint style then the next, for example Mcdermott uses a 3/8 ten joint into wood but they are not using the root dia as method of alignment so they have enough tolerance in their joint to allow for any movement.
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Vincent...
I believe you to be correct in wood is going to move. All we can do are things that will minimize this as much as possible. If using a synthetic material as a plug is what you feel is the best way to accomplish this at the joint then so be it.
BUT...again I think you may be over thinking the whole assembly by worrying about a thou or even two thou difference in the minor/major of the pin and the pin hole in the shaft. Being as skilled as you are I'm sure you realize that a thou difference equates to .0005 on both side of the pin. A .002 thou size difference = .001 on both sides.
IMO......of this whole equation.....the most important is the two mating faces and how flat and relative they are to the center line of the cue.
A normal human will not be able to tell any difference at the outside of the joint between being absolute dead on center or being .001 off.
Of course we all strive to achieve the most precision we can with the tools we have and knowledge we use but I believe if using a flat faced joint you are going to be faced with this challenge no matter what material is used.
If you use a synthetic material such as phenolic the minor/major differences are going to have to be at least slightly different to be able to mate the two pieces anyway. Then as time moves on, wear may still have its effect.
IF it's so very important to the builder to have a very snug fit at least in maple you can have a "compression" fit on the major of the hole and the minor of the pin that may be the snug fit you're attempting to achieve. However, It's my belief that you can have it too snug and make it a struggle to lock the two mating faces together.
I don't care for a cue that I have to work at to mate the shaft with the butt.
I have found of all the methods I've tried in wooden threads I prefer a "slight" interference fit at the initial build and let the chips fall from there.
It's been my experience that due to any humidity changes where my cue is going to end up the difference is not going to be significant enough to have any effect on the way the cue will mate together by doing it this way.
There may be that oddball one or two over the course time but I haven't heard of or seen one of mine yet.
Maybe I've just been lucky.
I'm about to try an African Blackwood insert. Any thoughts?
Thank you.
I use a flat minor thread. That minor is machined to exactly .0005" smaller than the drill that creates the hole for it to fit. The depth of thread doesn't matter so much as the minor fitting the bore. It cannot be dry fitted. It simply will not fit, and locks up as if it is being cross threaded. The bore & threads have to be lubricated, which allow for the pin to be force fit. Once the pin has been in that first time, it will forever & always retain that fit. Granted, the lubrication is the key, as it lasts forever & also seals the pores of the wood. It gets poured in & pressurized until I see it begin to bubble out of the wood's pores further down the shaft. The threads, simply put, are saturated throughout with the sealer/lube. The shaft does not fit the pin tightly as you'd imagine, considering the tight tolerance. Rather it fits very smooth.
That may seem extreme to some, but there's a purpose for such a smooth fit. I use sanding arbors on the finish. Any shaft I make will fit any butt I make with almost zero ledge. It's a fit much like you get when the two components are sanded together, except that every single piece is exactly compatible. I can make a shaft today for a butt I made 5 years ago, without having the butt on hand, and I know for certain the shaft will fit perfectly flush. There's a value to that confidence in consistency, and it cannot be had unless the minor of that pin fits the bore damn near perfect. Any slop in the fit will show up as an overlap/misalignment when the shaft is screwed onto the butt. And the only way I can get that fit without it locking up is to use the sealer/lube that I use. As luck would have it, due to the thorough saturation, it also prevents the wood from swelling/shrinking.
The saturation is exactly why I personally prefer wood. My sealer/lube will not saturate synthetics, so rather than become integral, it merely rests on the surface. Over time it will wear away. Being thoroughly saturated in the wood, it will never wear away. This joint system is also why I do little more than drill a hole & tap it. I cannot have any fluctuation in bore size or else none of this works out. The only way I could retain a level of consistency was to keep things as simple as possible, which means using only a drill bit & tap. It has nothing to do with hit or playability. It has everything to do with long term consistency in fit. Year after year, cue after cue, every shaft fits every butt as if they were sanded together. They are all exactly the same. To me, that means something.
I think it'll be great. Report back & let us know.
Thank you both Dave and Eric for the in depth response. You both have given food for thought and different angles to consider.
3/8x10 , will post pictures