# Why does saliva produce a better looking finish than oil when machining steel?



## romartin (Jun 4, 2012)

I have known this trick since I was a lad using my fathers lathe but I don't know why it works. Is there a product which produces a similar result?


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## ronkh (Jun 4, 2012)

:fan:
??


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## 90LX_Notch (Jun 4, 2012)

Wow. This has to be the strangest first post ever. Should be interesting to say the least.


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## lazylathe (Jun 4, 2012)

Odd indeed!!

Although a quick google reveals that thisis recommended by a poster on lathes.co.uk!
When drilling some oils are too viscous when using very small drills.
Says to apply a small drop of saliva which is just right for the job.

I am thinking too much bacteria etc....

Andrew


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## Blogwitch (Jun 4, 2012)

It's an old trick I use occasionally if I am putting in a small centre, but I have never tried it for drilling deeper holes.

It is quicker and easier than reaching for the cutting oil bottle, and where I used to work, all the old hands used the same trick for centre drilling.


John


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## n4zou (Jun 4, 2012)

Another thing saliva does better than anything else is preventing your dive mask from fogging up. That was the first thing I learned in US Navy Diving Class. Spit in your mask and smear it all around with your fingers. The only positive aspect of this was never worrying about someone stealing your mask.


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## b.lindsey (Jun 4, 2012)

Well that's a new one to me and one i won't be teaching my machine shop students as long as other more ...shall we say commercial...alternatives are available.

Romartin, welcome to the site. Perhaps you can post a short introduction in the welcome section about yourself....that always helps.

Regards,
Bill


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## TroyO (Jun 4, 2012)

LOL... saliva, blood.... everything I make seems to get one or the other (Or both) on it.... LOL.

If it makes you feel better I usually scrub stuff off with dish soap and water before assembly.


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## steamer (Jun 4, 2012)

lazylathe  said:
			
		

> Odd indeed!!
> 
> Although a quick google reveals that thisis recommended by a poster on lathes.co.uk!
> When drilling some oils are too viscous when using very small drills.
> ...




Even if it does work...there's no way in hell anything in my SHOP let alone lathe is going to get my spit on it....My shop is not that hygenic.

And Yes Romartin...please do post in the welcome section when you get a chance....

Dave


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## romartin (Jun 10, 2012)

Thank you all for your comments. Believe it or not, my question was serious - it DOES work (and I still don't know why). For small enough steel objects I always lubricate the final cut using my finger on which I have carefully perched a blob of saliva. When the cut is over, I carefully dry the part and then wipe it with an oily rag. I learned this process in the early 1950s probably from advice in an issue of "The Model Engineer". Thank you Andrew for your google research; without that comfort I would now start to develop a complex. I promise not to conduct experiments using other body fluids.
I have just done a post in the welcome section.
Ian


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## modelman1838 (Jun 10, 2012)

I know it is usual to machine brass dry without cutting lubricant, but usually when drilling and threading it does make an awfull squeak. I then apply a bit of saliva on with my finger,it may not help the cutting but at least it stops the squeaking.
 Hugh


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## Tin Falcon (Jun 10, 2012)

maybe some water soluble oil diluted with water to recommended ratio. hmm new one to as well. 
Tin


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## BAH101 (Jun 10, 2012)

I will make the assumption that you should never use your tongue as an applicator ;D


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## Siddly (Jun 10, 2012)

I thought I knew most old school engineering dodges thanks to my mentor, an incredibly foul mouthed and disreputable ( but heart of gold ) machinist who learnt his trade in the 1960's

He never told me about that one though, and it seems right up his street as well


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## Blogwitch (Jun 11, 2012)

Siddly  said:
			
		

> I thought I knew most old school engineering dodges thanks to my mentor, an incredibly foul mouthed and disreputable ( but heart of gold ) machinist who learnt his trade in the 1960's



This is the problem with modern day machinists, they want everything 'just so' and if it can't be bought, they don't want to know about it.

Get hold of some old freebie download books from the turn of the century, especially manufacturers lathe operating manuals, and it will open your eyes as what you can do with your lathe.

