Safety

[finneyb]

There has been an accident -reported on a US site I visit. Basically, a 12" platter has blown up and the turner was seriously injured ie hospitalised. There are no details of speed, did he get a catch etc but there is discussion going on that seems to be focussing an face shields. To be frank they are missing the point, I must admit to being irritated because they have been told by others that face shields will not protect from a blow up but they keep going on about face shields.

I posted this below, I thought it was worth repeating here:

The ANSI (American National Standards - UK's equivalent would be BS or EN) test as described must be testing the ability to protect from small projectiles that would cause damage to the eye or face. The hazard of a piece blowing up needs to be addressed by other means, including:

1. Using appropriate speed. The formula diameter in inches x rpm = 6000 -9000 works and was used before face shields where available. Even using the formula a further reduction in speed is appropriate if the piece is not round, off centre etc. For roughing use 6000 in the formula; for finishing cut use 9000 in the formula when everything is symmetrical; and something in between for general turning.

2. Stand out of the line of fire

3. Listening for sound changes etc.

4. Wrapping doubtful pieces in tape or similar.

5 Not turning that piece if you are at all concerned - there is not a shortage of wood, pick another piece it’s far cheaper.

A flimsy piece of plastic tested to ANSI isn't going to save you for a lump coming off - it is NOT Bionic. But it may protect your eyes and is therefore essential.

Brian

 

[jpt]

I would disagree that a face shield wont protect you if a piece blows up, in my experience it will.

I was turning an 15" platter and went too deep and parted off the piece.


The piece came off the lathe hit my face mask then embedded itself in the roof insulation. There was only minor damage to the face mask as can be seen in the photo below just to the left of the press stud on the bottom of the mask you can see a white line where the piece hit the mask. I neede to buy a new shield but apart from that no damage to me.


I never turn without wearing one.

john

 

[finneyb]

John,

That is something more than a face shield.
You could ride a motorbike with that helmet.

Brian

 

[Paul Hannaby]

Brian,
The ANSI and EN tests are designed to test the visor / goggles are capable of withstanding an impact from a flying object. The protection offered varies so it pays to check what you are using. I agree with what you are saying about taking precautions but that shouldn't be instead of using a visor, it should be as well as.

I have two visors on my workshop, one is ANSI Z87+ and the other is EN166 1B. The Z87+ is described as high impact and the EN166 1B is described as medium impact but both these are above the basic (Z87 and EN166 1F) low impact standards and offer greater protection.

As JPT already pointed out, his Airshield (which has a low impact EN166 1F visor) didn't break when hit by a flying object so it did some good but personally, I prefer to use the higher protection visors available so I wouldn't use an Airshield.

I'm not suggesting any visor is going to protect you against everything but using the right one definitely improves your chances of survival.

 

[finneyb]

Paul,

I'm not saying don't wear the face shield.
You need to take further measure upstream of the piece blowing up, then hopefully you don't test the face shield.

An extract from the US posting
'.....was badly injured when a plate he was turning flew off of the lathe and hit him in the head. (at least this is what the police and I were able to reconstruct. We found a few pieces of the plate but not all of them) Fractured skull, eye orbit fracture. He had facial reconstructive surgery and a plate in the frontal skull bone as the bone was shattered) on Saturday and had been in a drug induced coma until Sunday. He improved tremendously yesterday, but doesn't remember anything about the accident, except the fact that the plate he was turning was beautiful wood!
He had his helmet on and it was broken as we found pieces in the shop.'


Brian

 

[jpt]

HI Paul

You got me worried for a few moments there as when I brought the airshield I am sure I was told it was medium impact. I have just been out to check it and the visore is marked as BS EN166 1B3.

I also have a high impact face shield for those extra tricky jobs.

I agree a face shield is not the only answer you need common sense as well to try and prevent any problems before they happen but a face shield of the correct type goes a long way to stopping injury if the worse happens.

JOHN

 

[Sheptonphil]

Paul,

I'm saying don't wear the face shield.
You need to take further measure upstream of the piece blowing up, then hopefully you don't test the face shield.

Brian

I really can't understand that statement. :?: Don't wear the face shield!

After taking further measures upstream, and HOPEFULLY you won't test the faceshield.

I wouldn't dream of turning without mine, it doesn't mean I am going to be less careful, just if the wood blows because of a defect at least I have protection. By the same token should we all not wear seat belts and just drive more carefully, ignoring that ice may just throw the equation slightly?

Phil

 

[finneyb]

Phil,

Apologies - I missed the word 'not' out.
That's why you couldn't understand it.
I've now edited the original.

For the avoidance of doubt - I'm saying wear the face shield at all times. BUT do the other precautions so that hopefully the face shield will not have to be used in anger.

Brian

 

[Sheptonphil]

Thanks for edit, I thought this was a new anti H&S method. :?

