Tap Drill Size Chart

M36 x 3 Tap Drill Size

Tap drill

33 mm 1.2992 in

Use a 33 mm drill (1.2992 in) for 77.0% thread.

Fine thread M36 x 2? Use 34 mm. (1.3386 in, 77.0% thread)

The drill size for a M36 x 3 tap is 33 mm (1.2992 in). If you are wondering what size drill bit a M36 x 3 tap needs, that is the one: it leaves 77.0% of thread, which is the figure standard tap and drill charts are built around. Below are the other holes you might want for this size - a larger drill for tough material, the form-tap hole, and the clearance holes for the bolt that goes in.

Every drill for M36 x 3

Tap drills and clearance drills for M36 x 3 (Metric fine, 3 mm pitch). Percent of thread is the figure stored for each drill, which reproduces from the major diameter and pitch of M36 x 3.
Use Drill Decimal in mm % thread
Standard tap drill Cut tap, general use (D - P) 33 mm 1.2992 33.00 77.0%
Inch substitute Closest inch drill if you have no metric set 1-19/64″ 1.2969 32.94 78.5%
Hard material Stainless, tool steel, anything that fights the tap 33.5 mm 1.3189 33.50 64.2%
Form (roll) tap Theoretical 34.67 mm - starting point, check your tap maker's chart 34.5 mm 1.3583 34.50 —

Clearance holes for a M36 x 3 bolt

A clearance hole is not tapped. It is the hole in the part the bolt passes through, so it is always larger than the thread.

Clearance holes for M36 x 3 per ISO 273. Clearance depends on the bolt diameter alone, so every M36 thread shares these figures.
Fit Hole mm Hole in
Fine 37.00 1.4567
Medium 39.00 1.5354
Coarse 42.00 1.6535

M36 x 3 dimensions

Nominal dimensions for M36 x 3. The basic internal minor diameter is the hole a 100% thread would start from, which is why no tap drill is ever that small.
Dimension Inch mm
Major diameter 1.4173 36.00
Basic internal minor diameter 1.2894 32.75
Pitch 0.1181 3.00
Thread designation M36 x 3

What the hole looks like

Cross-section of a M36 x 3 tapped hole, drawn to scale The drilled hole is 33 mm, 1.2992 inches or 33.00 millimetres across. The tap cuts outward from that wall to the major diameter of 1.4173 inches. A 100 percent thread would reach in to the basic minor diameter of 1.2894 inches, shown as a dashed line; the difference is why this drill gives 77.0% of thread. major 36 mm drill 33 mm · 33 mm dashed = 100% thread at 32.75 mm
M36 x 3 in section, to scale. The accent line is the thread the tap cuts from a 33 mm hole; the dashed line is where the crest would sit at 100% thread. The gap between them is the 23.0% of thread this drill leaves behind.

Work out a different hole for M36 x 3

Pre-filled with M36 x 3. Change the material, the tap type, or which drills you actually own, and it picks the closest real drill and tells you the percent of thread you end up with. The tables above are the published figures and do not depend on this.

The general-purpose target

Tap type
Drills you have

Best drill you have, cut tap, 70% target

1-5/16″1.3125 in33.34 mm68.3% thread

Theoretical hole 33.27 mm

One size down, deeper thread33 mm 1.2992 in · 77.0%

One size up, easier tapping33.5 mm 1.3189 in · 64.2%

For comparison, the published chart drill for M36 x 3 is 33 mm at 77.0% thread.

Notes on M36 x 3

Middle pitch at this diameter
At 36 mm the data holds 3 pitches: M36 x 4, M36 x 3, M36 x 2. M36 x 3 sits between M36 x 4 and M36 x 2.
Not the same as M36 x 4
M36 x 4 and M36 x 3 share a 36 mm major diameter but not a pitch, and they take different drills: 32 mm for M36 x 4, 33 mm for M36 x 3. The taps and the fasteners are not interchangeable.
What the standard drill gives you
33 mm leaves 77.0% of thread (D - P). That is in the normal 65-80% band most shop charts aim for.
Stainless, tool steel and other tough material
33.5 mm opens the hole to 64.2% engagement. Less material for the tap to cut means less torque and less heat, at the cost of some thread depth.
Using a form (roll) tap
A form tap displaces metal instead of cutting it, so it needs a larger hole: 34.5 mm, against a theoretical 34.67 mm. Treat that as a starting point and check your tap maker's chart.
Closest inch size
1-3/8-6 is the nearest inch thread by diameter (34.93 mm against 36 mm). It is a planning reference only. The two are not interchangeable: the pitches differ, and a bolt from one will not run into a hole tapped for the other.

Related sizes

Same diameter, different pitch

Next size up and down

Closest inch size

1-3/8-6 1-7/32″ · 1.2188 in · 30.96 mm · 72.1% 34.93 mm major against 36 mm

Not interchangeable. 1-3/8-6 is the nearest size by diameter, nothing more. The pitches differ, so a 1-3/8-6 fastener will not run into a M36 x 3 hole and forcing one will strip both.

Guides for tapping M36 x 3

Longer reads on the decisions behind the numbers above.

All guides →

M36 x 3 tap drill: common questions

What size drill bit do I need for a M36 x 3 tap?
A 33 mm drill, 1.2992 in. That leaves 77.0% of thread, which is the standard chart figure for M36 x 3.
What is the drill size for a M36 x 3 tap in inches?
The 33 mm tap drill measures 1.2992 in. If you only have inch drills, 1-19/64 in (1.2969 in) is the closest, giving 78.5% thread.
What drill should I use for M36 x 3 in stainless steel?
Use 33.5 mm instead of 33 mm. It leaves 64.2% of thread rather than 77.0%, so there is less material for the tap to cut and less chance of snapping it.
Is M36 x 3 the same as M36 x 2?
No. Both are 36 mm threads, but the pitch differs, so the drills differ: 33 mm for M36 x 3 and 34 mm for M36 x 2. The taps and the fasteners are not interchangeable.
What is the clearance hole for an M36 x 3 bolt?
For a medium fit, 39 mm per ISO 273. A clearance hole is not tapped; the bolt passes straight through it.
A 4 × 6 in card with the drills for this size.