The people who ran machine tools in those days had to come up with all sorts of tricks and fixes to do things that we laugh about nowadays, because we can just go out and buy 'stuff' to do these jobs, those chaps couldn't. Just like starters today, they can't afford to get it all at once, so a lot of these old tricks should be shown, just so that they can start to use their machines to the full. 
This main post might sound unhygienic, but I can tell you, there are most probably worse things hanging about in the far reaches of peoples shops, unless of course you are one of those people who prefer to clean up every last scrap of swarf, and even polish the floors, rather than machining.

When I started to show my machining on here, many moons ago, people were amazed at some of the things I got up to by means of getting the job done, but they weren't my ideas, just ones that I had picked up during my travels and by reading old books.

There is very little new any more, just old ideas brought up to date.

Maybe one day, someone will release a new wonder lube called 'lesser spotted tapeworm spit', and the chap will make a million.


John


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## steamer (Jun 11, 2012)

Hi Bogs,

I don't think any of the comments were derogatory Bogs,,,But I have to say most here hadn't heard of that one before......

Dave


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## Siddly (Jun 11, 2012)

Bogstandard  said:
			
		

> This is the problem with modern day machinists, they want everything 'just so' and if it can't be bought, they don't want to know about it.



I think you are being a teeny bit unfair Mr Bogs. I constantly see amateur machinists on the net doing some really clever and resourceful stuff.

One thing that does worry and puzzle me is the lack of emphasis on benchwork, todays solution to every task seems to involve a machine when sometimes a file could do the same job quicker ( considering the set up time on the machine and assuming proficiency with a file )

A couple of years ago a friend of mine showed me the curriculum for an introductory engineering course he was considering taking. While 30% of it consisted of what I can best describe as compulsory political correctness the module on benchwork was actually optional !

It's a hobby horse of mine, benchwork. Probably because I once hated it, but then grew to like it. Nothing like the zeal of the converted


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## Blogwitch (Jun 11, 2012)

Dave,

Heard of which one?

Siddly,

I wasn't aiming specifically at newcomers, a lot are very talented, but the people who seem to think that everything to do a job can be bought.

You only have to look at the questions, and not just on this site either, usually, how do I do this and what tool can I buy that will do it for me.

Tools do help, but a lot of times, bits and bobs in your workshop can be utilised without going to the nearest tool store or webshop.

I can hardly use my machines any more, but it isn't a case of buying new tools that will get the job done, but what I can remember about how to do jobs without any special ones. In fact there are now some bits in my shop that I don't think I can use any more, like my four jaw chuck, but I never liked four jaw work anyway, so it isn't much of a loss, I will just use my faceplate or mill a lot more.

I also fully agree with you about the benchwork. If it can be marked out, it can usually be made with a hacksaw, files and a drill. But the problem with that is muscle power, and it takes too long, people just want to push a button and have the machines do everything for them.

They haven't really found the secret of why a lot of us do model engineering the 'old' way.

I will just add, I am not against semi automation, power feeds etc, I have had to do it with almost all my machines, otherwise I would have to give up machining completely, as I am basically working with one hand now, but I still get onto the bench to the best of my ability, and rough it out now and again, to me that is pure therapy and enjoyment. 
That is just a small part of the above 'secret'.


John


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## steamer (Jun 11, 2012)

Saliva John...


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## Siddly (Jun 11, 2012)

John - I should take a moment to thank you for the plans and write up on that steam engine. I downloaded those a month or two ago from somewhere or other ( I'm assuming you are the same Bogstandard )

While my level of interest in steam engines is roughly zero ( which is why I can't even remember what kind of steam engine it was, they are all greek to me  ) the machining tips had me either nodding my head in approval or more usually exclaiming 'wish I'd thought of that' 

Top Job


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## Tin Falcon (Jun 11, 2012)

> This is the problem with modern day machinists, they want everything 'just so' and if it can't be bought, they don't want to know about it.


It depends on your definitions of a machinist. Is a lathe operator or a mill operator a machinist they do machining.
There are production machinists that make a single part over and over or maybe an operation or two on that part before it goes to another machine to get finished. Then there are job shop machinists.and CNC machinists. Last but not least hobby machinists. 
In the industrial world time is money . If shop time is worth $120 per hour the boss would much rather pay 6 bucks for a insert cutter with three edged than use 10 minutes( $20) worth of time to sharpen a bit. the same goes for home made recipes. In the home shop learn and do as you see fit it is your shop. And if folks do not learn and use the old ways to some extent they will be lost forever. 

