3/8-10 "A" joint bolt?

Cue Crazy

Cue Crazy

AzB Silver Member
Silver Member
I'm curious, I've used 3/8-16 threads to join the handle with the forearm, but have never tried 3/8-10. I'm wondering why I don't hear of more people using that thread pattern.Of the people that use a bolt in the "A" joint, Is It more a matter of the 3/8-16 being more cost effective or more easily available, or because the fine threads don't cock to one side as bad as a 3/8-10 might? What I'm wondering is can the coarser thread cause more problems with runnout in the joint by pushing the face away at one side, and even If glued successfully with no run out, over time could It force the 2 pieces being joined against each other? Also would piloting the ends of the bolt to fit the bottoms of the threaded holes help with at all?

Greg
 
Cue Crazy said:
I'm curious, I've used 3/8-16 threads to join the handle with the forearm, but have never tried 3/8-10. I'm wondering why I don't hear of more people using that thread pattern.Of the people that use a bolt in the "A" joint, Is It more a matter of the 3/8-16 being more cost effective or more easily available, or because the fine threads don't cock to one side as bad as a 3/8-10 might? What I'm wondering is can the coarser thread cause more problems with runnout in the joint by pushing the face away at one side, and even If glued successfully with no run out, over time could It force the 2 pieces being joined against each other? Also would piloting the ends of the bolt to fit the bottoms of the threaded holes help with at all?

Greg
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Greg, I use both and I do not think there is major a difference. The last time I bought materials I purchased three 3/8-10 Aluminum threaded rods that were 48" long. I use the 3/8-10 stock when I have a concern about weight and when the balance will not effected.

hope this helps
 
Greg, a 3/8-10 should actually be stronger due to it's coarser threads getting a much deeper grip on the wood. I use this style in my newer "A" joints. I make mine from wood, though, much like threading ferrule tenons. The pin should not stress the face of the joint. Your tenon should fit smoothly into the bore without noticeable slop in any direction. Once this is achieved it negates the pin as a load bearing joint & the tenon/bore becomes the load bearing joint while the pin simply acts as an internal clamp to hold the two pieces together while the epoxy dries. Once glue has cured, the pin is no longer a strength providing component. I dry fit my forearm to handle with no pin & spin on the lathe to check run-out, if that gives any clue how smoothy the tenon fits into the bore. The pin literally is nothing but an internal clamp to hold them together while glue dries. Everything should fit so well that the pin cannot pull it off center.

I might add that a 3/8-10 with it's deep v-groove threads is much less likely to vibrate loose from the wood and cause that infamous "buzz". Even less likely to buzz if the pin is wood ;)
 
I've used metal bolts on my lower end brands and other projects but don't use them on my signature brand.

Main concern for whether to use the 16t vs 10t is cost but you'll have less stripped female wood threads with the 10t if you're a CM who can't estimate from feel the jointing pressure applied when joining the forearm and handle.

Problem with having metal bolt connectors is that they can cause ill-construction-method wobble. If you have no way to guarantee that the bolt is centrally located then you can end up with a bowed cue, right out of the lathe, caused by centrifugal imbalance. This happens more with the heavier A-joint bolt cues, 3/8" connecting bolts, which causes some CMs to lean more towards using the 5/16" variety or lighter metals. Aluminium has a weigth-to-volume ratio close to most hardwoods used in cuemaking so effects of centrifugal imbalance while turning on a lathe at low speed is close to nil. Do a dial indicator test with varying speeds and you'll see for yourself.
 
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bandido said:
I've used metal bolts on my lower end brands and other projects but don't use them on my signature brand.

Main concern for whether to use the 16t vs 10t is cost but you'll have less stripped female wood threads with the 10t if you're a CM who can't estimate from feel the jointing pressure applied when joining the forearm and handle.

