Stop Plates

[Run n Gun]

Okay guys, what exactly is a “stop plate” and where can I find a couple of them? All I know is the results of hitting one stops a timer. I'm sort of Steel Challenge… err ah… well, challenged!

A little background; I was out digging around the “South 40” at the gun club and unearthed not one but two plate racks! They're pretty rough shape but all of the plates are there and I just so happen to be the GM of a steel fabricating company. Resurrection is imminent.

I have a Pact Mark IV timer and the book says I can hook up two stop plates. I think a little man Vs man thing with two plate racks would be cool.

So I’ll repeat the question; Where can I buy them and will they work with 8” plates?

Thanks,

[EricW]

RNG,

I think the only difference between a stop plate and a regular one is the addition of a switch. How you set the switch up, I have no clue. I've never seen a stop plate used at the few steel matches I've been to. I think if you got some heavy-duty roller switches and just set them up so that the switch actuated them in the plate *up* postition and used the normally closed set of contacts, the switch would actuate the instant the plate was hit. Make sense?

For switches, you'll need to get something pretty industrial to take the pounding. Don't be suprised if they cost $20-30 bucks a whack either. Don't try to rig it up with stuff from Radio Trash. You'll only have to do it twice.

E

Edited August 26, 2003 by EricW

[diehli]

Can't help with the switch for a stop plate thing, but from a shooter's perspective I can think of something that might bother me:

You telling me which way I have to shoot the plates on a plate rack. I know it doesn't sound like that big a deal, but if I like to shoot left to right, and you put the stop plate on the left and tell me I HAVE to shoot it right to left, I'd be a bit annoyed.

If, however, you're talking about putting some sort of stop plate behind or in between the two plate racks, that makes sense. Then I can decide (if the stop plates are in between the two plate racks) if I want a long transition between the rack and stop plate, or if I just shoot it backwards... at least I still have the option.

I don't know... something to think about... or not.

Good luck!

[George]

Stop Plates? A couple of definitions for this one. A traditional stop plate was utilized in the early days of IPSC shooting when electronic timers were unavailable. A stop watch and a horn started the shooter. The last target engaged would be a freshly painted round steel plate (typically 8"). Ringing & marking the plate indicated to the RO running the timer to stop it (yeah, that's really how it was done in the early days). A single steel plate at the end of any stage can be designated as a stop plate and hitting it indicates the shooter is done even while using a modern timer.

In Man On Man competitions a pair of stop plates determine who wins. It is usually set up so that two small identical arrays of falling steel are simultaneously engaged by two competitors with the stop plate for each competitor being the last item engaged.

The simplest Man On Man stop plate setup is two poppers set at a slight angle so they fall over each other. The shooter whose popper is on the bottom wins. No Muss, No Fuss.

The other way is to use two fixed, or hanging (but unable to fall with an impact) steel plates and attach mercury contact sensors to the back with foam doublestick tape. These sensors are available in normally open, and normally closed options and are typically used for burglar alarm sensors (I got the ones I used in the past from Radio Shack). The normally open output when cabled to the stop plate input on a timer will supply a negative edge pulse from the bullet impact which causes the mercury switch to momentarily close.

Be sure to protect the wires and all components from splatter in any form, and experiment with various thicknesses of the foam mounting tape to get the sensitivity set right. I made this type of setup work at our club once without too much ado. There isn't much worry about the switch on the back of the plate (or even on the stand) taking the shock, it's the splatter that kills the components in the long run, usually wires. I got the ones I used to work on various types of plates. If the steel is making good mechanical contact with the stand, then the sensors can be on the stand and still get the amplitude of shock wave it needs to make the switch activate. If the steel hangs by wires or such, the sensors will have to be directly on the back of the plate to get the pulse amplitude required.

I have never seen a "Plug-N-Play" solution for this. To my knowledge you are entering the realm of the custom job here.

Good luck,

[shred]

The Steel Challenge uses some sort of sensor-in-a-box mounted on the plate stand to detect the hits. I didn't see a manufacturer's name on them, but I'm pretty sure Blackwater Target systems makes the plates and stands, so they may also be the source for the bullet-strike indicator.

