View Full Version : Machining dangers

Ron Horton
11-17-2006, 05:58 PM
Greetings to all-- Getting close to lighting off my new mill, and after reading your informative posts, I got to wondering--What is/are the most dangerous things that can happen during machining operations-- I don't mean cuts, burns, foreign bodies in eyes, but really dangerous things to look out for, or not to do-- High speed projectiles come to mind-- If something wrong can be done out of ignorance, I can usually find a way to magnify it--
Thanx, and Best regards, Ron

On the other hand, we have, the other hand--

A.K. Boomer
11-17-2006, 06:16 PM
I would say besides stuff like fiddling with your step pulleys and bumping your start switch at the same time/and or leaving your draw bar box end wrench on and fireing up your mill in low -------- My general rule of thumb is as the diameter of your tooling increases so does your danger, whether your holding tooling or material (I have a 3 jaw R8 chuck so this applies to material on my mill also )--- the larger things get the more attention you need to pay on the task at hand, and make it a must to go through your check list before turning on the start switch, is your collet tight, is your drawbar where it belongs, is the part clamped properly and on and on...

11-17-2006, 06:50 PM
wear safety glasses. double check all your setups. keep yuor free hand in your pocket. wear safety glasses

11-17-2006, 07:25 PM
Dont walk barefoot in the shop, especially around the mill and grinder.
The drill press is VERY dangerous, clamp your work down!
Don't try to touch a fly cutter at speed with your tongue to show off to your friends.
Honestly, the drill press, leaving a chuck key in the lathe, stock out the end of a lathe whipping around, long trails of sworf slicing your fingers off, etc.

11-17-2006, 07:37 PM
Don't wear gloves.
Don't wear long-sleeve shirts.
Don't wear neck-ties.

Oh dear, here's where Evan shows his machine room attire. :eek:

Don't point at a running bit to show your friends.
Don't get the wife mad.

11-17-2006, 07:51 PM
leave shoes in work shop, dont bring them out.
i have a nasty batch of shaper chips that are like a fish hookand thicker
but with 100 barbs that turn up in al sorts of places , like at work , relatives houses ............

bolt it down on the drill press .

install foot kick switches wherever you can.

if youve got all yer fingers then keep them on

he who dies with the most fingers wins .

11-17-2006, 08:14 PM
Today I switched to carbide inserts on the lathe...with a fancy factory toolholder and everything.
Yes...I can hand grind HSS bits very well and will keep using them.
However...my new "helper"...damn near got (pick one) a finger or fingers or hand cut off the other day.
We were using brazed carbide bits at fairly low rpm. A long curly ribbon was coming off and piling itself behind the toolpost right into the chip pan where it should have.
All of a sudden the ribbon shot straight out towards us (I WAS keeping an eye on what she was doing), she put her hand out to stop it from hitting her and it almost started wrapping itself around her hand.
I stopped the works and everything was ok...but this could have been a real mess.
Only thing I can figure is the steel heated up and changed the tool pressure or perhaps there was some chip welding going on that changed the direction of the ugly, razor sharp ribbon.
She's only allowed to used inserts with chipbreakers now.
Once she's more comfortable with operating the lathe I'll teach her how to use HSS, etc.
Times like this I wish I had my ol' SB9....great machine for a beginner!

john hobdeclipe
11-17-2006, 08:18 PM
On the other hand, we have, the other hand--

keep it that way

In my years of working with large, production woodworking machinery, I learned to always try to think of everything that can go wrong and how it can happen, then fix it. Don't "assume" anything. And when something does go wrong, stop and analyze how it happened, and figure out what to do to keep it from happening again

And slow down, take your time. Think.

And do all of this with your safety glasses on!

Herm Williams
11-17-2006, 08:51 PM
No rags larger than 6 in sq., no sanding strips longer than 6 inches. No rings.