Problem with having metal bolt connectors is that they can cause ill-construction-method wobble. If you have no way to guarantee that the bolt is centrally located then you can end up with a bowed cue, right out of the lathe, caused by centrifugal imbalance. This happens more with the heavier A-joint bolt cues, 3/8" connecting bolts, which causes some CMs to lean more towards using the 5/16" variety or lighter metals. Aluminium has a weigth-to-volume ratio close to most hardwoods used in cuemaking so effects of centrifugal imbalance while turning on a lathe at low speed is close to nil. Do a dial indicator test with varying speeds and you'll see for yourself.
Click to expand...
WOW!
A freebee!
Or http://www.indelco.com/pc-10422-1252-aic1.aspx
 
qbilder said:
Greg, a 3/8-10 should actually be stronger due to it's coarser threads getting a much deeper grip on the wood. I use this style in my newer "A" joints. I make mine from wood, though, much like threading ferrule tenons. The pin should not stress the face of the joint. Your tenon should fit smoothly into the bore without noticeable slop in any direction. Once this is achieved it negates the pin as a load bearing joint & the tenon/bore becomes the load bearing joint while the pin simply acts as an internal clamp to hold the two pieces together while the epoxy dries. Once glue has cured, the pin is no longer a strength providing component. I dry fit my forearm to handle with no pin & spin on the lathe to check run-out, if that gives any clue how smoothy the tenon fits into the bore. The pin literally is nothing but an internal clamp to hold them together while glue dries. Everything should fit so well that the pin cannot pull it off center.

I might add that a 3/8-10 with it's deep v-groove threads is much less likely to vibrate loose from the wood and cause that infamous "buzz". Even less likely to buzz if the pin is wood ;)
Click to expand...


You hit on just about all the reasons I was asking. I dry fit Mine too. matter of fact that's what I was doing tonight, running a few cues between centers that I've had ready to glue, but hanging for a couple of years, and Why I had this on the brain.

3/8-10 would definatly grab better IMO. I've only had one strip on me a few years back when using the finer thread, but It was strange, dry fitting- I could tighten as much as I wanted with no stripping, as soon as I put epoxy in, It stripped without ever really grabbing. I didn't over torque It, It just never snugged up to begin with. It was strange because the threads weren't a sloppy fit or anything. They actually fit very well during dry fitting.

Guess I had a flashback of that cue tonight:D , and It got me thinking about switching over to a coarser thread. I have thought about using threaded wood pins on some cues where I don't need the weight. I haven't trred It yet though.

Thanks for sharing thoughts on this guys. Guess I'll give a couple of them a shot and see how I like the coarse thread.

Greg
 
bandido said:
I've used metal bolts on my lower end brands and other projects but don't use them on my signature brand.

Main concern for whether to use the 16t vs 10t is cost but you'll have less stripped female wood threads with the 10t if you're a CM who can't estimate from feel the jointing pressure applied when joining the forearm and handle.

Problem with having metal bolt connectors is that they can cause ill-construction-method wobble. If you have no way to guarantee that the bolt is centrally located then you can end up with a bowed cue, right out of the lathe, caused by centrifugal imbalance. This happens more with the heavier A-joint bolt cues, 3/8" connecting bolts, which causes some CMs to lean more towards using the 5/16" variety or lighter metals. Aluminium has a weigth-to-volume ratio close to most hardwoods used in cuemaking so effects of centrifugal imbalance while turning on a lathe at low speed is close to nil. Do a dial indicator test with varying speeds and you'll see for yourself.
Click to expand...



If everything goes as It should I have no issues with an imbalance as it stands now. I wouldn't be honest if I said that I've never experienced It, but everyone crawls before they walk, and I'm no different;) . Even though I'm not having issues with that, past experiences of It did come to mind when wondering If the coarser pin would have any adverse effects. My tooling for tapping 3/8-10 is actually alot easier to keep centered, so that also was a factor in asking the questions. Actually that was probably one of the main reasons I asked. That and the fact I felt It would grab better.

