Classifier setup tolerances

[Sarge]

I seem to recall reading something more or less “official” on how close the tolerances are on classifier setup. We are having a local discussion on this and am trying to find it again. I just can’t remember where I saw it.

  I personally feel exact duplication is the goal but realize that’s going to be pretty tough to repeat from coast to coast, match to match. 

Thanks!

[Lee Cabana]

Sarge -

 

I’ve never seen anything on this is USPSA - could you be thinking of Steel Challenge where there is a small amount of tolerance variation?

[Bench]

32 minutes ago, Sarge said:

 I personally feel exact duplication is the goal but realize that’s going to be pretty tough to repeat from coast to coast, match to match. 

Thanks!

Not only match to match or coast to coast (since we all use the same "yard stick") but what I've seen is duplication of set up once totally shot up targets are replaced and not set to the original classifier dimensions.

[Sarge]

18 minutes ago, Lee Cabana said:

Sarge -

 

I’ve never seen anything on this is USPSA - could you be thinking of Steel Challenge where there is a small amount of tolerance variation?

No. USPSA classifiers

[DKorn]

1 hour ago, Sarge said:

I seem to recall reading something more or less “official” on how close the tolerances are on classifier setup. We are having a local discussion on this and am trying to find it again. I just can’t remember where I saw it.

  I personally feel exact duplication is the goal but realize that’s going to be pretty tough to repeat from coast to coast, match to match. 

Thanks!

 

Was this the thread you were thinking of:

 

 

I think ultimately exact duplication should be the goal, but we also have to recognize that this stuff is getting set up by relative amateurs using tape measures, and often in uneven terrain, so it’s never going to be absolutely perfect. Target stands lean, ground is uneven, poppers tilt to one side or the other, etc. I’d say the biggest thing is to get it as close as we can, and then ensure that any slight variation that we can’t eliminate doesn’t affect the shooting challenge. If someone has a problem with the setup and others aren’t sure whether it’s an issue or not, someone can always document the details and send them to NROI before submitting the classifier to USPSA.

[Sarge]

I think it was more like a FS story or one of the downrange email thingies. I have searched the forums pretty thoroughly I think.

[DKorn]

17 minutes ago, Sarge said:

I think it was more like a FS story or one of the downrange email thingies. I have searched the forums pretty thoroughly I think.

 

I seem to recall something along those lines as well, but I can’t find anything either. I’ll keep looking and let you know if I find anything helpful. 

[Sarge]

8 hours ago, DKorn said:

 

I seem to recall something along those lines as well, but I can’t find anything either. I’ll keep looking and let you know if I find anything helpful. 

[MikeBurgess]

My fear is if USPSA did publish a set of tolerances they would likely cause more problems than they would solve.

unless it was almost stage specific. Any guidance should be that it needs to be set as close as reasonable without altering the shooting challenge.

 

the tolerance for positioning a no shoot on a shoot target may be 1/16" or less but the tolerance for the distance between 2 targets may be 2 or 3 inches and the distance from targets to shooting area may be 2 or 3 feet 

 

Think about El Pres if the targets are 31 feet from the box 4'9" to the shoulder and one side is 2'9" apart and the other is 3'3" does that make any real difference in the shooting challenge?  I say no but if you overlay a no shoot edge of A to edge of no-shoot rather than overlaying the perfs that may be different enough to make a difference. 

[motosapiens]

there is no such thing as 'exact' in the real world, and if you try to define an official tolerance, that won't be exact either, since exactness is a purely mathematical concept.

 

if you can look at something with the naked eye and tell it's wrong (like targets or poppers are not spaced the same when they are supposed to be), then it should be fixed. Using mike's examples above, an inch or so difference in the spacing between el prez targets would be hard to notice, and would not make any significant difference, however an eighth of an inch difference in no-shoot or hardcover placement is easily noticeable and makes a big difference. It is generally easy for a normal person with a tape measure to stay within tolerances that keep it from being noticeable or significant if they pay attention.

