Drill and Tap Size for Grease Zerks

[Pooh_Bear]

I need to drill some holes in some tube stock and
then tap them for grease zerks.
What size drill and which tap do I need to use?

Thanks.

Pooh Bear

 

[Renze]

Depends on what thread of grease zerks you use. For anything i build, i standardised on M8 standard thread. But there is also M6, M10, M10x1.5 (fine thread) which is interchangeable with G1/8 but on your side of the pond there are probably UNF threaded zerks too...

Find out what thread of zerks you can buy most easily, and then google what to tap and drill.

 

[BukitCase]

Some are 1/16" NPT, but to be sure I'd get zerks AND tap and drill at the same place if possible - likely any REAL auto parts store can help.

iCrank NPT Thread Tap Drill Size Chart (Inch)

Drill Size Chart

Some places sell combinations of tap and tap drill, others make you work for it - the above links should help either way... Steve

 

[MrPete]

Any that I have installed have been 1/8 NPT. I agree with bukit get you zerks first.

 

[bandaidmd]

I think 1/8"npt and 1/4 x 28 are the two most popular here. most tap kits have both of those sizes if not buy the one you already have a tap for.

 

[Mendonsy]

There are all sorts of sizes both in inch and metric thread dimensions including some that press in also. Your best bet is to go to your local Tractor Supply (or whatever) get the zerks first so you can make the holes match what you can get.

 

[jwmorris]

As others have said there are many many different options.

Zerk Fittings / Grease Fittings

There are even drive type that you just drill a hole and hammer them in, then you don't even need to buy a tap.

There are also thread forming fittings that you drill a hole and they tap the hole themselves.

 

[FTG-05]

There are bunch of different type zerk fittings including but not limited to pipe thread, straight thread, inch and metric. Here is one page of examples: McMaster-Carr (click on the "grease fittings" link, upper left).

 

[bigtiller]

I put thousands of them in over the years at the factory. I never seen a threaded hole for a grease zerk. The zerks were all self tapping.

 

[Soundguy]

I think 1/8"npt and 1/4 x 28 are the two most popular here. most tap kits have both of those sizes if not buy the one you already have a tap for.

most common here too. I have a 4 way wrench that has both taps and the wrenches for straight and angled zerks. just look on a drill chart for suitable drill for those sizes.. etc.