Strobe lamp for interrupted turning?

[Raul McCai]

I have a couple of winged bowls I'm double turning to let them dry ten turn again. Presenting the tool to the outer periphery can be a bit of a challenge what with the thing almost 18" in diameter. SO I thought maybe a strobe might help me see the thing the same way an old school timing light lets you see the marks on your flywheel or balance-wheel when tuning a car ( remember those things?).

It's sort of looking like it might be worth the effort.
What do you use to find severely interrupted cuts for tool presentation?

 

[hockenbery]

I saw a demo by Ron Gerton a few years ago using a strobe..
The way it worked was to freeze the image of the work in your mind.
He used some sort of timing mark on the faceplate to sync the strobe when the lathe slows down as you cut.

Ron was using the strobe to freeze features on odd shaped burls so he could incorporate a particular structure of burl in the surface of the turning.

For a winged bowls most folks feel for the wood and cut it. When I do natural edged bowl or winged bowls I can usually see the edge by aiming a light across it. I can see my tool on the side I'm cutting and the finished side I'm trying to follow as a ghost image(air and wood).
on wings the less curve the wings have the easier to turn.

Double turning compounds the problem of turning. In a single turning you are feeling for the round turned surface. Feeling for a warped surface and turning it round will be a more difficult task as you have to turn both surfaces and will have given up some of the mass in the rough turning. If I were doing a double turning I would use a backing of a plywood disc to turn one face of the dried wings. This would eliminate the chatter from the thin wood on one side.

The stobe may help you see it but you still have to cut the surface.
I'll see if I can find an article by Ron.

 

[hockenbery]

The AAW JOURNAL spring 2001 has an article by Russ Fairfield on Square edge Ne bowls.
He discusses the ghost image and using light to see it.

This article talks about Ron's demo and how the author builds and uses a strobe
http://www.larsstole.com/Lars_A_Stole/techniques_files/notes.pdf

Rudy Lopez will be doing a couple NE Winged bowl demos at KC. (Rudolphlopez.com)
Al Stirt will be doing a couple of square edge platter demos at KC.
Both show excellent techniques for turning thin wings.

Jimmy Clewes oriental box demo and videos are also excellent method for turning wings.
All three use a side ground gouge.

 

[Leo Van Der Loo]

Do you want to see only a small area of your turning ??

Strobes or the effect is apparently vey hard or disorienting on some people.

I have had some strobing effects with fluorescent lights and a bowl with light area, I did not like it.

 

[Fred Belknap]

I have been experimenting with a laser to find the invisible edge of a NE bowl. I think the strobe light idea has merit but it might be rather dangerous to work close to it. I't thinking a magnetic pick up off the spindle to control the strobe could work. Here is picture of the laser mount that I have been experimenting with. I have now moved it to where my shaving jacket is hanging to get a closer to 90 degrees to the bowls. It also helps align the bowl on the chuck to get a balance effect.

 

[hockenbery]

Turning an 18" winged vessel can be dangerous. Relatively few turners have the skills to turn an 18" winged bowl.

Controlling and seeing the interrupted cut on a large piece requires skill and practice to master it. A larger piece should be built up to. The risk of breaking off an edge, splitting the whole piece, or ripping it from the chuck is greatly reduced with experience and skill.

Turning a dozen shallow natural edge bowls in the 8" range will build skills in seeing and turning the interrupted cut.
Start with 8 x 6 blanks. By the 5th one these will take 20 minutes each 10 for faster learners
When you are compfortable use 10x 6 blanks.. start with 1/4" wall thickness then do a few with 1/8" walls.
Turning 3 side spindles with a bowl gouge is terrific practice for the interrupted cut.

Once you are comfortable with the interrupted cut on NE bowls do a few successful winged bowls at increasingly larger sizes beginning with small ones.
8" winged bowls then 10-12" winged bowls then 13-15" winged bowls
If you have done successful bowls at each size then doing and 18 or 20" will be achievable with your developed skill set.
You can use boards to turn winged platters.

