CNC Milling Split Clamp Saddle Bracket with 0.01mm Clamping Fit and Precision Slit Bore
Split Clamp Saddle Bracket
,Bore First Then Slit
,0.01mm Clamping Fit
A split clamp saddle works as a spring, not just a hole. The bore is cut to your measured shaft, a slit releases one side, and a bolt closes the bore onto the shaft with controlled preload.
- Bore fit0.01 mm clamping bore, cut to the measured shaft and pre-slit
- Slit0.8–2 mm kerf, sawn after boring so the bore springs closed evenly
- Order size1 piece, with slit prototypes in 3–7 working days
- QualityISO 9001:2015 system; 6061-T6 / 7075-T6 and 304 stainless
- OptionsClamp test on request; exporting since 2008
A split clamp saddle works by elastic deflection: the bore is cut slightly to size, a slit releases one side, and a bolt pulls the two halves together so the bore closes onto the shaft with controlled preload. Every failure mode comes from the sequence, not the drawing — a bore cut after slitting will not be round, a slit sawn too wide cannot close, a slit sawn before the bore relieves stress in the wrong direction, and an anodized bore changes the grip.
So the order is fixed: bore first, then slit, then the clamp bolt hole, with the bore spring measured after slitting. We machine these from 6061-T6 or 7075-T6 billet, and the clamping surfaces are masked before anodize so the grip does not change between the first delivery and the tenth.
| Stage | Operation | Why the sequence is fixed |
|---|---|---|
| 1 | Billet and stress relief | Block sawn oversize, faced and relaxed so the bore stays round once the slit releases the section. |
| 2 | Base and datum | Base face, mounting holes and reference edges machined on the datum used for bore and slit. |
| 3 | Bore boring | Bore finished to the shaft fit before any slit exists; roundness and taper checked while the section is still closed. |
| 4 | Slitting | Slit sawn to drawing kerf with a slitting saw on the machine tool, not by hand; kerf and slit depth measured. |
| 5 | Clamp bolt hole | Cross bolt hole drilled and counterbored through the split, square to the slit so the clamp closes evenly. |
| 6 | Spring check | Bore measured closed and open to confirm the gap closes by the amount the design needs. |
| 7 | Anodize with masking | Type II 10–15 µm; bore, slit faces and bolt counterbore masked so grip and bolt fit are unchanged. |
| 8 | Final inspection | Bore diameter, slit kerf, bolt squareness and mounting pattern recorded; parts bagged individually. |
| Feature | Held to | Verified by |
|---|---|---|
| Clamping bore diameter | ±0.01 mm | Bore gauge, closed and open |
| Bore roundness | 0.01 mm | CMM roundness scan |
| Bore taper | 0.01 mm over length | CMM axial scan |
| Slit kerf width | ±0.1 mm on 0.8–2 mm | Pin gauge and vision check |
| Slit depth | ±0.3 mm | Depth gauge |
| Bolt hole squareness to slit | 0.05 mm | CMM |
| Base flatness | 0.03 mm | Granite plate plus indicator |
| Mounting hole position | ±0.05 mm | CMM |
| Anodize thickness | 10–15 µm Type II | Coating gauge, batch record |
The bore is quoted against your measured shaft, not the nominal: for a clamp that grips, we cut to a light clearance and rely on the spring to close; for a clamp that locates only, we open the bore to the clearance you specify. Send the shaft size and the grip requirement together and the two numbers go on the drawing before cutting.
- Material: 6061-T6 standard; 7075-T6 where clamping load is high; 304 or 316L stainless for wash-down or corrosive duty; brass for non-marring applications.
- Finish: Type II anodize 10–15 µm in black, clear or colour; hard anodize 25–50 µm on wear faces; chromate for conductive areas; bead blast matte before anodize.
- Geometry: single slit, double slit, offset slit, hinged two-piece version, flange base, slotted base for adjustment, saddle with rubber or PTFE insert groove.
- Clamping: single cross bolt, twin bolts, grub screw preload, lever cam pocket, torque specification recorded on the drawing.
- Size: bore 6 mm to 120 mm, body 25 mm to 220 mm, bolt M3 to M12.
- Input: STEP, IGES, X_T, DXF, PDF, or a worn clamp we measure and re-model before machining.
A split clamp drawing gives away shaft sizes, bolt positions and the interface of the machine it belongs to. We sign a mutual NDA before the file is opened — ours in English or Chinese, or your own form — and return a countersigned copy before work starts. Access is limited to the project engineer, the milling programmer and the cell supervisor, with the file in a restricted folder rather than the shop network. No photographs are taken of customer parts for our catalogue or website, customer parts are never displayed or reused as samples, subcontracting requires your written approval, and at program close files and inspection data are deleted or returned with written confirmation.
