Need help setting up my Oehler Chrono [Archive] - Glock Talk

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XDRoX
04-28-2010, 15:02
I recived this email from Oehler regarding my chrono questions:
Chris,

Thank you for contacting us.

Screen Spacing

1) The detection error on your screens, assuming normal conditions, is approximately 1/8". This means approx. a 0.5% error for a 2 ft screen spacing, 0.25% for 4 ft spacing which calculates at +/- 8 fps for a 3,000 fps projectile.

Note: The Model 33 needs 1 foot of screen spacing for every 1,000 fps of expected veleocity. If you are chronographing loads around 3,200 fps, you should be using at least a 4 ft screen spacing.

2) I don't know what model of screens you have, but Skyscreen III's are available as are diffusers, and other replacement parts. Call 512-327-6900 or visit our on-line store at www.oehler-research.com (http://owa.helixcharter.net/exchweb/bin/redir.asp?URL=http://www.oehler-research.com).

Regards,
Gary Stafford

So the good news is I can buy anything I need from Oehler and they seem to be very helpful.

The bad news is I don't understand these instructions:crying:

I interpret this to mean that I have an option of how far apart to put the screens, but that can't be right can it? Isn't the exact distance between the screens what measures the speed? What am I missing?

Colorado4Wheel
04-28-2010, 15:11
http://www.glocktalk.com/forums/showthread.php?p=13722278

GioaJack
04-28-2010, 15:30
Chris:

I read it to mean that for every 1000 fps of expected velocity you'll need to separate the screen by one foot. If you shooting mid .38's or .45's it looks like you can use just one foot spacing. I would imagine you'd probably want to go with the two foot spacing for your 9's.

Also looks like your measurements are going to have to be pretty much dead on... only a 1/4 inch fudge factor with two foot spacing.

Was nice of them to send you the information though. Good luck.

Jack

IndyGunFreak
04-28-2010, 15:32
Step 1. Shoot the power button to turn it on.

;)

IGF

GioaJack
04-28-2010, 15:33
Step 1. Shoot the power button to turn it on.

;)

IGF


Even I'm not that cruel. :supergrin:

Jack

XDRoX
04-28-2010, 15:37
Thanks for the responses. The bell is about to ring for 4th period and I have to teach 35 14 year olds the meaning of pi, how to find the circumf and area of a circle. I hope no one asks any velocity questions. I'll read your posts after school gets out.:supergrin:

GioaJack
04-28-2010, 15:44
Thanks for the responses. The bell is about to ring for 4th period and I have to teach 35 14 year olds the meaning of pi, how to find the circumf and area of a circle. I hope no one asks any velocity questions. I'll read your posts after school gets out.:supergrin:


Hell, I've known the meaning of 'pi' since I've been four years old... pumpkin, apple, blueberry, cherry, lemon meringue... they all mean the same thing... YUM, YUM. :pepper:

Jack

rg1
04-28-2010, 19:07
Edited: didn't catch that it is a model 33 and not a 35P. If your unit only has two skyscreens and you don't get the start and stop skyscreens exactly spaced at 2ft or 4ft or whatever then you will get a false reading and not the exact velocity and you won't know it. Shorter spacing is easier to transport and set up, longer spacing more accurate.
Learned something this spring about my 35P. Took it out and it wouldn't read and gave error messages or an unrealistic velocity reading. Found that if I slightly squeeze the plugged in cables that it would read but if I wiggled the plugs it would record a velocity or give and error. Called Oehler and they said to take a coarse cloth, leather, or similiar and polish the plugs (male plugs only) of the 3 skyscreens. (DON'T USE ANYTHING ABRASIVE). It worked and it hasn't missed a single shot since from pistol to big rifles. The plugs weren't corroded or anything but some oxidation or build-up that you couldn't even see must have taken place.

kshutt
04-28-2010, 20:04
Hell, I've known the meaning of 'pi' since I've been four years old... pumpkin, apple, blueberry, cherry, lemon meringue... they all mean the same thing... YUM, YUM. :pepper:

Jack

All that snow is making you delirious, Jack! :supergrin:

GioaJack
04-28-2010, 20:37
All that snow is making you delirious, Jack! :supergrin:


Snow finally melted today, most of it, with the help of 60 mph Chinook winds. Just came back in from letting the dog out... starting to rain, supposed to change over to snow by morning and be crummy through the weekend.