[Run n Gun]

Update:

shred, I went to the Blackwater site and while they make a lot of cool stuff, I couldn’t find even a reference to a stop plate, same with MGM. Then I tried to call Pact to find out if, indeed, the timing circuit was a “simple circuit” and which type (no, nc) was appropriate. Nobody answered the phone at 10:35 PDT (?). I’ll try again tomorrow. I hope that all I need is a couple of RCA jacks, wire and some simple switches (maybe as simple as a couple of copper strips riveted at appropriate spots) and I’ll be in business!

Eric and George, thanks for all the help, and if it really isn’t simple, all of the help I’M SURE you will be then.

300lbGorilla, actually I was thinking of setting one up to run right and the other to run left with a coin flip deciding who get their choice, after that the winner gets “lane choice”, like in drag racing!

Ed

[shred]

Yeah, I tried to look around Blackwater Target's site too-- not much there. The Steel Challenge impact sensors are well down the stand from the plate-- probably to help avoid accidental lead-induced failure.

Were I going to make one for falling steel, I'd try a plunger-type switch on a plate stand. Set the plate on top, it holds down the switch, knock the plate off, switch is released. A hinged plate would also work. Armor the mechanism and cables well. Bring spares. Check into car door switches and such.

It might be possible to use the metal plate itself and a couple copper strips on the stand for such shenanigans, but you'll have to keep everything relatively clean for good contact.

[Wildman]

Keep trying PACT. When I've seen the timers used, they stop the clock on bullet impact. Usually, everyone makes an even number of runs, like 4 runs, throw out one, switching sides each time. Avoids, or helps, avoid the shooter preference issues

[THS]

I made these once in the long distant past.

Radio Shack had the NO switches, wire and the RCA jacks. I used a plate on top of the switch, and when the bullet moved the plate the switch changed, stopping the timer.

The PACT can use NO or NC switches, and host 2 plates. Remember, if you use the #2 plate input jack the microphone on the timer is disabled and it works, is looking for, man vs. man only. Using plate jack one will keep the microphone logging the splits and the stop time as well.

Hope this helps,

Tom

[tightloop]

Stop plates were used in the distant past of IPSC shooting. At the '82 Nat'ls, for instance, the Colorado Speed Shoot stage was, various head shots at various ranges and the "stop plate" was a 6x6 white steel on a post at 20 yds. It was hinged to the post to avoid twisting and showing an edge.

The easiest man/man steel are the 1/3 size poppers adjusted so the one which is on the bottom is the winner, with any number of targets B4 shooting the stop target.

The problem with electrical stop plates is that the gremlins can creep in on match day and won't leave till after the match is over. What do you do if it is raining? Using gravity plates, either it is up or down, no controversy, but you do have to repaint and reset them.

Take your pick and good luck.

[Flexmoney]

I can see a switch working on a plate that topples, but, the vibration kind...how does it tell that the shooter didn't just hit the stand?

[old shooter]

I think that the solution is not to use a mechanical switch, but an electric peizo. I am straining my brain right now, I have done this and remember using a round buzzer from radio shack, and breaking the black plastic off and using the piezo what-ever-it-is-called. When subject to vibration, it will send a small electric signal. I have also used it as a crude pickup on acoustic string instruments. I am sure one of the smarter electrical people on the list know of this.

Mike

[Wildman]

Flex, it’s kind of like the speed shoot at Bianchi or the NATS. No matter what the clock says, if a plate or popper is still standing, its a fault, called by the RO. A slow run with all the plates down beats a faster run with one or more plates left standing. You can't go back for a pick-up shot after hitting the stop plate.

As I recall, the clock stopped well before the stop plate hit the ground. Seems like I do recall a stopped clock one year (Mid 80's?) before all the plates were even shot at. Maybe splatter from the first shot. Only seen that happen once, and in succeeding years, it seems like we used a shield around the stop plate. Memory, as is everything else, is starting to go.

[shred]

I can see a switch working on a plate that topples, but, the vibration kind...how does it tell that the shooter didn't just hit the stand?

At the SC, there's a large (as in railroad-tie large) wood post in front of the steel stand, which is pretty small.