Machine Screw
Metric and imperial machine screws for tapped holes and nut assemblies.
A machine screw does not form its own thread. It goes into a tapped hole or takes a nut, which moves the whole specification onto three things: thread form and fit, grade class, and finish. Get those three right and the rest is head style preference.
Ehons produces machine screws across metric, UNC, UNF and BSW threads in carbon and alloy steel, with grade classes from 4.6 to 10.9 and the SAE J429 range. Because they come off the same lines and the same finishing plant as the rest of the catalogue, an assembly can be specified in one consistent coating rather than mixing suppliers and mixing plating colours.
Why buyers choose it
- Full thread range: metric, UNC, UNF and BSW
- Grade classes 4.6 to 10.9 including SAE J429 Gr.2, Gr.5 and Gr.8
- Same finishing plant as the rest of the catalogue, so colours match across an assembly
- Carbon steel and alloy steel to suit the load case
Send the mating thread, the grade class and the finish and the size will be confirmed against the closest standard before quoting. Samples of this item are free of charge.
Specification
| Standard | ASME, ASTM, IFI, ANSI, DIN, BS, JIS |
|---|---|
| Material | Carbon Steel, Alloy Steel |
| Grade / Class | 4.6, 4.8, 5.6, 8.8, 10.9, SAE J429 Gr. 2, Gr. 5, Gr. 8, A307 A/B, A394, A449 |
| Thread | M, UNC, UNF, BSW |
| Finish | Self Colour, Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black Oxide, Nickel, Chrome, HDG |
| Packing | 15 KGS/CTN, 48 CTN/Solid Wood Pallet |
| Loading Port | Shanghai or Ningbo |
| Minimum Order | 500 kg |
| Payment | T/T, L/C |
| Samples | Free of charge |
| Main Markets | EU, USA, Canada, South America |
Specification as published by Haiyan Ehons Industrial Co., Ltd.. Head style, drive and thread length are specified with the order rather than fixed by the catalogue.
Technical detail
| Standards | Produced to ASME, ASTM, IFI, ANSI, DIN, BS and JIS references. |
|---|---|
| Material | Carbon steel or alloy steel. |
| Grade class | 4.6, 4.8, 5.6, 8.8 and 10.9; SAE J429 Gr.2, Gr.5 and Gr.8; ASTM A307 A/B, A394 and A449. |
| Thread | Metric, UNC, UNF and BSW. |
| Finish | Self colour, plain, zinc plated in clear, blue, yellow or black, black oxide, nickel, chrome and hot dip galvanised. |
Problems this screw solves
Mixed suppliers give mismatched plating
Two batches of clear zinc from two plants rarely match visually. Buying the whole assembly from one finishing plant removes the problem.
Grade class gets assumed rather than stated
A screw that looks identical can be class 4.8 or 10.9. Ordering against an explicit grade class avoids a substitution that only shows up under load.
Thread fit is ignored until assembly
A tapped hole and a screw have to share a tolerance class. State the mating thread when you order and the fit is checked rather than assumed.
Where it is used
- Assembling machine guards, covers and access panels into tapped holes
- Electrical enclosure and switchgear assembly
- Sheet metal assemblies using nuts or captive nuts
- Maintenance kits where a fixed grade class has to be matched exactly
Who buys it
Machinery builders, electrical panel assemblers, sheet metal fabricators and maintenance distributors who buy by grade class and thread rather than by application.
Quality control priorities
Thread gauging is the primary check on this item: go and no-go ring gauges on samples through each run, plus hardness testing to confirm the grade class after heat treatment. Plated high-grade parts are routed for baking to address hydrogen embrittlement.
Customisation
Head style, drive and thread length are all open. Where a screw has to match an existing assembly, send one original part; measuring a sample settles the thread form faster than a description does.
How it compares
Against a self-tapping screw
A machine screw needs a prepared thread but gives a removable, re-usable joint at a defined grade class. A tapping screw makes its own thread once.
Against a set screw or bolt
Terminology varies by market; what matters is the grade class, the thread and whether the shank is fully or partially threaded. State those three and the part is unambiguous.
Against stainless fasteners
Carbon and alloy steel here. Where the environment demands stainless, say so at enquiry stage so the material is quoted rather than substituted.
Installation notes
Specify by grade class, not by look
Give the class on the order line. Visual inspection cannot distinguish 4.8 from 8.8.
Bake plated high-grade screws
Any electroplated part above class 8.8 should be baked after plating. Confirm this on the order.
Match thread tolerance to the tapped hole
Supply the tap designation where the fit is tight.
Torque to the class, not to feel
The installation torque that suits a class 4.8 screw will under-tension a class 10.9 one in the same size.
Frequently asked questions
Which head styles are available?
Can you supply to a specific DIN or ANSI number?
Do you supply nuts and washers to match?
What is the minimum order quantity?
Which finishes are offered?
What payment terms do you accept?
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Packed 15 KGS/CTN, 48 CTN/Solid Wood Pallet. Loading at Shanghai or Ningbo. Minimum order 500 kg for this item.