Laser - Hollowing Tools Question

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DocStram

DocStram

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I would appreciate it if someone could help me grasp the concept of using a laser light to judge a hollow vessel's thickness.

I understand how the laser light is used with a hollowing tool to show you where exactly the point of the cutting tool is located . . . . but, I don't understand how the laser light can indicate the thickness of the wall of the vessel.

Will somebody explain it in easy to understand terms?
 
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Al,

When I still have mine, I actually never set the laser at the end of the cutting tip. I set it about 1/4" forward the cutting edge. Once it starts getting close the outer edge of the bowl you can see (and hear) ;)

It doesn't indicate the thickness per se but helps you gauge it before it is too late.

Hope this helps.
 
Never heard of it helping to guage thickness but I know quite a few tools that use it to guage depth. Would you care to post a link or tell me where I can see this thing? You've got me curious.
 
while I know they don't do this, they could.

if the laser is set at a fixed distance from the cutter, then the laser could measure the distance to the wood surface and a small calculation later would reveal the thickness. Again, I don't believe any manufacturer is using a laser in this way, but they could do so fairly simply. Laser measuring devices are fairly common now after all.
 
Originally posted by turned_for_good

Never heard of it helping to guage thickness but I know quite a few tools that use it to guage depth. Would you care to post a link or tell me where I can see this thing? You've got me curious.
Click to expand...

Here's one website that talks about using a laserlight to determine wall thickness: <center>
http://tnvalleywoodclub.org/Articles/hollow_cal.htm</center>

As you scroll down the page you'll come across this description:

Note that the laser assembly acts as a caliper in that it is preset to the desired distance from the edge of the cutting tool so that when the laser dot drops off the side of the vessel, the thickness of the wall at that point is the preset value. This picture shows that tool just at the entrance of the vessel, so that, using a scale, the turner can preset the desired thickness. Once the tool is inserted into the vessel the laser dot will show on the vessel's surface. As the thickness of the wall decreases with the cut, the dot will approach the side of the turning and ultimately begin to get oblong and disappear off the edge completely as the cut is continued.



Here's another example from the Clark Hollowing System:<center>
http://www.theokspindoctor.com/hollow.html</center>

Laser Thickness Guidance Device attaches to the hollowing bar. This device holds a laser emitter to allow the turner to see how thick the hollow form is during hollowing. An easy push of a button on the laser activates the laser light. The laser holder articulates and tilts to get around the middle radial arm of a steady rest. This is a must when used with a steady rest. A unique fitting at the end of the laser holder arm makes re-adjustments and realignment of the laser much easier. The laser scaffold virtually eliminates vibration of the laser light. Admittedly, when turning large diameter pieces, the steady rest itself does interfere with the laser but long vertical holders can be made to put the laser entirely above the steady rest as seen in an example on my Customer Gallery page.
 
Maybe this crude paint illustration might help?


2008563739_laser-thickness.jpg
 
Originally posted by Tea Clipper

Maybe this crude paint illustration might help?


2008563739_laser-thickness.jpg
Click to expand...

Ron ... thanks for taking the time to make the drawing. I think I need a little narrative to help explain it. Here's what I'm wondering .... I can tell where the red light is from the laser ... but, how can I tell where the green is? It would make sense to me if the hollowing tool had two laser lights ... one showing where the cutting edge of the tool is and another showing the outside of the vessel. But, there's only one laser light. Am I making sense? Sorry, but I'm confused by how you can tell depth of the wall from just one laser light.
 
Al,

As I mentioned above...if you know how far you set the light in reference to your cutting tool...then you can tell once you are near the edge. This is vs going blind and estimating or keep on stopping to check the thickness with a caliper. Even masters find the eyeball method hard and lose turnings because they over cut and create a hole.

Note that how you present the tool and make the cut also affect the actual thickness left as the light "falls over the edge" of your turning so keep that in mind.
 
How about Lyle Jamieson's explanation:

The whole idea of the laser is really simple. You set the laser light so that the beam of light passes by the cutting tip at the distance you want your wall thickness. The distance between the light and the cutter is your wall thickness. (See Illustration 1) While the light shines on top of the hollow form, the cutting tip is hogging away wood inside the vessel. When the laser shines around on the side of the vessel, slow down and watch your cutting pace. As the light no longer shines on the turning, it skips off the edge of the form and shines on the floor.You stop cutting! The set distance between the light and the cutter is now the desired wall thickness. Go back lightly now and smooth away any tool marks without reducing wall thickness any further.


To set the laser lock down all supporting hardware so that all you have to move for an adjustment is the bracket holding the laser. Now all future adjustments can be made easily by moving or swiveling the laser holding bracket at the end of the tubing that supports it.

https://www.lylejamieson.com/tools/lasertool.asp
 
Duh!! Now, I get it!!

For some reason I thought you were supposed to line the laser light up exactly on the cutting tool. That's why none of it made sense to me. Thanks everybody for your patience and spelling it out for me.
 
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