11-17-2006, 09:05 PM
I am reminded of this story now. One day I went to look at a used Bridgeport mill that the guy clearly lied about. When I got there, the price suddenly went from 100$ to 600$ and the side mounts of the table that support the leadscrew and wheels for the X axis were missing. He said thats just the nature of the machine. Knowing full well this jack ass lied to me on the phone and thought I was an idiot, I went along with it, to waste as much as his time as I possibly could. I had him thinking I was going to take everything he had off his hands. Well He didn't have any hands, he had 2 hooks. I can only imagine what he did to get that way.
Anyhow I felt VERY good when I told him, "hey , I'll give ya a call after I think about it." I could hear him cursing to his friend on the phone as I was walking out to my car.
Asshat lies to me? Yeh Im gonna have some fun.

11-17-2006, 09:52 PM
No long hair,a man will fit between the chuck and column on a drillpress,I witnessed that.I also witnessed the aftermath of someone getting the're hair sucked into a benchgrinder that was running a wire wheel,guy's head busted the guard on the grinder before a hanful size chuck came out.

11-17-2006, 10:02 PM
Years ago I let a large drill bit get ahold of a brass fitting I had mounted up in a drill vise. The vise took off and whacked me in the hand at least 3 times before I got it outa there. I know cuz I was bleeding in 3 places!


11-17-2006, 11:31 PM
Oh dear, here's where Evan shows his machine room attire.

Let's just say that you don't want to leave anything hanging out that could get caught on something. :D

Back when I actually had hair there was a time when I wore it pretty long, like pony tail partway down my back. One day I was working on a high speed document handler on a big copier (BIG) with the covers off and the interlocks cheated. I was cycling it which is constant running. My hair drifted over and caught in a shaft. Before I could blink it yanked my head down and bashed it against the document handler. Fortunately that knocked loose the interlock cheater and it stopped immediately. It wasn't easy unwinding my hair from the shaft as I was forced to do so while looking up at a 45 degree angle at the ceiling.

11-17-2006, 11:44 PM
SP made a good point that I would have forgotten. Remember the softer material will grab. Another words if your dilling a piece of soft brass or aluminum, it needs to be held down a lot tighter than the same item if it was steel.

11-18-2006, 12:19 AM
I think the most important thing is that whenever you have a bad feeling about a setup or job simply stop and think about it. If something is running and doesn't feel right stop it right then and figure out what's happening. It's faster in the long run to setup the work properly than to do it all halfa**ed and have to bandage yourself or redo the ruined work. I think I've ruined more work and caused more damage to myself by not doing those things than anything else. Still have all 8 fingers and both thumbs, though.

Oh, yeah, just as soon as you get complacent with a machine it'll bite you. Grinders are not your friend, bandsaws go through thumbs a lot faster than 1" steel, lathes will fling setup tooling that wasn't bolted down, mills are more than happy to pull your thunb through the endmill with the rag you had in your hand.

A.K. Boomer
11-18-2006, 01:14 AM
mills are more than happy to pull your thunb through the endmill with the rag you had in your hand.

That one just shook me up a little, i could see that happening in a blink of an eye (an eye covered with safety glasses that is)

iv used little scraps of rags and i think im even going to knock that off...

and I know its already been mentioned but watch out for long strands of machined material coming off of lathe operations, get to know what kind of material is bad (like 304 SS, nasty stuff and will think nothing of taking a finger right down to the bone as quick as a razor blade...)

11-18-2006, 03:17 AM
Lightly hold your chip or oiling brush with your thumb and index finger, this way if it were to grab it will easily slip out of your hands. Get good quality safety glasses that you can wear for hours on end, especially if you don't wear regular glasses. Keep the floor clean of anything slippery and wear non-slip shoes. Set up your machines so that no one can walk up behind you, if that's not possible put up a chain with a warning sign. In my shop at work no one is even allowed to speak to me let alone walk up on me with a machine running. Make this clear to everyone. By boss startled me one day from behind, I nearly fell into my big lathe! Big signs and chains went up the next day.

Your Old Dog
11-18-2006, 07:30 AM
If someone already mentioned this one i didn't read it.

When running the lathe in reverse you should always bring the tailstock into play. To not do that sets up a situation where the chuck can unscrew itself from the headstock and start making its rounds of the room at high speed :D

I keep long nose pliers on my lathe to remove long chip curls from the cutter.

