{"id":4806,"date":"2026-09-16T08:21:58","date_gmt":"2026-09-16T08:21:58","guid":{"rendered":"https:\/\/www.henghuahose.com\/?post_type=product&p=4806"},"modified":"2026-09-16T09:05:08","modified_gmt":"2026-09-16T09:05:08","slug":"metric-lock-nut-adapter-8c","status":"publish","type":"product","link":"https:\/\/www.henghuahose.com\/de\/product\/metric-lock-nut-adapter-8c\/","title":{"rendered":"Metric Lock Nut 8C (Hex Lock Nut for Bulkhead and Panel Mounted Adapters)"},"content":{"rendered":"
\"Metric<\/figure>\r\n\r\n\r\n\r\n\r\n\r\n

Why the Metric Lock Nut 8C Belongs in Every Service Kit<\/h2>\r\n\r\n\r\n\r\n

The metric lock nut 8C<\/strong> is a machined steel hex nut used to lock a bulkhead fitting, a panel mounted adapter or a stud end onto the structure it passes through. It is the small part that decides whether the joint stays put. When the nut is tightened against the fitting shoulder it clamps the panel or the manifold wall between itself and the shoulder, which both anchors the fitting mechanically and compresses the sealing element at the wall face.<\/p>\r\n\r\n\r\n\r\n

Lock nuts get replaced far more often than the fittings they hold. They are removed and refitted each time a panel is opened, they are the part that gets dropped into a machine frame, and they are the part that is over-torqued and stripped by a fitter working with the wrong wrench. Keeping the correct metric lock nut 8C in stock is what turns a two-hour shutdown into a ten-minute job.<\/p>\r\n\r\n\r\n\r\n

The 8C series is a straightforward, single-purpose range: metric fine pitch threads from M10X1 up to M33X2, one hex across flats per size, and a face that is machined square so that it bears evenly on the panel. A small number of sizes exist as separate catalogue entries under a suffixed part number, and those must be ordered by part number rather than by thread size alone.<\/p>\r\n\r\n\r\n\r\n

Core Advantages<\/h3>\r\n\r\n\r\n\r\n
    \r\n
  1. Machined and square-faced<\/strong> \u2014 the bearing face is machined to sit flat against the panel or the fitting shoulder, so the clamp load is distributed instead of being carried on an edge.<\/li>\r\n
  2. Metric fine pitch across the range<\/strong> \u2014 the whole metric lock nut 8C series uses metric fine threads, matching the metric adapter families used on the same machines.<\/li>\r\n
  3. Hex sized for standard wrenches<\/strong> \u2014 each size takes an open-end or ring wrench from the normal range, so no special tool is needed on site.<\/li>\r\n
  4. Available as a stock service item<\/strong> \u2014 lock nuts are consumables; the series is offered so that a spare is always on the shelf next to the fitting it belongs to.<\/li>\r\n
  5. Traceable material<\/strong> \u2014 nuts are machined from controlled steel stock with batch labels, and material test reports are available on request.<\/li>\r\n
  6. Free cross-reference<\/strong> \u2014 send the fitting part number or a photograph of the nut you are replacing and we will confirm the size within 24 hours.<\/li>\r\n<\/ol>\r\n\r\n\r\n\r\n

    Technical Specifications<\/h2>\r\n\r\n\r\n\r\n

    What Is a Metric Lock Nut?<\/h3>\r\n\r\n\r\n\r\n

    A metric lock nut is a hex nut with a metric fine pitch thread, used to lock a threaded component in position rather than to fasten two parts together with a bolt. In hydraulic practice the nut is threaded onto the mounting section of a bulkhead fitting or a panel mounted adapter, and it is tightened until the panel is clamped between the nut and the machined shoulder of the fitting. The same type of nut is used to lock stud ends and adapters that pass through a bracket.<\/p>\r\n\r\n\r\n\r\n

    Two properties matter more than the thread itself. The first is the bearing face: it must be flat and square to the axis, because the nut carries the clamp load and any rock in the face reduces the sealing force at the wall. The second is the hex across flats: it has to suit the wrench that can actually reach the position, which is why the standard hex matters as much as the thread in service.<\/p>\r\n\r\n\r\n\r\n

    Thread and Dimensions<\/h3>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
    Symbol<\/th>\r\nMeaning<\/th>\r\nUnit<\/th>\r\n<\/tr>\r\n<\/thead>\r\n
    PART NO.<\/td>\r\nCatalogue order code for the nut<\/td>\r\n–<\/td>\r\n<\/tr>\r\n
    THREAD E<\/td>\r\nMetric fine pitch thread of the nut<\/td>\r\nmm pitch notation<\/td>\r\n<\/tr>\r\n
    A<\/td>\r\nNut height, the overall axial thickness<\/td>\r\nmm<\/td>\r\n<\/tr>\r\n
    S1<\/td>\r\nHex across flats, the wrench size<\/td>\r\nmm<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n\r\n\r\n\r\n

