joint pin question

[scdiveteam]

Royce,

All the tapering of my shafts from .920 to .850 the concentricity pin is the driver on the dead center of my saw machine. Because the driver pin is screwed into the shaft insert with a very tight initial fit there is no lateral play. When the shaft is done after the buffing wheel, the device is removed and the shaft is hand fit to the tightness I require at facing on each cue during ring line up.

So because the pin is perpendicular to the precision face the axis is concentric to the taper contour on the first cut. My shafts are processed between the 60 degree wood centers down to .920 before the pin is installed and I chuck hard on the six jaw and back chuck. The jaw marks turn out pretty fast and the is no collet involved.

So if you are processing your shafts between wood centers what is confusing to visualize a threaded device made of brass doing the same job while it is embedded in the threads very tight.

When shafts are at finished size you don't have to re chuck it and drill and tap it because it is already done. Because the shafts are tapered around this device it is kinda like the reverse of boring when the ID of the bore runs true with the OD. There is never a collet on my shafts and the pin stays in the cue during sanding and finishing. As I said, I never test roll my shafts until both the shafts and butt is buffed and ready to ship. That is a pretty strong confidence in the method. Many people have visited my shop and know how it is done. My mentor Ray Hernandez turned me on to this and it is second nature to me now.

Next time you around Chicago please stop by my shop and see this method work as I would be very happy to demonstrate.

I am not the only Cue Maker that does this method as it has been around a very long time. I won't speak for others but they are out there. Maybe someone else might weigh in???

I hope I have made it a little clearer. :grin:

Rick

 

[RBC]

Royce,

All the tapering of my shafts from .920 to .850 the concentricity pin is the driver on the dead center of my saw machine. Because the driver pin is screwed into the shaft insert with a very tight initial fit there is no lateral play. So because the pin is perpendicular to the precision face the axis is concentric to the taper contour on the first pass. My shafts are processed between the 60 degree wood centers down to .920 before the pin is installed and I chuck hard on the six jaw and back chuck. The jaw marks turn out pretty fast and the is no collet involved.

So if you are processing your shafts between wood centers what is confusing to visualize a threaded device made of brass doing the same job while it is embedded in the threads very tight.

When shafts are at finished size you don't have to re chuck it and drill and tap it because it is already done. Because the shafts are tapered around this device it is kinda like the reverse of boring when the ID of the bore runs true with the OD. There is never a collet on my shafts and the pin stays in the cue during sanding and finishing. As I said, I never test roll my shafts until both the shafts and butt is buffed and ready to ship. That is a pretty strong confidence in the method. Many people have visited my shop and know how it is done. My mentor Ray Hernandez turned me on to this and it is second nature to me now.

Next time you around Chicago please stop by my shop and see this method work as I would be very happy to demonstrate.

I am not the only Cue Maker that does this method as it has been around a very long time. I won't speak for other but they are out there. Maybe someone else might weigh in???

I hope I have made it a little clearer. :grin:

Rick

Rick

OK. So as I understand it, once your shafts are tapered down to .910" at the joint, you install your stepped insert and mount an pin, with a 60 deg center on it's back end, on which you perform the remaining turning passes.

So here is my question. If your insert is in the shaft and concentric to the exterior taper when the joint is at .910" in diameter, then how can the insert remain concentric when the shaft moves between tapers?

It's a very simple question. If the insert is concentric then, but the shaft moves afterwards, the shaft will have a new center concentric to the new exterior after turning. Since the insert was concentric to the previous exterior, it is now not concentric to the new exterior.

Please don't clutter any response with talk about anything prior to installing this pin at the .910" point. Please don't clutter any response with talk about when or how you roll a shaft or anything like that. I'm just interested in whether your shafts stay dead straight from the .910" mark all the way through the remaining tapers. Or not.

I'm really just trying to figure out exactly what it is that you're doing. Either you don't do what you say you do, or you don't get the results you say you get. I'm really just trying to figure it out.