[ampleworks]

Until someone makes a set of calipers that can measure 100 feet we'll always have to have some level of acceptance for things being slightly off. Measuring tapes capable of going 75' have a good amount of flex/stretch in them so when you're laying out something like CM 09-09 you can easily end up with +/- several inches.

 

Myself, I try to get within an inch on distance and placement of target stands but there's absolutely no reason we cannot be accurate to 1/8" as far as target height and overlaying no-shoots or hard cover. The stage diagram clearly show what to do.

[motosapiens]

12 hours ago, ampleworks said:

Myself, I try to get within an inch on distance and placement of target stands but there's absolutely no reason we cannot be accurate to 1/8" as far as target height and overlaying no-shoots or hard cover. The stage diagram clearly show what to do.

 

1/8" on no-shoot placement (especially if it involves lining up perfs) is imho well outside the variance that should be tolerated.

[MikeBurgess]

14 hours ago, ampleworks said:

Until someone makes a set of calipers that can measure 100 feet we'll always have to have some level of acceptance for things being slightly off. Measuring tapes capable of going 75' have a good amount of flex/stretch in them so when you're laying out something like CM 09-09 you can easily end up with +/- several inches.

 

Myself, I try to get within an inch on distance and placement of target stands but there's absolutely no reason we cannot be accurate to 1/8" as far as target height and overlaying no-shoots or hard cover. The stage diagram clearly show what to do.

for target height sure 1/8" on initial staple up is possible, but unless your stands are hard mounted to a foundation and the sticks are bolted in place that 1/8" is likely off after the first shooters hits get taped.  In my neck of the woods most ranges are gravel so one rock shifting under the stick or stand move the target way more than 1/8" in several directions. 

 

 

[ampleworks]

12 hours ago, motosapiens said:

 

1/8" on no-shoot placement (especially if it involves lining up perfs) is imho well outside the variance that should be tolerated.

Every target vendor is slightly different. Having shot targets from four different vendors and each were slightly different. With that said, if you expect someone to be within 1/32" on a target overlay then why not on distance? Do you also measure everyone's start box and expect those to be within 1/32" as well?

 

Unfortunately, if HQ came out with a tolerance on things then people would just abuse and use the tolerance exception as an excuse for sloppy work.

[Sarge]

Since we are getting more focused on perfs and very small measurements let me add what sparked the question so maybe we can get turned back around. 

06-02 calls for a dividing wall that is 6’ tall X 6’ long. Club has no 6’ long walls and wants to substitute an 8’. This change doesn’t obscure more targets etc so in effect doesn’t affect the stage. Regardless I still say classifiers should be set up as described. 

  There seem to be two camps regarding this. Those that believe as I do that there should be as close as possible to zero alterations and those that think a target 5 feet away is really no different than putting it at 4 feet.

  I always think if you start getting loose with the interpretations then things will spiral out of control. Before long we will just be pacing off and eyeballing instead of actually measuring.

  Another important point to ponder is, is the stage mentioned able to be shot faster with see through walls vs solid walls? I think so.

[DKorn]

Here’s the way I look at it. Having worked as a Quality Engineer in manufacturing, every dimension needs to have a tolerance. It’s impossible for any measurement to be perfectly exact - all it takes is for someone to bring out a more precise measuring instrument and at some number of decimal places it will never be perfect.

 

What that tolerance should be can be decided by USPSA/NROI, or they can leave it open to each club (MD/RM) to decide what’s close enough.

 

The best way to do this is probably for NROI to establish general tolerances that apply to every classifier - something like target stand position +/-A, target height +/-B, No shoot and hard cover placement +/-C (or make some of them percentages, but fixed numbers are easier for people to work with). Then, they can also add specific callouts to the setup notes for classifiers where something  that would be within the normal tolerance has been determined to affect the shooting challenge, like target position changing what is visible from where.

 

Careful drawing of the diagrams can avoid tolerance stacking issues as well - so if you want a target at 15’ and one at 30’, you mark them accordingly, not one at 15’ and one 15’ from that.

