cutting/tapping fluid

Hello all

I've spilt the the last of my tapping fluid (oops) . My question is can I use the cutting fluid for my lathe neat instead of buying 500ml of dedicated tapping fluid. Reason I ask is i've 2 gallons of the soluble type which will probably see me out.

I don't see any reason why not, but somebody more informed than me may know better .

Regards

Paul

I use un diluted soluble oil applied by brush for some turning and boring jobs. For tapping you really need the extra lubrication gained from the Rocol type of tapping compounds. I use the past tapping compound because I find the liquid versions not so good for tapping difficult materials like 316 stainless EN19T ETC.

I'v been using Caterpillar Tappet assembly lubrication fluid, got a part full container from my diesel mechanic nephew, it seems to work ok.

Ian S C

Buy a tub of tallow, lasts for ever and quite cheap and gives nice definition

Mick

I used to have to cut many lead screws for machinery repairs on a conventional DSG toolroom lathe and never really had much success trying different strength levels of soluble cutting oil at the time. It never gave me much confidence though..

This being well before the advent of CNC with their higjh speeds and flood lubrication where cutting fluids do work well when properly mixed, monitored and controlled.

Like many others at those earlier times I experimented with various home brew compounds to try and improve consistancy and finishes. The most successful for me was in fact carbon tetrachloride, but for health and safety reasons around the early 80's ( I think ) it became a massive no no.

Mick Henshall is quite right in actually suggesting tallow, which is also good on dead centre work. I had quite a lot of success also using it for screw cutting when mixed with graphite.

We used to mix powdered graphite into lightly melted tallow to soak our cycle and motorcycle chains in ( before sealed chains were in use ). This mix was also tried for screwcutting with some good results on certain steels.

Rocol and comparible alternatives took the gueswork out of trying homebrews. For me though, the Ambersill Tufcut is good on the tougher steels, stainless and duplex stainlesses like monel, zeron 100 etc.

Edited By MalcB on 12/05/2016 15:50:39

It has never caused me any problems , the only thing i would check is if it is corrosive to aluminium which i doubt but some tapping fluids are and instead of nice chips coming out of the hole you get black gunk .

Ian.

I find Rocol RTD very good especially when drilling and tapping stainless steel, I have a tub of tallow in the workshop but I've found it's getting harder to source locally now that plumbers aren't wiping lead joints.

John

thank you for all your replies, I will buy some more rocol and try my best not to knock it over. I've put a magnet in the bottom of my tub now!

regards

Paul

I found liquid Rocol RTD stains and possibly corrodes steel. Because of this I have quite a few sorry looking taps and dies. They still work, though. RTD marmalade is OK. However you have to prevent it from attracting swarf.

JA

JA, I agree with you re liquid RTD staining. My boring head looks very second hand from using it.

Buy a tub of tallow, lasts for ever and quite cheap and gives nice definition

Mick

Can be hard to find , most engineering suppliers stock the rocol stuff , and look at you like ,  you`ve been off the planet for how long ? though i did see tallow listed on ebay not too long ago . Tallow comes in more than one grade so be sure to look for tapping grade , ordinary lard is alright for a close second ............b

Micks right last for ever ........tallow mixed about half n half with rocol was very good on aircraft grade s/steels for drilling and tapping , add a little bit of paraffin to help it mix

Yes Mick i did watch Hand made on the silk road ! worth watching !!

Edited By bodge on 13/05/2016 01:29:26

Edited By bodge on 13/05/2016 01:32:51

Edited By bodge on 13/05/2016 01:43:20

Edited By bodge on 13/05/2016 01:46:16

Well said Bodge, pleased somebody else watched " Handmade" I was wondering as my post attracted nil response

Mick

What about colloidal graphite? About 15 quid from a well known site.

Tallow sounds pretty good though

You should be able to get Tallow from a decent electrical wholesalers - we still use it for threading conduit.

Andy

Despite having at least half a tin of Rocol RTD still to use, and being a total cheapskate, I use bacon fat.

Not too different from tallow, probably, and seems to work pretty well.

Apologies to any vegetarian readers.

Howard

Is bathroom soap still made from tallow? Might work ok if it is. Nice pleasant smell in the workshop at the same time!

Bacon fat usually contains salt, which will rust the heck out of things. Refining the fat by boiling in water, as is done
with tallow, can reduce the salt considerably but how much work does one wish to put in to tapping lube??

Tallow doesn't contain salt unless it is added after for use in cooking.

Pete

Edited By Peter Krogh on 15/05/2016 07:33:47

Probably 95% of my hand tapping is done dry. I only need to use Rocol on 'orrid materials like some stainless steels, or possibly when using big taps, ie, greater than 1" diameter. The problem with using whatever one's choice of tapping goo is having to clean it out afterwards. A lot of my holes have studs loctited in, which doesn't work too well if the hole is contaminated.

For machine tapping on the repetition lathe I use a flood of soluble oil, mainly to wash away the swarf. Machine tapping on the vertical mill is normally done dry, except for aluminium where I use a squirt of WD40 to prevent BUE.

Andrew