If you fail with an 8" winged bowl it is much less catastrophic than failing with an 18" one
If you succeed with a 15" one then it is very likely you will succeed with the 18" one.

This is the kind of turning skills that can be built quickly with mentoring. A weekend class with Ellsworth will give you the skills then you put in the practice.

 

[olaf Vogel]

Winged bowls that size are definitely a challenge. You want to ensure that your setup and skill level is up to par, to avoid any dramatic incidents.

The idea of using a strobe for this makes my head hurt. Too many things to coordinate.
But I'm very sensitive to flicker on screens, lights etc.

I also use a high intensity light that is very directional, to maximize shadows.
Mount that almost inline with the wing, so that you can see the edge.
That will get you in the ballpark. The rest is just "feel".

Normally I put the tool rest as close as I dare, hand spin the piece a few times to ensure clearance.
Then your tool presentation must be extremely delicate until you feel the tic.

To practice my skills for this, I set up a simple test case. I took a wooden board, of width and length close to the size of the turning. Screwed that onto a faceplate, centred. And than fired it up. Its basically a big propeller.

This is the point where I saw a big whirling blade and thought "why hell am I doing this?!?!"
(this is a great time to bail....

Then I practiced my tool presentation.

Sure you can still screw up. But there's very little mass to the board, if/when things start to fly....

A few logical tips
- Obviously stay out of the line of fire.
- I prefer big, heavy tool handles for this. All the mass at the end really helps steady things.
- small tool tips - I use my 1/2" Thompson gouge
- work SLLLLOOOOOWWW
- higher speed is better - reduces the time between tics
- green wood is much nicer to work with than dried - those tics are much softer. Screwup are more forgiving.
- for larger winged bowls I do NOT turn them twice. They distort too much. I just sand heavily.

This got my skill up to where I managed this one thats 27" across.

 

[hockenbery]

@olaf Vogel
Nice piece. Turning it endgrain is another complication - nice job!
I Like what you have done with this one.
Size is impressive too.


My style would be to turn two face grain bowls with the crotch flame in the bottom.

I rarely turn anything large endgrain other than an occasional Norfolk Island Pine piece.

 

[Bill Boehme]

I have a couple of winged bowls I'm double turning to let them dry ten turn again. Presenting the tool to the outer periphery can be a bit of a challenge what with the thing almost 18" in diameter. SO I thought maybe a strobe might help me see the thing the same way an old school timing light lets you see the marks on your flywheel or balance-wheel when tuning a car ( remember those things?).

It's sort of looking like it might be worth the effort.
What do you use to find severely interrupted cuts for tool presentation?

That would be extremely dangerous because you don't know the exact path of the winged vessel since you only see a fixed position. The flicker can also be spatially disorienting.

 

[hockenbery]

That would be extremely dangerous because you don't know the exact path of the winged vessel since you only see a fixed position. The flicker can also be spatially disorienting.

There is a lot of potential danger in cutting an 18" diameter winged vessel with or without a strobe.
This is the type of form that should be attempted only with lots of practice on similar smaller forms.

My only experience with a strobe is having seen Ron Gerton's demo. Ron had the strobe set to fire on the same position of the lathe every rotation regardless of the lathes speed. What you would want to do on a grossly symmetric vessel is adjust the strobe to fire when one wing is just at the tool rest so that you would cut where you want to. The cool thing about wings is that all of them are cut the same.

The flicker for me was annoying but I assume you get used to it.
It did however clearly show a couple of spikes on a burl that Ron wanted to have on the rim.

For a grossly symmetric form the strobe is just an introduce complication.
We can see both sides of the wing the thickness and the previois cut lines with positioned task lightning.
I have done a,lot of interrupted cut pieces without a strobe.

 

[Raul McCai]

In my imagination I had the strobe timed to illuminate the work right where I need to present to tool. If I can get this it, may be useful The strobe I have uses sound as well as a manual speed adjuster. Manually It's not so helpful because I can't get time the instant I turn it on with much precision have been fooling around with an air gun blowing across the workpiece the interruption triggers the strobe. That has some promise.
Some.