Royce

 

[LGSM3]

So even though the face is 100% perpendicular to the shafts OD the tapped hole is angular or not parallel to center line if the shaft moves....that where yall r going with this?

 

[scdiveteam]

Rick

OK. So as I understand it, once your shafts are tapered down to .910" at the joint, you install your stepped insert and mount an pin, with a 60 deg center on it's back end, on which you perform the remaining turning passes.

So here is my question. If your insert is in the shaft and concentric to the exterior taper when the joint is at .910" in diameter, then how can the insert remain concentric when the shaft moves between tapers?

It's a very simple question. If the insert is concentric then, but the shaft moves afterwards, the shaft will have a new center concentric to the new exterior after turning. Since the insert was concentric to the previous exterior, it is now not concentric to the new exterior.


Royce

Royce,

What is the difference whether the shaft is being driven on a brass 60 degree center or wood 60 degree center. The device runs true with the dead center and there is no rumming going on. If you wish to perceive that is not the case then I have nothing more to say. My shafts when finished are awesome. The device does not wiggle if that is what you are theorizing here.

The taper bar will always repeat the contour from the joint to the ferrule end. The shafts were cut from 1" dowels on the same machine. Even if they were store bought blanks with a different taper, my taper bar will cut the contour for the entire length and reveal the taper bars mirror image.

As the elevation of the frame is dialed down for each cut the contour remain the same differential numbers between the joint and the ferrule end are:

13 mm is .339
12.75 mm is 348
Ect.
Ect.

If the final joint size is .850 the taper differentials are always the same. Because my shaft has a parabolic taper on the joint side the drop is pretty severe coming off the joint and because of this I must have the face of the driver device stick out of my shaft face the same distance on every shaft so that are all tapered the same. I use .570 as this critical dimension and leave a 5/16 tenon sticking out of the ferrule about 3/16 to allow for blade clearance on that end so the ferrule is not nicked when the E-Stop kicks in.

Rick

 

[qbilder]

So even though the face is 100% perpendicular to the shafts OD the tapped hole is angular or not parallel to center line if the shaft moves....that where yall r going with this?

That's part of it. And considering that it is not parallel to center line, a very tight fitting pin will either not allow the faces to contact flush, or else the pin will be stressed out of place. In a nut shell, if a shaft moves any time during the cut phase, the end result will be the same as a bent joint pin, except mirrored.

 

[cutter]

joint pin

Give up boys, he just doesn't see the problem

 

[scdiveteam]

That's part of it. And considering that it is not parallel to center line, a very tight fitting pin will either not allow the faces to contact flush, or else the pin will be stressed out of place. In a nut shell, if a shaft moves any time during the cut phase, the end result will be the same as a bent joint pin, except mirrored.

Eric is right when he says "if the shaft moves at any time" but that is not the case.

I guess I will have to make a video and figure out how to post it here.

The device is very tight and in much more compression than a normal pool cue make up. That is why i adjust the stepped minor on each shaft to fit the butt after I buff the finish so it is very tight as the facing occurs. This step allows my ring geometry to stay lined up over time because you can't power the facing and degrade the inserts threads. The final tweaking is adjusted so two hands can make the face but can't rotate past it even a touch. I guess you could do that with a pipe wrench if so inclined. LOL

Rick

 

[RBC]

Eric is right when he says "if the shaft moves at any time" but that is not the case.

I guess I will have to make a video and figure out how to post it here.

The device is very tight and in much more compression than a normal pool cue make up. That is why i adjust the stepped minor on each shaft to fit the butt after I buff the finish so it is very tight as the facing occurs. This step allows my ring geometry to stay lined up over time because you can't power the facing and degrade the inserts threads. The final tweaking is adjusted so two hands can make the face but can't rotate past it even a touch. I guess you could do that with a pipe wrench if so inclined. LOL

Rick

Sorry Rick, but your super duper stepped concentric insert with more than normal compression has nothing to do with what happens when a shaft moves slightly after it's tapered.