I never stand inline with anything that is spinning up to speed like grinding wheels or lathe chucks with oil in them.

Don't bring two sides of the shops electrical circuits where you can get across both sides (220V). As an example, don't run you lathe off one side of the 220 line and then run a small lathe mounted grinder on the other side of the 220 line. If there is a problem you come come incontact with 220.

Pay attention to what you're doing. I don't do any machine operations while I hve company in the shop. I can't talk and run the lathe or mill at the same time. things happen fast.

Tin Falcon
11-18-2006, 11:42 AM
Here is a good list not all inclusive but covers most of the basics some have already been covered.

Machine Shop Safety

• Safety Glasses
Even when you're not working on a machine, you must wear safety glasses. A chip from a machine someone else is working on could fly into your eye.
• Wear Hearing Protection as required (If you have to raise your voice to speak to someone 3 ft away hearing protection should be worn).
• Clothes and Hair
• Check your clothes and hair before you walk into the shop. In particular:
If your hair is caught in spinning machinery, it will be pulled out if you're lucky. If you're unlucky, you will be pulled into the machine.
Roll up sleeves. Neckties, scarves, loose sleeves, etc. are prohibited
No open toed sandals. Wear shoes that give a sure footing. If you are working with heavy objects, steel toes are recommended.
• Safe Conduct in the Shop
Be aware of what's going on around you. For example, be careful not to bump into someone while they're cutting with the bandsaw (they could lose a finger!).
• Keep Machinery Area Clear. Do not put unneeded items on or around machines.
• Keep Walkways Clear. Remove tripping hazards, and clean spills up immediately.
• Concentrate on what you're doing.
• Don't hurry. If you catch yourself rushing, slow down.
• Don't rush speeds and feeds. You'll end up damaging your part, the tools, and maybe the machine itself.
• Listen to the machine. If something doesn't sound right, turn the machine off.
• Don't attempt to measure a part that's moving.
• Don't let someone else talk you into doing something dangerous.
• If someone speaks to you while you’re running a machine, keep your eyes on your machine and not on the person.
• If you get tired or are feeling ill, turn machine off and advise the instructor.
• Machining
• Study the machine. Know which parts move, which are stationary, and which are sharp.
• Double check that your work piece and tool are securely held.
• Remove chuck keys and wrenches.
• Use no rags on machinery while it is in operation and/or in use.
• Do not place any tools or other metal objects on machine ways.
• Do not clear chips from machines with bare hands. Use pliers or a chip brush.
A dirty machine is unsafe and uncomfortable to work on. Do NOT use compressed air to blow machines clean! This endangers people's eyes and can force dirt into machine bearings.

Do not grind aluminum or brass on a grinding wheel
Regards Tin

11-18-2006, 05:53 PM
V-belts will take off fingers as quickly as tool bits will. Keep the guards on.

Check your machine's grounding. The guy who rigged up the outlets in your shop may not have understood grounds very well. Check drum switches on your bigger machinery carefully to see that the grounds are NOT switched (grounds which aren't connected don't do you any good at all). Not all electricians understand drum switches very well. If the grounds aren't right, don't use the machine until they are.

If you have a rotary converter for 3-phase, depending on the exact circuit you may want to turn it off when leaving the shop even for short periods. Some rotaries will stop in case of a momentary power failure, but not restart properly, and will draw their starting currents until your shop fills with smoke.

If your shop is big enough to have a fork lift around, don't let anybody use it. Fork lifts may cause more serious injuries than all other shop equipment added together.

Keep the floor clear near the machines. New stock, cutoffs, swarf, etc. will trip you. Especially the cutoffs you've just made.

And here's one which really saved my cookies on one particular occasion. When carrying something heavy - say, a 150 pound rotary table - make the conscious decision before picking it up that if you start to lose it for any reason, just let it go and don't try to save it. Concentrate on keeping your feet and hands from ending up under it. A new rotary table is far cheaper than surgery and rehab for your foot or hand.

