--- title: "Leveling pads and leveling bolts for injection molding machines" url: "https://www.imspares.com/injection-molding-machine-parts/feet/leveling-pads/" --- # Leveling pads and leveling bolts for injection molding machines How the leveling pads and leveling bolts under an injection molding machine work, the main types, signs of wear, how to replace a bolt, and what to send for a quote. Injection molding machine leveling pads, also called leveling mounts, are the adjustable feet under the machine base. Each one is a **leveling bolt**, screwed through the base frame and held by a lock nut, standing on a pad on the floor. Turning the bolt raises or lowers that point of the machine: this is how the machine is set level when it is installed and corrected later. In the drawing, the leveling foot bolts are highlighted under the base, above the anti-vibration pads. ## How a leveling bolt works The bolt is threaded into a tapped hole, a threaded boss or a nut on the base frame. Its lower end sits in a seat in the center of the pad, often a cup or a ball seat that lets the pad sit flat on a floor that is not perfectly flat. Designs differ: on some machines the bolt turns in the frame and its tip sits in the pad, on others the bolt is fixed to the pad and the frame rests on a nut on the bolt. Turning the bolt converts a large rotation into a small change in height, which allows fine adjustment of a heavy machine. Because the base frame is stiff, raising one foot also changes the load on the others. That is why leveling is done in small steps, and why every foot must still carry load at the end. When the machine is level, the lock nut is tightened against the frame so that vibration cannot turn the bolt. ## Types of leveling mount - **Bolt and separate pad.** The bolt end sits in a seat in a separate [anti-vibration pad](https://www.imspares.com/injection-molding-machine-parts/feet/anti-vibration-pads/), so either can be replaced on its own. This is the arrangement shown in the drawing. - **Leveling pad with integrated seat.** A rubber and steel pad made for leveling, with a seat for the bolt, such as the flower-base type in our [anti-vibration foot pads](https://www.imspares.com/parts/mc-tl-07/). - **Wedge-type leveling units.** Used under some heavy machines: a screw drives a wedge that raises the load, which gives fine adjustment under high loads. - **Anchor bolts.** Where the manufacturer requires the machine to be fixed to its foundation, anchor bolts hold it down; they are a different part from the leveling bolt, and the two may be used together. ## Choosing the right leveling bolt - **Thread.** The thread size and pitch must match the hole or nut in the base frame. The [leveling foot bolts](https://www.imspares.com/parts/mc-tl-01/) we supply are 45# steel in threads from M20 to M48. - **Length.** The bolt must be long enough for the adjustment range you need, with full thread engagement in the frame and room for the lock nut. - **End shape.** The end must match the seat in the pad, whether flat, rounded or ball-ended. - **Load.** The bolt and the pad together must carry the load at that foot. The load is rarely shared equally between feet: the manufacturer's foundation drawing often gives the load at each one, and the pad supplier gives the pad's rating. ## Signs of wear or failure - The bolt cannot be turned: the thread has corroded or seized, often from cooling water or cleaning water around the feet. - A bent bolt or a damaged thread, sometimes from a machine that was dragged or dropped during moving. - A loose lock nut, so the level drifts over time. - A worn seat in the pad, or a pad that is cracked or flattened. - The machine rocks, or one bolt turns freely: that foot carries no load. ## Replacing a leveling bolt Replace one foot at a time, so the machine is always supported by the others. 1. Stop the machine and find the jacking points in the installation manual. Never jack the machine under a part of the frame that is not designed for it. 2. Place a hydraulic jack at the jacking point next to the foot and raise it only enough to take the weight off the bolt. Put solid blocks under the frame as a safety support, and never put hands or feet under a raised machine. 3. Loosen the lock nut and unscrew the old bolt. Note its height, or count the turns, so that you can set the new one close to it. 4. Clean the thread in the frame and check it for damage; chase it with a tap if needed. 5. Put anti-seize compound or grease on the new bolt's thread, fit it with its lock nut, and set it to about the same height as the old one. 6. Seat the pad centered under the bolt and lower the machine onto it. 7. Check the level and adjust as described in the [leveling procedure](https://www.imspares.com/injection-molding-machine-parts/feet/leveling-procedure/), then tighten the lock nut while holding the bolt with a second wrench. If the pads are worn too, replace them in the same operation. ## What to send for a replacement quote - The machine brand, model, serial number and weight. - The number of feet. - The bolt's thread size and pitch, overall length and end shape, and the lock nut size. - The pad type and diameter, if you need pads as well. - Photos of an old bolt, in place and removed. See the [machine feet guide](https://www.imspares.com/injection-molding-machine-parts/feet/) for how the bolts and pads work together. ## Questions ### What is a leveling pad on an injection molding machine? A leveling pad, or leveling mount, is one of the adjustable feet under the machine base: a threaded leveling bolt through the base frame, standing on a pad on the floor and held by a lock nut. Turning the bolt raises or lowers that point of the machine. ### What is the difference between a leveling pad and an anti-vibration pad? The leveling pad is the whole adjustable foot, bolt and pad together. The anti-vibration pad is the rubber and steel part under the bolt that damps vibration and grips the floor. ### Can I adjust the leveling bolts with the machine standing on them? Small corrections are normally made with the machine standing on its feet and stopped, by loosening the lock nut and turning the bolt. To change a bolt or a pad, or to make a large correction, take the weight off that foot with a jack at the jacking point the manufacturer shows. ## Replacement parts - [MC-TL-01 Machine Leveling Foot Bolt](https://www.imspares.com/parts/mc-tl-01/): Adjustable leveling foot bolt for injection molding machine installation.