راهنمای سوراخکاری، نصب شفت و نصب پولی زمانبندی should be approached as a drive-system decision. The useful starting point is the mating belt and machine interface, followed by tooth count, working width, shaft mounting and duty conditions. This guide explains the checks that help an engineer or buyer turn timing pulley bore shaft into an RFQ that can be verified against a catalogue row or drawing.
Identify the Drive Before Comparing Dimensions
For timing pulley bore shaft, identify the complete belt marking before comparing pulley diameters. HTD is a curvilinear synchronous system and the nominal pitch must stay associated with its profile family. Record the driver and driven tooth counts when an existing ratio must be preserved. For a new drive, document the target speed ratio, driver speed and expected load before choosing tooth counts. This prevents a component-level decision from overriding the machine requirement.
For a replacement project, compare the measured value with the installed belt and machine arrangement before deciding that a catalogue row is equivalent. For a new project, document the design basis so later maintenance teams can understand why the pitch, tooth count and mounting style were selected.
Dimensions That Control the Installation
A pulley can match pitch and tooth count yet still fail to fit the machine because the bore, hub, flange or axial position differs. Measure the shaft interface, belt-face width, hub projection on both sides and the belt line relative to a stable machine datum. Where a taper bush is used, record both the pulley series and bush code. Where a finished bore is required, include fit, keyway and any retaining method on the drawing.
For a replacement project, compare the measured value with the installed belt and machine arrangement before deciding that a catalogue row is equivalent. For a new project, document the design basis so later maintenance teams can understand why the pitch, tooth count and mounting style were selected.
Operating Conditions That Belong in the Selection
The same nominal timing pulley bore shaft component can see very different service depending on the machine. Starts per hour, reversing, shock loading, continuous operating time, temperature, contamination, cleaning and access for tensioning all influence the drive. A compact automation axis emphasizes repeatable motion and controlled alignment, while a conveyor or process machine may emphasize continuous duty and service access. Supply these conditions instead of asking the pulley to be selected from size alone.
For a replacement project, compare the measured value with the installed belt and machine arrangement before deciding that a catalogue row is equivalent. For a new project, document the design basis so later maintenance teams can understand why the pitch, tooth count and mounting style were selected.
Inspection Points Before Installation
Inspection should focus on dimensions that affect the drive: the shaft interface, axial location, tooth condition, face width and any drawing-controlled runout or datum relationship. A generic quality statement does not define acceptance. If a dimensional report, material document or order-specific record is required, identify it before production. During maintenance, watch for flange damage, edge wear, debris and signs that the pulley has moved on the shaft.
For a replacement project, compare the measured value with the installed belt and machine arrangement before deciding that a catalogue row is equivalent. For a new project, document the design basis so later maintenance teams can understand why the pitch, tooth count and mounting style were selected.
Open Questions to Close Before Ordering
What exact HTD profile and width is installed or specified?
What ratio or existing tooth count must be preserved?
What bore, fit, keyway or taper-bush arrangement is required?
How much hub projection and flange clearance is available?
What are the speed, load, starts, reversing and operating hours?
Which drawing, material or inspection records must accompany supply?
What to Send With the RFQ
Send profile, tooth count, belt width, shaft interface, hub/flange details, quantity, destination and a drawing or replacement measurement sketch. Add speed, ratio, load, center distance and environment for a new drive. Review the خانوادههای محصولات HTD، استفاده از راهنمای انتخاب, or compare the relevant application notes.
The Shaft Interface Is a Controlled Feature
Record shaft diameter, intended fit, keyway or bush, hub length and the axial belt-line reference. For replacement parts, measure both sides because the hub can be asymmetric.
Keep measured values, catalogue references and project requirements clearly separated. If a required point is not stated in the relevant catalogue table or approved drawing, include it as an RFQ question or drawing requirement instead of filling the gap with a plausible but unverified value.
Do Not Convert Maximum Bore Into the Ordered Bore
Where a taper-bush table shows a maximum bore, treat it as a limit for that bush configuration rather than the shaft size to order. The actual shaft and bush code still need to be specified.
The purchasing record should keep a clear link between the machine requirement and the selected pulley. That means the complete belt or profile identity, tooth count, working width and shaft-interface information remain together with the product code. Any special material, finish, controlled tolerance, marking or report requirement should be stated separately so it cannot be mistaken for a universal feature of the whole family.
Procurement and Documentation
Once the selection is clear, keep the accepted product identity, quantity, destination and drawing revision on the same purchase line. Standard catalogue parts are normally planned around production-quantity minimums, while larger or higher-value items can be reviewed against the practical order value. Qualified new-client samples of 1–5 pieces may be reviewed at sample pricing when the configuration and manufacturing route are suitable.
Mixed-model orders can be consolidated toward a practical order value of about USD 1,500. Special materials and special processes follow the minimum quantity required by that process. Very small one- or two-piece requests are handled only as qualified engineering validation or paid-sample cases rather than retail replacement orders.
Lead time is confirmed after the technical definition is clear. Standard parts are typically planned at 10–25 business days, custom components at 20–45 business days, and project-based assemblies or related equipment at 45–120 business days where applicable. EXW, FOB, CIF and DAP are commonly supported; FCA, CFR, CPT, CIP and DDP can be discussed for suitable shipments. Treat these as planning ranges, not a shipment promise before order review.