I asked you to answer my questions, but obviously you simply don't care to. That's fine. It's ok if you don't want to. I'm completely ok with it. I now have all I need, so I won't be bothering you anymore.

Have great night and happy cue building!

Royce

 

[Sheldon]

Eric is right when he says "if the shaft moves at any time" but that is not the case.

Shafts can, and do move between cuttings. Not always, but it does happen. The point you are missing, is that if the shaft doesn't remain perfectly straight between tapering cuts, YOUR THREADS WILL NO LONGER BE PARALLEL TO THE CENTER OF THE SHAFT.

 

[Canadian cue]

Rick the part you dont get is that just because the end of you drive pin with the 60* centre may run concentric the other end of the pin which is embedded in the shaft may not . That is what everyone is trying to tell you. You can not run your indicator on it to verify it doesnt. So if your shaft moves at all your joint pin installed in the butt will try and pull your shaft off axis, so even if the OD of your shaft is perfect and the joint face is perfectly faced sqaure the pin will be forced to bend when the the face of the shaft and butt meet.

 

[qbilder]

I guess I will have to make a video and figure out how to post it here.

Oh that's easy. The way I do it is with a photocaptive canagus equipped with a truncated glass lens, custom concaved to an exact geometry within .0000000001". I rotate the elongating device precisely to achieve repeatable & accurate focus results, then depress the record button at the optimum moment to achieve maximum effect of the videographical climax. I know that's a probably a bit excessive but I won't accept anything but the tightest tolerances, and that's what this is all about.




Sorry, Rick, I couldn't help myself oke: All in good humor. WTF ever happened to just drilling a hole & tapping it?

 

[scdiveteam]

Shafts can, and do move between cuttings. Not always, but it does happen. The point you are missing, is that if the shaft doesn't remain perfectly straight between tapering cuts, YOUR THREADS WILL NO LONGER BE PARALLEL TO THE CENTER OF THE SHAFT.

Warning: This is long winded thread and not suitable for all who may assume too much based on their individual expert opinions. LOL


Hi Sheldon,

Yes shafts do move from time to time and from my experience with this method, after resting, when they move they recut the taper between the two centers. At least that is what happens in my universe. Maybe it is the stiffness of the pin sticking out .570 that creates more leverage on the center's ramp or something like that. I really dont know.

Just for record, during my response to Eric I said "the shafts don't move". It was in reference to the fact that I thought he was referring that somehow the pin moved within the threads. Of course we all know physical shaft wood can move!

There has been a lot of questions towards me in the last two pages of posts here and I would like to ask a question myself? How many of you guy have ever made a shaft with a device like this and not just on wood centers on both ends. I would guess that answer to be "none". So that kinda makes me the expert in this area and being the expert i have a few things to report after doing this for ten years plus.

After turning all my shafts to final and tweaking the stepped minor to my facing torque, I observe the following repeatable conditions.

1) The shafts roll true on a flat surface plate I have in my shop for such testing.

2) The cues roll true on that surface when joined to the shaft and the ferrule rolls even on the surface without bobbing.

3) The cues roll true when they are rolled on the rail and there is no elevation change at the joint during the rolling process.

Is this not the prime directive when building a cue wether you are Ernie or a newbie right out of the box? I think so.

Also, my shaft geometries have a parabolic taper from the joint to +16" transitioning into a modern pro or super pro taper from +18 to the tip. When my shafts are rolled on the surface plate they reveal a substantial air gap between the shaft and the plate. More so than than all of the cues I have seen.

The air gap in this area is very constant when the shaft is rolled individually or when joined to the butt this gap is also very consistent. I don't ship shafts with taper rolls as is my policy. Do I have cues in the field with a slight taper roll on a shaft? Yes and I would be lying if I stated no. We are working with wood and we all know wood can change after it leaves the nest.

