How do I read this drawing?

[briannmilewis]

Well I need some help reading a 444 Marlin cartridge drawing from Lees Reloading second edition. May be obvious to everyone, but that has never stopped me asking a dumb question.



Along the top edge of the cartridge, .470 and .455 diameters are indicated. Does this mean that from the .455 indicted by the arrow, from that point to the end of the case, the cartridge remains at .455 diameter in order to allow a good grip on the bullet?

I have noticed that some drawings on Steve's Pages do not indicate interim diameters on long tapered cases.

Just wanted to make sure I am reading these Lee drawings correctly.

[Nobade]

No, a parallel section is not indicated in that drawing. Normally if it had one, it would be shown with a shadow line where it started and be dimensioned twice - once where it started and again at the end of the case. Looking at a drawing I have of the 444, shows the same thing. It appears the case is a straight taper from the rim to the mouth. Of course once there is a bullet seated in the case it will be straight for as long as the bullet is.

[briannmilewis]

Nobade...thanks, I get it.

[chipsoles]

Hello Brian,
 Start at the extreme left end, with a rim .514"D.x.063" lg. Next is an extractor clearance groove, .450"D.x .025" w. The next dim. is the .470"D., which is the head dia., a straight from the groove, but .200 from the head face. Next is a taper, 1.800" in length to the .455"D., 2.00" from the head face. Now the case straightens for the remaining .425" length, which is almost one caliber, to .455"D. If it did not have a straight
section, there would be no area in which to seat the bullet. The double dimensions, and shaded lines that Nobade is refering to might be in situations where there are radii in the internal, or external angles. Then you
need to dimension the points of tangency instead of point of intersection, as you do with sharp corners.
 If I am out of place, please let everyone tie me to the whipping post.
With regards,
R.L. "Bob" Queberg

[briannmilewis]

Thanks Bob...if yer wrong...I'll watch!

[chipsoles]

Brian,
 Do your folks know that you are watching stuff like that after they go to bed? You naughty boy! I have read & drawn lots of tooling drawings, over the past forty-five years. Normally a tapered section has a dim.
to locate it's start axially, along w/ a major dia.. Then, either dimension the angle in degrees, minutes, seconds, or the amount of taper/linear unit. On small amounts such as these case body tapers, the major dia.(D),minor dia(d), and the length(l) of the tapered section are dimensioned. (D-d)/2= side opp  l= side adj  if you need to calc. the actual angle, to set a compound rest, sine bar, etc.
 As far as the comment about not having dimensions at both ends, meaning that it could not be straight. Each Draftsman/Engineer has his, or her own preference on what is really needed, and some cad software
has limitations/inconsistancies, about how things are done. But once a straight dia. has been dimensioned, there is no reason to do it again, as it has not changed. It costs your boss money to add dimensions that
have no value, and they clutter up a complex drawing with lots of details in multiple views, such as injection mold drawings, with water lines etc.
 Your ".223 Short" is what got me in this in the first place. I will talk to you over there.
 Any time that I can help someone learn this stuff, just ask, there is no use for a life time of Toolmaking skills in the cemetary.
Regards,
Bob

[Nobade]

Hi Bob,
I agree with your take on that drawing. Normally that would be the case (no pun intended). But if you full length size a 444 case and measure it, you'll see it has a constant taper all the way to the mouth. The expander die and later the bullet make it straight afterward. Just like a 458 win mag or 458 Lott.

[chipsoles]

Hi Nobade,
 I had to go back upstairs to see what the question was in the beginning. I will have to take your for the dimensions on a straight case, as I have never loaded anything but those with "bottle necks". Brian's first
question, to you, or to anyone, was whether the .455"D. continued to the end of the case, as it was illustrated. With the dimensions given, the answer would have to be yes. One, because of the given dimensions,
and also, due to the fact that the illustration shows a bullet seated in the case, which will expand the brass the last .001"-.003", on the diameter, according to personal taste. But then, I could sit on a stool and learn a lot from you about that part of the game. What do you chase with a .444? Deer/Bear?? Blue shoulders?? Rifle? Handcannon?
 All that I had tried to do was hold a "short course" in a couple of the rules of reading, and making drawings, that I have picked up, either in school, or on the shop floor, over 44 yrs. as a toolmaker. Now it is my turn to learn from you. Doesn't the .444 fl die have an expander button, on the decapper, or at least provisions for one? The expander die?
Best regards,
Bob