A Practical Decision Sequence
Start with shaft diameter, fit requirement, key/bush method and hub length. Keep the machine requirement separate from the catalogue choice: first identify what the drive must preserve, then compare only the rows or drawings that match that identity. This keeps a familiar-looking pulley from being accepted before its functional interfaces have been checked.
For an existing machine, preserve the original relationship before making changes. For a new design, record the target ratio, operating context and installation envelope so the shaft-interface definition can be reviewed later without relying on memory or a photograph alone.
Build a Measurement Record
The most useful measurement set contains shaft measurement, key or bush details, hub projection, axial datum and drawing. Mark which values were measured on the machine and which values came from a catalogue or released drawing. When a feature is inaccessible, photograph its relationship to a stable datum and identify it as confirmation-required rather than filling the gap with an assumed value.
Dimension drawings should be viewed at full readable width. Never scale a screenshot and then treat the scaled dimension as a measurement; use the printed value and the correct construction type.
One Failure Mode Worth Avoiding
A common error is quoting a bore diameter without identifying the complete shaft connection. That can produce a part that appears close in the catalogue yet changes ratio, belt line, mounting or service access. Resolve the conflicting feature before requesting price so the quotation refers to one mechanically coherent configuration.
If two candidate configurations remain possible, send both the machine measurements and photographs and the preferred option. The quotation can then identify which interface still needs confirmation instead of silently converting uncertainty into a specification.
Turn the Technical Choice Into a Quote-Ready Line Item
State the HTD/profile family and complete belt information.
Provide the tooth count, working width and relevant dimension or drawing references.
Define the bore or bush, shaft data, hub projection and belt-line position where applicable.
Add quantity, destination, required documents and the drawing revision used for the request.
When one item above is genuinely unknown, label it for confirmation. A precise open question is more useful than a plausible value that was never measured.
Questions Buyers Commonly Ask
What should be confirmed first?
Confirm shaft diameter, fit requirement, key/bush method and hub length. That prevents later dimensions from being compared across the wrong product family or installation route.
What information is most useful for a replacement?
Send shaft measurement, key or bush details, hub projection, axial datum and drawing, plus clear photographs before the old pulley is removed. The photographs preserve axial orientation and neighboring clearances that a loose part cannot show.
When should a drawing be used?
Use a controlled drawing whenever the catalogue row does not completely define the shaft interface, hub/flange arrangement, finish, tolerance or inspection requirement that matters to the machine.
Do Not Separate the Interface Decision From the Exact Model
Material, bore and taper-bush availability can change with pulley size and construction. Use the material and mounting information stated for the selected row rather than assuming every member of the pitch family can be supplied identically. If the machine needs a feature outside the supported row, move to a drawing-controlled custom review.
A taper-bush maximum bore is a capacity limit for that bush, not the ordered shaft diameter. State the actual shaft size. For straight-bore work, state the required finished interface and any keyway or locking feature explicitly. Hub projection and the belt centerline should remain visible on the drawing because they can decide whether the part installs correctly.
Material Requests Need a Functional Reason
Where several materials appear in the catalogue family, choose from the configurations actually supported. If a special material, coating or treatment is required by the environment or customer standard, state it as a controlled order requirement and discuss the process MOQ. Do not infer material solely from the color of a product photograph.
For inspection, identify what the material choice or interface is expected to control. This makes a material document, dimensional record or other report meaningful to the actual order.
The Shaft Interface Should Be Defined After the Pulley Family Is Fixed
The shaft connection cannot be selected reliably before the belt-side identity is known. Fix the HTD family, tooth count and working width first, then review the bore or taper-bush route, hub length, keyway where applicable and axial location. This sequence prevents a convenient bore choice from steering the project into the wrong pulley family.
For replacements, measure the actual shaft and document shoulders, spacers, retaining features and available withdrawal space. A nominal shaft size does not by itself define the finished fit, keyway or tolerance. When those details are not published in the catalogue row, they belong on the project drawing rather than in a generic product description.
For taper-bush arrangements, keep the exact bush designation tied to the supported pulley row and shaft. For straight-bore custom machining, state the finished interface and inspection requirement explicitly so the purchasing record is reproducible.
Do Not Turn a Shaft Measurement Into an Assumed Fit
A measured shaft diameter identifies the physical shaft but does not automatically define the intended fit, tolerance or keyway. Those controls come from the machine drawing, design intent or an approved replacement specification. Record the measured value as a field measurement and keep it separate from the dimension that will be released for manufacture.
Also record axial locating features: shoulders, spacers, nuts, collars or retaining rings. The bore can be correct while the pulley still sits in the wrong belt plane if the hub or locating stack differs from the original arrangement.
Define the Shaft Interface Only After the Belt-Side Geometry Is Fixed
The shaft connection controls how the pulley locates, transmits torque and maintains its axial position. Before deciding bore, keyway or taper-bush details, confirm the HTD family, tooth count and working width. This prevents a custom shaft feature from being added to the wrong pulley family.
A shaft diameter by itself is not a complete interface definition. Replacement work may also depend on fit, keyway, shoulder position, retaining method, hub projection and available installation space. If any of those features are machine-critical, place them on the controlled drawing rather than relying on a verbal note.
Record actual shaft diameter and any controlled fit requirement.
Identify keyway dimensions or the documented taper-bush designation as applicable.
Measure hub projection, shoulder location and belt centerline.
Define the datum and acceptance value for any controlled shaft-interface dimension.
For obsolete machines, previous repair work may have changed the shaft from the original design. Measure the current interface before ordering a replacement and keep that information with the service record.