In the end it may just end up in my Daughter's Haloween display she and her husband love to decorate for holidays and they'd get a kick out of it. So one way or another this little gizmo will find a home.

I hear ya Al about the skills needed to approach a big interrupted cut. Turning this sort of reminds me of a job I used to run every year on an engine lathe with a 48" diameter face-plate festooned around the diameter with fixtures each holding a work piece and my task was to put a specific radius in a certain location at a specific orientation on each part. Guy who did it before me used a little acid brush to lube the cut. I got a squirt bottle instead.

 

[john lucas]

In a piece like that where the 2 ends aren't the same length I'm not sure how much the stobe would help. You would see a stationary bowl but it might not even be where the wings protrude depending on where the sensor is on the shaft. So you would still have to find the outer wing. I rub the bevel gently coming out from the inside until I don't hear the tik tik. The I move the handle a hair to pick up the cut and proceed down the bowl. Since the wings can sometimes be invisible this method has always worked for me. I usually do an inch at a time and check wall thickness and then never go back because the wood starts to move and you can easily make one end thinner or possibly get the leading edge of each side thinner depending on how the wood moves. Never been brave enough, or maybe just haven't found it necessary to turn one that large.
I learned or at least improved on my technique trying to turn one piece handled mirrors. The handle completely disappears on those you have to find it by feel. The end us at the maximum swing of my lathe which is about 10 1/2" or what it would be like to turn a 21" winged bowl.

 

[Charlie Knighton]

One piece handheld mirrors.....logical progression

 

[Fred Belknap]

I use a red dot laser and put it on the tip of the longest wing. It gives a pretty good indication where to start your cut.

 

[Bill Boehme]

In a piece like that where the 2 ends aren't the same length I'm not sure how much the stobe would help. You would see a stationary bowl but it might not even be where the wings protrude depending on where the sensor is on the shaft. So you would still have to find the outer wing. I rub the bevel gently coming out from the inside until I don't hear the tik tik. The I move the handle a hair to pick up the cut and proceed down the bowl. Since the wings can sometimes be invisible this method has always worked for me. I usually do an inch at a time and check wall thickness and then never go back because the wood starts to move and you can easily make one end thinner or possibly get the leading edge of each side thinner depending on how the wood moves. Never been brave enough, or maybe just haven't found it necessary to turn one that large.
I learned or at least improved on my technique trying to turn one piece handled mirrors. The handle completely disappears on those you have to find it by feel. The end us at the maximum swing of my lathe which is about 10 1/2" or what it would be like to turn a 21" winged bowl.

I am not advocating using a strobe, but I thought that I would add to what you have said. The strobe could be set to double the rate so that it fires twice per revolution. This would show the two wings superimposed on top of each other like a double exposure in film. Also, you don't see the results of what is being cut in real time ... it will be one revolution behind (or a half revolution behind if the strobe is firing at double the RPM. If turning a large diameter piece the RPM needs to be dropped to prevent flutter which means a longer time lag between the actual cut and seeing it.

Personally, I think that it is easier and safer to use your ears and listen for the (hopefully) faint tic-tic sound, use your sense of fine touch to confirm what you hear, and use good lighting with a black background to show the shadowy outline of the wings. And be careful where you stick the tool or any part of your body that you want to keep. My preference is to drop the handle of the bowl gouge really low and very lightly shear cut the wood. Planning things out is very important to get a good shape, because the wings need to be worked in stages in order to minimize flutter.

 

[john lucas]

Derek Weidman uses lasers that make a line and cross each other to show exactly where he wants to cut. His off center turned carvings are incredible. He uses the crossed lasers to help locate the piece at the angle he needs to make the proper cuts. If they were adjustable you could put them exactly where the edge of the piece is. At least one edge anyway.

 

[Bill Boehme]

Derek Weidman uses lasers that make a line and cross each other to show exactly where he wants to cut. His off center turned carvings are incredible. He uses the crossed lasers to help locate the piece at the angle he needs to make the proper cuts. If they were adjustable you could put them exactly where the edge of the piece is. At least one edge anyway.

