If you bore your 0.381 hole before tapping it the barrel of the tap acts as a pilot for the tap, making it easy to have your threads concentric with the bore.
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- Thread starter metalware10
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There's nothing wrong with the actual standard 3/8x10. Somethings today are completely over thought. Joint screws is one of them. You just need the correct tap or grind your threads.
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JC
Coos Cues
Think .390"
I considered all that and ultimately decided it was not necessary to bore the hole for the barrel which makes life much simpler. That is of course if your pin matches the tools out there. Which .381" does not. I bought a 25/64 stubby 3 flute carbide bit and realized that I could drill a hole and then take the bit out of the chuck, turn it around and it fit snugly in the hole and ran without runout facing the opposite direction. So I figured if the pin barrel was the same size it would run true and fit snug too. I figured right on that one. Now it takes about a minute from start to pin ready to glue with no measuring of anything.
This was only possible when I bought a real lathe. Could not accomplish this on a taig using the same drill bit.
JC
The other thing you need to consider is that the pins are quite long and your tapped hole is at the bottom of a 2.5in hole. So in order to use a standard tap to thread that hole you need the clearance on the pilot dia. So unless you are using speacial extra long taps which although fairly common I still rather be able to use common standard length taps. I do have an extra long tap I use for weight bolts but would rather only use it for that task so it will stay sharp as long as possible. So making my pins with the 0.381 barrel works for me.
JC
Coos Cues
Of course .381 works just fine as there's a bunch of really good people using it, I just found it to be too much work for me to achieve the ends and started thinking about an easier way.
The pins I'm using have 1.8 inches buried and the 3/8 10 bottoming tap I got from atlas reaches the bottom easily. The threads are a little loose on the pin threads and centers up easily without putting side stress on the barrel. After all these threads only purpose are to anchor the pin until the glue dries so they don't need to be super tight, just reasonably centered. If you look at these pins without measuring them you will not distinguish them from the ones Tom makes for atlas.
I was told many times starting out that the pin hole must be bored to ensure a straight pin and eventually figured out this was not true. Your mileage may vary :smile:
BTW your pins look great. I don't think I will ever have the skill to make my own like that. I also made my minor .297 so I can use a 19/64 bit to drill it and it works just as well as the barrel hole. No reamer required.
JC
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