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M10 grease nipple or 1/8 BSP: which thread you have

Updated: 23 October 2026

You have a nipple in one hand and both a metric packet and a BSP packet look as if they might start. The usual mix-up is an M10 grease nipple or a 1/8 BSP nipple, because both sit near 10 mm and neither name is the outside diameter. This page separates metric pitches from BSP, from 1/4-28, and from 1/8-27. It does not rank kits. Prices, once the old nipple has a full name, are on the [grease nipple comparison](/hub/diy-supplies/grease-nipple). Peter F. used Kingfisher's UK pages and the twelve amazon.co.uk listings captured on 21 October 2026. We did not gauge a housing. A qualifying purchase can earn a commission at no extra cost to you.

You have a nipple in one hand and both a metric packet and a BSP packet look as if they might start.

Our top picks

Nikovoke Nikovoke straight set, size line M8x1

Best overall

Nikovoke Nikovoke straight set, size line M8x1
4.3/10about £3.99
View offer
Swpeet Swpeet 246-piece metric and inch kit

Rank 2

Swpeet Swpeet 246-piece metric and inch kit
7.0/10about £16.99
View offer
Nadinsta Nadinsta 100-piece M6 M8 M10 kit

Best value

Nadinsta Nadinsta 100-piece M6 M8 M10 kit
6.8/10about £7.89
View offer
On this page
  1. 1.Why 10 mm is not a thread size
  2. 2.The metric pitches UK machines actually use
  3. 3.BSP, UNF and 1/8-27
  4. 4.What these listings print

Why 10 mm is not a thread size

A caliper can put you in the 6 mm, 8 mm or 10 mm class. It cannot give you the pitch, and it cannot say whether the form is metric or a 55° pipe thread. Kingfisher's BSP page is clear that 1/8 and 1/4 are pipe-size names, not the crest diameter. R1/8 on that page is 1/8 x 28 BSPT, and R1/4 is 1/4 x 19 BSPT. M10 x 1 is a metric fine thread. The two can both measure near 10 mm, and they do not interchange. A correct thread winds in by hand for several turns. A near miss catches, sometimes for one turn, and then goes tight. Finishing that turn with a spanner cuts a drunken thread in the housing. Back it out while the damage is still a scratch.

The metric pitches UK machines actually use

Kingfisher ties the common hydraulic cone sizes in DIN 71412 to M6 x 1, M8 x 1 and M10 x 1, and sells M8 x 1.25 separately. M8 x 1 and M8 x 1.25 are the everyday trap on a title that only says M8. The coarser pitch is the one a lot of ordinary M8 bolts use, and the two will cross-start. An M10 x 1 nipple in an M10 x 1.5 hole does the same thing one size up. None of the twelve listings claims DIN 71412 in a line that stands alone.
Nikovoke Nikovoke straight set, size line M8x1

Testsieger

Nikovoke Nikovoke straight set, size line M8x1
4.3/10about £3.99
View offer

BSP, UNF and 1/8-27

BSP on Kingfisher's page is a 55° thread. The 1/8 size is 28 threads per inch in the tapered R form, and the 1/4 size is 19 threads per inch. A tapered nipple in a parallel hole can still be the same family. 1/4-28 is not 1/4 BSP. Kingfisher treats SAE-LT as a tapered lubrication thread under SAE J534, and parallel 1/4-28 UNF as a different fitting. Do not assume they swap because both say 1/4-28. Match the part you removed, taper included. 1/8-27 is another inch thread. Kingfisher places 1/8 x 27 PTF under SAE J534, not under BSP. The Swpeet bullet lists 1/8-27 and 1/4-28 and does not print BSP. Leave the name as 1/8-27.

What these listings print

Only the two Nikovoke size attributes print a metric pitch: M6x1 on one ASIN and M8x1 on the other. Each title still says straight M6, M8 and M10 nipples, and each piece-count field says 1. A pitch that contradicts the title is a clue, not a contents label. Nadinsta, Nadisean, REJOECE, ANVINKU and TRILINK say M6, M8 and M10 with no pitch at all. Swpeet names 1/4-28 and 1/8-27 as well as the metric sizes, at £16.99, and it still omits the metric pitch. Once you can say M8 x 1, or 1/8 x 28 BSPT, or 1/4-28, ignore any row that does not print that name. Caps and piece counts are on the grease nipple assortment page.

Common questions

Is M10 the same as 1/8 BSP?
No. M10 x 1 is a metric fine thread. 1/8 BSP, in the R form Kingfisher sells, is 1/8 x 28 BSPT, a 55° pipe thread, and the 1/8 is a pipe size rather than the crest diameter. They can both measure near 10 mm, which is why a caliper confuses them. They do not run in the same hole.
Is M8 x 1 the same as M8 x 1.25?
No. M8 x 1 is the fine pitch Kingfisher lists among the common DIN 71412 sizes. M8 x 1.25 is the coarser pitch, sold separately, and it is what many ordinary M8 bolts use. A title that says only M8 has skipped this choice. SOS Agricultural's mixed pack is a UK contents list that prints both.
What is 1/4-28 compared with 1/4 BSP?
They share a fraction and not a thread. 1/4 BSP in Kingfisher's nipple range is 1/4 x 19 BSPT. 1/4-28 is 28 threads per inch. Kingfisher separates tapered SAE-LT, under SAE J534, from parallel UNF, because the seal is not the same. A packet that says 1/4 without 19 or 28 has not finished the sentence.
What is 1/8-27 on the Swpeet listing?
It is the size the Swpeet bullet prints, next to 1/4-28 and M6, M8 and M10. The listing does not call it BSP. Kingfisher treats 1/8 x 27 PTF as an SAE J534 thread, not as 1/8 x 28 BSP. Use 1/8-27 only where that is what came out.
Does a tapered nipple need tape?
Tape does not correct a mismatch. Kingfisher prefers a tapered metric nipple because it can seal in a parallel hole of the same metric thread without sealant. If the manual specifies a dry thread or a sealant, follow the manual. If the families differ, tape will not make them the same, and tightening further damages the housing.
How do I measure a nipple I have removed?
Use diameter only to see whether you are near 6 mm, 8 mm or 10 mm, then identify the pitch. A thread gauge, or a known nipple from a labelled compartment, separates a 1 mm metric pitch from 28 tpi and from 19 tpi. Read any stamp on the old nipple before you trust a packet it did not come from.

Related pages

How to fit a grease nipple

Best grease nipple kit

Grease nipple

Grease nipple assortment: check pitch before count

Grease nipple not taking grease: ball, gun or joint

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Listings captured 21 October 2026. Updated October 2026.

  1. Kingfisher metric hydraulic grease fittings (retrieved 21 October 2026)
  2. Kingfisher BSP hydraulic grease nipples (retrieved 21 October 2026)
  3. Kingfisher 1/4-28 hydraulic grease fittings (retrieved 21 October 2026)
  4. HSE: hydraulic injection injury (retrieved 21 October 2026)
  5. HSE: track tensioning (retrieved 21 October 2026)
  6. Pressol: DIN standards for lubrication (retrieved 21 October 2026)
  7. Skill Shack: how to grease nipples (retrieved 21 October 2026)
  8. UK Planet Tools: Sealey AB009GN assortment (retrieved 21 October 2026)