 

It’s really not that complicated, just something that requires a little bit of thought by whoever draws the classifier diagrams and writes the notes, and a little bit of extra effort at setup to verify the measurements. 

[nasty618]

5 minutes ago, DKorn said:

... every dimension needs to have a tolerance. It’s impossible for any measurement to be perfectly exact...

 

...can be decided by USPSA/NROI, or they can leave it open to each club (MD/RM) to decide what’s close enough.

 

Agreed 100%.  Either a thing is defined or it's left open for personal interpretation.  I think it (level of tolerance) should be defined.  

[shred]

When in doubt, ask DNROI.  The amount of 'acceptable' varies by situation but is often larger than you'd think.  If its unlikely to change the scored percentage significantly, it'll probably be allowed.

 

[MikeBurgess]

5 hours ago, Sarge said:

 

  There seem to be two camps regarding this. Those that believe as I do that there should be as close as possible to zero alterations and those that think a target 5 feet away is really no different than putting it at 4 feet.

  I always think if you start getting loose with the interpretations then things will spiral out of control. Before long we will just be pacing off and eyeballing instead of actually measuring.

 

I think you may be miss interpreting my point of view.

Yes, 4' is different (20%) from 5' (20%) but is 75'  instead of  76' (1.4%) the same thing? I say no, I would not toss a classifier that was supposed to be 25 yards if it turns out the target was 76'. I would and have tossed classifiers because hard cover or a no shoot was off by a fraction of a inch.

 

I agree that classifiers should be set as close as possible, where I run into problems is when people believe the tolerance should be smaller than reasonable. the real issue is figuring out what is reasonable, for me I have set reasonable as is any error either egregious 4' not 5' or does the error change the shooting challenge? I need two no's to pull a classifier.

 

 

 

 

 

[broadside72]

6 hours ago, Sarge said:

Since we are getting more focused on perfs and very small measurements let me add what sparked the question so maybe we can get turned back around. 

06-02 calls for a dividing wall that is 6’ tall X 6’ long. Club has no 6’ long walls and wants to substitute an 8’. This change doesn’t obscure more targets etc so in effect doesn’t affect the stage. Regardless I still say classifiers should be set up as described. 

  There seem to be two camps regarding this. Those that believe as I do that there should be as close as possible to zero alterations and those that think a target 5 feet away is really no different than putting it at 4 feet.

  I always think if you start getting loose with the interpretations then things will spiral out of control. Before long we will just be pacing off and eyeballing instead of actually measuring.

  Another important point to ponder is, is the stage mentioned able to be shot faster with see through walls vs solid walls? I think so.

 

This type of variance, at least to me, is not acceptable as it affects the time to finish the stage as it requires more time to move the extra distance. So your club is at a disadvantage in this case.

An inch here or there in target and wall placement is one thing. Target overlap should be exact as possible (even the official targets may have variations in size, etc) and that is doable within the tolerances of the targets dimensions themselves. 

[DKorn]

12 minutes ago, broadside72 said:

 

This type of variance, at least to me, is not acceptable as it affects the time to finish the stage as it requires more time to move the extra distance. So your club is at a disadvantage in this case.

An inch here or there in target and wall placement is one thing. Target overlap should be exact as possible (even the official targets may have variations in size, etc) and that is doable within the tolerances of the targets dimensions themselves. 

 

You’re thinking of the wrong wall here. The 6’ vs 8’ wall was the one running front to back, so all it does is prevent you from seeing extra targets if you lean way around the other wall. 

 

 

[broadside72]

I couldn't zoom so I didn't realize there was another wall there. if it is not impacting the view fo T3 and T4 or the poppers from opposite side then i see no issue

[DKorn]

14 minutes ago, broadside72 said:

I couldn't zoom so I didn't realize there was another wall there. if it is not impacting the view fo T3 and T4 or the poppers from opposite side then i see no issue

 

It wasn’t. Someone probably put 6’ on the setup notes either as a minimum to create the correct views or because that’s what they used when they first set it up. 

 

For what its worth, the MD actually ended up cutting a wall down from 8’ to 6’ for this one.