PDA

View Full Version : bending ar plate


fogducker
05-01-2010, 08:32 PM
im making up a few shooting gongs 12 inch dia. using 3/8 ar 400 pl...im thinking of putting a dished radius of about 24inches on them...
can this material be dished in the cold form??

OLD MAN
05-01-2010, 08:39 PM
the dish can be dangerous.:)

fogducker
05-01-2010, 08:50 PM
the dish can be dangerous.:)

as in the process of dishing it or using it as a gong?

MarkBall2
05-01-2010, 09:28 PM
Using as a gong. The bullet will deflect & ricochet to an unintended area. You would be better off with just using up to 3/8" flat plate........mild steel.

You want the back stop to stop the bullet. Even mild steel will ricochet bullets back at you. If flat plate is placed with a slight angle at the base to deflect the bullet down, if the bullet doesn't penetrate, it's deflected to the ground in front of the target.

Ricochet's can kill just as easy as undamaged bullet.

digr
05-01-2010, 10:17 PM
I guess I don't understand the 12" DIA. with a 24" radius

OLD MAN
05-02-2010, 12:41 AM
i think a 1' round with a 2' radius or 1/2 the diameter:)

moe1942
05-02-2010, 07:51 AM
I guess I don't understand the 12" DIA. with a 24" radius

I think the numbers are backerds..:D

TEK
05-02-2010, 09:08 AM
I was on a dirt spread with a couple of buddies, playing with guns...

One guy took his .375H&H Magnum and shot at a pc of 1-1/4 plate, about 60 ft away..

It was a soft-point bullet, half jacketed....

At the shot, I thought a bug had flown past my head, and flinched,but James started yelping---

The bullet had made a crater on impact,inverted itself, and came straight back, in chunks...

I was untouched, but what hit James was the jacket, inside out, and hot...

It went through his light jacket and tee shirt, hitting him on the short ribs,cutting to the bone and melting into his t-shirt...

He was alright, we went to the hospital---but thats another story

Shooting at steel can be very fun, just use proper care and angle your plate so the bullets go down, not backatcha---:rolleyes:

H80N
05-02-2010, 12:38 PM
in the 50s and 60s there were a lot of guys that got shot by firing at tv picture tubes in the local dump... there was a heavy conical steel yoke shield on the back and neck of the crt that had pretty much perfect geometry to reflect the bullet double bank ..... directly back to it's point of origin... thus they got shot by the tv set.... these shields were heavy and stout enough that I can remember one scheme in pop-mech or science where they suggested using them for automobile wheel stands....

Edit Addl.... lest someone thinks I forgot... CRT's also had the additional problem of launching the neck from vacuum implosion when broken or shot at... but that is a totally different danger than the reflected bullet problem....

platypus20
05-02-2010, 01:01 PM
I guess I don't understand the 12" DIA. with a 24" radius

12" diameter piece of steel, rolled or dished to a 24" radius, in this case basically like slicing the end off of a 48" diameter ball.

I buy pieces of steel roll to the radius of the boiler shell for repair patches all of the time


jack

fogducker
05-02-2010, 04:11 PM
12" diameter piece of steel, rolled or dished to a 24" radius, in this case basically like slicing the end off of a 48" diameter ball.

I buy pieces of steel roll to the radius of the boiler shell for repair patches all of the time


jack

that is correct

fogducker
05-02-2010, 05:20 PM
but back to original question...is it safe to cold form ar400 plate?

MarkBall2
05-02-2010, 05:36 PM
Yes, you can cold form AR plate, with enough pressure.

Depending on the application, heat treating may be required afterward, however it wouldn't be necessary if you are using it as a target.

The problem is, if you shape it into a curved surface, the possibility of ricochet back to the shooter or the firing line. If you wish to use this as a "gong" type of target, just cut the AR plate in a circle & hang it. AR plate has a nice ring to it when struck.

But with a hard plate like this, you better have the distance quite a distance from you or the firing line. A berm between you & the target would be a good idea too.

fogducker
05-02-2010, 05:45 PM
thanks markball....i have a 300 ton press that will form it no problem..i just did not know if it was advisable to do so...
but back to all other comments..it looks like it best to leave the plate flat and angle it a bit...
thanks all for your comments:)

MarkBall2
05-02-2010, 05:54 PM
Yes, the base should be angled away from the shooter approximately 5-10 degrees. If the plate is 24"x24", the base should be mounted approximately 1.5" away from the shooter in relation to the top of the target. Doesn't take much to equal 5 degrees. This way, any ricochet's are deflected downward in front of the shooter.

MarkBall2
05-02-2010, 05:57 PM
A couple of shots of the range in Louisville Nebraska.

First one is at 200 yards, second one is a larger picture of the 200 yard targets.

precisionworks
05-03-2010, 04:49 AM
AR400 is easily cold formed with a hydraulic press. It isn't much different than A36 mild steel except that more tons are required for the same bend. Your 300T press should be more than adequate for the thin plate you want to bend.

Scott Hightower
05-03-2010, 04:07 PM
You can't move 400 very far without splitting it although you should get close to your goal without a problem. If you heat it, the plate will be annealed and won't be 400 anymore so cold is the only way to go.

Scott

http://www.welders360.com/

partsgurut
05-03-2010, 04:21 PM
i think if you were to put the dished side toward you the bullet should always reflect of in a direction away from the shooter not back at you, as it would if turned the other way around. However, I am still for the push the bullet to the ground side of things. Having it hit the top side and ricocheting up at a 45 who knows where it is going to land.