11-18-2006, 10:19 PM
Had a cut-off disc shatter in the angle grinder (5"). No big deal, grinder guard and safety specs saved any injury. A shard of the disc sliced through an air hose, which then started lashing around like a demented serpent, throwing swarf everywhere. If you've got compressed air in the shop, wear eye protection AT ALL TIMES.
Rgds, Lin

11-18-2006, 10:41 PM
Watch Orange county Choppers, anything they do, YOU DON'T.. OKAY?

I hollered at my wife while thumbing the channels, CARROL come watch this.. the boy, had a piece of aluminum boring a hole, holding the part by hand.. NOW 2 horsepower motor, with belt reduction torque increase.. yep.. took it right away from him.. and some skin.. I understand now, it's a sitcom..

Ya don't spit into the wind, don't pull the mask off the Lone ranger and ya don't mess around with Jim.. (Jim Croce?)

11-19-2006, 02:44 AM
Jim Croce, alright. Don't catch a 600 lb. bar while it is falling off a forklift. It was catch it, or have it impale me against a concrete wall. You don't walk so good after that. Well, nothing's so good after that.

A.K. Boomer
11-19-2006, 12:15 PM
Speaking of forklifts; I had my mill delivered to my bro's shop because he has a lift, i was disassembling my mill and moving things around like a mad man, had to use the lift with a strap to move the mill head to where i wanted it, get done and unhitch it and go do something else, walk back to the lift and something makes me stop (musta seen it out of the corner of my eye) heres the fork lift tongs at eye level and i almost ran into them,, would have been ugly because i was at a brisk pace --- Always put your lift all the way down no matter how brief you think you will be back to use it! so easy to forget,,, maybe even paint them bright yellow or orange once in awhile too...

Im real lucky i seen that one at the last second..

john hobdeclipe
11-19-2006, 07:25 PM
Think about fire. Look around your work area and think of the possibilities for a fire to get started, and plan what you would do. Be sure to have fully charged, functional fire extinguishers at each potential exit (that includes windows) and make sure that you have a clear path to these exits at all times.

Think about where stuff is in your shop. We all have at least some flammable solvents in our shops. I have lacquer thinner, mineral spirits, paint stripper, adhesive remover, alcohol, etc. and it stays in the corner away from the exit.

Considering windows as possible emergency exits, be sure you can get them open in a hurry, and that if you have to go out the window, that there is something reasonably safe to land on...not a pile of scrap, broken parts, big rocks, or a cactus garden!

How quickly and easily can you get to the circuit breaker panel? And once there, are you then trapped?

Think about it.

Think about ignition sources...grinding sparks, cutting & welding sparks, electrical malfunctions, . When you use a handheld grinder, where are all those sparks going, and what's over there that may ignite?

Ed Tipton
11-19-2006, 07:50 PM
OK guys, here goes...In the valve shop for Mueller valves in Decatur, Il. They did have a very good safety program, and one of the safety issues was the wearing of hair nets.
We had one very competant female operator who was running a Leland-Gifford drill press, without her hair net on. She did nothing wrong other than not wearing her hairnet. One of the other workers unknowingly came up behine her and plugged in a floor fan, which immediately blew her hair into the drill press. Nasty scene!! She got mangled pretty good, and missed several months of work, and required extensive plastic surgery before returning to the plant.
When it happens, it happens fast! And if others are present, you need not necessarily do anything wrong.
On the flip side, I am almost always alone when in my shop, and I have to admit, I do sometimes cut corners where safety is concerned. I am cautious by nature, and I do still have all my fingers, toes and appendages, and most of my hearing, vision, and hair. Well vision and hearing anyway, but I am haunted by the prospect of suffering a severe injury, and nobody else being in the immediate area. Hopefully when it happens, I will scream loudly...and someone will hear and respond.:D

11-19-2006, 08:51 PM
One of the other workers unknowingly came up behine her and plugged in a floor fan, which immediately blew her hair into the drill press. Nasty scene!! She got mangled pretty good, and missed several months of work, and required extensive plastic surgery before returning to the plant.

