Dangers from wood flying off the lathe

[Randy Heinemann]

I was recently reading a post concerning face protection on this Forum and a lot was said about face protection with a shield. I am new to turning (about 2 years into it), turn mostly bowls, and to date, have not turned any large bowls (nothing over about 7" finished). I use a Trend Airshield Pro, mainly because I use it for all woodworking I do for filtering the air I breathe even though I use a cyclone and HEPA vac depending on what I'm doing in the shop. I always have my ceiling hung air cleaner turned on while working.

For me, since the bowls that have come off the lathe have been relatively small and I wasn't turning at a particularly high speed, I have never come close to getting anything thrown back at my body. I also try to stay "out of the way" but I'm sure don't always do that.

So, my question (finally) . . . what resources are available, either print or internet, which describe the various dangers and how to avoid them. I have access to the AAW resources online as a member and am reading whatever is available there.

I personally believe that the Airshield Pro, while not rated for impact, will protect me from possible dangers and it gives me protection from dust in the bargain. I may be wrong but would at least like to know all the facts.

Thanks for any help you can give.

[Roger Chandler]

The Trend Airshield Pro has the same Z87 rating that the Uvex Bionic face shield has and other commonly available face shield protectors that are sold as face protection. If you want something that is really heavy duty, then a hockey mask, a riot shield like the police use is a step up from most of what turners use.

Keeping good turning practices, like using correct jaws on your chuck, properly formed tenons, or using a faceplate are pretty good means of avoiding a problem altogether. Not much will protect you from a large piece, not held properly, and turning at high speed, so develop a good routine where you always check the speed dial/pulley before you turn your lathe on. Adhere to the AAW guidelines on turning speeds, and you should be okay.

[Mark Hennebury]

I am not a turner, but it would seem to me that a heavy metal guard over the lathe would do a better job than a face shield alone. Along with some common sense.


https://www.facebook.com/Gereedschappelijk/videos/280639049331296/?t=14

[Richard Coers]

When judging what kind of face shield to buy, consider something that you wouldn't mind wearing when someone approached and attempted to hit you in the face with a ball peen hammer. Maybe it's a little hammer in your case, but it's the kind of protection you need if you want complete safety.

[John K Jordan]

Do you mean info about the dangers and how to protect from them, or info about how to prevent the piece from coming off the lathe?

I can't remember every having a bowl or blank come off the lathe. (I had one break at a defect and a piece flew off.) On the other hand, I was in a class once and one guy had a 7-8" bowl come of the lathe at least four times. His problem turned out to be improper chucking technique PLUS lacking the skills to prevent catches. Both of these things can be fixed.

I think it is important to use the proper protection, but even more important to first figure out why the piece is coming loose.

Maybe you can get an experienced turner to come and see just how you are mounting and turning.

Perhaps describe a few things:
- type of wood
- green or dry
- thickness of the blank, say for typical 7" bowl
- fixing method(s), faceplate, chuck
- for chuck, using a tenon or recess
- for chuck, dovetail jaws?
- methods of work (order of things)
- what kinds of tools you are using
- if green wood, if the chuck is re-tightened periodically
- speed of lathe for that 7" bowl, for roughing and finishing cuts
- where in the process the piece comes loose
- what you were doing when it comes loose (roughing,

I can describe briefly how I usually work for bowls and platters (typed quickly - hope I didn't forget anything important!)
- I almost always turn dry wood
- flatten at least one face (top), usually both faces
- round the blank on the bandsaw
- mount the top in a Glaser screw chuck
- use the tailstock for additional support if needed
- turn round, then face off for the base
- back off tailstock support if used
- cut a recess in the base for expanding a chuck with dovetail
(a proper recess is usually stronger than a tenon)
(I use Nova dovetail jaws from 2" to 4", depending)
- turn the base and outside/bottom profile
- smooth, sand and sometimes finish (depending)
- reverse the piece and hold with a chuck in the recess
- turn the inside, rim
- smooth, sand and finish
- if removing the recess, reverse and jam chuck with tailstock support
(or use cole jaws, or use vacuum chuck, or finish the supporting central nub by hand)

It is important to make the properly sized tenon or recess. It is extremely important to have the proper depth of the recess or tenon, cut the dovetail properly if using dovetail jaws, and turn the proper seating surface for the face of the jaws to bear against. You may know all this but some don't. Sometimes a person has terrible problems that are solved with the proper holding. For example, occasionally someone makes a tenon too long so it bottoms out at the bottom of the jaws, makes a recess too deep so the face of the jaws don't properly bear against the inside, or makes it too big so the jaws only grip in several places instead of all the way around.

