Engineering Hardware manufactures custom screw to a drawing, a sample or a dimensioned sketch, in sizes, materials, strength classes and finishes the standard range does not cover. They are made by cold heading and warm forging. The catalogue range is already made to GB, ASME B18.6.3, ASME B18.3. Minimum order 2,000–5,000 pieces; samples within 7 days of drawing approval.
Screw outside the standard range — a size that is not in the table, a head that is not in the standard, a material or a finish that the catalog part does not come in.
What is already made in this family
The catalog carries 131 standard screw products, built to these designations. A special part is normally a variation on one of them rather than a blank sheet — which is what keeps the tooling cost down:
- GB
- ASME B18.6.3
- ASME B18.3
- ISO 4026
- ISO 7045
- ISO 7046
- ISO 4762
- DIN 7985
- DIN 912
- ISO 10642
Standard parts in this family
What can be changed on a screw
- Dimensions — lengths, diameters and head sizes outside the standard table.
- Thread — fine pitches, left-hand threads, partial threading, non-standard thread lengths.
- Material — grades the catalog part is not stocked in, up to and including the customer's own specified steel.
- Strength class — a higher property class than the standard part, where the material and heat treatment allow it.
- Finish — plating, passivation or coating to a salt-spray requirement rather than to a default.
- Head and drive — a drive that is not in the standard, or a head form specific to the assembly.
- Marking — part numbers, logos or traceability codes on the head.
Materials this family is supplied in
The grades the catalog already describes for these parts. Anything outside this list is quoted against the drawing.
- A2 Stainless Steel
- A4 Stainless Steel
- Grade 8 8 Steel
- Grade 12 9 Steel
How a custom screw is made
Which of these applies depends on the drawing and on the quantity. Volume is what usually decides it: forming needs tooling and pays it back over a run, machining needs none and does not.
Cold Heading
Forming a head on a wire blank at room temperature, in one or several blows, with no metal cut away.
Warm Forging
Forming between cold and hot — hot enough to reduce the forming load, cool enough to keep the tolerance.
Thread Rolling
Forming a thread by pressing the blank between hardened dies, displacing metal rather than cutting it.
CNC Machining
Cutting to a program rather than to a setting, so the hundredth part matches the first.
Drilling
Producing a hole — through, blind, cross-drilled or as the pilot for a thread.
Knurling
Rolling a pattern into a surface to make it grip — either a hand or an anchoring surface.
EDM
Eroding metal with controlled electrical sparks, with no cutting force at all.
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.
No drawing?
Most replacement parts arrive without one. None of these routes is a problem, and all of them end with a drawing produced for your approval before anything is cut or formed.
- A physical sample
- The most reliable route. The part is measured, the thread and finish identified, and a drawing produced for your approval before anything is made.
- Photographs with a scale
- Photographs against a ruler or a caliper, ideally with a thread pitch gauge reading. Enough to identify a standard part or to start a drawing for a non-standard one.
- A hand sketch
- A sketch with the dimensions that matter is a perfectly good starting point — the drawing gets made from it and comes back to you to check.
- The assembly it goes into
- Sometimes the fastener is wrong in the first place. If the joint is described rather than the part, a better part can be proposed.
Draw it here
No CAD, no account, nothing to install. Draw the part in your browser, generate a real ISO metric thread from M1 to M100 with the end treatment it needs, dimension it, and export a PDF or a DXF to attach below. Sheets run to two metres for long studs and threaded rod.
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.
Which screw standards do you already work to?
The catalog carries parts built to GB, ASME B18.6.3, ASME B18.3, ISO 4026, among others. A special part is usually a variation on one of these rather than a new design.
How is a custom screw manufactured?
Depending on the drawing and the volume: cold heading, warm forging, thread rolling, cnc machining, drilling, knurling, edm. Forming processes need tooling and repay it over a run; machining needs none, so it is the usual route for a first article or a short run.