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angle of points

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
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Unread postAuthor: SpudFarm » Mon Aug 04, 2008 1:30 pm

the only thing you need is a welder, angle grinder and a bench grinder..

if you want them shiny you can polish them
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Unread postAuthor: jimmy101 » Mon Aug 04, 2008 3:24 pm

I wonder if oil quenching these rounds might work better than water quenching. The sharp tip of the round will act as a nucleation site for steam bubbles. The tip may end up cooling too slowly for decent hardening.
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Unread postAuthor: SpudFarm » Mon Aug 04, 2008 3:43 pm

oil did not work the way i wanted it to..

i can get hold of -50C cooling spray..
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Unread postAuthor: jimmy101 » Mon Aug 04, 2008 5:40 pm

SpudFarm wrote:oil did not work the way i wanted it to..

i can get hold of -50C cooling spray..

I'm not sure if the -50 spray will work. The temperature of the coolant really isn't all that important. The important thing is the heat capacity. I believe you generally want a high heat capacity. Cooling sprays have extremely low heat capacities, as do gases in general. The movemnt of the cooling spray increases it's effective cooling ability but I doubt it'll get anywhere near what water or oil will do.

What kind of oil did you try? There are oils specifically designed for heat treating.
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Unread postAuthor: SpudFarm » Mon Aug 04, 2008 5:46 pm

i used old motor oil, i have heared that it works well.

and i will take your tip on that and try to find that kind of oil
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Unread postAuthor: SEAKING9006 » Mon Aug 04, 2008 5:53 pm

Spudfarm, it's USED motor oil that you want to use. What it does is that when it cools the metal, carbon from the combustion process, and fouling on the engine block, is combined with the hot steel to make the carbon content slightly higher.
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Unread postAuthor: SpudFarm » Mon Aug 04, 2008 5:58 pm

i don't let motor oil age when we run a snowmobile company so old equals used :D
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Unread postAuthor: judgment_arms » Mon Aug 04, 2008 6:36 pm

You don't want to water quench tool steel, it'll crack or at the vary least not harden properly.

ANY kind of heavy oil will work, I've used old olive oil draind out of the deep fryer as a quenchent before...

You might try brine; way back when, people used brine for quenching knives when oil was hard to come by.

You could also try lard, I've heard of people using that...



Also, to what point are you heatin' the steel to?
you should be takin' it to about cherry before you quench, you sure you're gettin' it hot enough?




Also, APFSDS rounds are made of depleted uranium, not tungsten-carbide. ;)
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Unread postAuthor: Hotwired » Mon Aug 04, 2008 9:45 pm

Actually they're made of DU or Tungsten.

DU's still the best thing to be firing in someone elses country where leaving radiation isn't going to worry you but tungsten's still used.
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Unread postAuthor: Gippeto » Tue Aug 05, 2008 12:10 am

I fixed the link in my previous post. :oops:

For the sake of convenience;

http://www.dfoggknives.com/hardening.htm

This should help you get your darts properly hardened.
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Unread postAuthor: Ragnarok » Tue Aug 05, 2008 10:15 am

SpudFarm wrote:i don't care about depleted uranium since i have no way to get my hands on it..

Well, that's probably a good thing. Not stuff to mess with lightly.

I notice you were talking about a 35 degree angle - really, like I said before, any more than 30 degrees is just making unnecessary trouble for yourself.
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Unread postAuthor: SpudFarm » Tue Aug 05, 2008 10:21 am

i have no way to messure it..

can you make a guess from the picture?
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Unread postAuthor: Ragnarok » Tue Aug 05, 2008 10:36 am

SpudFarm wrote:can you make a guess from the picture?

Oops, missed that picture - that's pretty much a 50 degree angle on that dart, which won't be very efficent.

If you've not got a protractor or anything, and you're just doing a conical point, to get an overall ~30<sup>o</sup> angle, the whole point will need to be roughly twice as long as the diameter of the rod.

However, under optimal conditions with a hard enough tip, an ogive point might well be a more efficent penetrator though.
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Unread postAuthor: ramses » Tue Aug 05, 2008 10:36 am

I maybe I am retarded, but there seems to be so many ways to measure the angles. what angle are we actually measuring? my guesses from the pictures will be based on the angle shown in the attached picture.

from left to right in the picture on the first post: 40, 42,60
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Unread postAuthor: judgment_arms » Tue Aug 05, 2008 10:50 am

To figure out what the angle is you could make a jig with an interior angle of what ever angle you want, while you're at it put sandpaper in it and use the jig to grind the point.
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