Overview
A drive-in grease fitting, also called a push-in or push-type grease fitting, installs into a smooth, untapped hole without threading. A serrated shank presses in and the ribs bite the hole wall by interference, so the fitting stays put once driven flush. It is the standard repair for stripped or oversized threaded holes, and common on production lines where tapping would slow assembly.
They solve a familiar problem: when threads are damaged, no threaded replacement will seat. A drive-in fitting restores grease access in seconds with a drill and a hammer.
Specifications
| Parameter | Declared specification |
|---|---|
| Shank diameter | 3/16″, 1/4″, 5/16″ (drill the hole to the same diameter) |
| Shank design | Serrated, 0.25″ long |
| Overall length | 0.52″, 5/8″, 3/4″ |
| Head angle | 0°, 45°, 65°, 90° |
| Material | Zinc-plated steel or 303 stainless steel |
| Pressure rating | Up to 8,000 PSI |
| Check valve | Ball check valve |
| Head size references | DIN 71412 |
| Temperature range | -40°F to +300°F (-40°C to +149°C) |
How It Works and Size Selection
Holding force comes from the serrated shank: each rib cuts slightly into the hole wall as the fitting is driven, and the surrounding metal locks the shank in place. No tapping or thread sealant needed.
Shank diameter equals hole diameter: a 3/16″ fitting in a 3/16″ hole, 1/4″ in 1/4″, 5/16″ in 5/16″. If the old hole is worn slightly oversized, step up to the next shank size so the ribs can still bite.
Overall length sets head stand-off from the surface: 0.52″ for tight spaces, 5/8″ as standard, 3/4″ for extra coupler clearance. Head angle sets grease gun approach: 0° straight on, 45° or 65° angled, 90° from the side.
| Factor | Drive-in | Threaded |
|---|---|---|
| Installation time | Seconds | 2-3 minutes |
| Hole preparation | Drill only | Drill and tap |
| Damaged or oversized holes | Suitable | Not suitable |
| Removable | No, single use | Yes |
| Pressure rating | Up to 8,000 PSI | Higher ratings available |
If the hole still has sound threads, a threaded nipple is the better option; see our M6 grease nipple page. Unsure which shank diameter fits your part? Contact our team for a quote.
Installation and Use
Tools: a hammer of 8-12 oz, an installation tool or drift punch, and a drill bit for new holes.
- Drill the hole to the exact shank diameter.
- Clear chips and debris from the hole.
- Set the fitting square over the hole.
- Place the installation tool on the fitting head.
- Tap with the hammer until the fitting sits flush.
- Finish with a pull test to confirm grip.
In soft aluminum, open the hole 0.001-0.002″ larger so the shank seats without distorting the surrounding metal. Treat installation as permanent: the fitting will not come out cleanly, so plan the location first.
Applications
- Water pumps with damaged or stripped fitting holes
- Air compressors on production lines
- Generators that need fast maintenance access
- Old machinery with worn threaded holes
- New equipment assembly where tapping would slow the line
Maintenance
There is no fixed service-life figure, so treat these as inspect-and-replace items. At each lubrication round, check that the head is intact, no grease escapes around the shank, and the coupler still seats squarely. The ball check valve keeps dirt out between greasing intervals. If a fitting loosens, leaks, or deforms, replace it with a new drive-in fitting of the same shank diameter.
FAQ
What is a drive-in grease fitting?
A push-type grease fitting that installs into a smooth hole without threads: a serrated shank is hammered into a hole of matching diameter, and the ribs grip the wall to hold the fitting in place.
Is a push in grease fitting the same as a drive-in fitting?
Yes. Push-in, push-type, and drive-in are everyday names for the same method: press the serrated shank into an untapped hole instead of screwing the fitting in.
What size hole do I drill for a drive-in fitting?
Match the hole to the shank diameter exactly: 3/16″ shank in a 3/16″ hole, 1/4″ in 1/4″, 5/16″ in 5/16″. Undersized makes installation hard; oversized prevents the ribs from gripping.
How do I choose the overall length and head angle?
Pick 0.52″ for confined spaces, 5/8″ as the general choice, 3/4″ for more stand-off. Use 0° for straight-on access, 45° or 65° angled, 90° for side access. For a threaded 90-degree access point, see our 90-degree grease nipple page.
Can I remove and reuse a drive-in fitting?
No. The grip comes from ribs cutting into the hole wall, so removal damages both the fitting and the hole. Treat every installation as single use.
What pressure can a drive-in grease fitting handle?
They are declared up to 8,000 PSI working pressure, with a ball check valve preventing backflow. Above that, choose a threaded fitting.
Do drive-in fittings work in damaged or oversized holes?
Yes. If you can drill or ream the hole to one of the three shank diameters, the serrated shank will grip; for a slightly worn hole, move up one size.
What temperature range do they cover?
The declared range is -40°F to +300°F, equal to -40°C to +149°C, in both zinc-plated steel and 303 stainless steel versions.
When should I avoid a drive-in fitting?
Skip it above 8,000 PSI, where fittings must be removed often, in very hard or crack-sensitive material, or on precision equipment where hole damage is unacceptable; use a threaded fitting there.
Who makes these fittings and how do I order them?
They are made by IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006. For sizing help or drawings, email inquiry@isohitech.com or request a quote.
