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Custom Manufacturing

Tapping

Cutting or forming an internal thread in a drilled hole.

The choice that matters is between a cutting tap and a forming tap. A cutting tap removes metal and produces a chip, which has to go somewhere — forward in a through hole, back out of a blind one, and getting that wrong is how taps break. A forming tap cuts nothing: it displaces the metal, leaving a stronger thread with no chip at all, and works beautifully in ductile materials and badly in brittle ones. Hole size differs between the two, which is the detail most often missed.

What Tapping is the right choice for

  • Internal threads in nuts, blind holes and tapped components
  • Forming taps: ductile materials, where thread strength matters
  • Cutting taps: cast iron, brass, and anything that will not flow

Where it is the wrong choice

  • Blind holes need the right flute geometry or the tap breaks
  • Forming taps need a different, larger pilot hole than cutting taps

Parts produced this way

Usually combined with

Tapping is rarely the only operation on a part. On most jobs it sits in a sequence with:

Order terms

Minimum order
2,000–5,000 pieces. The exact figure depends on the part: it is set by the tooling the drawing calls for, and is confirmed when the drawing has been reviewed.
Samples
Within 7 days of drawing approval.
Drawing
Preferred, but not required — a sample, photographs or a sketch is enough to start.

What a quotation needs

Nine things, and a drawing settles most of them at once. Where a field is unknown, say so — an assumption stated is better than a blank, and several of these can be recommended rather than specified.

Drawing
A 2D drawing (PDF or DWG) or a 3D model settles almost every other question on this list at once.
Dimensions
Diameter, length, head size and any features — enough to know what is being made.
Tolerance
Tolerance is the single biggest cost driver. Tell us which dimensions are critical and which are not — holding everything tight costs money on features nobody measures.
Material
Carbon steel, alloy steel, stainless, brass, aluminium, titanium — or the application, and we will suggest one.
Strength grade
Property class to ISO 898-1 (8.8, 10.9, 12.9) or stainless class to ISO 3506 (A2-70, A4-80). This decides the material and the heat treatment together.
Thread standard
Metric coarse, metric fine, UNC, UNF, BSW or a pipe thread — and the tolerance class if it is specified.
Surface finish
Zinc, hot-dip galvanised, black oxide, Dacromet, Geomet, nickel, passivation, or plain. Salt-spray hours if you have a requirement.
Quantity
Annual volume and first-order quantity. Volume changes which process is the right one, so it changes the price more than most buyers expect.
Application & environment
What the part holds together, and what it has to survive — temperature, vibration, chemicals, salt. This is what lets us catch a specification that will not work before it is made.

Questions

What is the minimum order quantity for a custom part?

Between 2,000 and 5,000 pieces for most parts. The exact figure depends on the part: it is set by the tooling the drawing calls for, and is confirmed when the drawing has been reviewed.

How long does a sample take?

Within 7 days once the drawing has been approved. The drawing stage comes first, and for a part being reverse-engineered from a sample it is where most of the time goes.

Can you make a part without a drawing?

Yes. A physical sample, photographs against a scale, or a dimensioned sketch are all workable starting points. A drawing is produced from whichever of those you have and sent back for approval before anything is made.

When is Tapping not the right process?

Blind holes need the right flute geometry or the tap breaks. Forming taps need a different, larger pilot hole than cutting taps.

Which fasteners are made by tapping?

In this catalog: nut, threaded insert, machined component, standoff & spacer. Whether it is the right process for a particular part depends on the drawing and the quantity.

Send the part

A drawing answers most of this at once. If you do not have one, fill in what you know and attach a photograph — samples follow within 7 days of the drawing being approved.

A 2D drawing (PDF or DWG) or a 3D model settles almost every other question on this list at once.
Diameter, length, head size and any features — enough to know what is being made.
Tolerance is the single biggest cost driver. Tell us which dimensions are critical and which are not — holding everything tight costs money on features nobody measures.
Carbon steel, alloy steel, stainless, brass, aluminium, titanium — or the application, and we will suggest one.
Property class to ISO 898-1 (8.8, 10.9, 12.9) or stainless class to ISO 3506 (A2-70, A4-80). This decides the material and the heat treatment together.
Metric coarse, metric fine, UNC, UNF, BSW or a pipe thread — and the tolerance class if it is specified.
Zinc, hot-dip galvanised, black oxide, Dacromet, Geomet, nickel, passivation, or plain. Salt-spray hours if you have a requirement.
Annual volume and first-order quantity. Volume changes which process is the right one, so it changes the price more than most buyers expect.
What the part holds together, and what it has to survive — temperature, vibration, chemicals, salt. This is what lets us catch a specification that will not work before it is made.
Solve the arithmetic shown in the image.