"Unknowingly" ???, yeah right. I'd sue the company and the twit that turned on the fan for everything they had or will have then settle for half fault.

Joking around in a shop is careless negligence.

11-19-2006, 11:09 PM
"Unknowingly" ???, yeah right.

Not so easy to blame someone in every case. Just last week I was talking to a woman whose son - complete with long hair - had worked in a shop. He was standing, not operating anything, when he turned his head to look at something. Hair flew out a little bit behind him, not much but enough to catch in a drill press. This was an odd one, as it didn't pull his hair out or pull his head into the machine, it tore about half his scalp off - it was hanging on by a flap. He eventually recovered, but there are still scars on his scalp which won't grow hair.

Ron Horton
11-20-2006, 12:12 AM
Greetings to all-- Very informative posts here, shows there are many things to cause injury-- Thought I would share an incident I was involved in years ago (pre-OSHA)-- I was on the rescue truck and went to a reported electrocution at a shipyard-- Seems an electrician was working in a hot 480 V panel when another guy came up behind him and goosed him and shouted at the same time-- The screwdriver the electrician was using went away with a flash and a bang-- We got there and the electrician was OK, but we treated the other guy for a severly split eye-- I can still remember a large sign in that shop which said:
"HORSEPLAY NOT ALLOWED"-- A tough way too learn a lesson-- Best regards, Ron

On the other hand, we have, the other hand--

Ed Tipton
11-20-2006, 06:46 AM
Well, at the time it happened, it was felt by everyone that it was just an industrial accident, and that it was not due to an intentional or malicious act on anyones part. She did receive a cash settlement that i heard was pretty substantial, but she still suffered a horrible injury involving lots of time, money and pain.
The guy who did it was a friend of hers, and needless to say, he felt terrible about it. Nobody blamed him, and most people just filed it under the "**** happens" category.
I just told the story because I think it points out how things can happen even in a safety conscious environment. There was no horseplay involved, and everyone was just doing their job, but someone got injured.
As was previously stated, things happen fast. When you have people moving in and around equipment, especially rotating equipment, where there are cutting edges, tripping hazards, possibly less that adequate training, tons of pressure, flying objects (chips) etc. I think anyone can readily see the potential for an accident. There are precautions that can help, but it is wise to remember that the hazard is still there even if we respect it.
Here in our little town we have a very highly respected machinist who routinely does excellent work. He is highly thought of, and is careful and meticulous in his work, but he has only seven fingers. He lost three fingers in three separate accidents.
Just because you are good at your work, accidents can happen to you to.

There is no shortage of experts, the trick is knowing which one to listen to.:)

11-20-2006, 07:32 AM
Hi guys. All these horror stories bring to mind my days as an apprentice wood machinist when I left school (Too many years ago now)

Safety was ALWAYS paramount. I myself had to go to the local college one day a week on a H&S course.

However, accidents still happen.

In the shop was a 20 inch table saw, TCT tipped blade was fitted as standard as we worked with hardwoods, teak,mahogany,beech Etc.

One morning, I fitted a freshly re ground blade into the table saw and proceeded to slice up some 12" wide teak boards. (Try finding those these days without emtying your bank account)

Well, I guess someone must have had a sign or something nailed to this tree.
As The saw got halfway through. I heard a "whizzzzzz" noise.
I switched off the saw and isolated it to check the teeth on the blade. One was missing.
The wood had the remnants of a six inch nail in it...

I finally found the missing tooth....embedded in the brick wall behind me, a good twenty feet away.
Moral of story....

Just because you checked everything. Doesn't mean things won't go wrong.

Let's all be careful out there guys.

11-20-2006, 09:12 AM
The best safety advice for the shop that I've heard was right here.

Whenever you're doing something in the shop, especially when you're about to "flip the switch", think about what could happen. This goes a long way. Is that setup really stable? Are all the wrenches and chuck keys off the machine and where they belong? The list is endless.

I can't think of a single "oops" I've had in the shop that couldn't have been prevented with more of this kind of thinking.

