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How to use cutting fluid on the edge, not the bench

Updated: 23 October 2026

You have a tin in one hand and a drill in the other, and the easy mistake is to coat the bench and then wonder why the bit still squeals. This is how to use cutting fluid so the film is on the edge that is cutting, the chips can leave the flute, and the residue comes off afterwards. Products Compared is the editorial team behind the [drilling and cutting oil comparison](/hub/diy-supplies/drilling-and-cutting-oil). The notes below follow the Health and Safety Executive’s metalworking-fluid guidance and a university tapping note. They are not a ranking of bottles, and they are not a COSHH assessment for an employer. A qualifying purchase can earn a commission at no extra cost to you.

You have a tin in one hand and a drill in the other, and the easy mistake is to coat the bench and then wonder why the bit still squeals.

Our top picks

Anchorlube Anchorlube 8 oz, part 3010

Best overall

Anchorlube Anchorlube 8 oz, part 3010
9.3/10about £18.75
View offer
OB41 OB41 cut tap drill fluid, twin pack

Best value

OB41 OB41 cut tap drill fluid, twin pack
8.1/10about £13.72
View offer
SIP SIP 5 litre ISO 23 neat oil

Alternative

SIP SIP 5 litre ISO 23 neat oil
6.2/10about £51.95
View offer
On this page
  1. 1.Put the film on the edge
  2. 2.Drill the hole, then back the tap off
  3. 3.Wipe what you leave behind
  4. 4.A short safety box, and when to stop

Put the film on the edge

Paste, wax, foam or a brushed neat oil belongs on the cutting edge and in the hole before the tool rubs. Put a dab of paste on the lips of the bit, or on the tap. If you are using neat oil, brush it on. A pool on the vice does not reach the point that is getting hot. OB41 reviews say the foam clings and then drips, and that a wide jet coats the bench, so aim at the edge. A neat oil runs unless it is brushed. When the film will not stay, the cutting paste versus spray page is the comparison. HSE guidance says to apply fluid where the tool meets the workpiece, at the lowest amount that still lubricates.

Drill the hole, then back the tap off

Add fluid again as the edge goes deeper. A shallow hole in thin plate may need only a second dab. A deeper hole needs fluid each time you return, because the first dab leaves with the chips. Blue or straw-coloured chips are a heat sign. Do not let the bit dwell. A stationary edge polishes and hardens the metal. Speed and feed on stainless sit on the cutting fluid for stainless steel page. The University of Cambridge tapping note says to use cutting fluid, to clear the threads as the flutes need it, and not to force a tap or it breaks. Start square, in a hole that is already the tapping size. The taper starts the thread, the intermediate often finishes a through hole, and the plug cuts to the end of a blind hole. Reverse before the flutes pack.
Anchorlube Anchorlube 8 oz, part 3010

Testsieger

Anchorlube Anchorlube 8 oz, part 3010
9.3/10about £18.75
View offer

Wipe what you leave behind

Wipe water-based paste off steel the same day. A review reports light rust when residue is left on steel. That is a buyer report, not a lab test. Lubri-Cut is beeswax plus cutting oils, and you still clean it off with a rag. Do not pour used oil or paste down the sink. Do not add water to SIP neat oil or to Tap Magic. Those listings give no mix ratio. An emulsion around 5–7% oil belongs to a sump, not to the bottle in your hand.

A short safety box, and when to stop

The Health and Safety Executive treats these fluids under COSHH. Prevent breathing mist, swallowing, and skin contact where you reasonably can. The harms HSE names include dermatitis and lung disease, including occupational asthma and hypersensitivity pneumonitis. Wash with soap and water. Do not blow fluid off your skin with compressed air. Gloves can catch near a rotating chuck. Aerosols take their flammability class from the Aerosol Dispensers Regulations 2009, then GB CLP in Great Britain and EU CLP in Northern Ireland. A flash point of 180 °C on a neat-oil can is not that aerosol mark. Stop for a broken tap you cannot afford to lose, for fluid in the eye, and for breathing symptoms that follow your time in the workshop. A GP is the right call for the health cases. This page is not an employer’s COSHH assessment.

Common questions

How often do I add more while drilling?
Add more as the edge goes deeper and the first film leaves with the chips. A shallow hole in thin plate may need only the first dab. A deeper hole needs fluid each time you come back in. If the chips turn blue or straw-coloured, the edge is hot. Do not park the bit in the bottom of the hole and hope the oil on the bench will cool it.
Why do I reverse a tap?
You reverse a tap so the chips do not pack the flutes and wedge the tool. Clear the threads as often as they need it, add fluid, and continue. Forcing a packed tap is how it snaps. A hand set starts with the taper, often finishes a through hole with the intermediate tap, and uses the plug tap when a blind hole needs a full thread to the end. The hole must already be the tapping size, and the tap must start square.
What happens if a water-based paste stays on steel?
Reviews say to wipe it off. One review reports light rust when water-based paste was left on steel. That is a buyer report, not a corrosion trial, and it is still a reason to clean the work the same day. Wax paste is a different residue. You clean that with a rag or a spatula as well. Do not pour either down the sink.
Can I thin this bottle with water?
Not if it is a neat oil or a cutting fluid sold without a mix ratio. SIP and Tap Magic in this set are not soluble coolants, and adding water does not make them one. Figures such as 5–7% oil in an emulsion belong to machine sumps, not to these bottles. If the paste is too stiff, follow the tin. Do not invent a ratio the listing never printed.
When do I stop and call someone else?
Stop for a broken tap you cannot afford to lose, for fluid in the eye, and for breathing symptoms that follow your time in the workshop. A GP is the right call for the health cases. A sump that several people react to, or a contaminated sump that needs disposal, is beyond a shed note. This page does not replace a COSHH assessment at work.

Related pages

Cutting oil buying guide

Drilling and cutting oil

Best cutting oil UK for the hole you are about to drill

Cutting paste vs cutting oil spray when it runs off

Cutting fluid for stainless steel after a burnt bit

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Updated 22 October 2026.

  1. HSE: About metalworking fluids (retrieved October 2026)
  2. HSE: MW series index (retrieved October 2026)
  3. HSE: MW2 skin (retrieved October 2026)
  4. HSE: GB CLP (retrieved October 2026)
  5. Aerosol Dispensers Regulations 2009, Schedule 1A (retrieved October 2026)
  6. GOV.UK: Aerosol Dispensers Regulations 2009 (retrieved October 2026)
  7. MSC UK: Neat cutting oils (retrieved October 2026)
  8. Oil Store: What is cutting fluid? (retrieved October 2026)