JKJ


I was recently reading a post concerning face protection on this Forum and a lot was said about face protection with a shield. I am new to turning (about 2 years into it), turn mostly bowls, and to date, have not turned any large bowls (nothing over about 7" finished). I use a Trend Airshield Pro, mainly because I use it for all woodworking I do for filtering the air I breathe even though I use a cyclone and HEPA vac depending on what I'm doing in the shop. I always have my ceiling hung air cleaner turned on while working.

For me, since the bowls that have come off the lathe have been relatively small and I wasn't turning at a particularly high speed, I have never come close to getting anything thrown back at my body. I also try to stay "out of the way" but I'm sure don't always do that.

So, my question (finally) . . . what resources are available, either print or internet, which describe the various dangers and how to avoid them. I have access to the AAW resources online as a member and am reading whatever is available there.

I personally believe that the Airshield Pro, while not rated for impact, will protect me from possible dangers and it gives me protection from dust in the bargain. I may be wrong but would at least like to know all the facts.

Thanks for any help you can give.

[Stan Calow]

Maybe what is missing in books and videos regarding safety, is showing where the pieces are likely to go, and how to tell when and what situations are more likely to cause a workpiece to explode. I think the only common discussion in beginners' books is a cryptic statement like "stay out of the line of fire" but no description of what the line of fire is - left, right, center, etc. Does that change based on what you're turning, the tool in use, the method of holding, etc. Advanced and intermediate books assume you already know.

I think the helmet is a good idea, but a rocket to the chest or somewhere worse, is not fun either.

[John K Jordan]

Maybe what is missing in books and videos regarding safety, is showing where the pieces are likely to go, and how to tell when and what situations are more likely to cause a workpiece to explode. I think the only common discussion in beginners' books is a cryptic statement like "stay out of the line of fire" but no description of what the line of fire is - left, right, center, etc. Does that change based on what you're turning, the tool in use, the method of holding, etc.
I think the helmet is a good idea, but a rocket to the chest or somewhere worse, is not fun either.

The principle line of fire is be somewhere in a plane perpendicular to axis of rotation, could be any angle before it bounces. I think you make a good point - the "line of file" should be defined in beginner instruction. I can imagine some ways to do this effectively with a drawing or 3D rendering. A rendered animation would be great in a video. I've always assumed everyone knew what line of fire meant - I think I'll make it clear in demos in case someone doesn't. Thanks.

I've heard demonstrators claim to know just where a turning or chunk would go if it came off the lathe (the angle in the plane) but I never understood how they could know. I think it could initially go almost anywhere in that plane.

Those I've seen after the fact were close to the plane based on the evidence. I've seen holes in a ceiling above a lathe, dents in a wall behind a lathe, and heard stories of being struct in the chest or face shield. In jr. high school one guy in shop class launched a spinning bowl over his left shoulder, bounced a few times across 30 ft of shop floor and workbenches, and went through the window.

I suspect it could travel to the side of the plane a little depending on what other forces were on it at the time (from the chuck and tool), where in the rotation the forces were applied and then what and where the piece hit before bouncing. Seems to me for it to fly very far to the left or right would take a significant strong side force, say from striking something like the tool rest just "right", and then perhaps striking something else.

Also, unless you pry the piece out of the chuck with a catch or aggressive cut, the most likely time for a piece to come off is when spinning up. The best advice I've heard is to always always always stand to the side of the plane when spinning up something other than a finial or miniature.

