3/16″ Drive-In Grease Fitting, Press-Fit Zerk

What a Drive-In Grease Fitting Is

A drive-in grease fitting is a press-fit zerk. It has no thread at all. The shank carries serrations, and those serrations bite into the bore of a drilled hole to hold the fitting in place. On this part, 3/16 is the shank diameter. It is not a thread callout, and it is not the 3/16-32 thread that some buyers expect when they read that number.

OEMs choose drive-in fittings because assembly is fast. There is no tapping step, no chip to clear from a threaded hole, and no torque callout to control on the line. The housing is drilled, the bore is deburred, and the fitting is pressed home. That suits high-volume housings where a threaded port would add an operation without adding function.

Technical Specifications

Inch values are primary below, with metric equivalents shown alongside. The shank diameter is the governing dimension for hole fit.

Drive-In or Threaded 3/16 Fitting

Two different products carry a similar number, and they are not interchangeable. This page covers the drive-in fitting, where 3/16 is the shank diameter and the body presses into a drilled hole. A separate 3/16-32 threaded version exists in the market, and that buyer wants a thread cut into a port. Before ordering, check the hole. If it is smooth and unthreaded, you need the drive-in part. If it carries a thread, look at a 5/16-24 UNF threaded fitting or browse threaded hydraulic-type grease fittings instead.

Installation Steps

1. Drill the correct hole size for the shank.
2. Deburr the bore so the serrations seat cleanly.
3. Support the back of the housing.
4. Press the fitting in square to the bore.
5. Check that it is fully seated.
6. Grease the fitting and verify flow through the ball check.

Head Styles and Sizing

Drive-in bodies are made in several head styles so the grease gun can reach the fitting from a workable angle. Straight heads suit open housings. Angled heads clear nearby bosses, webs and shafts. The shank stays the same across those variants, so the hole does not change when the head style changes. If your access problem is an angle rather than a port type, a 90 degree grease nipple may solve it. Metric port threads are covered separately, including M10 metric grease nipples.

What Is Supplied

Drive-in grease fittings in the shank size shown above, with a ball check and a serrated shank. Tell us your hole dimensions and head style, then request a quote.

Frequently Asked Questions

Is 3/16 a thread size on this fitting?

No. On this fitting, 3/16 is the shank diameter. There is no thread on the body at all.

How does the fitting stay in the hole without a thread?

Serrations on the shank bite into the bore wall. The press fit holds the fitting once it is driven home.

What hole size does the shank need?

The hole is drilled to suit the 3/16 shank, held to the tolerance shown in the table above.

Can I install it in a threaded hole?

No. A threaded port will not hold a serrated shank properly. Use a threaded fitting in that port instead.

Does a 3/16-32 threaded version exist?

Yes, as a separate product. Confirm which you need by checking whether your hole is smooth or threaded.

What tools does installation need?

An arbor press or a hammer-in installation tool. Either drives the fitting squarely into the prepared bore.

Can a driven fitting be removed and reused?

It can be removed, but the serrations are typically disturbed. Replace the fitting after removal rather than reinstalling it.

Does the fitting have a hex?

Yes, a small hex on the head. It gives the grease coupler a stable seat during service.

Which head styles come in drive-in form?

Straight and angled heads are both available on drive-in bodies, with the same shank underneath.

Can IsoHiTech confirm hole and shank sizes before ordering?

Yes. IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006, supplies drive-in fittings in the sizes above. Send your hole dimensions to inquiry@isohitech.com or via the quote page for confirmation.