The Shop > Tools
Anybody build Dan Gelbart angled laser centre finder?
Arbalist:
As it's spinning I don't think the spot needs to be very round. For most purposes it's tracing a circle. Whilst we're doing this though a nice round spot may be useful. I've made a small hole in a post-it with a scriber and held it over the beam, it makes the dot smaller and certainly appears to make it rounder, so that' seems like it's easily doable. :thumbup:
I forgot to mention. I'm impressed with Dan's setup and I fully understand why Pekka wants to make something similar. Most others though have made spindle mounted versions and I'm leaning in this direction so I can mount it in any of my chucks/collets.
vtsteam:
Collimating lens , fixture rigidity to reduce line size, use of a pinhole.....I think you're on the right track, :beer:
vtsteam:
--- Quote from: Arbalist on April 16, 2015, 10:37:07 AM ---As it's spinning I don't think the spot needs to be very round. For most purposes it's tracing a circle.
--- End quote ---
It is tracing a circle, but the thickness of the perimeter of that circle depends on the orientation of an elliptical spot. If the minor axis of the dot (the narrower diameter) is set up in your spinning fixture so it is parallel to the axis of the fixture (a line from the diode to the center of the quill), your projected spinning line will be thinner than if you arrange it perpendicular. Just sayin......
Arbalist:
--- Quote from: vtsteam on April 16, 2015, 10:56:40 AM ---
--- Quote from: Arbalist on April 16, 2015, 10:37:07 AM ---As it's spinning I don't think the spot needs to be very round. For most purposes it's tracing a circle.
--- End quote ---
It is tracing a circle, but the thickness of the perimeter of that circle depends on the orientation of an elliptical spot. If the minor axis of the dot (the narrower diameter) is set up in your spinning fixture so it is parallel to the axis of the fixture (a line from the diode to the center of the quill), your projected spinning line will be thinner than if you arrange it perpendicular. Just sayin......
--- End quote ---
Yes, you're quite right. And it could make quite a difference. As the Laser body is round though adjusting it to the best position is easy providing the design allows for it.
appletree:
I started writing this post but was called away before submitting, what I was about to say is now in part history as more has been posted since I started writing, either way this is what I was going to say.
Although the quality and definition of the spot is of value, the human eye is very clever at estimation etc. I imagine that the imperfect dot will be repeatably imperfect so that quicker and possibly more accurate results may come from centering the target point in the middle of a slightly larger rotating beam rather than centering the laser dot on the target, if you follow what i mean
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