Questions
Bulk fastener questions, answered.
Minimum quantities, standards, coatings, documentation and lead times into African markets — the questions buyers ask before the first order.
- Why .net and not .com?
- The .com belongs to a different, unrelated business. Our Africa-focused supply operation is fastenersupply.net. If it is not .net, it is not us — Africa buys fasteners on .net.
- What is the minimum order?
- We are a bulk supplier. Enquiries generally start around 500 kg of a single line or a mixed package of one tonne and up, including recurring call-off volumes.
- Do you sell to the public?
- No. We supply businesses: merchants, fabricators, contractors, roofing manufacturers, mines and plant maintenance teams.
- Which standards do you supply to?
- DIN and ISO metric, plus ASTM and imperial where specified. Grades 4.8, 8.8, 10.9 and 12.9, stainless 304 and 316, and galvanised finishes to the exposure class you need.
- How fast is a quote?
- Complete the six-question enquiry and we come back with pricing and an indicative lead-time band, usually within one business day.
- What is the difference between grade 8.8 and grade 10.9 bolts?
- Grade 8.8 has a minimum tensile strength of 800 MPa and yields at 640 MPa; grade 10.9 reaches 1000 MPa tensile and 900 MPa yield. Use 8.8 for general structural work and 10.9 where the connection is highly loaded or pre-tensioned. Never substitute upward without checking — 10.9 is harder and more sensitive to hydrogen embrittlement in plated finishes.
- Can you supply bolts to ASTM instead of DIN?
- Yes. We supply ASTM A325 and A490 structural bolts and imperial UNC/UNF threads alongside metric DIN and ISO products. Tell us the specification in the enquiry and we quote against it rather than converting on your behalf.
- Which drill point do I need for my steel thickness?
- A #2 point handles up to roughly 2 mm, #3 up to 4 mm, #4 up to 6 mm and #5 up to 12 mm of steel. If the point is too small it work-hardens and burns out before it breaks through; if it is too large the screw takes longer to seat. Tell us the purlin or sheet thickness and we specify it for you.
- What is a Class 3 or Class 4 coating?
- They are corrosion-resistance classes used for roofing fasteners, measured in salt-spray and Kesternich cycles. Class 3 suits most inland exposed roofing; Class 4 is specified within a few kilometres of the coast or in aggressive industrial atmospheres.
- Do I need a hardened washer under a grade 8.8 bolt?
- Under a pre-tensioned or high-strength connection, yes. A mild steel washer indents under the head and the joint loses pre-load. Hardened structural washers to EN 14399-6 or ASTM F436 are specified for exactly this reason.
- Should the washer finish match the bolt finish?
- Always. A plated washer paired with a hot-dip galvanised bolt corrodes preferentially and stains the connection. We supply matched finishes as standard.
- When should I use a chemical anchor instead of a through bolt?
- Use chemical when the concrete is cracked, low strength or hollow, when you are fixing close to an edge or between anchors, when embedment must be deep, or when the stud size is non-standard. A through bolt expands and generates edge stress — chemical anchors bond instead of expanding.
- What anchor works in hollow block?
- Expansion anchors are unreliable in hollow block. Use a chemical anchor with a perforated sleeve, or a purpose-made cavity fixing sized to the wall thickness. Send us the block type and the load and we will specify it.
- How do I choose rivet grip range?
- Add the thickness of every layer being joined and pick a rivet whose published grip range brackets that number, ideally near the middle. Multi-grip rivets cover a wide window and let you carry fewer lines in stock.
- What is the difference between an open and closed-end rivet?
- An open-end rivet has a hollow body that stays open after setting; a closed-end rivet is sealed at the tail, which stops moisture and dust passing through the joint. Closed-end costs more and is worth it on exposed or weathertight work.
- Why won't standard nuts run onto hot-dip galvanised threaded rod?
- Galvanising deposits 45–85 microns of zinc on the thread flanks, so a standard nut binds. Nuts for galvanised rod are tapped oversize after coating. We supply them matched — if you buy rod and nuts from different sources you will find this out on site.
- What is the difference between threaded rod and a stud bolt?
- Threaded rod is a stock length you cut as needed. A stud bolt is a finished item cut to a specified length with chamfered ends, usually to ASTM A193 for flanged pipework, and supplied with matched heavy hex nuts.
- Which roofing screw do I need near the coast?
- Within about 5 km of the coast, specify Class 4 coated fixings or a stainless 304 head with a carbon drill point. Directly on the shoreline, use stainless 316. Class 3 fixings will show head corrosion within a few seasons in salt air.
- How many roofing screws per square metre?
- It depends on the sheet profile and purlin spacing, but a common IBR or corrugated roof runs roughly 6–8 fixings per square metre including side laps. Send us the profile and purlin centres and we return the quantity with the quote.
- What do you need to quote a non-standard fastener?
- A dimensioned drawing or sketch, the material grade, the finish, the quantity and the required date. Photographs of the worn part help. If you have a CAD file, send it — it removes interpretation from the quotation.
- What is the lead time on made-to-drawing fasteners?
- Typically four to eight weeks in production plus shipping, depending on process and quantity. Add roughly a week if you want a first-article sample approved before the batch, which we recommend on any repeating item.