I have seen Derek Weidman at SWAT and even if I had lasers along with smoke and mirrors I still couldn't do what he does.

 

[john lucas]

You are right about that. You have to have the vision in your head. I have a problem with drawing. I can draw something if you put it right in front of me. Take it away and ask me to draw it and I can't. The same would be true for trying to duplicate Derek's work.

 

[hockenbery]

I have seen Derek Weidman at SWAT and even if I had lasers along with smoke and mirrors I still couldn't do what he does.

Derek is doing demos at KC this year. One is titled drawing on the lathe. His work is amazing.
He is crazy in a GOOOOD WaY. His work amazes everyone.

 

[R Henrickson]

Derek Weidman uses lasers that make a line and cross each other to show exactly where he wants to cut. His off center turned carvings are incredible. He uses the crossed lasers to help locate the piece at the angle he needs to make the proper cuts. If they were adjustable you could put them exactly where the edge of the piece is. At least one edge anyway.

I saw Derek do a number of rotations at the OVWG symposium last year, and did a weeklong class with him at Arrowmont this past summer. No lasers were used or mentioned.

 

[Raul McCai]

I think I like the laser idea. The Stobe is not proving to be a really great option. I tried using sound to time it with an air gun. It works sort of, kind of, but not terribly well. But Hey~!! It was definitely worth the investigation.

The strobe I have has only two modes (1) sound response or (2)manual attenuation with a knob. I'm unable to get the thing to time it's firing precisely. I don't think it'd work with a Hall effect switch on the power cord and a magnet on the hand spinner. That'd cause surging the electrics over and over with on off line voltage and probably toast it in minutes. But It's not a closed question whether that form of activation might be useful.

 

[john lucas]

You need a strobe that uses a marker placed on the spindle. When we had a club demo for ease and speed sake he used a rare earth magnet. Worked great during the demo but after the meeting he was showing someone how to use it on a smaller spindle and cranked the rpm's up and it threw the magnet somewhere. we have yet to find it.

 

[Bill Boehme]

Generally, the electronics in xenon tube strobes have to charge up a capacitor to sufficient voltage before it will activate the firing circuit. Until you get up to the high dollar devices you are fairly limited on maximum frequency as well as duty cycle. For example my Canon flash can do a couple two second bursts at about 30 Hz but then it needs to rest for about ten minutes to let the xenon tube cool off or else it will overheat and greatly shorten the life of the flash.Since these little flashes cost around $600 I am very gentle with them.

If you're really feeling adventurous, instead of using a flash you could use a video camera set to a low frame rate and sync the lathe motor speed to get a stationary rolling shutter effect (think of the old westerns where the outlaws are chasing a stagecoach and the wheels look like they are turning slowly backwards .... that's the rolling shutter effect). If you can manage to do that, the next step would be to turn while looking at a monitor rather than looking at the real world. Nothing to worry about ... I'm sure that it's no worse than turning while blindfolded.

 

[hockenbery]

If you're really feeling adventurous, instead of using a flash you could use a video camera set to a low frame rate and sync the lathe motor speed to get a stationary rolling shutter effect ....... I'm sure that it's no worse than turning while blindfolded.

Interesting concept.
I turn watching video - i find it to be effective and safe.

I have been using video to hollow for a couple years. I watch the monitor and see the tool move into the form then use marks on the screen overlay to cut the wall thickness. TV gave me a giant boost in confidence when hollowing and I was especially confident before using the tv.
With TV it is like having a 100% confidence with the cut rather than a 95% confidence. Closing that gap is indescribably huge.

Going to some sort of freeze frame technology changes the dynamics. Not sure how you would synce the video to the lathes rpm. A big issue with using strobes is that the lathe looses rpms when you cut so the strobe has to slow it's rpms to match. The strobes use a timing mark.

 

[Leo Van Der Loo]

A bump on the spindle a pair of points wired in a 6V or 12V circuit with a coil, that would power your automotive strobe,
just some rigging to do but I can see that work, still that narrow piece of turning that is visible doesn’t sit too well with me

 

[Bill Boehme]

Interesting concept.
I turn watching video - i find it to be effective and safe.