JKJ

[Stan Calow]

JKJ "I've always assumed everyone knew what line of fire meant". That's just it. I know what it literally means - enough that you got my attention! Its the lack of specificity after that. It could be in any direction? That would mean no place is safe to stand. Always perpendicular to the rotation? Is it different for a spindle or end grain turning, from a bowl? Yes a few diagrams for beginners would be appropriate.

Just my pet peeve. Some of those books and videos spend more time talking about how the author likes to grind his gouges, than they do about safety.

[John K Jordan]

JKJ "...It could be in any direction? That would mean no place is safe to stand. Always perpendicular to the rotation? Is it different for a spindle or end grain turning, from a bowl? Yes a few diagrams for beginners would be appropriate.


As I tried to say, it is perpendicular to the rotation unless something changes it, but it can't really change much unless it hits and bounces sideways. So no place is "safe", that's why we wear face and eye protection when turning (and grinding, and hammering, and...). Fortunately, each bounce will absorb some energy so I think even a rare side bounce would be far less damaging than a direct strike in the "line of fire."

As someone mentioned, the safety cage is your real protection from the face smashing potential of large wood. I enjoy turning smaller things so I rarely turn large blanks. When I do, I use the tailstock (hard for a piece to come loose that way) until most of the mass is removed. If that wasn't possible for some reason I'd use the safety cage. One came with all of my larger lathes. (And I know where they are!)

Those I know who turn really large blanks outboard hold the with a large faceplate with lots of screws.

I've done a LOT of spindle turning. I've never had one come off the lathe but I have had them break - the pieces just fall harmlessly. Even at high speed there is very little kinetic energy in a thin spinning mass, nothing to compare to that in a large diameter mass. (a physics calculation will show this) If a typical spindle somehow did come loose it would simply spin and fall harmlessly. Spindle turners sometimes don't even stop the lathe when turning between centers but just back off the tailstock and catch the finished piece and mount the next blank while the lathe is spinning. I do this sometimes just to check the work without having to wait for the lathe to spin down - just catch it with my hand as the drive center disengages and it stops instantly.

Even though a spindle wouldn't break your face, it is still very important to wear eye protection since even a small chip could be painful or damaging. We have the kids wear face masks for everything, even if turning something small or sanding.

397845 397846 397847

I think end grain pieces of substantial diameter (boxes, vessels) should be respected the same as bowl blanks since they can have a lot more energy than thinner spindles, i.e. use a lower speed, wear face protection. Where the cutoff point is between a thin and thick spindle is a matter of judgement. For beginners I always provide a face shield. After they are more experienced they can decide for themselves.

397848

JKJ

[Reed Gray]

Things that come flying off the lathe..... Well, a bad mount for one will do it, especially if you have a catch..... Unbalanced piece and too high speed, there was a tale of Dave Ellsworth sending a bowl blank through a wall when the AAW Symposium was at UC Davis many years ago because he didn't check the speed setting first before turning on the lathe. Turning a piece of wood that has defects in it, no matter if you can see them or not. No matter what, stand out of the line of fire....

https://www.youtube.com/watch?v=F4qIM_-Jzgk

robo hippy

[John K Jordan]

Well there you go, Reed posted a link to his video talking about the line of fire and where to stand for various bowl cuts with a scraper. Not exactly what you were looking for but perhaps useful. https://sawmillcreek.org/showthread.php?269780-Dangers-from-wood-flying-off-the-lathe&p=2871583#post2871583



Maybe what is missing in books and videos regarding safety, is showing where the pieces are likely to go, and how to tell when and what situations are more likely to cause a workpiece to explode. I think the only common discussion in beginners' books is a cryptic statement like "stay out of the line of fire" but no description of what the line of fire is - left, right, center, etc. Does that change based on what you're turning, the tool in use, the method of holding, etc. Advanced and intermediate books assume you already know.

I think the helmet is a good idea, but a rocket to the chest or somewhere worse, is not fun either.

