Cutting fluid for Alluminium

[Rick Hughes]

nntp.aioe.org is down today ... so resorting to GoogleGroups

I need to drill & tap some 3/8-16 UNC blind holes in 6061 aluminium heat treated to T6 Just ordered a new set of taps and a 5/16" drill .......... For ferrous & stainless I use Molyslip MWF Many moons ago when I worked in engineering the advice was always to use White Spirit or Turpentine as cutting fluid, (or paraffin at a push) I did a quick Google to see if things have changed, and people now seem to suggest that WD40 is the preferred cutting fluid ... anybody any particular views on this

[Cursitor Doom]

Yeah, well for turning anyway, WD40 is reckoned to be just the job.

[tabbypurr]

W40 is white spirit with a very little mineral oil

NT

[rick]

I thought white spirit was a gp thinner made to be a Turpentine substitute.

[tabbypurr]

It's much thinner & more volatile, a solvent rather than oil

AIUI Turps substitute & white spirit are similar but not quite identical. TS has less negative effect on paint handling properties than WS.

NT

[Alan Dawes]

That's correct but it is made from mineral oils from the distillation of crude oil which is much cheaper to produce than turpentine which is made by the distillation of the resin from mainly pine trees.

Alan

[879]

[tabbypurr]

DIY turps is not real turpentine though

NT

[newshound]

I think that is a very reasonable description.

Some might be interested in the following info, which gives the carbon number range and boiling range for various crude oil distillates

Petrol 4-12 30C-200C Kerosene 6-16 190C-260C White spirit 7-12 145C-174C Diesel 8-21 200C-350C Lube oil 18-34 200C-350C

Note that the "boiling range" for mineral oil is for the reduced pressure conditions in an oil refinery: mineral oils will oxidise significantly if you try to boil them in air.