BTW, my butt also has a compound taper with a slight parabolic curve from the cap to the 1.008 A Joint, then a conical taper to the nose. There is a reason for this geometry but we won't get into that at this time, one bag of worm at a time please!

There are a lot of things going on here and if the method I am using failed when a shaft moved a little after resting it would show up in spades and be amplified by these geometries that exist.

So every time I build a cue, I am either the luckiest guy in the world or just maybe there is more to this method than meets the eye. So you can go ahead and say I am BSing the forum, call me names or whatever and I am ok with that because the things you guys are saying are truly things that you believe. What I see from my perspective is some very smart and experienced people who have gained confidence with the method they use and have zero experience with the system being discussed here.

Things are not always what you may think they are. I am not one of those closed mouth types who guards so called secrets, we all know the type. I truly like people and also have no problem sharing anything I know concerning cue making or anything else. So my bringing up this method of cutting shafts was an attempt to share a methodology with this forum in a collective way.

All of the table talk and theorizing about the matter at hand is good for all of us because this is a process of peer check and review. They only thing that is a problem here is that I am the only one who has absolute confidence in this method because of the stellar results it has afforded me. In no way any I trying to grandstand and take credit for it as it was not contemplated in my brain by design. It was taught to be by a tool and die engineer who was one of my mentors. I have created steps and made changes concerning technique over the years to make observed improvements.

Logic tells us that in order to make statements and draw conclusions that we must rid our minds of prejudice and make observations based on double blind algorithms concern the rooting out of the truth. I have tried to do this in my journey as a Cue Maker in all phases of the development of my procedures.

While many here are telling me that the alignment of the insert's threads to the X axis of the taper OD will not continue to be parallel if there is movement of the physical wood. I am here to say that that is just not the case and the movement cut out and is re tapered true on the next pass. My finished shafts and cues reflect otherwise as they speak for themselves.

I am not the smartest guy in the world but I am pretty darned smart and know how to judge a cockeyed cue or taper. So the idea concerning physical shaft wood moving and blowing the concentricity of the threaded insert and the pin device out of line is not the case from my seat.

We all have our opinions and theories concerning this topic obviously but I have the experience and practical hands on with this and will continue using it as I think it is a superior method.

4 years ago after I posted the method with pictures, Arnot called me at home out of the blue and told me I was full of crap concerning the same issues that are being said today. At least this time it has been a civil discussion. LOL

I still love you guys but have to respectfully disagree with the some of your statements posted here because in the final analysis, I have to trust my own eyes and ears concerning results.


JMO,

Rick

 

[Dave38]

I gotta start cutting my shafts at Rick's place, as it seems from his statements, that his shaft wood doesn't 'move' due to stress/moisture, etc..... must be a 100% success rate....100 shaft blanks go in and 100 straight finished shafts come out.
Dave

 

[Dave38]

Oh that's easy. The way I do it is with a photocaptive canagus equipped with a truncated glass lens, custom concaved to an exact geometry within .0000000001". I rotate the elongating device precisely to achieve repeatable & accurate focus results, then depress the record button at the optimum moment to achieve maximum effect of the videographical climax. I know that's a probably a bit excessive but I won't accept anything but the tightest tolerances, and that's what this is all about.
QUOTE]

Rick couldn't have said it better.....hahahaha
:rotflmao1::rotflmao1:
Dave

 

[scdiveteam]

I gotta start cutting my shafts at Rick's place, as it seems from his statements, that his shaft wood doesn't 'move' due to stress/moisture, etc..... must be a 100% success rate....100 shaft blanks go in and 100 straight finished shafts come out.
Dave

Hey Dave,

Re paragraph two if you can read and comprehend.

After doing so you may wish to amend your statement.

Part of the problem with forums is that many tend to scan and don't take the time to comprehend what some is saying. This results in a knee jerk reaction.

I am guilty of that at times and when I scan and knee jerk I always look like a horse's arse. Wouldn't you agree.