I have been using video to hollow for a couple years. I watch the monitor and see the tool move into the form then use marks on the screen overlay to cut the wall thickness. TV gave me a giant boost in confidence when hollowing and I was especially confident before using the tv.
With TV it is like having a 100% confidence with the cut rather than a 95% confidence. Closing that gap is indescribably huge.

Going to some sort of freeze frame technology changes the dynamics. Not sure how you would synce the video to the lathes rpm. A big issue with using strobes is that the lathe looses rpms when you cut so the strobe has to slow it's rpms to match. The strobes use a timing mark.

I thought about that, but there is a big difference between hollowing where the cutter is inisde the vessel and turning a winged vessel where your hands are very close to those big propellers. That was really a tongue in cheek suggestion anyway. The slowest video frame rate is 24 FPS which translates to 1440 RPM at the spindle ... much too fast. You could do stop motion ... or intervalometer ... forget that I mentioned that.

 

[hockenbery]

I thought about that, but there is a big difference between hollowing where the cutter is inisde the vessel and turning a winged vessel where your hands are very close to those big propellers. That was really a tongue in cheek suggestion anyway. The slowest video frame rate is 24 FPS which translates to 1440 RPM at the spindle ... much too fast. You could do stop motion ... or intervalometer ... forget that I mentioned that.

First, a winged bowl can be turned quite well watching the shadow image and/or feeling for the cut. The less curve the easier it is. With more curve on the wing it gets harder to see as the curve will either block view of the tool or block view of the other side of the wall. This whole discussion is about

Video would have to run through some computer software. Certainly a computer can either pick the frames of interest or snap a picture at a specified interval. With enough computer power the frames can be interpreted to freeeze the image or with less horsepower freez on a marker.
Video can be used to duplicate spindles by overlaying what you want to copy with the blank being turned. I think Alan Z has done something along these lines.

With the right software we could add a warning beep when the wall is getting too thin.

 

[Raul McCai]

Nothing to worry about ... I'm sure that it's no worse than turning while blindfolded.

HAHAHA I'm still trying to turn while not watching the tool/work interface but instead watching the profile of the work over top of the turning. I think that Scot or maybe he's a Brit who has moved to the USA teaches that.

About the camera: Thiming on cameras lags behind the real action being videoed which might lead to fingers having flown across the room before the amputee sees it happen. What could go wrong?

 

[Raul McCai]

Just so ya all know what a lunatic I can be. I've abandoned the strobe and am considering the Lancelot rotary chainsaw tool in an angle grinder on the lathe. Sort of the same as a Dumore Tool Post Grinder but wilder.

 

[hockenbery]

Just so ya all know what a lunatic I can be. I've abandoned the strobe and am considering the Lancelot rotary chainsaw tool in an angle grinder on the lathe. Sort of the same as a Dumore Tool Post Grinder but wilder.

I have a Lancelot. It is fairly easy to control if you hold the grinder with two hands and the work piece is clamped in place or heavy enough to be immobile.
There are several better choices our there. I think the carbide blades are easier to control and leave a better finish. I don't do any of the big carving now and if I did I would use the arbotech with 2" carbide wheels.

I used mine a lot 20 years ago to true chain sawn blanks to turn over the bed of the lathe when I was trying to turn 11.999" bowls on a 12" lathe
Last time I used it was to cut spiral windows in the hollow form in the photo inspired by Stewart Mortimer.

A couple of years ago Dennis Doebler was hurt badly trying a one handed cut on an unsecured workpiece. One of the graphic references google returns:
http://www.spswoodturners.org/carving-accident.

Be safe,
Al

 

[Joe Greiner]

Just so ya all know what a lunatic I can be. I've abandoned the strobe and am considering the Lancelot rotary chainsaw tool in an angle grinder on the lathe. Sort of the same as a Dumore Tool Post Grinder but wilder.

Beat you to it.

