9 replies to this topic

[Spacedude4040]

Collimating My Advance HoTech CT Laser

I purchased this Ho Tech Advance CT Laser collimator years ago and just decided to check if all the laser were still aligned. So I measured and duplicated the pattern using Corel Draw and place it on a wall some 15` away. Once I got the unit squared up I noticed how off the beams were.
So most of the beams are going in the same direction so either this unit was dropped big time by the courier or the laser were not tight enough from Ho Tech or both! Come to think about it, maybe it could be from someone who borrowed it
Any how it an easy fix that you can do. You need to cut or peel away the yellow sticker over top of the laser screw caps on all lasers affected and take caps off. My center unit looked good.
Now there`s three Allen set screws that you can tighten or loosen to adjust the laser to hit the pattern on the wall. I can tell you it’s a lot easier to have a helper to say what direction the dot needs to move then to do it by yourself. Your helper can use a ruler flat against the wall to point the direction you need to go.
First you need to shoot it squarely to a wall and the take your print out and match up the horizontal, vertical line and center spot with the laser pattern. Then you will see which ones are off on the circle.

 

   
1st pic is laser off at 15`

2nd pic is laser dead on!

 

 

                      
This pic is the back of collimator with three caps off ready to be adjusted.

 

 

This is a great tool to use and its best to keep it up to spec by doing it yourself cause if you send it back  for them to adjust you might get it back worse if a courier drops or throws it around when its returned to you.
There is a good lesson here also.................. always test your collimation tools before collimating!
If anyone wants the PDF to check your CT laser out just pm me with your email and once you print it out hold it up to your collimator with laser off to see if your printer is scaling the image smaller or bigger and adjust printer settings.
As always use at your own risk.
Hope this helps

 

 

 

 

[BobT]

Excellent post!  Thanks, I'll pm you for the pdf and check mine out.

 

BobT

[Traveler]

So your SCT collimator help has to be collimate too?

[choward94002]

I've made a few modifications to this design that makes it easier for me to use ... mainly, I attached it to a sheet of plywood with spray adhesive then used a drill press to bore out the target holes on the radius and on the center, then a table saw to cut a 1/8" kerf in the center line ... finished up with some black paint (OK, sharpie) in the holes and kerf ..

 

This lets me "bury" the laser lines and dots when i'm on target ... if I can see red then I've got some adjustments to do! 

 

Great idea though ... and yes, you need to collimate the Hotech once in awhile

[TG]

A thought just occurred to me. When trying to line up the spots on the target to the laser spots, how do we make sure that the target and collimator are square to each other? You will get false misalignment if they are not.

 

Tanveer

[choward94002]

A thought just occurred to me. When trying to line up the spots on the target to the laser spots, how do we make sure that the target and collimator are square to each other? You will get false misalignment if they are not.

 

Tanveer

I am using a plumb level when I hang my plywood sheet (the OP had it taped to a wall, which is most likely plumb) ... that takes care of the vertical aspect ... height can be measured from the center emitted to the center hole on the target sheet, that will take care of the vertical displacement ... since this is happening indoors I'll do this in a hallway, measure off the horizontal distance from the central emitter to the wall and move the target to the correct offset from the wall on it's end, that should take care of the horizontal displacment ...

 

Good catch, I hadn't considered making sure the target with in line with the source!  ... must ... get ... more ... coffee ...

 

[TG]

I am using a plumb level when I hang my plywood sheet (the OP had it taped to a wall, which is most likely plumb) ... that takes care of the vertical aspect ... height can be measured from the center emitted to the center hole on the target sheet, that will take care of the vertical displacement ... since this is happening indoors I'll do this in a hallway, measure off the horizontal distance from the central emitter to the wall and move the target to the correct offset from the wall on it's end, that should take care of the horizontal displacment ...

 

Good catch, I hadn't considered making sure the target with in line with the source!  ... must ... get ... more ... coffee ...

 

I

The above procedure you outline will assure that the centers are lined up but I'm not sure how this ensures that there is no tilt between the target and the collimator. If there is any tilt, it will look like the laser alignment is off. If one could eliminate tilt, using the paper target at a distance and using a spotting scope, one could align the collimator very well.

 

But another thing occurred to me: I own a 12" flat (uncoated). I can just aim the collimator at the flat, and see if the spots return back to the lasers. Using a long distance improves the accuracy (which is doubled by using the flat). I could also place the target sheet over the flat once I'm aligned. 

 

Tanveer

[choward94002]

The above procedure you outline will assure that the centers are lined up but I'm not sure how this ensures that there is no tilt between the target and the collimator. If there is any tilt, it will look like the laser alignment is off. If one could eliminate tilt, using the paper target at a distance and using a spotting scope, one could align the collimator very well.

 

But another thing occurred to me: I own a 12" flat (uncoated). I can just aim the collimator at the flat, and see if the spots return back to the lasers. Using a long distance improves the accuracy (which is doubled by using the flat). I could also place the target sheet over the flat once I'm aligned. 

 

Tanveer

Hmm ... I don't have an optical flat but if i used a mirror on the wall to bounce back to the Hotech and align off of that it would get the Hotech square to the mirror (I couldn't collimate based on that, since the mirror isn't optically flat) ... as long as I kept the target at the same angle as the mirror (I can use a long level and mark it on the floor to keep the angle) that will get me closer to "no tilt" ...

 

Your optical flat idea is probably the best, that way you can double the effective distance and since you're looking at dots right next to you it's easier to align (I was going to use a spotting scope, somehow I can't get people as enthusiastic about holding a ruler up to a bunch of dots as I'd like) ...

[Spacedude4040]

OK I think the two of you are over complicating this. 

Just measure your laser distance over from a wall and up from the floor at laser.

Adjust the laser pattern to be the same from the wall and floor, any minor errors don't worry about. Walls are pretty square for the most part. (If you want it to be perfect do it like a gun sight. Tip up the laser so you can see it from behind the laser with another point. Then put a piece of tape on wall and do it for the next axis. Line up the cross hairs to the tape and you are squared up. I really think this would be in nessary.)

Match target to pattern on wall, it can be like this x  or + or anything between, then tape it to wall matching the vertical and horizontal bars and centre dot.

The reason I think it's unnessary is the fact that you are shooting out at 15' which is 180" away. When you use the HoTech CT you are only one tube length away so let's say an 8" scope to be approximately 20 or less inches away before it hit the corrector plate. So doing the math, any errors you have at adjusting the Collimator at 15' will be reduce to like 1/9th - 1/10th of that error which is pretty dead on. 

To get more precision you need to increase the distance from wall and laser, but red lasers have tendency to increase in size a the distance does.

A final star tweak may be neassary after that.

Remembr a moving mirror system will have more error built into it then the HoTech Laser.

Mike

[Spacedude4040]

I dug up a pic I had.