JMO,

Rick

PS: try storing your shafts within the pyramid tent for keeping shop razor blades sharp. Very few know how the power works for keeping shaft wood straight. It's an old Indian trick passed to them my ancient aliens. LOL. Chris Hightower is very wise and dares not include this is his book out of fear of the curse that my result from heap power medicine.

 

[JoeyInCali]

My question is, what is wrong to boring and threading the shafts after you get to final size ( or really close to the final size ) ?????
You work with the shallow center holes you created in turning that shaft multiple times until you get to the final size.
Once in final size, you bore the hole concentric to the outside of the wood then thread it . Or you can install your inserts then and thread that part.

 

[scdiveteam]

My question is, what is wrong to boring and threading the shafts after you get to final size ( or really close to the final size ) ?????
You work with the shallow center holes you created in turning that shaft multiple times until you get to the final size.
Once in final size, you bore the hole concentric to the outside of the wood then thread it . Or you can install your inserts then and thread that part.

Joe,

There is nothing wrong with doing that as it is a standard procedure that many use with great results.

When you do this at final do you use a collet between the shaft and the jaws?

I do that all the time in cue repair on shafts that wander into my shop. On new shafts I use my pin deal with no collet at .910 to .920. I chuck hard with my 6 jaw and back chuck and the shaft never breaks free or spins out while doing this work. I like that part of the equation.

Rick

 

[JoeyInCali]

Joe,

There is nothing wrong with doing that as it is a piece of cake.

I do that all the time in cue repair on shafts that wander into my shop.

Rick

Ok.
When did you change A-joint size to over an 1.000" ?
Should you not send me doodles ?

 

[scdiveteam]

Ok.
When did you change A-joint size to over an 1.000" ?
Should you not send me doodles ?

It's funny that you should bring that up. My a joint is small because I loved the playability of my Kershenbroch form the 80s. When I started making cue I played with a cue from the Philippines that had a thinner handle and fell in love again.

So maybe I should send some doodles to Manilla for not changing it. LOL:grin:

Do you you a collet when live threading your pin hole?

 

[RBC]

The use of collets has been mentioned quite often in this thread. Most of those times, vave been in reference to a separate piece between the chuck jaws, or whatever holding device being used, and the cue or shaft. This is a pretty common practice used primarily to avoid leaving tooling marks on the surface of finished products. Some use home made collets made of UHMW, Delrin, or something similar and bore them to "match" the taper on whatever it is that they are machining. On the surface, this seems to be a very good thing to do. And it is, depending on the level of accuracy you're after.

However, you have to keep in mind that any time you compound tolerances, no matter how slight, they add up quick. Meaning that if you're collet is very very accurate and only has .0006" runout (the likelyhood of holding .0006" in plastic with the tools we use isn't really even conceivable) when that is compounded with the expected .001" to .002" of your scroll chuck, you're getting pretty big runout pretty fast. Unless it is used to reduce or prevent tool marks, then it may be adding in runout that isn't necessary.

It is certainly possible to dial in the chuck each time so they are below that .001" number. But it screams the question of why then do you need a collet. Specifically given that any possible tooling marks will be machined away.

At our shop, all our shaft joint work is on what we call a "Partial" shaft. The Partial is completely tapered and finished except for the joint end which is larger in diameter than a typical joint would be, and has a cylinder section for easy work holding to perform the collar and joint work.

Our joint work is performed exclusively on machines equipped with real "collets" (both 5C and 16C) as the holding members. We don't use any special made collets during this operation as they can't make it more accurate, only less accurate.

After that a very simple short taper pass is taken on the shaft using the newly threaded hole for the center. This leaves a properly sized joint, centered on the newly installed joint mechanism and no chance for tooling marks as the surface is freshly machined after the joint work is installed. Also, the small amount of material removed from the largest part of the cue shaft has virtually zero chance of accounting for any movement of the cue shaft itself.

I thought I would just throw that out there for those interested enough to read it. Maybe it will help someone, maybe not.


Royce