    Full Size Table<\/h3>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
    PART NO.<\/th>\r\nTHREAD E<\/th>\r\nA (mm)<\/th>\r\nS1 (mm)<\/th>\r\n<\/tr>\r\n<\/thead>\r\n
    8C-10<\/td>\r\nM10X1<\/td>\r\n6<\/td>\r\n14<\/td>\r\n<\/tr>\r\n
    8C-12<\/td>\r\nM12X1.5<\/td>\r\n7.5<\/td>\r\n17<\/td>\r\n<\/tr>\r\n
    8C-14<\/td>\r\nM14X1.5<\/td>\r\n7.5<\/td>\r\n19<\/td>\r\n<\/tr>\r\n
    8C-16<\/td>\r\nM16X1.5<\/td>\r\n7.5<\/td>\r\n22<\/td>\r\n<\/tr>\r\n
    8C-18<\/td>\r\nM18X1.5<\/td>\r\n7.5<\/td>\r\n24<\/td>\r\n<\/tr>\r\n
    8C-20<\/td>\r\nM20X1.5<\/td>\r\n8<\/td>\r\n27<\/td>\r\n<\/tr>\r\n
    8C-22<\/td>\r\nM22X1.5<\/td>\r\n8<\/td>\r\n27<\/td>\r\n<\/tr>\r\n
    8C-24<\/td>\r\nM24X1.5<\/td>\r\n8<\/td>\r\n30<\/td>\r\n<\/tr>\r\n
    8C-26<\/td>\r\nM26X1.5<\/td>\r\n8<\/td>\r\n32<\/td>\r\n<\/tr>\r\n
    8C-27D<\/td>\r\nM27X1.5<\/td>\r\n10<\/td>\r\n32<\/td>\r\n<\/tr>\r\n
    8C-30<\/td>\r\nM30X2<\/td>\r\n10<\/td>\r\n36<\/td>\r\n<\/tr>\r\n
    8C-30D<\/td>\r\nM30X1.5<\/td>\r\n10<\/td>\r\n36<\/td>\r\n<\/tr>\r\n
    8C-33<\/td>\r\nM33X2<\/td>\r\n10<\/td>\r\n41<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n\r\n\r\n\r\n
    \r\n

    The table above is transcribed from the metric lock nut specification table. Note that 8C-27D and 8C-30D are separate catalogue entries in a thread size that also appears elsewhere in the range \u2014 choose by PART NO., not by thread size alone<\/strong>, because the nut height and the thread pitch differ between the entries. Metric lock nut 8C sizes outside this table are machined to order. Confirm the thread, nut height and wrench size against your fitting drawing before release.<\/p>\r\n<\/blockquote>\r\n\r\n\r\n\r\n

    Materials and Finish<\/h3>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
    Component<\/th>\r\nStandard material<\/th>\r\n<\/tr>\r\n<\/thead>\r\n
    Nut body (8C)<\/td>\r\nCarbon steel, machined from bar stock<\/td>\r\n<\/tr>\r\n
    Surface protection<\/td>\r\nPlated finish as standard practice for hydraulic adapters<\/td>\r\n<\/tr>\r\n
    Alternative on request<\/td>\r\nStainless steel nuts for washdown, brine or aggressive environments<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n\r\n\r\n\r\n

    Working Pressure and Operating Envelope<\/h2>\r\n\r\n\r\n\r\n

    A lock nut does not seal; it clamps. Its requirement is therefore mechanical rather than hydraulic: it must develop enough clamp load to hold the fitting against the panel through the full range of vibration, pressure cycling and thermal expansion that the machine sees. The pressure ceiling of the joint is set by the fitting and the panel, not by the nut, but a nut of the wrong material, the wrong height or a stripped thread will remove the clamp load and the joint will leak at the wall face.<\/p>\r\n\r\n\r\n\r\n

    Two service points follow. First, always match the nut to the fitting rather than to a thread gauge: the same thread pitch appears in more than one catalogue entry with different nut heights. Second, on machines that run hot, re-check the clamp after the first thermal cycle, because the panel and the fitting expand at different rates and the clamp load can relax.<\/p>\r\n\r\n\r\n\r\n

    Where Lock Nuts Are Used<\/h2>\r\n\r\n\r\n\r\n

    The metric lock nut 8C is used wherever a hydraulic component is anchored by a threaded mounting section:<\/p>\r\n\r\n\r\n\r\n