 

[Bill Boehme]

Dear Santa,

You know that Lancelot carving tool I said that I wanted? Scratch that tool off my Christmas list.

ps, how come I never got that Red Rider air rifle when I was a kid?

View: https://www.youtube.com/watch?v=YleZvTSDC6s


I've been sorta good all year, if that counts for anything.

 

[olaf Vogel]

Beat you to it.View attachment 21572 View attachment 21573

I'm assuming you aren't considering winged bowls with?
Cuz the idea of a spinning tool cutting wings while the lathe is under power... that thought really scares me.

However, the idea of mounting a grinder / router or other has been done before
http://www.owwm.org/viewtopic.php?f=5&t=174104&p=1191320&hilit=router+lathe#p1191320

I took a shot at it as well http://www.olafvogel.com/atw-router-lathe.html
with limited success. The real issue was matching the cutting depth with lathe RPMs.
The RPM's need to be VERY low - I started turning it by hand, no power.

The idea has some merit and I created a few interesting designs. Then I decided to build a bigger shop and got sidetracked for a a few years...

 

[john lucas]

I did an experiment a few years ago with the Lancelot vs the Arbortec. contrary to what many people say the Arbortec is no more safe than the Lancelot. Or I should say just as dangerous. I've used the Lancelot for many years. Just couldn't justify the price of the Arbortec but I will say it is a better tool. The Arbortec does cut cleaner and the shaving that hit your arm aren't as sharp. both tools can grab quickly if you stick them in like the end of a chainsaw. Both tools are very controllable if you use what I call a scraping action, that is pulling it across the wood so the arc of the tool cuts. If you stick it in the wood with the blade vertical it can run up the bowl jerk out of your hands and cut you very badly. I have some photos of a man who did that. We elected not to show those but sometime this spring I will be doing a video on angle grinder safety.
If you want a good tool that is pretty safe buy the Arbortec mini. Cuts just about as fast as the big cutter but is far more controllable and therefore safer. As Al said no matter what you use, keep both hands on the grinder.
As Al said lock the bowl in position and then use the grinder on it. They also make flap discs and 36 grit sandpaper discs that remove a lot of wood and are far safer than the Lancelot of Arbortec. I've used many methods to lock the bowls. A wooden parallel jaw clamp will sit on the bed of the lathe and can be clamped around the chuck. You can wrap a strap clamp around the chuck and bed and apply enough pressure to hold the bowl pretty well. I used to use a wedge that looked like a morse taper and wedge it between the motor and handwheel on my powermatic. I still grab that from time to time because it's so quick. Indexing of course it probably the best way. My Vicmarc chucks have index holes in the back. I made a springy sort of pole that mounts on the bed of the lathe and sticks in the index holes. This is my preferred method. Of course you can buy index wheels that mount between the chuck and headstock. The ironfireLLC is Nylon and runs less than $30. The Alisam is aluminum and really nice but runs about $100. Here is a photo of my Alisam index wheel with my own index pin. I like it much better than the one that comes with the Alisam. To use it with a chuck I simply rotate the spring arm 180 degrees so it points toward the chuck. I have a wooden version that I use for demos that is much easier to build for the average Joe.

 

[Bill Boehme]

John, when you use the grinder like a scraper, does that mean the blade is horizontal (parallel to the bed) rather than oriented like the one in Joe's post? Have you looked at anything for limiting the depth of cut?

 

[Leo Van Der Loo]

I remember our first right angle grinder, as these were brand new in the industry, a 7” Bosch, and we learned to be aware of the power of that machine, a good hold with 2 hands and in a pulling away from you use.
I still have a scar on my leg when it grabbed and directed itself in a left swing where my left leg was, nothing real bad just a rough surface cut and with a bandage on it work resumed, the coverall got patched and that was it for a lesson learned, couple of employees did something similar and than we all knew what not to do, the power and speed you really need to respect and handle it accordingly .

I have a couple of the small 4.5” grinders and these are nowhere near as powerful, but yes you still do need to know how to use them, and stay out of the line of the real fire, as you’ll be burning pretty fast if grinding steel

 

[Gerald Lawrence]

Dear Santa,

You know that Lancelot carving tool I said that I wanted? Scratch that tool off my Christmas list.

ps, how come I never got that Red Rider air rifle when I was a kid?