Everyone here has his or her goals in the home shop.And in the home shop money may be time. Most of us work and are lucky to get 8-16 hours a week in the shop . and if someone wants to learn to build an engine they may not want to use valuable time to make tools. time making tools is not wasted if you like it and enjoy the time doing it, It builds skills and the money that could have been spent on a tool can be used on materials. 
It is a personal choice. What is right for a retired guy with a well equipped shop may not be the best choice for a working guy just starting out. 
Yes learning eye hand coordination is valuable . Learning to draw free hand and on the computer is also valuable. 
There is nothing wrong with learning bench work or learning CNC. 

Bogs I respect you and you opinion. what you do and how you operate your shop is likely the best way for you. 
Each one here has to learn his or her own path in this hobby. Many people, many counties many perspectives based on life experience and choices. 
And yes i need to admit any tool whether a file or a cnc machine is ony as good as the operator behind it.
The most important tool in this hobby is the human brain. 

We are all here to share our experience and show options. Only the guy or gal at the other end of the monitor can choose what tools and technologies books etc go into the shop. Also what projects come out. 

Happy and safe machining to all. 
Tin


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## Blogwitch (Jun 12, 2012)

Siddly,

Glad you enjoyed the read, I was attempting to show even a beginner, that complex looking parts are not that difficult to make if a little thought is put into the process, and the more experienced you became, the more complex parts could be tackled with just basic machining facilities.

I lost count of the number of downloads that book has had, plus also the number of running engines that have been made, it runs into many thousands for the 'book', and all for free!!!


Tin,

I don't think anywhere ever have I said that CNC and all of it's related sidelines is wrong, that is a personal choice on how people do things. 

I was trying to get across that in many situations, problems CAN be solved by 'old time' methods without going to the expense of purchasing more and more tooling. Am I to be decried for doing that?

But please, just one more point, can you please stop using the phrase 'hobby machinists' or such terms.

I for one class that as an insult, and I am sure a lot of others do as well. I would prefer to be called a model engineer, which as far as I can make out, covers what we attempt to do here. It has a better 'ring' to it.


John


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## steamer (Jun 12, 2012)

I don't think anyone is decrieing anything John.  I for one agree with your position that many things can be done with simple methods. Often times that is not what people try first....but that's OK too. If you get where you want to be with some wiz bang piece of "kit" or a simple hand made reamer...but you had fun and learned something doing it either way.....I don't see the down side.......and agreed "Model Engineer" does have a better ring to it doesn't it?

Now what is it about Saliva that makes for a better finish....inquireing minds want to know! ;D....anybody?


Dave



PS I've read that cow's milk does wonders too....though I'm not trying that either! I can only imagine what my shop would smell like on a hot summer's day! :big:


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## Rayanth (Jun 12, 2012)

Dave, your next task is to try it with beer. If it don't work, you can always just drink the rest ;D

-Ryan


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## Tin Falcon (Jun 12, 2012)

John : I think we are both trying to remind folks to keep an open mind. 


> I don't think anywhere ever have I said that CNC and all of it's related sidelines is wrong, that is a personal choice on how people do things


 All methods are valuable to lean old and new another point we agree on. .




> But please, just one more point, can you please stop using the phrase 'hobby machinists' or such terms.


In no way did I intend to imply that one type of machinist is more or less skilled or valuable than another. 
A hobby or maybe a better term Amateur is simply one that typicality has his or her own shop and machines for there own goals .Model engineer does indeed cover what we do . But not all folks that machine for a hobby that do not build models. yes most of us here, that is the focus and goal of the forum. 

I agree also in the fact that learning simple basic tools and methods is valuable and arguably foundational. there are times when a file is a more suited tool to a job than a mill
It is all good bogs this is a hobby and we are all here for fun. 
tin


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## Siddly (Jun 12, 2012)

steamer  said:
			
		

> Saliva John...



Sounds like one of the Delta Blues singers I like to listen to in the workshop ;D


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## steamer (Jun 12, 2012)

Rof}

That was worth the karma!

Looking back on this thread...there's a song there somewhere!

Dah Den da den...


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## rhitee93 (Jun 12, 2012)

steamer  said:
			
		

> Looking back on this thread...there's a song there somewhere!
> Dah Den da den...



