Captured Hollowing jig with Laser

[Gary Conklin]

So I made a captured hollowing system with a laser. I love it already after just 1 use except for this one little thing, I turned right through the bottom of the piece. It was then that I realized 2 things.

1. I have never even seen a system in person or in use.
2. I have no practical knowledge of how to set up the laser.

So the questions are this: How do I set the laser? IIR when the dot falls off the piece you have reached your mark, right?

Help greatly appreciated.

[David Christopher]

Gary, I have the jamison rig and a DVD that came with it if you want the DVD PM me your address and I will send it to you.....its pretty informative

[Ryan Baker]

Actually, you can set up the laser any way you want ... as long as you remember what that is and use it accordingly.

You could set it to point right at the cutting edge of the tool, so it will show you where the edge is. You could set it away from the cutting edge by the desired wall thickness so that (as you suggested) it 'falls off the edge' when you get there.

Remember when you go around corners that you may need to adjust the laser ... a laser referenced to the left of the cutter won't keep you from going through the bottom.

[Steve Schlumpf]

Gary - I try to keep the laser in-line with where I am cutting. Every time I change where I am cutting on the inside of the form - I have to reset the laser.

[Chip Sutherland]

draw a line parallel to the edge on old business card where the distance from edge to line is the wall thickness you want (3/16,1/4,3/8, etc). Make several cards for different wall thicknesses. With the card edge pressed against the tip of the cutter/scraper set the laser to touch the line drawn on the card. Hint: the laser will be hitting air.

The real trick is that as the cutter is pivoted to cut the profile of the vessel, the laser needs to be set at 90 degrees to the cutter so you have to account for the profile that will be cut next. So always set your cutter position first then set the laser.

It's best to work only 1 inches at a time for vessels with tight profile (short squatty) changes or 2 inches if the profile change is subtle (tall long). Lyle Jameson's DVD is excellent in all respects because I didn't know to account for the profile until I saw Lyle's DVD. The person who told how to do this must have watched his DVD, too.

The bottom is a little different. I set the cutter to touch the actual cutter tip that shows me exactly where my cut is. I've not funneled a piece yet with this method. I find the transition from sidewall to bottom is trickier to gauge the tickness but I'm okay with that part of my piece being thicker. I like a little more ballast in the base for stability.

The hardest part of all this is keeping track of my business cards. Heaven forbid I clean the shop.

[Ken Fitzgerald]

Gary,

One easy way to figure out how to use the laser is to use it to turn/hollow a bowl.

Basically, let's look at your cutting tip as if you were standing on your tail stock looking down on the cutter. If the cutter was pointed directly at the headstock....12 o'clock....and you wanted the bottom thickness to be 1/4" you would set your laser to point at 12 o'clock....1/4" beyond the end of the cutting tip. Then as you hollow, when the laser drops off the wood ....the bottom is 1/4" thick.

Let's say you were hollowing at 9 o'clock....to the left....you would point your cutting tip to 9 o'clock and then set the laser to be set at the end of the tip and 1/4" beyond....thus when the laser drops off the side ...the side is 1/4" thick...

Each time you reset the cutting tip angle, you have to adjust the laser setting to that angle and for the wall thickness.

What Jamieson teaches is to use a notecard......draw a line parallel to the side of the card at a distance from the edge...the distance is equivalent to the desired wall thickness. Then at the center of the line, draw a line perpendicular to the 1st line and put an arrow head at the end of this line pointing away from the first line.

When you set up your laser....you point the arrowhead in the direction you'll be cutting and place the edge of the card at the edge of the cutting tip. Adjust the laser to align with the intersection of the two lines. Now the laser should be set off the end of the cutting tip by the desired wall thickness. Remember to reset the tip and the laser each time you change cutting angles.

Turn the outside of the hollowform as you would turn the outside of a bowl. Then hollow the inside.

Work from the outside in and turn the outside to finish thickness and work towards the bottom. The reason is as you hollow, and your walls get thinner, you will be losing support to turn.

Good luck..The Jamieson video makes it easy!

[Steve Schlumpf]

Gary,

Hope that a couple of simplified drawing can help get the idea across. The main point being you want the laser to be in-line with the cutting edge of the tool. Doesn't matter what tool you are using - you need to know which part of the cutter will be contacting the wood and align your laser with that cutting surface.

In the first photo - you have to use your imagination here - when hollowing the inside of the neck area of a hollow form - figure out where the cutting edge will contact the wood. Align the laser with that point and adjust for whatever thickness you want to achieve. As you get closer to the final thickness you will notice that the laser is getting closer to the edge of the turning - just before it moves off the turning it will become somewhat elongated as it paints the radius of the turning.

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Photo 2 shows the basic idea when hollowing the sides of the form.

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Photo 3 shows when you hollow the corner radius.

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When hollowing out the bottom of a form I use a different cutter - a straight bar cutter - but the setup is exactly the same.

Hope that helps a little. If you still have questions - please ask!

[Gary Conklin]

Thank you all. These appear to be the same principles I was using except I wasn't compensationg for the direction changes,

Steve! Thanks for taking the time to draw that out.

[Richard Madison]

Cool photos Steve.