Using Biodiesel as a machining fliud - Video

[chrisjh]

I have been using biodiesel for some time now on my CNC lathe. The water soluble coolant that I used previously was causing problems with the linear bearings seizing (presumably from oxidation) following periods of inactivity.

I know of a professional CNC turning company that uses oil that looks like, and has the consistence of honey, so decided to abandon water based coolant for an oil based solution. The cost of such oil coolant is prohibitive so I decided to use biodiesel. This worked fine but left a sticky residue. I now dilute the biodiesel with ordinary diesel (ratio 3 parts biodiesel to 1 part diesel). This leaves no sticky residue and the machine is now very clean.

Biodiesel has a high flash point (higher than ordinary diesel) and has excellent lubrication properties.

The part being machined in the video is part of an oil filter adaptor I manufacture.  I had some 32mm threaded adaptors which were not popular so I decided to re-machine them to 27mm thread.

The material being cut is 12L14 steel and DOC during roughing is 0.4mm at a feedrate of 0.25mm/rev. The finish cut is done at 0.1mm/rev. Threading is done at 900rpm.
 
I also mix biodiesel with kerosene for manual applications with a squirt bottle on my manual lathe and milling machine. I also use raw biodiesel as a hand tapping lubricant (works great).

See video here  http://www.youtube.com/watch?v=jxEk4o5OLT4

Regards

Chrisjh

[DaOne]

Interesting. Does it smell like french fries when you cut? Nice work on the gang tooling as well. If you don't mind me asking, how do you adjust the height of the tools?

[Tweakie.CNC]

Hi Chris,

Take care inhaling that smoke.  

Research has shown that the particulates produced from biodiesel are indeed less harmful to health than from diesel fuel but the research did not cover any long term exposure and as you are mixing it 3:1 with diesel anyway, well...........

There is an engineering shop near me and at break time many of the employees stand outside smoking cigarettes and breathing in the fumes from the passing traffic  

Tweakie.

[BR549]

Please be very careful with any flammable coolant.

 The GOOD water soluables have been around a LONG time without causing corrosion to machines . MIght want to try another brand.

Just a thought(;-) TP

[Hood]

My friend had a lovely Bullard twin turret Lathe that used neat oil and he wishes he had switched over to soluble. The tip on a parting tool broke and within seconds the whole machine was a ball of flames. Only good thing is I got the turret off it and now have it fitted to my lathe
Hood

[chrisjh]

Hi All,

I thought this thread would invoke some comments!!

I agonized over the decision to switch to biodiesel but decided that because most of the work that I do is considered "light duty" and low frequency, I would try it.  I have 2 fire extinguishers handy but I am comforted by the high flash point of diesel and even higher for biodiesel; and an experiment that my Dad demonstrated to me in the 1950s.  He poured some diesel into a 44 gallon drum bung (well away from the drum of diesel) and threw lighted matches into the diesel.  It refused to ignite.  The same experiment performed with petrol produced predictable results; very exciting for a 6 year old lad.

I always use a fan in my workshop to blow the smoke away from me when cutting.  I used to use expensive Rocol cutting oil for heavy cuts in my manual lathe and it gives off  similar amounts of very obnoxious smoke.

I still use a water based coolant in my CNC mill as the ways and ball screws are better protected.

As for French fries, biodiesel derived from waste cooking oil when burnt, does indeed have that smell of "fish and chips" about it.  The first time I smelt the exhaust of my mate's Toyota Landcruiser, I commented to him that he would be likely to attract cats.

As to the height setting of the tools in the gang tool block, everything is totally dependent on the centreline of the bored 16mm holes being at exactly the same height as the centreline of the lathe.  That way, all drilling tools have to be correctly aligned. 

The master tool (it is a 35° diamond shaped carbide insert) is mounted in a homemade tool holder.  I carefully made sure that the tip of the insert was exactly on the centreline of the tool holder.  The same design approach was used for the threading tool holder. 

The parting blade holder (not shown in this video) was a bit trickier.  It is also homemade and mounted upside down and cuts from the rear side.  I fitted an "anti-rotation" block at the rear of the tool holder with 2 x M8 Screws that I adjust to "rock" the tip of the parting blade until it is on the centreline. 

The gang tool block is mounted on 2 x Ø32 aluminium blocks, secured by 2 x M8 Caphead screws to the main cross slide tool plate.  By careful skimming of the 2 x Ø32 aluminium blocks, I was able to “adjust” the tool tips to be aligned.  I checked all tools for correct height and was very pleased to see that theory was correct.  I can remove the gang tool block to fit other setups and when I replace the gang setup, I find that tool tip height is 100% repeatable.

Amazing what you can do with Solidworks.  You can check that everything fits, does not interfere, moves as designed and intended before you have cut any metal.  It invokes a high level of confidence.

Regards

Chrisjh

[Tweakie.CNC]

I always use a fan in my workshop to blow the smoke away from me when cutting.  I used to use expensive Rocol cutting oil for heavy cuts in my manual lathe and it gives off  similar amounts of very obnoxious smoke.

That is just about the worst thing you could do - stir up the air, mixing in any toxic particles from the diesel (which are seldom visible) 
A better solution may be an extractor system.

Tweakie.

[Sam]

The first time I smelt the exhaust of my mate's Toyota Landcruiser, I commented to him that he would be likely to attract cats.

Thank you for the laugh!

[Hood]

Bit of a difference between throwing matches on diesel and having a red hot piece of metal getting oil poured onto it, especially when the metal is getting kept hot by the friction. Granted in the afore mentioned case the tip had broken so it was steel to steel but that can easily happen and usually happens when you turn your back for a few seconds I had a U Drill that welded itself to some stainless in a fraction of a second when a tip broke and I was actually watching it at the time, first I knew was when I saw the red glow through the white water and by the time I hit the E-Stop it was well knackered, if that had been neat oil  I would not have been reaching for the E-Stop but likely calling the fire brigade

Just be careful and dont get complacent.

Hood

[RICH]

I always use a fan in my workshop to blow the smoke away from me when cutting.  I used to use expensive Rocol cutting oil for heavy cuts in my manual lathe and it gives off  similar amounts of very obnoxious smoke.

That is just about the worst thing you could do - stir up the air, mixing in any toxic particles from the diesel (which are seldom visible)   
A better solution may be an extractor system.

You need an agent, ingnition source, and oxygen. There is a low and high level of ignition and also the enviroment condition comes into play.
Pop just didn't have the right condition. Didn't mom ever tell you that if you play with matches you'll get burnt! 

RICH