[Brian Deakin]

You may find the information in the links below helpful

https://vimeo.com/68649135

https://vimeo.com/68649130

and
https://www.youtube.com/watch?v=N7BjRcSDurM&t=2274s

[Randy Hogan]

I'm pretty much a newbie myself and I've had 2 come off the lathe. One at 1400 rpm and one at 2200 rpm. Both had cracks or defects I didn't catch and both came apart when they came off. And I would say being struck by one of the pieces could be life threatening. All kidding aside.

[John K Jordan]

I'm pretty much a newbie myself and I've had 2 come off the lathe. One at 1400 rpm and one at 2200 rpm. Both had cracks or defects I didn't catch and both came apart when they came off. And I would say being struck by one of the pieces could be life threatening. No kidding aside.

Yikes! I'm glad you were not hit!!! 1400 rpm may be fine with a smaller diameter piece, depending on the shape.

I know a lot of people like to turn things with a lot of voids, bark inclusions, and other defects and they can look great. But they scare me - I don't even like to turn pieces with hairline cracks.

A friend of mine turned large bowls with so many voids there was no way they could stay together when hollowing the inside. He came up with a method: He first turned the outside outboard at a slow speed, easier to stay well out of the "line of fire" just in case. Then before hollowing out the bowl he wrapped the entire outside with overlapping layers of nylon-reinforced "strapping" tape. This held the piece together when the inside support was cut away.

JKJ

[Michael Mills]

Back when I started I had the letters SSS taped to the headstock as a check list until it became habit. It is now 6 S's. Even though the last is a bit in jest after watching some youtube videos I had to add "try not to do anything stupid".

Speed is the biggest culprit IMO.

1st. Speed. Always check first or go to lowest setting. Also check rotation if you have reverse.

2nd. Security. Faceplate screws, chuck jaw screws, proper fit of jaws to blank, Headstock locked down,
Tailstock locked down, Quill locked unless drilling. Drives – 2 or 4 prong/spur properly set.

3rd. Soundness. Wood soundness. Cracks, voids, punky (rot), inclusions, or other defects. May need to stop and check during turning.

4th. Safety. A+ rating eyewear or faceshields. Sleeves up using bungies/garters (if necessary). Hair tied back. Proper dust mask as needed.
Nothing underfoot like cords, wax (from initial returning), or excessive shavings. Standing out of the line of fire.

5th. Sharpness. I know lots of folks place this first. Generally dull tools just make for an unpleasant experience and beat you to death in turning compared to maybe a dull tool (knife) when whittling.

6th. Stupidity. Don't be stupid.

[Dale Bonertz]

As stated there are many variables to the line of fire. As a general rule it is a cone shape coming off the front (rim) and back (chuck, face plate or holding method) of a bowl/piece all the way around the rotation of said piece. I say general rule since ricocheting and fluttering could become a factor. The faster your spinning generally makes that cone a bit tighter since the velocity flings it quicker thus straighter line from the holding method to the rim as referenced by what Robo shows in his video. The thinner (wall thickness) the bowl becomes the cone shape becomes more like a funnel shape. This is because velocity will want to throw it straight however you have the effect of air catching the lighter piece or the piece shatters which can make the piece wobble/flutter more (watch a bird glide with their wings set and how winds can make them wobble/flutter and change direction a bit in flight). These things happen fast and most times we as humans wince and close our eyes as its happening.

Other variables are the heavier the piece, if it comes out of your holding method, the more likely it will be drop down from a 3 o'clock to 9 o'clock area. In other words it will drop or go down rather than up due to the weight (again reference Robo's video). Don't be fooled though because that is generally and not always. In Robo's video his came loose at a bark inclusion or damage from a storm and not from his holding method. Those types of objects can come free in any spot around the rotation meaning if it came free at the 12:00 point in rotation it could very well come right at your head if you are standing in that cone line of fire. As everyone says the best method is do not stand in the line of fire as the best option for safety. Just try to understand some forces from weight, size, speed and etc. to understand the higher risk "line of fire" areas for the piece you're turning and where you are in the turning process. This is hard for newer turners so I agree this subject could be covered much better in books and demonstrations. Those who have been turning longer understand these areas of expectations of where something most likely will go if it comes loose, unfortunately by experience from it happening and not by some divine knowledge.

