Is Knurling a health hazard?

I note that Knurling on items like gym equipment is regarded as a hygiene risk due to skin deposits left in the knurl harbouring bacteria. It maybe worth giving our knurled items a clean now and again. Probably a minimal risk but we often have cuts and scratches on our hands which could provide an easy entry for anything growing in our Knurling. As we are usually the sole user of our tools cross contamination is unlikely but it might save ourselves from something nasty to clean Knurling now and again.

Mike

Personally I've never really been bothered by it but I can see the logic in it, not only that but it just doesn't look very nice to make something and the knurl has already picked up a lot of dirt.

I'd just use a wire brush, or acetone is supposed to be very effective at removing grease, Then I've heard about people who lacquer metal which has a knurl.

Michael W

I used to design production jigs and fixtures for high volume parts and stopped using knurled many years ago. It is a health hazard if used every few seconds during an eight hour shift as it will wear into the skin. But for odd use in the model shop I wouldn't worry.

I fear that we will end up living in a totally sanitised world, until one year the whole human race will die because of our under-exercised immune systems.

More than one study has found children growing up on farms suffer fewer infections.

Neil

Exactly, . Couldn't agree more

In theory we already have a gigantic bacterial colony living within all our innards, so anyone who claims to be totally clean is a hypocrite. Our digestion actually relies on this happening in order to bolster the immune system.

Not only that but growing up on a farm would probably be a lot of fun for most kids, so they'd be more likely to feel well even on a bad day. 

Edited By Michael-w on 15/05/2017 23:14:52

It was a jig fitter that mentioned to me that Knurling is regarded as a hazard but a quick google only came up with the gym reference. What reminded me was I bought a used nippy vice and the knurl was pretty skanky so I skimmed it and re knurled. My mum always says we all eat a bit of dirt before we die, I think we do clean too much and we seem to be breeding a generation who have endless allergies to almost anything, something is going wrong somewhere. I rarely dress minor cuts and abrasions in the workshop and never wear gloves, the only time I use a plaster is to stop the workshop looking like an abbatoir if something won't stop bleeding. Seems to have worked for the last 50 years!

Mike

+2.

I was chopping up some chicken breasts for the wok when my friend's 16yo daughter admonished me for using the same knife to chop the carrots, onions, broccoli and snow-peas that were going into the same wok after the chicken had browned.

I was advised all about 'Cross Contamination' which was taught to her at school.

I felt quite sad that her school had not taught simple logic and 'raison de etre' behind this advice.

Imagine the horror when I shot a deer and offered 'Bambi' steaks to the Saturday BBQ.

When the fresh trout started to appear on the menu my friend's daughter finally realised that there are other sources of food than the supermarket and so we caught a few fish.

The sweet girl now has no compunctions about about shooting a rabbit or catching a trout.

* Danny M *

Seriously guys, have we not got something better to do?

Tony

What? You're on the clock or something? We're just jawin' away here, passin' the time. I've nothing else to do right now, so .......

Pete

Mike, best clean the end of all your files while you are at it, (not the handle end)

Although Knurling has the ability to collect skin and bacteria I wonder if anyone has ever actually caught anything from one. It is scary the number of times I have seen people leave one of the traps in a washroom and walk straight out the door, I wouldn't want to be sharing a knurl with him, especially as I am a nail biter.

Mike

Gee gents always remember you have to "eat you peck of muck" each day just to keep the bodies defence mechanism on its toes !!
Lots of truth in the old sayings !

I'd be really really really surprised if someone has actually caught a disease from handling a knurled surface. We worry about all the wrong stuff.

One recent study found that the most germ-ridden surface in most of our lives is the handle of the petrol pump at the service station. Touched by hundreds of people a day and never cleaned, then you come along and hold it for minutes solid while filling up.

No theory about it. Several kilograms of bacteria inhabit the average human gut. In fact, the number of cells of bacteria in the average human gut outnumbers the number of cells in the human body. So in reality, the bacteria is the dominant lifeform. The body is just there to carry it around. (And to drink beer.)

Its alright to make light of the question but when someone suffers from skin problems, dermatitis, then it is no laughing matter. I am sure those people would prefer the designer to give some thought to handling rather than ignore the potential health problems. I agree we all have to eat some dirt,I do on a regular basis, and have knurled fittings in my workshop. But I was answering for the full time work place, were handling is for thirty five hours or more a week not the odd minute a month.

Howard, definitely knurling is not a good idea on a production jig handled constantly for an 8 hour shift. Like rubbing a file on your hands all day long, to be sure. We used to use that Plastidip stuff on the QA clamps on car body spot weld jigs etc that operators were doing up and undoing all day long.

I think though if a person has dermatitis they might be best to wear cotton gloves when handling gym equipment. What is the alternative? Slippery bars on 100kg weights while bench pressing and someone loses their grip?

You can't catch Dermatitis, Psoriasis etc, from another person. It's either genetic or from various irritants and allergens .

If you suffer from similar then you make your own choices to minimise the risks be it barrier creams, gloves etc, skin/bacteria from a knurled surface isn't going to affect it, though other irritants things like oil might. It's all common sense, I get a particularly nasty type of Psoriasis. I know what I can and can't do and how to do it, I don't need 'elf and safety to tell me what I can and can't touch,.

When you wash your hands you turn the tap on with your dirty hands, wash them and then....turn off the dirty tap with your clean hands. What do you conclude from that? Then of course, you leave the room by grabbing the dirty handle on the way out.

"Washing" hands is simply a process of dilution, not cleansing. The closer you are to places of contamination, the filthier(?) they are. Luckily our bodies are used to dealing with sensible concentrations of bugs.

As for knurls, unless they are poorly made ie have swarf and splinters hanging off them, what is the worst that will happen? The ingrained "dirt" is just grease and muck unless you work in an abattoir or sewerage works. The risk from long term ingestion of grease and oil is not from bugs but from the impurities in the petroleum derived oil and grease itself. This seems to increase the risk of developing cancers of the digestive system, bowels, lower gut and the neighbouring external bits like your ball bag and ring piece - particularly if you are handling used engine oil which has higher concentrations of nasties like pyrobenzene. These originate in the petrol and become dissolved in the engine oil. So burning (reclaiming??) used engine oil in furnaces, heaters and engines is really not recommended.

Murray