Phil

 

[Roger C]

Hi Brian I agree with your 5 suggestions except the tape rather hot melt glue. the problem I have with all the stories of exploding turnings nobody says where the person was standing when it occurred. John maybe you would like to tell us where you were standing and where was the tool rest when the platter hit the shield. The other thing that gets my hair up is the placement of the on/off switch. I note that a lot of lathes have it on the head stock or close to it.So when the proverbial starts to hit the fan you are going to be in the firing line trying to get to the switch. I have two on/off switches on my lathe one half way between h & t stock and the other below the tale stock, mounted on the railway sleeper the lathe is bolted to and both have to be on to operate lathe, any one of the switches can be used to switch off. regards Roger C

 

[finneyb]

Roger,

I have seen lathes with a fixed AND a moveable on/off switch in a magnetic box - some movable switches also have a speed control. I think the movable switch is worthwhile. What concerns me, as the movable will be an add-on, is the wiring-in of the movable switch. Did you fit your own second switch?

I have an Axminster AWVSWL 1200D, any experience of wiring a second switch into one?

Brian

 

[YewTube]

Brian

You can rig an emergency OFF switch by getting an extension cable with a switched socket. Plug your lathe into it and place it at the tail end of the lathe. It won't work as an ON/OFF switch for regular use as your NVR switch will trip out but it will save you an underwear change if everything goes pear shaped.

Bill

 

[finneyb]

Bill,

I like your thinking.
I would prefer a mushroom type

, rather than a switch, located at the tailstock end.

Do you know if this would work if I wired it in between the wall socket and the lathe's NVR switch, as you suggest for the switched socket.
In particular, will it take the earth wire

Brian

 

[YewTube]

Brian
I have one of those on my lathe. I have wired from wall socket, through the mushroom switch to a socket. Both the mushroom switch and the socket are next to one another and fastened on the tailstock end of the lathe. You can run the earth through the mushroom switch to the socket if there is no provision for the earth. The lathe is plugged in to the socket.
I have placed them at waist height so that I can use my hip to kill the power.

Bill

 

[finneyb]

Bill,

That look likes a solution, thanks.

Brian

 

[Paul Hannaby]

Bear in mind that if you have a variable speed lathe, it may take a lot longer to stop if you just kill the power instead of using the inverter controls. This may be more dangerous than using the usual stop control. A better alternative, albeit slightly more complex to connect, would be something that replicated the stop control but used the quick access emergency stop button.

 

[finneyb]

Paul,

I do have a variable speed lathe and I see what you're saying. I'll do a test tomorrow - stop with the NVR button and then by pulling the wall socket, (had a beer tonight so can't do it now, been walking today and deserve it!) and see what the difference is.

Can't immediately see how to wire into the NVR button - will need look tomorrow.

Brian

 

[YewTube]

Brian

Let's not get confused here. The solution with the mushroom button is an EMERGENCY STOP. It will work under all circumstances and it will work with all lathes. It will work if the inverter fails, if the lathe becomes live, a bowl breaks apart, if you get an appendage trapped, e.t.c.

You can make a remote flying lead by getting an instruction manual for the inverter fitted to your lathe and duplicating the controls. The speed, on/off and reverse functions are controlled by low voltage signals to a terminal strip on the inverter. Needless to say you can kiss your warranty goodbye. I would only attempt this if you know what you are doing and understand electrical circuits.

The NVR button is a fancy on/off switch and provides power to the inverter according to the manual. (downloadable from Axminster)

Bill

 

[finneyb]

Bill & Paul,

1. Just did the test of stopping by pressing the NVR and stopping by pulling the wall socket - there was no difference that I could see.

2. Bill, I realise that a flying lead is a 'nice to have' but would involve infringing the inverter warranty - that simply is not going to happen. If the lathe had a DOL (Direct on Line) starter there appears to be a chance of adding a flying lead. BUT lathe, as most other modern lathes except top of range, has a Low Priced NVR - see next point.

3. Did some reading last night and found this paper 'http://homepage.ntlworld.com/bob.minchin/Induction motors - Issue2.pdf ' Use of Induction Motors in the Home Workshop by R C Minchin. Page 17 Low Priced NVRs, see below, is interesting in that it states categorically that Low Priced NVR's cannot have a remote start stop (I suspect because there is nowhere to connect to - which was the problem I was having).

4. The solution I'm taking is a red mushroom button near the tailstock to cut the mains supply.

Bill & Paul thanks for your help

Brian

Extract from paper
' Low Priced NVRs
With the drive for ever-lower manufacturing costs there are some NVRs coming on the market with slight different arrangements. It is now quite common for the start button to act mechanically onto the main power switch which saves a small amount of internal wiring and in some cases the stop button works similarly. There is nothing fundamentally wrong with this approach apart from removing the ability to have remote start and stop buttons that was always an option with the DOL starters shown above.'

 

[YewTube]

Brian

The DOL/NVR switch cuts power to the inverter. It will need to reboot every time you cut the power to it and will revert to its default settings (including speed).

I have have an all singing and dancing Dremel with torque control, digital speed control and the works. Thought I would make a foot control switch for it so that I could use both hands when using it. Took me an age to figure out why the speed went down every time I switched it off. Reason was that it was rebooting to the low default speed. Now, on the other hand, my £18 version from LIDLs works a treat.

Bill