[Randy Heinemann]

An interesting bunch of responses to my post and I appreciate the useful information, especially the link to Reed Gray's video. I will watch that as he always provides very useful information. To be clear, I take all the precautions I know about, including:

Cutting almost all my blanks round.
Cutting a dovetail shaped recess in the bottom of my bowls that matches my Nova jaws.
Not turning at excessively high speeds.
Standing to the "right" of the blank or, when turning the inside way toward the right side of the lathe.
Learning how to turn with either hand so I don't put myself in front of the blank very much.
When I feel any vibration which I think is abnormal, I shut off the lathe and check if the blank is secure.
Wear the Airshield every time I turn.

So I am doing quite a bit already. Just wondered about other resources which might be out there that would give me a check on whether I'm missing something.

The only bowls that have come off the lathe for me were small ones which I believe didn't have deep enough recesses, thus causing the wood around the recess to crack.

[Randy Heinemann]

Watched the video. Another great one! I have questions about speed. I mostly turn in the mid-range of a 3-step midi-lathe. I have electronic control over the speed on this step from about 550 to 1,400 rpms. Since I cut my blanks round I usually start a little above the bottom end and, for small bowls up to 5", may end up close to the top end of that range to finish. Does that sound like a reasonable speed for those bowl sizes? What about 5" - 8" bowls? 8" -12" bowls? I know there are a lot of factors but what would generally be recommended for those two size ranges?

[robert baccus]

Buy new gouges with "long and strong" shafts--maybe 3" or so.

[Perry Hilbert Jr]

Ft pounds of energy = mass x (velocity squared) Though we are not speaking of sonic velocities as in the case of a bullet, we are talking 5 or 10 pounds at up to 20 miles per hour. OUCH. Still can fracture an orbital bone, take out an eye, necessitate nasal reconstruction, even cause a severe concussion. For that reason, I have a special steel basket that prevents the piece from hitting me.

[Randy Heinemann]

Not sure how that helps but I already own “ long and strong” gouges.

[Randy McCreight]

I started woodturning at my local community college several years ago. After the semester ended, I was searching online for more information about bowl turning. I stumbled on Lynn Yamaguchi's story of her very bad accident while turning a bowl. It nearly persuaded me to stop turning! Very sobering, indeed.
Start here for her story: http://lynneyamaguchi.com/index.php/category/accident-recovery/
She has calculated how strong a face protector must be to stop a high speed projectile.

[Fred Belknap]

Several years ago I got hit in the chest with a coring that broke free before I thought it was ready. It knocked the wind out of me and sent me to my knees. I'm glad it didn't hit my face shield.

[Sam Beagle]

Everyone takes off there metal cage on the 3520. I would never turn without mine. It saved me big time just 2 days ago. Had a plum piece blow apart at 1500 rpms

[Stan Calow]

After reviewing the whole thread, it occurred to me to ask why face shields don't seem to provide any protection for the throat, and no one has come up with some padded aprons or chest (and, uhh, lower) protection. If there is equipment like that, please point it out. Police riot shields seem unwieldy. If there aren't such things, it seems like a design opportunity for some smart person.

[Richard Coers]

After reviewing the whole thread, it occurred to me to ask why face shields don't seem to provide any protection for the throat, and no one has come up with some padded aprons or chest (and, uhh, lower) protection. If there is equipment like that, please point it out. Police riot shields seem unwieldy. If there aren't such things, it seems like a design opportunity for some smart person.

Can't visualize how any traditional turner would need protection below the belt. Do you stand on a stool? Maybe use a wheelchair? Once saw a very early David Ellsworth demo where he would sit on the bed of the lathe to hollow. Hockey masks are also a choice for better face protection, and goalie mask if you want throat protection. Buying a lathe with a wire cage over the work may be another choice to handle your concerns.

[Stan Calow]

Thanks Richard, if the consensus of experienced turners is thatadditional protection for the throat has not been found necessary, I'll respect that. I'll re-examine my setup, looking at that cone of the line of fire versus the "area of concern". But I would have thought at least chest protection would be a given.