I don't care! Going down the hill tomorrow to see about picking up a new Kimber. Leaving for Ft. Worth Saturday morning, if I get the Kimber I'll take it and a bunch of ammo with me and shoot it down there... IN SHORTS!!!

Jack

fredj338
04-29-2010, 01:13
Don't know how familiar you are with the Oehler 35 P and whether your unit has a paper printer or not.
I think XDrox has a 33. You'll want to use 24" spacing as a min. You can go to 48". Then the unit will have to be calibrated for the screen spacing. ASk Oehler how to do that.

srd
04-29-2010, 05:43
Set your screens at EXACTLY 2 feet spacing on your bar, plug them in and go for it. At that spacing you can read up to 2,000 fps unless you play with hi speed projectiles and then space them at 4 to get 3,000 fps. I am assuming you have 2 screens unlike the 35p which has 3 for the proof channel. By the way congratulations on being a teacher !! Did my student teaching and found i didnt have the patience for it. Mine was HS automotive. Keep it up !!

XDRoX
04-29-2010, 08:33
I think XDrox has a 33. You'll want to use 24" spacing as a min. You can go to 48". Then the unit will have to be calibrated for the screen spacing. ASk Oehler how to do that.

Yes, so we are on the same page. This is what I didn't understand. If there is a way to tell the unit how far apart the screens are (which I figured there must be) then all makes sense. I just emailed Oehler with the question.

Fred, if you have time can you click on the link Steve posted. It seems to have good info but I can't follow it.

By the way congratulations on being a teacher !! Did my student teaching and found i didnt have the patience for it. Mine was HS automotive. Keep it up !!

Thanks, I love it. Been doing it for 7 years and really enjoy it.

XDRoX
04-29-2010, 08:56
Wow, talk about quick service. They emailed the instruction manual within 10 minutes of my request.
I'll start to look though it and post back.

fredj338
04-29-2010, 11:40
Wow, talk about quick service. They emailed the instruction manual within 10 minutes of my request.
I'll start to look though it and post back.

2 foot spacing
sw1 off--sw2 on--sw3 off--sw 4 off--sw5 off
Apparently there are switches, either externally or internally, flip them per instrctions & then mount youjr screens to exactly 24". A piece of CR tubing will work, drill the center & tap for a tripod mount.

GLShooter
04-29-2010, 19:15
I have an old Model 12. I set the screens at 4' and called it good. That will cover most of what I shoot except some real hot 20's.

I now use a Millennium CED. It uses a 2' bar for spacing that can't change and will handle them all.

Greg

That Oeheler is super nice. Congrats. -- G.

WiskyT
04-29-2010, 19:29
Thanks for the responses. The bell is about to ring for 4th period and I have to teach 35 14 year olds the meaning of pi, how to find the circumf and area of a circle. I hope no one asks any velocity questions. I'll read your posts after school gets out.:supergrin:

pi times the radius squared for area and pi times the diameter for circumfrence. Now can I get some friggin' respect around here?

GioaJack
04-29-2010, 19:38
pi times the radius squared for area and pi times the diameter for circumfrence. Now can I get some friggin' respect around here?


Looks like someone knows how to use Google. :whistling:

Jack

WiskyT
04-29-2010, 19:41
Looks like someone knows how to use Google. :whistling:

Jack

Looks like someone knows how to hate:whistling:

GioaJack
04-29-2010, 19:52
Wisky, what'da ya mean hate... you're my little buddy. Us old guys gotta stick together. (I still don't believe you knew all that stuff without looking it up. :supergrin:)

Jack

Bob2223
04-30-2010, 08:31
All that snow is making you delirious, Jack! :supergrin:

Snow ?
He's the same way during the summer ? :whistling:

Bob

WiskyT
04-30-2010, 15:46
Wisky, what'da ya mean hate... you're my little buddy. Us old guys gotta stick together. (I still don't believe you knew all that stuff without looking it up. :supergrin:)

Jack

I remember all of that stuff from HS. My short term memory is the problem. I intended to make something of myself and paid attention in HS. The road to hell is paved with my good intentions...