Dongguan Changxinda Precision Technology Co., Ltd has been machining custom parts since 2008: 15+ years, 90 to 100 staff, 50–60% exported to North America and Europe, 200+ customers served, turnover in the RMB 10–20 million band. The floor holds 4-axis and 5-axis CNC machining centres, turn-mill combined lathes and CNC lathes under an ISO 9001:2015 system, producing parts for medical, robotics, automotive, aerospace, automation, laser, LED, lithium battery and precision instrument programs. Milling, boring, slitting, anodize coordination and inspection are all in our own hands in Dongguan.
Split clamps and saddle brackets from this plant ship into ten industries. Each line is a category we machine regularly, with the parts customers actually order.
| Industry | Typical parts we machine |
|---|---|
| Consumer electronics | Phone, tablet and laptop housings / heat spreaders / camera brackets / VR and AR headset structural parts / smart wearable enclosures |
| Automation and industrial equipment | Automation jigs and fixtures / module frames / linear guide blocks / motor mounts / sensor housings / conveyor line components |
| Semiconductor and vacuum | Vacuum chamber bodies / vacuum fittings / precision bases for semiconductor equipment / thermal and insulating parts / inspection tooling |
| Medical equipment | Surgical instrument bases / medical instrument housings / endoscope components / aesthetic device structural parts (medical grade aluminium and stainless) |
| Automotive | New energy motor housings / battery end plates / sensor brackets / lighting structural parts / retrofit components / hydraulic valve blocks |
| Aerospace and UAV | Aircraft structural parts / UAV frames / landing gear components / avionics instrument housings (lightweight precision parts) |
| Optics and photonics | Optical lens barrels / lens mounts / light source heat sinks / camera module brackets / inspection optical platforms |
| Telecom | 5G heat dissipation cavities / filter components / signal adapter structural parts / telecom equipment enclosures |
| Robotics | Robot arm joint parts / robot bases / reducer housings / AGV structural components |
| Instrumentation | Test equipment housings / precision gauge bases / flow meter components / laboratory equipment parts |
All ten sectors run through the same plant and the same ISO 9001:2015 inspection discipline — only the material, finish and documentation package change.
- Prototype: 3–7 working days after drawing approval including anodize; 10–14 days where a clamp test is specified.
- Small batch 10–100 pcs: 7–14 working days in a reserved milling cell slot.
- Repeat orders: run from archived programs, fixtures and the anodize rack; bore and slit are cut to the same mid-band values every time.
- Capacity: 10,000 pieces per month across the plant.
- Visibility: a dated progress note with photographs of your actual clamps at boring, slitting and inspection.
- Shipping: slits protected, parts bagged, foam-lined export carton, express or air and sea per your forwarder.
- Rush: overtime slots and an express anodize line held weekly; tell us the deadline and we confirm before you order.
Because slitting releases residual stress and changes the section stiffness. A bore cut after the slit is measured on a sprung body and comes out oval once the bolt is tightened; boring first, then slitting, keeps the bore round and makes the closed dimension predictable. We measure the bore both closed and open on the first part of every batch so you see the spring.
Enough to close under the bolt without the two faces bottoming out — typically 0.8–2 mm depending on bore size and wall thickness. Too wide and the clamp cannot develop preload; too narrow and the slit closes at the surface while the bore stays loose. Send the bolt torque you intend to use and we recommend the kerf before cutting.
It would if the bore were coated, so the bore, slit faces and bolt counterbore are masked. The visible body still gets the full 10–15 µm Type II coating. On clamps that repeatedly open and close, hard anodize on the outer faces gives better wear resistance while the bore stays bare aluminium.
Yes. Send the measured shaft diameter, the bolt torque and whether the clamp grips or only locates; we set the bore and the kerf to suit and, where the shaft is worn, cut to the worn size rather than the original drawing. Reverse engineering of an existing split clamp is routine work.
One piece, no tooling charge. Price follows bore size, body size, slit configuration, bolt pattern, material and finish, and a written quotation normally returns within 24 hours of receiving the drawing or model.
Yes. NDA signed and countersigned before the file is opened, access limited to the engineer, programmer and supervisor, no photographs of customer parts, and nothing about your program in our catalogue or website without written permission.
Attach the drawing or model with the quantity and the deadline, and you will get a quotation, the process route including slit and anodize steps, and a firm delivery date. NDA paperwork can be dealt with in the same exchange.
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