Grease Fitting Dimensions: Metric and SAE Sizes Explained
Grease fitting dimensions come down to thread size and angle, and this guide covers the metric and SAE sizes in the kits below.
On this page
You are under the car with the grease gun in hand, and the fitting on the joint will not take the coupler. That mismatch is what grease fitting dimensions are about: the thread size and the angle have to match the part, or the coupler will not seat and the grease goes nowhere. This guide covers the metric and SAE sizes, the straight and angled shapes, and the kits that carry them.
As an Amazon Associate I earn from qualifying purchases. GarageToolHQ earns a commission when you buy through links on our product pages, at no extra cost to you. Read our affiliate disclosure.
Below: thread sizes, a size chart, how to match a fitting, and the kits.
255PCS Grease Fittings Assortment,SAE & Metric
A 255-piece SAE and metric grease fitting kit in galvanized steel, with straight, 45 degree and 90 degree fittings in 1/4 inch, 1/8 inch, M6, M8 and M10 sizes, a wrench set and a divided case.
Pros
- 255 pieces across 1/4 inch, 1/8 inch, M6, M8 and M10 sizes
- Straight, 45 degree and 90 degree fittings in each size
- Spring-loaded ball check valve for dual sealing
- Wrench set and divided case with a size label
Cons
- Per-size counts in the bullets do not add up to the 255 pieces in the title
- Straight fittings are listed as 180 degree in the size breakdown
- Weight not stated on the listing
- No warranty term is stated
OURU 260PCS Grease Fittings Assortment Kit
A 260-piece SAE and metric grease fitting kit in galvanized steel, with 15 size and angle combinations, caps in two materials and a 7-11 mm wrench set, in a divided case.
Pros
- 260 pieces in 15 size and angle combinations
- Caps in two materials included
- 7-11 mm wrench set included
- Divided case with a label, 7.56 x 5.0 x 1.38 inches
Cons
- No per-size piece counts stated
- Thread pitch is not stated for the M6, M8 and M10 sizes
- No warranty term is stated
- No fitting length is stated
OURU 90PCS Grease Fittings Assortment Kit
A 90-piece SAE and metric grease fitting kit in galvanized steel, with 1/4 inch, 1/8 inch, M6, M8 and M10 sizes in straight, 45 degree and 90 degree shapes, a wrench kit and a divided case.
Pros
- 90 pieces across SAE and metric sizes
- Straight, 45 degree and 90 degree fittings
- Wrench kit included
- Divided case with thick partitions and a label
Cons
- No per-size piece counts stated
- Thread pitch is not stated for the M6, M8 and M10 sizes
- No warranty term is stated
- No weight or case size stated
NEIKO 50466A Grease Fitting Assortment, 110 Piece
A 110-piece metric grease fitting kit in zinc plated A3 steel, with M6-1 and M10-1.5 fittings in straight, 45 degree and 90 degree shapes, in a plastic storage case with an organization chart.
Pros
- 110 pieces with the count per size stated
- M6-1 and M10-1.5 threads stated
- Straight, 45 degree and 90 degree fittings
- Storage case with an organization chart
Cons
- Metric sizes only: M6-1 and M10-1.5
- No wrench set is listed
- No warranty term is stated
- No weight stated
Grease Fitting Dimensions: What the Numbers Mean
A grease fitting, also called a Zerk or a grease nipple, is a small hydraulic check valve on a bearing or a similar assembly that feeds lubricant to the working parts inside. The grease gun coupler snaps onto the fitting, and the valve seals it after greasing.
A fitting is matched to the part by its thread size and angle. Thread sizes here are M6-1 and M10-1.5 on the NEIKO kit, and 1/4 inch, 1/8 inch, M6, M8 and M10 on the SAE and metric kits. Angles run straight, 45 degree and 90 degree, and the angle decides whether the grease gun can reach the fitting.
Grease Fitting Size Chart
The chart lists the thread sizes in the kits on this page and the angles each size comes in.
| Thread size | Angles | Kits that carry it |
|---|---|---|
| M6-1 | Straight, 45 degree, 90 degree | NEIKO 50466A |
| M10-1.5 | Straight, 45 degree, 90 degree | NEIKO 50466A |
| M6 | Straight, 45 degree, 90 degree | OURU 90, OURU 260, Vesmikit |
| M8 | Straight, 45 degree, 90 degree | OURU 90, OURU 260, Vesmikit |
| M10 | Straight, 45 degree, 90 degree | OURU 90, OURU 260, Vesmikit |
| 1/4 inch | Straight, 45 degree, 90 degree | OURU 90, OURU 260, Vesmikit |
| 1/8 inch | Straight, 45 degree, 90 degree | OURU 90, OURU 260, Vesmikit |
How to Match a Grease Fitting to the Job
Start with the fitting already on the part: read its thread size and angle, or match it against the fittings in the kit until the thread and the angle agree. A straight fitting suits a fitting the grease gun can reach head-on, while a 45 degree or 90 degree fitting suits a tight spot where the gun must come in from the side. The OURU 260-piece kit lists a 7-11 mm wrench set, the OURU 90-piece kit includes a wrench kit, and the Vesmikit kit includes wrenches that make removal and installation easier.
Grease Fitting Kits for the Garage
The kits below carry the metric and SAE sizes in the chart above.
Use rated jack stands on solid ground, wear eye protection with power and air tools, keep fuel-burning equipment out of a closed garage, and follow the manual for every tool. Read our Safety Disclaimer.
FAQ: garage tools
What is the standard grease fitting size?
Sizes vary by part: the kits here carry M6-1, M10-1.5, M6, M8, M10, 1/4 inch and 1/8 inch fittings in straight, 45 degree and 90 degree shapes. Match the thread and the angle on the part the fitting screws into.
What does M6-1 mean on a grease fitting?
M6-1 is a metric thread size on the NEIKO kit, and M10-1.5 is the other metric size in that kit.
Are SAE and metric grease fittings interchangeable?
No. SAE sizes such as 1/4 inch and 1/8 inch and metric sizes such as M6, M8 and M10 use different threads, so a fitting must match the thread on the part.
What angle grease fitting should I use?
Use a straight fitting where the grease gun reaches the fitting head-on, and a 45 degree or 90 degree fitting where the gun must come in from the side or the space is tight.
Do grease fitting kits include a wrench?
Some do. The OURU 260-piece kit includes a 7-11 mm wrench set, the OURU 90-piece kit includes a wrench kit, and the Vesmikit kit includes wrenches for removal and installation. Check the listing for the kit you buy, since wrench sets differ by kit.
Related: best grease gun, best wheel bearing grease and the engine and shop equipment hub.
