Conveyor Bolts, Nuts and Fasteners

Plant lists typically include metric hex bolts and nuts for stringers and frames, holding-down bolts for drive bases, liner bolts for chutes, idler-frame fasteners, and stainless or coated sets for wet or coastal plants. Grade, thread, length, coating (zinc, galvanising, paint-over, stainless) and locking method (nyloc, prevailing torque, spring washers, lock wire where specified) belong in the specification.

Corrosion and vibration are the South African realities: Highveld UV on coatings, KwaZulu-Natal and Eastern Cape salt air, wash-plant slurry, and constant vibration on idler frames. Fasteners that loosen bury themselves in fines and are found only when a frame shifts. Underground plants may have additional owner specifications for coatings and traceability — attach those if they exist; do not invent a grade.

Belt mechanical joints look like “fasteners” in English but are a belt-repair product with belt thickness, clip type and installation tooling. If your stores code is for belt clips, use Mechanical Joints. If you are bolting a walkway, chute or plummer, stay here.

Common applications

Fastener enquiries range from a shutdown bolt kit to a site-wide standardisation. Typical uses:

• Structure and walkway bolting — Stringers, trestles, handrails, kick plates and grating clamps. Coating and grade should match the steel specification, not a mixed box of leftovers.
• Idler frame and pulley housing fasteners — High vibration; locking and correct length so threads are not short in the housing. Often replaced as a set when frames are swapped.
• Chute liner and skirt-board bolts — Must not stand proud into the material stream after lining. Countersunk or specific liner bolts should be named if that is the duty.
• Drive-base and guard fasteners — Including holding-down bolts where civil anchors interface with the drive skid. Say if chemical anchors or holding-down bolts are in scope.

Industries that use this equipment

Mines and quarries consume large volumes of structural fasteners on galleries and idler frames, with vibration and dust as the service conditions.

Wash plants, coal prep and coastal terminals need corrosion-aware coatings or stainless in selected areas.

Cement and process plants often have owner bolt specifications inside a turnkey or fabrication package — attach the spec rather than paraphrasing.

Food and packaging areas may require stainless for hygiene; that is still this category if the bolts are for frames, not belt clips.

Specifications buyers should consider

The list below is a briefing checklist, not a datasheet. Exact ratings, dimensions and standards must come from the duty, existing plant records and the supplier quotation — do not treat generic web copy as a specification.

• Duty: structure, idler frames, pulley blocks, liner bolts, civil anchors, mixed kit — listed separately.
• Diameter, pitch, length, grade if known, and standard (metric as default on modern plant).
• Coating or material: plain, zinc, galvanised, stainless, other.
• Locking method required.
• Quantities by line item, not a single “assorted bolts” lump if you need comparable quotes.
• Owner or mine specification references if they exist.
• Confirmation this is not belt clips / hinge joints.

Factors that affect selection

• Match coating to environment; mixing stainless and carbon steel can create galvanic issues on wet plants — ask rather than guessing.
• Vibration joints need a locking method, not only a higher grade.
• Liner bolts are a wear-item geometry, not a generic hex bolt.
• Civil anchors are a different product from stringer bolts; include embedment notes if you have them.
• Belt mechanical fasteners are a different page and a different supplier pool.

Common problems and failure considerations

• Loose idler-frame bolts leading to tracking and roller loss.
• Corroded nuts that cannot be removed in a shutdown, stretching the outage.
• Proud liner bolts tearing belt covers.
• An RFQ that says “fasteners” and receives belt-clip quotations.
• Grade substitutions that do not meet an owner spec, discovered at site inspection.

Maintenance considerations

• Torque-check critical joints (drive bases, pulley blocks, walkway connections) on a planned interval.
• Replace seized fasteners rather than rounding them off during a panic stop.
• Keep coating systems consistent when replacing a handful of bolts in a galvanised frame.
• After chute lining, inspect the belt path for proud heads.
• Do not reuse heavily stretched or corroded bolts on tension joints.

Questions buyers should ask suppliers

• Are you quoting to our line list and spec, or a generic commercial grade?
• What coating and locking devices are included?
• Can you kit by conveyor or by shutdown area?
• Are certificates of conformity required and included?
• Lead time for stainless or special liner bolts versus commercial hex?
• Please confirm you are not quoting belt mechanical fasteners.

What to include when requesting a quote

Clear briefs produce comparable quotations. Include what you know, and mark estimates separately from measured values. Photos and drawings help more than extra adjectives.

• Line list: size, length, grade, coating, quantity.
• Where they are used (structure, liners, plummer, anchors).
• Locking method.
• Any owner specification PDF.
• Kitting and labelling needs.
• Explicit “not belt clips”.
• Site and shutdown date if installation is included.

Related conveyor information

Related components: mechanical joints, structure, idlers, pulleys.

Guides: Choosing a Conveyor Supplier in South Africa, Industrial Conveyor Maintenance Guide.

Resources: How to request a conveyor quote, Conveyor maintenance guide.

Frequently asked questions