Another "instinct" that I've taken a lifetime to develop goes like this: As I'm applying "strength" to a task, when I get to about half of the maximum force I'm physically able to apply, the hairs on the back of my neck stand up. Stop and think. There are very few tasks in my life that require my physical "100%", or even half of that. Especially when lifting something or turning a wrench. What are my knuckles going to smash into when the bolt breaks free, the wrench slips, or the part breaks? If it takes all I've got to lift or move it, maybe I should be using a "helper", be it mechanical or organic. We humans have a long history of developing things that allow us to work with stuff bigger and stronger than we are.

I'm scheduled to undergo back surgury next week because of such a lapse. I was standing, applying force, using a crowbar, and standing in an odd position. Twang! Now I have a fractured disk interfering with a nerve to my leg. I'm not crippled or anything, and it's mostly pain, rather than being debilitated. The surgury is expected to clear it up, and I should be back up to speed by the end of the year. But it sure is a stupid way to relearn the lesson.


11-20-2006, 09:42 PM
Always keep your shirt tucked in, not only will you look better, ha ha. One night real late in my shop, I was boring out 8" pipe collars half way, to slip on weld to old well heads, not rocket science(right), gett'in late I was tired & my denim welding shirt by now is hanging out, as I lay over the lathe look'in in the 9th collar I had turned, with one to go. Before I knew what was goin on the lead screw had my denim shirt tail, remember my leaning over the lathe position, ( don't ever do this ) with the shirt wrapping more, I go for the switch, by now which I can't reach, then the panic set in & I ripped loose, with minor bruses & scrapes. Picture this as I did after I got loose, its 2:00 AM, nobody's goin to stop in, the wifes a mile away at the house sleeping, when that machine started eating, it just wasn't going to stop. Since then, No more late nights, if your tired or in a hurry, go do something else, I have alot more RESPECT for all machines ever since.

Good Luck, & BE CAREFUL !!!!!!!!!!!!

11-21-2006, 05:38 PM
Lots of good advice here.

One thing us home shop guys have going for us is fewer people around. The danger seems to go up geometrically as the number of occupants increases.

In this usage 'occupant' includes nosy neighbors, curious squirrels, pets, belligerent spiders, etc., not just people actually doing something useful there.


Alistair Hosie
11-21-2006, 05:55 PM
I can usually find a way to magnify it--
do tell do tell that kind of information would be invaluable to his ludshup.

11-21-2006, 07:08 PM
Not sure what kind of mill you have but do be very very very careful if you have a setup that requires climb milling. If you can redo the setup to eliminate that it would be better. I have seen more parts fly due to climb milling than any other operation.

11-21-2006, 07:27 PM
Outstanding thread!
About a month ago I was stripping wire while adding some new limit switch wiring to my mill. I was just using a simple 15$ wire stripper/crimper tool.
I was in a hurry to finish it up.
I still have no idea how I did it but the very last wire I had to strip, somehow my hand slipped and I took the tip of my middle finger off as well as strip the wire. That was that. Instant trip to the ER.


11-23-2006, 10:59 AM
One late night in a hurry, I was leaning over the lathe, turning the thread out of a 8" pipe collar, to make slip on weld threads for old well heads. The untucked portion of my denim welding shirt, got wrapped on the lead screw, note my posture( leaning over the bed, tired, looking in the collar) this was the 9th collar for the night with 1 more to do! So I relize whats going on, now I can't reach the switch, Now panic sets in & I ripped loose with minor bruises & scrapes. Now thoughts are running wild, its 2:00 AM, alone, the wifes a mile away at the house sleeping !!!

So be sure and tuck in your shirt, ( besides you'll look neater to ) Be careful & enjoy, I have alot of respect for all machines since. If your tired go do something else!! Glenn,the lucky one!!!

11-24-2006, 12:09 AM
I have a habit of taking the cutting tool out of the lathe toolpost before unshipping a large workpiece. I you've ever dragged the back of your arm across a nicely sharpened hss toolbit, well, you get the picture. Working on little pieces, I'll just roll the carriage down out of the way. But if the piece is large enough to require my physical 'presence', then I just get the tool completely out of there before I get busy.