Learning the laser

[John Sincerbeaux]

Still trying to get used to using a laser when hollowing. Seems to me that while the laser can be very accurate, the turner needs to be very accurate with the laser? I had a conversation with Lyle Jamison in regards to hollowing. I remember him telling me how much more efficient it is to hollow with a laser. But I have found that you have to constantly adjust the laser to the cutter head orientation. And on a large HF, there are a lot of varying changes going on requiring several adjustments. And combine that with all the vibration which can easily throw the laser out of position??
Is there a learning curve with learning to use and TRUST the laser?

thanks

[Bill Boehme]

If possible, identify the source of vibration and try to minimize it. The laser arm needs to be very stiff and also as light as possible. If you can separate the battery and switch from the laser diode itself, that will help. I have the Steve Sinner hollowing rig and laser and it is reasonably solid although they all will vibrate if you are making heavy cuts. The arm is one inch square aluminum tubing. The attachment to the boring bar needs to be rock solid and the vertical arm also needs to be rigid as well.

Of course, it is a good idea as you get close to the desired wall thickness make your cuts much lighter ... that will help with vibration. It might take a bit of visualization on your part to imagine the projection of the beam on a flat surface because the cylindrical shape really amplifies the closeness as the beam approaches the edge. If the laser position was set up correctly, things aren't as critical as they might appear. Just aim for the middle of the blur and you will be on target. Even if the beam completely falls off the side, that only means that you have gone slightly thinner than intended. Unless you are shooting for an absurdly thin wall, it's no big deal. For a large hollowform a wall thickness of a half inch or even more is OK. People who buy hollowforms want something for their money. If it is as light as a feather, they won't spend a ton of money on it. If a gentle breeze blows it over ... it's too thin

[nelson lasaosa]

Hi Bill. Although I´m still studying and gathering tips and equipment before as a diy get the first Wood blank turning, your approach to the laser topic seems great and of big help to me . Very pragmatic

[John Sincerbeaux]

Thanks Bill
Your analysis is spot on. I have the Steve Sinner laser. The vibration issue was due to me using a monro cutter withOUT the cutter shield which was too aggressive for dry wood. For green wood I think the cutter works best without the shield and angled down abt 20 degrees.
My last hollow form, I used the laser and I nearly went through the middle-side. It is a "fatal" error for that form. Now my confidence in the laser is low.
I belong to the dallas area club and know a guy at the Denton club. If you belong to either of those I am sure you know a couple of the guys who have tought me a lot about hollowing. They both turn very large HF's and ironically, they don't use lasers.

Thanks for the help.

[Bill Boehme]

Thanks Bill
Your analysis is spot on. I have the Steve Sinner laser. The vibration issue was due to me using a monro cutter withOUT the cutter shield which was too aggressive for dry wood. For green wood I think the cutter works best without the shield and angled down abt 20 degrees.
My last hollow form, I used the laser and I nearly went through the middle-side. It is a "fatal" error for that form. Now my confidence in the laser is low.
I belong to the dallas area club and know a guy at the Denton club. If you belong to either of those I am sure you know a couple of the guys who have tought me a lot about hollowing. They both turn very large HF's and ironically, they don't use lasers.

Thanks for the help.

I am in the Fort Worth Club, but several Denton club members also belong to Woodturners of North Texas. I know several membersd of the Dallas club because a number of WNT members who lived in Dallas decided to start a Dallas club around the time that I joined WNT. I also know some of the Dallas club members from other online forums.

I assume that you are talking about using the carbide cutter tip for the Munro articulated hollower which has a very sharp and aggressive hook angle. I think that using the carbide tip without the shield on green wood is just asking for trouble. Also, if you had it angled down, that means you probably did not readjust the cutting height to get it back on center ..... if so, you know that invites "self-feeding". Also, If you cut below (or above) center, remember that the edge as defined by laser light drop-off is not the same as it is when cutting on centerline, so give yourself a bit more cushion on the laser adjustment.

As far as cutters are concerned, I think it would be better to just use a simple quarter-inch scraper tip for green wood and save the Munro for turning after the wood has dried. Keep it a hair above center and then you can control it a lot easier. The guard position takes some fine tuning and some luck so be persistent until it is right. There's no prize for being fast when hollowing. I go slow and I run the lathe fairly slow.

Finally, don't blame the laser ... like any other tool you just need to adapt to it rather than trying to make it adapt to you.

[Sparky Paessler]

John

Yes it is easy to cut thru the side or top of a hollow form if you forget where you placed the dot in relation to the cutter. I have done it on a couple of forms in the past. That is why I have swapped over to a video system as that is no longer an issue when you can see the entire position of the cutter in relation to the piece. My system is simply a $30 camera from Amazon and an old flat panel TV I had sitting around. I just fed the camera into a composite input and taped a sheet of clear plastic on the screen that I use a small dry erase marker to draw the cutter on the screen with. Might be something to try in the future. I know I will not be going back to just a laser!

[David DeCristoforo]

I am very curious about this system of yours. I have all of the stuff you mentioned but I am having some trouble visualizing how it works. If the camera is mounted above the turning so that you can see the piece on the screen, how does the taped on piece of plastic with a cutter drawn on it relate? As I understand it, these systems will show an outline of the cutter superimposed over the form that will move with the cutter itself. Correct? Have you any pics of your system? I'd love some clarification on this!

[Sparky Paessler]

David I also had trouble visualizing how it would work with the camera at first. The best way I can explain it is that like the laser the camera is fixed in relation to the cutter so no matter how you move the rig the cutter does not move on the screen. With the cutter out of the form I draw around the cutter and also draw a circle around it at my wall thickness. When I put it into the vessel I see the vessel on the screen with the drawing on top of it. I then just cut until my thickness circle touches the edge of the vessel and my wall thickness is correct. The nice thing is I can "see" all around the cutter and the distance to the edge not just one point like with a laser.

[Sparky Paessler]

David I also want to clarify that I did not originate this method. Don't know who really did. There are a couple of commercially available systems out there that have various bells and whistles on them. I don't want to hijack Johns thread too much more. When I get my system back up on my new lathe I will take some pictures and do a separate post on my system.

[Doug Ladendorf]

Alan Z has a great video on the subject. I did not see his demo in Pittsburgh but I understand it was excellent. Trent Bosch has a product for this.

http://youtu.be/pidLwThKHSw

[Bill Boehme]

Trent Bosch is the originator of the idea. After that, the floodgates were opened with various copies and variants. I don't know if he is still selling his version, but I imagine that most people are going the home-brew route.

[David DeCristoforo]

OK...I'm gonna demonstrate, once again, just how dense I can be. I'm really stoked on putting one of these video systems together. But there is one thing that is not sinking in and that is how the outline of the cutter drawn on the screen overlay moves with the cutter bar.

[Matt Schrum]

OK...I'm gonna demonstrate, once again, just how dense I can be. I'm really stoked on putting one of these video systems together. But there is one thing that is not sinking in and that is how the outline of the cutter drawn on the screen overlay moves with the cutter bar.

The camera is fixed in relation to the cutter-- so it never moves from the center of the TV screen. Since the cutter is always in the exact same place (on the TV it'll look like the world is moving around the cutter-- the cutter will look stationary), you can trace around it on the screen and know it's always at that mark, even if the cutter is buried in your hollow form.

[Olaf Vogel]

Fantastic idea and great video.
Just figured out my next project

Thanks!

[David DeCristoforo]

Ahh... I see. The cutter becomes the center of the universe and everything revolves around it. Very zen!