# Transit calibration



## Gnella (Jan 16, 2009)

Anyone know how often to calibrate your laser transit or sight transit? I have topcon rl60b and topcon sight transits. I can't find the manuals and thought this would be more fun than looking on line.:laughing:


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## griz (Nov 26, 2009)

I have an old telescope I know is dead on and use it to check the laser & vice versa. I have the laser, Spectra LL550, done evry 2-3 years unless it has been dropped.
My Spectra has been a seriously bullet proof instrument.
Also have a PLS180 I check against the Spectra etc.


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## Upchuck (Apr 7, 2009)

I make sure lasers are calibrated every winter. One mistake can cost a lot of money.


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## cexcavation (Apr 17, 2008)

Take a piece of paper and set it out 50' or more and mark where your laser hits. 

Leaving the base exactly where it is, rotate the head unit 180deg. If you hit the same mark, no adjustment necessary. 

If you are too high or too low, calibrate the lazer to the point in the middle and recheck. 

There should be an allen head, etc. adjuster screw on the head unit to adjust the pendulum. 

This ensures the laser is running on plane. 

As far as a sight transit, you may be able to do some type of variation on this process using a helper.

Hope that helps.


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## pce (Apr 12, 2009)

I worked for Spectra Physics. We were trained to field calibrate lasers. I would always take them into the shop to have them done on the range, same with the transits. It is worth every penny spent to have done in the shop. One wrong grade shot will cost more than the range fee, which I think was $ 50.00. Don't take the chance. Danhoe


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## Gnella (Jan 16, 2009)

thanks everyone. I'm dropping them off at the shop today.:thumbsup:


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## cexcavation (Apr 17, 2008)

The method I described is straight out of the manual for my laser. I am not sure what they do differently at the range, but I have calibrated my laser and it is spot on from what I know....no complaints from foundation guys yet!!!!:laughing:


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## Upchuck (Apr 7, 2009)

> Posted by cexcavation
> The method I described is straight out of the manual for my laser. I am not sure what they do differently at the range, but I have calibrated my laser and it is spot on from what I know....no complaints from foundation guys yet!!!!:laughing:


While I'm sure your way is fine, I also take mine to the shop. I consider it a year tune-up for the lasers.


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