As far as having the feel for snugging the joint up. I have aquired that touch too, but I probably had that before I ever even built My first cue. Aquired that from past experiences in other fields. I can snug up as tight as I want dry, well, within reason. I guess I could break the thing if I tried, but for the most part they won't strip easily while dry fitting. When glueing them I have to be more carefull, but they still grab very well most of the time. Like I mentioned I had the one cue a few years back, probably in 2005, but it was a total fluke and never snugged at all once the glue was applied. It just felt like the threads went on forever.
 
Cue Crazy said:
If everything goes as It should I have no issues with an imbalance as it stands now. I wouldn't be honest if I said that I've never experienced It, but everyone crawls before they walk, and I'm no different;) . Even though I'm not having issues with that, past experiences of It did come to mind when wondering If the coarser pin would have any adverse effects. My tooling for tapping 3/8-10 is actually alot easier to keep centered, so that also was a factor in asking the questions. Actually that was probably one of the main reasons I asked. That and the fact I felt It would grab better.

As far as having the feel for snugging the joint up. I have aquired that touch too, but I probably had that before I ever even built My first cue. Aquired that from past experiences in other fields. I can snug up as tight as I want dry, well, within reason. I guess I could break the thing if I tried, but for the most part they won't strip easily while dry fitting. When glueing them I have to be more carefull, but they still grab very well most of the time. Like I mentioned I had the one cue a few years back, probably in 2005, but it was a total fluke and never snugged at all once the glue was applied. It just felt like the threads went on forever.
Click to expand...

Another precautionary measure when using bolts in the A-Joint is to have glue channels. One cause of wood thread stripping is hydraulic (and/or pneumatic) pressure, while joining, which can surprisingly go high enough to cause blow-out fractures. Initially, the pressure affects the wood threads enough to push them down and make it easier for the metal bolt threads to "climb" the wood threads to eventually weaken these wood threads and making them easier to strip.

Grind 3 evenly spaced glue channels and run a powered (Dremel) steel brush on the channel edges to knock the edge sharpness off to avoid a "tap" effect of the channeled bolt. This will relieve the pressure build-up.
 
bandido said:
Another precautionary measure when using bolts in the A-Joint is to have glue channels. One cause of wood thread stripping is hydraulic (and/or pneumatic) pressure, while joining, which can surprisingly go high enough to cause blow-out fractures. Initially, the pressure affects the wood threads enough to push them down and make it easier for the metal bolt threads to "climb" the wood threads to eventually weaken these wood threads and making them easier to strip.

Grind 3 evenly spaced glue channels and run a powered (Dremel) steel brush on the channel edges to knock the edge sharpness off to avoid a "tap" effect of the channeled bolt. This will relieve the pressure build-up.
Click to expand...




Thanks, but yes I have been cutting channels for some time, but like I mentioned, It only happened that one time in the "A", and that cue did have relief grooves. I'm not really sure what happened, unless the wood was soft, or My threads just weren't as good as they felt when I dry fitted. Now I suppose It's possible that I didn't clean up the channel as well back then, and It could have created a tapping effect like you mentioned making It easier to strip.

I learned about the Hydraulic pressure early on with My first cue. Oddly enough the "A" went fine on that cue, but when I installed the shaft pin, I bottomed It out, then I heard a noise. I kind of dismissed It until the glue dried, because I couldn't see anything from the front side, and when I pulled the cue out after the epoxy cured, I could see where It blew out behind the chuck on the inside of the spindle. I can still remember what a let down It was to find the crack in the forearm afterwards:( .
 
BLACKHEARTCUES said:
Hi Greg; I use the 3/8-10 aluminum & steel & have no problems...JER
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Thanks Jerry,

I guess with as many people saying they have used them, that It's not as uncommon as I thought. I'll definately give It a try.

The 16 has been working for me, I was just thinking tonight about trying the 10 because My taps for that thread are piloted, and center alot easier. It also seemed like the coarser thread would grab better, so I was thinking of changing over.

Thanks again to everyone that replied.