View: https://www.youtube.com/watch?v=YleZvTSDC6s


I've been sorta good all year, if that counts for anything.

Bill you will shoot your eye out.

 

[Raul McCai]

I started turning it by hand, no power.

Yah that's pretty much the plan.
I did a router on a lathe supported over head by a wood jig. The higher the lathe speed the worse the finish. But I did get the better than ten thousandths TIR Consistency I was shooting for along the diameter/length.

 

[Joe Greiner]

I'm assuming you aren't considering winged bowls with?
Cuz the idea of a spinning tool cutting wings while the lathe is under power... that thought really scares me.

However, the idea of mounting a grinder / router or other has been done before
http://www.owwm.org/viewtopic.php?f=5&t=174104&p=1191320&hilit=router+lathe#p1191320

I took a shot at it as well http://www.olafvogel.com/atw-router-lathe.html
with limited success. The real issue was matching the cutting depth with lathe RPMs.
The RPM's need to be VERY low - I started turning it by hand, no power.

The idea has some merit and I created a few interesting designs. Then I decided to build a bigger shop and got sidetracked for a a few years...

That contraption isn't for turning. The objective was to trim horribly out-of-balance pieces without the tedium of the hand-held Lancelot. And it turns in the wrong direction for turning anyway. Of course I rotate it by hand. I'm considering powered rotation with an ice cream maker motor as soon as I make a drive adapter and speed reduction to about 15 rpm or less.

I haven't checked their progress lately, but King Arthur's had been working on a tool post mount for the Lancelot.

 

[Joe Greiner]

I did an experiment a few years ago with the Lancelot vs the Arbortec. contrary to what many people say the Arbortec is no more safe than the Lancelot. Or I should say just as dangerous. I've used the Lancelot for many years. Just couldn't justify the price of the Arbortec but I will say it is a better tool. The Arbortec does cut cleaner and the shaving that hit your arm aren't as sharp. both tools can grab quickly if you stick them in like the end of a chainsaw. Both tools are very controllable if you use what I call a scraping action, that is pulling it across the wood so the arc of the tool cuts. If you stick it in the wood with the blade vertical it can run up the bowl jerk out of your hands and cut you very badly. I have some photos of a man who did that. We elected not to show those but sometime this spring I will be doing a video on angle grinder safety.
If you want a good tool that is pretty safe buy the Arbortec mini. Cuts just about as fast as the big cutter but is far more controllable and therefore safer. As Al said no matter what you use, keep both hands on the grinder.
As Al said lock the bowl in position and then use the grinder on it. They also make flap discs and 36 grit sandpaper discs that remove a lot of wood and are far safer than the Lancelot of Arbortec. I've used many methods to lock the bowls. A wooden parallel jaw clamp will sit on the bed of the lathe and can be clamped around the chuck. You can wrap a strap clamp around the chuck and bed and apply enough pressure to hold the bowl pretty well. I used to use a wedge that looked like a morse taper and wedge it between the motor and handwheel on my powermatic. I still grab that from time to time because it's so quick. Indexing of course it probably the best way. My Vicmarc chucks have index holes in the back. I made a springy sort of pole that mounts on the bed of the lathe and sticks in the index holes. This is my preferred method. Of course you can buy index wheels that mount between the chuck and headstock. The ironfireLLC is Nylon and runs less than $30. The Alisam is aluminum and really nice but runs about $100. Here is a photo of my Alisam index wheel with my own index pin. I like it much better than the one that comes with the Alisam. To use it with a chuck I simply rotate the spring arm 180 degrees so it points toward the chuck. I have a wooden version that I use for demos that is much easier to build for the average Joe.

With a lot of practice, and held flat like a surface grinder, I can get close to belt sander finish with the Lancelot.

King Arthur's has a miniature Lancelot, called Merlin, that's about 2" diameter, with a dedicated powerhead.