Taps & Dies.
I’ve just finished reading my Workshop Practice Series: Drills, Taps & Dies, so I’ve got a reasonable grasp on the subject.
I’m assuming the AF rifles are all in UNF, including the bottle.
Question on dies:
I assume a “die-nut” is a fixed-size die without a split, whereas a “split-die” allows the diameter of the cut to be varied slightly so a thread can be cut in stages? I further assume therefore that a special wrench is needed that can compress the split-die in stages to produce different depths of cut (shallow to deep).
The thread in the bottle, that would be UNF 1/2″ x 20 TPI?
I’ve been looking for places to buy taps & dies, I found one that offers good looking sets, but they’re made from “HQS” as opposed to HSS or Carbon-steel. They claim HQS is superior to HSS, but I’m thinking “yeah, right…”. HQS = High Quality Steel? Probably straight out of china.
I know, threads should be cut on the lathe, but my lathe requires changing loads of cogs to get particular threads, plus it’s a metric lathe. And the manual is about as much use as yesterday’s newspaper, so I’m about as inclined to get into thread-cutting with the lathe as I am with using my teeth.
TIA for any advice chaps. 🙂
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theoben bottles 400+ has the same threads as out talon bottles
I went out and bought a nut that matched the threads I wanted to make. And then i took a cut with the die, and it turned out to be too tight. I used the 3 wire method to measure it and adjust the die properly, and it worked great.
You could do it your way too.
How about take a wee cut and try the thread for size, adjust accordingly?
Eyeballing is okay for some things but you really need to learn precision work. Or you might as well stick to a dremel tool and hacksaw.
Eyeball? we are talking about a few thousands here, I would be impressed if you could eyeball that.
You measure it with 3 wires like this http://www.threadcheck.com/html/catolog_page18.html If you have Machinery’s Handbook, the method will be in it.
Holy schmoley! 😯
How about take a wee cut and try the thread for size, adjust accordingly?
The 1.5 mm is the thread pitch, or the distance from the top of one thread to the next.
Eyeball? we are talking about a few thousands here, I would be impressed if you could eyeball that.
You measure it with 3 wires like this http://www.threadcheck.com/html/catolog_page18.html If you have Machinery’s Handbook, the method will be in it.
How deep you cut the thread is something that needs to be matched to the threads it screws into. The tank has 2B threads, so you will need to adjust the Die to cut 2B threads.
Thanks Bikin.
I assume you’d adjust the die by eye, or does it’s holder have some kind of setting whereby you can ‘click’ from A to B?
M18 = 18mm diameter?
1.5 = ?
Yes, the tank has a metric thread. Airforce paid catalina cylinders to make a custom tank with non-standard threads for some reason.
How deep you cut the thread is something that needs to be matched to the threads it screws into. The tank has 2B threads, so you will need to adjust the Die to cut 2B threads.
“Different fits” meaning the shallower you cut the thread the tighter it’ll be, the deeper you cut it the looser it’ll be?
M18 x 1.5, is that metric?
A split-die is used to get different fits of thread, like 2A, or 2B etc. the ones I have use a small screw driver to change the cut depth. Threads on the bottle are M18x1.5
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And they cost too much.