Screw tip help.

[Mark Elliott]

I am getting ready to make my first screw tip horn and I have a question.   How do you turn/shape/thread the main body of the horn?   The only thing I can figure is file the end to the approximate size and run a die down on it.   If there is another way t do this, please let me know.  The only other thing I thought of (and I don't think it is a very good idea)  is drill a 1/4" hole in the end of the main body of the horn.  Tap that hole and thread in a bolt with which to hold the horn in a chuck for turning.   I would then ream out the internal thread when I was done.   This doesn't sound like a very good idea given that the slowest speed on my wood lathe is 500 RPM.

Thanks,

Mark E.

[Randy Hedden]

Mark,

Search archives for "Conner Prairie horn part 1" by Larry Pletcher

Randy Hedden

[Tim Crosby]

 This is another way to work the tips.

 http://americanlongrifles.org/forum/index.php?topic=8608.msg80994#msg80994

 Tim C.

[Jefferson58]

Mark:

Here's the condensed version of Larry's screw tip article from his site. 

http://www.blackpowdermag.com/featured-articles/post-3.php

Hope this helps.

Jeff

[Larry Pletcher]

Art DeCamp's lathe could be set to turn at under 200rpm.  Somebody on the list mentioned that his lathe's slowest was faster.  Mine is around 170rpm and I wish it were a bit faster.    500 might be a tad fast, but  I'd try it to see. If you have scrap horn to try it on, you might not be risking that beautiful, one of a kind horn the first time.

Seems like Tim C might be turning closer to 900.
Regards,
Pletch

[Randy Hedden]

Mark,

You don't need a lathe to do the spout part of a screw tip horn.  As far as that goes you don't even need a lathe to make the actual screw tip.  Drill a 1/4" hole in the spout end of the horn.  Place a 1/4" steel rod in your vise, horizontally, and mount the horn to the 1/4" rod.  I like to use a small "V" block in the vise jaws to hold the rod.  With the horn mounted on the rod, file down your desired length with a file.  I find that if I rotate the horn towards me while filing in the opposite direction I can make the filed length round within a couple of thousandths.  You might want to check the diameter with calipers as there can be hard spots that don't want to file down as easily as other parts of the diameter. Out of round by a couple of thousandths will not make any difference when threading.  You can make a guide for threading by making a rod which is 1/4" on one end and a slight bit under the minor diameter of the threading die on the other end, just so it slides on.  Place the 1/4" diameter in the 1/4" hole in the horn and slide the threading die on the larger diameter to square up the die in relation to the diameter on the horn. Then thread away.  You might want to lubricate the horn with some beeswax or light oil before threading.

Randy Hedden

[Randy Hedden]

Tap that hole and thread in a bolt with which to hold the horn in a chuck for turning.   I would then ream out the internal thread when I was done.   

Thanks,

Mark E.

Mark,

There is no need to ream out the internal threads, just ream a taper in the spout hole.  THat will take out some of the threads and still allow a tapered spout plug seal the horn.  Old screwe tip horns often show evidence of threads left in the spout hole.  That is how guys like Roland Cadle, Lee Larkin and Art DeCamp, don't know which one exactly, figured out how the screw tip horns were made on a lathe.

Randy Hedden

[Mark Elliott]

Guys,

Thanks for all the tips.   I think I now have enough information to get it done.   

Mark E.