Greg
 
If you have no way to guarantee that the bolt is centrally located then you can end up with a bowed cue, right out of the lathe
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just curious,how would the hole not be centrally located?
 
masonh said:
just curious,how would the hole not be centrally located?
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Getting a hole dead center is not so easy. If your stock is not centered inside the spindle, the your hole will start out going in center but will be off center by the time it gets to the end. Keeping the stock dead nuts center & your tail stock dead nuts is key to drilling the hole correctly, or there will be problems with off-center holes. Another cause is making the "A" joint too early & the assembled cue moving as it's turned down to size over periods of time. I assemble my cues roughly .015"- oversized, even my plain janes. I never assemble a cue where the wood needs anything more than a thin cut to be final size, learned that lesson early. If you assemble the cue as thick wood, then it moves even a tiny bit during the cutting to size cycles, your joint stud is now off center. The only way I know to keep it centerline is to do all the work at near finish size and do it very, very accurately, which is not so easy to do as it is to write.
 
now i may be way off base here,but if your tailstock is off say .004" and you drill with a .312" bit,the you hole will still be in the center but it will be .320" big instead of .312".

now if your tailstock was way off i could see soemthing being off,but most lathes are better than .005" accuracy.

like i said i could be totally lost here,but i have checked it by moving my tailstock around.right now i have it at .001" or under,but when i got it,it was .003 or so out and my holes were alway too big.they were still centered but too big.
 
masonh said:
now i may be way off base here,but if your tailstock is off say .004" and you drill with a .312" bit,the you hole will still be in the center but it will be .320" big instead of .312".

now if your tailstock was way off i could see soemthing being off,but most lathes are better than .005" accuracy.

like i said i could be totally lost here,but i have checked it by moving my tailstock around.right now i have it at .001" or under,but when i got it,it was .003 or so out and my holes were alway too big.they were still centered but too big.
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Of course they start center due to the self centering effect of the stock spinning. And yes, the hole will be slightly larger at the face, but not internally at the fulcrum, where the bit actually is centered. Offset your tailstock a few thou or just chuck some stock up without anything holding it centered on the back end. Drill a hole & then split the stock right up the middle with a bandsaw & observe the hole. You'll see what I mean by it will start center but will go off at an angle inside. Of course your bit type will have some effect on this. If you are using $50 carbide 3 flute, then it may not stray at all & do exactly as you say with boring a hole rather than drilling one. But for normal drill bits, it will go stray if not dead nuts centerline.
 
qbilder said:
Of course they start center due to the self centering effect of the stock spinning. And yes, the hole will be slightly larger at the face, but not internally at the fulcrum, where the bit actually is centered. Offset your tailstock a few thou or just chuck some stock up without anything holding it centered on the back end. Drill a hole & then split the stock right up the middle with a bandsaw & observe the hole. You'll see what I mean by it will start center but will go off at an angle inside. Of course your bit type will have some effect on this. If you are using $50 carbide 3 flute, then it may not stray at all & do exactly as you say with boring a hole rather than drilling one. But for normal drill bits, it will go stray if not dead nuts centerline.
Click to expand...

This is exactly the reason why any hole of any importance on any cue should be bored and not drilled with a tail stock.
You can also have the tip of the center of the tailstock on dead center
with the headstock but if the tailstock is canted or not in perfect a line with the center line of the lathe it may cause problems with punching holes.

<~~~another thing that can send things sideways is your machine not being in perfect level..........
 
Of course they start center due to the self centering effect of the stock spinning. And yes, the hole will be slightly larger at the face, but not internally at the fulcrum, where the bit actually is centered. Offset your tailstock a few thou or just chuck some stock up without anything holding it centered on the back end. Drill a hole & then split the stock right up the middle with a bandsaw & observe the hole. You'll see what I mean by it will start center but will go off at an angle inside. Of course your bit type will have some effect on this. If you are using $50 carbide 3 flute, then it may not stray at all & do exactly as you say with boring a hole rather than drilling one. But for normal drill bits, it will go stray if not dead nuts centerline.
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OK,that makes some sense to me.i use a 3 flute carbide but unfortunately it was closer to $80.i hat buying those things,but they are the closest thing to boring.
 
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