One day I was workin' in da shop
My drills making that horrible sound
Took a look 'round da shelves...
...but spit was all I found!

Dah Den da den...

(Someone else take it from here  )


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## steamer (Jun 12, 2012)

Rof}

As much as I would love to!  It's supposed to be my job to keep this thread on topic...... ;D

Dave


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## pkastagehand (Jun 12, 2012)

I expect if you dug deep enough (if the records aren't lost in some government archive) you'll find that our tax money funded a study on the use of saliva as a cutting fluid.

(Mostly) kidding. I suppose there are some enzymes or something in spit that somehow help lube/cool the cutting action in some way that is different than just oil but not being a chemist and/or biologist I wouldn't know what they are.

Reminds me of a tip I got from somewhere about driving nails in tough woods. Rubbing the nail across one's forehead or other oily/sweaty body part can make it drive much easier.

Paul


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## mklotz (Jun 12, 2012)

> Rubbing the nail across one's forehead or other oily/sweaty body part can make it drive much easier.



When joining the parts of a multi-segment fishing rod, it's common practice to first rub the male part of the connector along the side of the nose before inserting it into the ferrule/socket.

My dad, an avid fly fisherman, always referred to it as "face fat".


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## rhitee93 (Jun 12, 2012)

It used to be common practice to use "Nose grease" from the same location to cover up scratches on negatives when working in a darkroom.

Gross, but it does work fairly well.


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## 90LX_Notch (Jun 12, 2012)

My only concern with the use a saliva would be the controls to manufacture it. How could one assure the quality from one batch to the next? Certainly G.I.G.O. (garbage in, garbage out) applies. The range the properties of the saliva after a glass of water vs a glass of milk would be rather large. :


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## mklotz (Jun 12, 2012)

I seriously doubt that anyone who buys a jar of spit to use as a lubricant is going to worry much about quality control.

OTOH, the kinky sex market may have much more restrictive requirements. Can spit be pasteurized? Inquiring minds want to know.


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## 90LX_Notch (Jun 12, 2012)

It would very interesting in a CNC production environment with through the spindle tooling (coolant is passed through tool) running in conjunction with flood cooling.  :


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## steamer (Jun 13, 2012)

OK.....I give up... ;D


To the OP some 3 pages back.....I think this is going to be as good as it gets!......

My conscience is clear.......

Now how did that song go........? :

Dave


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## 90LX_Notch (Jun 13, 2012)

Dave-

Did you give up due to "dry mouth" from all the spitting? :big:

-Bob


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## romartin (Jun 14, 2012)

Wow! When I started this topic with what I thought was a simple innocent question, I thought that I would get a straight answer from one or more old timers and that that would be that. I surely didn't imagine that the theme would seed so many and so varied developments. 
In particular I followed with interest the debate on purchased special tools versus use of older and simpler methods. I recognized in these positions situations in which I have often found myself when, as far as I know from my experience, my present machines wouldn't do the job. Should I invest the time and effort (and sometimes cash) in order to have a new tool which will help me to do a better job? Or should I just get out the the hand tools and do my best at the bench?
- Almost always what I'm really after is quality of the product. I don't really care whether the job was done by hand or by machine. When buying shirts or souvenirs or whatever I`m not impressed by "Hand Made" labels.
- After all is there really a big difference between "Handmade with the help of a saw and a file" and "Handmade with the help of a lathe"? Both can come out well or come out badly - it depends on the skill of the builder in the use of his tools.
- If I decide to make a tool then it's usually because I'm pretty sure it will be useful and effective more that once.
- I have a very small workshop and part of deciding to make or buy a new tool is deciding where the heck to keep it.
Ian


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## 90LX_Notch (Jun 14, 2012)

Ian-

This has been a great thread. I learned something and got a few chuckles. I think this thread took the turns it did because it was your first. If it had been posted by one of the regulars, it would have taken a different path.

-Bob


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## steamer (Jun 14, 2012)

Glad we all learned something...and I'm glad I can still type....throats a bit dry at the moment.... ;D


Dave


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## Chazz (Jun 15, 2012)

Well in my Navy days, we used to 'Spit & Polish' our dress boots for inspections and parades. The wierd thing is, the spit produced a mirror finish far superior to 'tap' water? ???

Cheers,
Chazz


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