Removing Seized Morse Tapers and Faceplates During Lathe Maintenance

It’s not uncommon for a Morse-taper accessory to become stuck in the headstock or tailstock spindle. This typically occurs when you slam a Morse taper hard into the socket when the spindle is hot after a bout of high-speed turning. The hot socket shrinks around the cold Morse-taper center. Running the lathe until it heats up again usually cures the problem, but if this doesn’t work, more drastic measures are necessary.

The correct way to remove a Morse taper is to insert a knockout bar through the back of the spindle and drive it out with a snap of the wrist. If the Morse taper is stuck, however, repeated blows with a knockout bar will do no more than put flat spots in the bearings. The problem here is overcoming starting friction, and the best course of action is to get a heavy hammer and give the knockout bar one firm blow (which does less damage to the bearings than a series of light raps).

Once you have overcome starting friction, the rest of the force from your hammer blow goes into propelling the taper out of the spindle at high velocity. Have your other hand ready to catch the taper, or, if you’re unsure of your catching abilities, hold a scrap board against it. For tapers seized in self-ejecting tailstocks, the spindle has to be removed so that a knockout bar can be placed against the taper.

A faceplate can also become frozen on the spindle thread. A common cause is not threading a heavily loaded plate all the way home when initially mounting it on the lathe. When the lathe is started, the faceplate is screwed home with tremendous force. There are a number of remedies for this problem, the first being simply to get a bigger wrench. More leverage can be obtained by using a “cheater,” which is a short length of pipe that is slipped over the handle of the wrench (see the photo below left). Where possible, rest the wrench for the spindle against the lathe bed or headstock casting to provide a rock-solid stop. If the cheater doesn’t work, try hitting the wrench directly with a couple of blows from a lead or brass hammer.

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If these methods fail, you’ll have to resort to harsher remedies. Place a heavy brass bar against one flat of the faceplate nut and give it a sharp rap with a hammer (see the photo below right). The idea is to give the threaded portion of the faceplate a shocking blow at right angles to the axis of the thread, which will break up the molecular interaction between the two threads. If you go back to the wrenches, the faceplate will usually come right off.

In the unlikely event that no mechanical means will remove the seized faceplate, one final remedy is to use a propane torch to heat one flat of the threaded area (wear heavy leather gloves for this operation). It’s important to heat only one small area of the plate, which will cause the circumference to expand much as if you form a circle with your thumb and index finger then push the two slightly apart at the tips. Avoid heating the spindle and bearings as much as possible. When the plate is hot, use a wrench to remove it.

(i) A cheater will typically provide the extra leverage to remove a stubborn faceplate. (ii) Delivering a solid blow to the edge of a faceplate with a hammer and brass d rift often frees a frozen faceplate.
(left) A cheater will typically provide the extra leverage to remove a stubborn faceplate. (right) Delivering a solid blow to the edge of a faceplate with a hammer and brass drift often frees a frozen faceplate.

Author: Aliva Tripathy

Taking out time from a housewife life and contributing to AxiBook is a passion for me. I love doing this and gets mind filled with huge satisfaction with thoughtful feedbacks from you all. Do love caring for others and love sharing knowledge more than this.

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