Dave,
Since you and Bob confirm that kind of concentricity with live tooling, I will definitely take that info as gospel as you guys are Top Journeymen CMs here making a great product.
Respectfully,
Rick
Cutting wood threads with a tap.
- Thread starter Lexicologist71
- Start date
Dave,
Since you and Bob confirm that kind of concentricity with live tooling, I will definitely take that info as gospel as you guys are Top Journeymen CMs here making a great product.
Respectfully,
Rick
Without doing a bunch of extra typing, Bob pretty much nailed it. Do the setup on the butt in the lathe and prepare the bore for the pin on the center line of the butt. The barrel on my pin is .360... I prep the hole in the butt and use a .360+ gauge pin to test the fit. That's how tight the barrel fits into the bore. Again...as long as I have done my setup properly the pin can't be anything but well within a tight tolerance of an acceptable finished result.
compelling evidence
I installed a pin using live tooling this morning and video taped the procedure from start to finish. It took about 20 minutes total but that included all tool changes, setup changes, camera movement, etc. Actual time should be closer to 10 - 12 minutes.
I was disappointed to find that I don't have a good angle from which to record & my tool post blocks your view. So I decided to skip the preliminaries: indicating the cue, facing it off, drilling, boring & reaming the barrel diameter & finally, live tooling the threads. You all have your own methods anyway.
What I will show is the actual installation of the pin itself. You can see me glue it up, screw it in & check it with an indicator. The video lasts 5 minutes. It can get a bit tedious as I clumsily plod along but the point is to show an uncut video that leaves me with no opportunity to "tweak" my results. What you see is what I got.
Click HERE to see the video.
I installed a pin using live tooling this morning and video taped the procedure from start to finish. It took about 20 minutes total but that included all tool changes, setup changes, camera movement, etc. Actual time should be closer to 10 - 12 minutes.
I was disappointed to find that I don't have a good angle from which to record & my tool post blocks your view. So I decided to skip the preliminaries: indicating the cue, facing it off, drilling, boring & reaming the barrel diameter & finally, live tooling the threads. You all have your own methods anyway.
What I will show is the actual installation of the pin itself. You can see me glue it up, screw it in & check it with an indicator. The video lasts 5 minutes. It can get a bit tedious as I clumsily plod along but the point is to show an uncut video that leaves me with no opportunity to "tweak" my results. What you see is what I got.
Click HERE to see the video.
DAMN!:thumbup:
Props DZ.
Thanks to everyone who gave this some input. My question is really about the A joint. I am using wood threads (5/8 18 tpi) to attach my handle and forearm. The female threads are causing the problems. The wood in question is curly sugar maple.
Regarding the CA soak prior to tapping; how long do you guys advise I allow the CA to sit before pouring out? Thin or thick CA? I have thin and medium right now that I use for finishing.
And how do I go about posting pics? I tried it once before but his a wall along the way.
Regarding the CA soak prior to tapping; how long do you guys advise I allow the CA to sit before pouring out? Thin or thick CA? I have thin and medium right now that I use for finishing.
And how do I go about posting pics? I tried it once before but his a wall along the way.
I personally can't tell the difference between silver and sugar and all the other half dozen or so species of maple, but considering his general disdain for the softer maples, I can't imagine it being anything other than sugar, which is what he also said it was.
Hope you like run-on sentences. :smile:
My thoughts on this common problem:
If your .373 bore is concentric & the tapped hole that retains the pin is accurately tapped & the pin itself is straight - the installed pin MUST run true. If the pin runs out, then one of the 3 conditions isn't being met.
Let's assume the pin is straight & let's assume that your .373 hole (you DID bore it, didn't you?) is concentric. That leaves the tapped hole as being slightly off & distorting the desired location of the pin.
On the pins I use, the retaining threads are slightly undersize & only 1/2" long. The locating barrel (.382 on mine) is 1.125" long. The combination of a long locating barrel & short threads that can "float" works together to promote an accurately installed pin, even when using a tap.
There's another subtlety to this pin configuration: almost ALL taps are .005/.006" oversize. It's not a coincidence that the locating barrel is the same size. The bored hole now acts as a guide for the tap.
Now please understand that I'm not knocking your pin design but I can see room for improvement: shorten the retaining threads & lengthen the locating barrel. Making those threads undersize will also help. Trust me, you will never have one loosen or break free. Look at all the cuemakers who don't even tap their hole but simply press the joint pin in a hole a few thou undersize. They seem to be having good luck...for now
I bored & tapped for many years with good results but since I live-tool everything, life is just so much easier. Do I wipe off the excess glue & walk away without checking the pin location? No. That would be foolish. It takes only a few seconds to verify that it does, indeed, run true. And if, by chance, there is a problem, I'd rather catch it before the epoxy sets up. That said, I have not had to force a pin into location in a long time.
And, a final thought... If you are forcing the tip of a pin INTO location then you are, at the same time, forcing the base of the pin OUT of location. That's why opening up the bore to .376 helps.
Bob, awesome video..above you referenced "short threads that float" can you explain what you meant by this? Is it that the threaded hole is somewhat larger than the pin threads, meaning its not so tight that they bind up?
Yes. The joint pin threads are undersized enough that even if the tapped hole is off a bit, it will not induce side pressure that might cock the pin off at an angle. At the same time, the pin is still held securely.
Compelling evidence indeed! Thank you for taking the time to record, caption, and post that.
I think Rick was already sold, but I'm betting this sealed the deal.
I do know this guy who makes pretty handy jigs for cutting point stock on a skew, trimming tips on a radius and boring out rings. I could probably put you in touch with him to see if he could whip out a pin-setting fixture for you.
Sorry that I helped hijack your thread. The tropical hardwoods are the only woods that you can tap dependably. Maple is a 50-50 proposition at best. Straight grain works the best but the higher the figure, the worse your results will be.
Bob,
As per your comments, I measured my pin threads on the insertion side and they where indeed .006 different than my taps. I have and aluminum pin setting tool that in machined and I can hold my pin chuck it up. I will turn off .006 on a few pins and try them. I have 200 of these pins left but want to add Monel and your dimensional suggestions to the spec. The longer barrel and shorter insertions threads makes sence.
Great Video and thanks again for sharing.
Rick
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Don't the minors match to the tee ?
The major of the taps is almost over.
A 3/8 tap is never .375 afaik.
Not sure if that will be enough to help. You pretty much have to have an undersize pitch diameter so the threads are loose.
It's worth a try, though.
well said, thought thats what you meant. I think "side pressure" is where people run into alot of problems with extreme pitch threads...that and bottoming the pin out hard inducing even more.
Throw the 18tpi in the trash. If you're going to do it that way use a smaller number tpi....maybe an 11. You may at least have a little higher percentage of acceptable results.
I do know this guy who makes pretty handy jigs for cutting point stock on a skew, trimming tips on a radius and boring out rings. I could probably put you in touch with him to see if he could whip out a pin-setting fixture for you.
I contacted the guy this afternoon and imposed upon him to make me a jig on a rush basis. I was impressed with how receptive he was to my request. Job is done to my complete satisfaction & his price was very fair. Thanks for the tip!
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He said potential customers would be dealt with on an individual basis. Apparently, he found my company enjoyable & gave me the "insider" price. When I told him you might be interested in a jig, he started looking up new 5.0 Mustang prices online.
