PM Tailstock Quill Mechanism
The handwheel on the Powermatic tailstock assembly should turn freely to advance or retract the quill (sometimes called the ram). Sometimes, however, after considerable use, it may become stiff and hard to turn. This is an indication that the quill mechanism should be taken apart and examined. Probably all that is needed is cleaning and lubrication.
This article gives a procedure for dissembly and inspection of the quill mechanism.
Step 1 Remove the set screw on the back side. The end of this screw extends into
a slot machined on the side of the quill keeps it from rotating inside the barrel.
A 5/16” hex lock nut is installed on the screw and a 5/64” Allen wrench fits the
Loosen the hex nut and remove the setscrew. The sides of the slot in the quill bear directly on the threads, so check the threads for any signs of abrasion or unusual wear.
Hand hold the quill with your left hand and turn the handwheel. Does it move the quill more easily than it did before? If it does, the indication is that the setscrew is somehow responsible for the handwheel being hard to turn.
Step 2 Remove the handwheel. Two set screws hold the hand wheel in place. Use a 5/32” Allen wrench to loosen the screws and back them out a couple of turns. The hand wheel should then slide off the shaft. (The Allen wrench supplied with Oneway chucks for removing the chuck jaws works well here.)
Step 3 Check for burrs; remove the quill and lead screw. After the hand wheel is removed, you should be able to push the lead screw (and quill) through the barrel, toward the headstock. If it doesn’t go with a gentle push, check for burrs that may have been raised where the set screws made contact with the shaft. Remove these burrs with a few light strokes of a flat file.
Make doubly sure the quill is not locked in place by the locking mechanism at the top of the tailstock.
If, after removing the burrs, the lead screw still is hard to push through, there is a good probability that the quill is being bound up by dust, debris, and dried lubricant between the quill and the barrel. You can confirm this by twisting the quill in the barrel. It should turn easily. If it doesn’t, the quill is binding.
In this case, place a wooden block over the end of the shaft and tap it with a hammer. If it moves, you know you’re on the right track. Swap the wooden block for a dowel once the end of the lead screw is flush with the surface.
If the lead screw is hard to turn in the quill, it may be a good idea to temporarily
This completes the disassembly. Now it’s time to examine the components and try to determine why the hand wheel was hard to turn.
Step 5 Examine the surface of the quill. Be on the lookout for a stiff gunk of dust, oil, and grease, and if you find it, use mineral spirits or other solvent to remove it. Use a wire brush if necessary, but avoid sandpaper because it scratches the surface. On the other hand, steel wool is OK to use.
Step 6 Inspect the slot that runs the length of the quill. Look for scoring of the sides of the slot (produced by the threads on the set screw), and check for burrs at the corners at the top of the slot. Remove the burrs by sliding a flat file down the slot and then across the top of the slot.
Some scoring of the sides of the slot is normal, I think, because the top of the threads on the set screw bear directly against the sides – not a good design. If the scoring is severe, you may try cleaning it up with sandpaper, as shown below.
Step 7 Examine the interior threads at the back end of the quill. Clean the threads
as necessary. Moisten a paper towel with mineral spirits or other solvent, wrap
it around a dowel, and then screw the “wad” into the threads, scrubbing round-
Check carefully for damaged threads. Hopefully you will not find any damage, but
if you do and if a good cleaning doesn’t solve the stiff-
Step 8 Inspect the threads on the lead screw. Clean them if necessary with a wire brush. Look for any signs of deformed threads. If the threads look good after cleaning, apply a thin coat of light oil. If the threads are damaged, you may need to replace the lead screw, but this is unlikely.
Step 9 Check the bore of the tailstock. What you will probably find is an ugly, black coating of dried grease, oil, and sawdust. This can be removed by wrapping a rag around a stick, wetting the rag with mineral spirits, and then swabbing out the bore. Keep swabbing until no more of the black mess shows up on a clean rag.
The surface of the bore is not finely machined so it will never exhibit a really shiny surface. However, once the gunk is gone, you should be able to see the marks left by the machining operation, which indicates that the surface is clean.
Step 10 Put everything back together. First of all, everything should get a coat
of a light oil, such as 3-
Screw the lead screw a couple of inches into the quill.
Insert the quill and lead screw back into the bore of the tailstock. Work the quill around inside the bore to make sure every part of the surface is coated with oil.
Using the quill as a handle, wiggle the lead screw around until it finds the hole at the rear of the tailstock. Push the quill in until you feel the lead screw make contact with its seat.
Install the hand wheel. Position the handwheel so that one of the set screws seats on the shallow flat milled on the side. Push the quill to the rear while pushing the hand wheel forward. Tighten both set screws, but don’t over tighten and create a big burr that you will have to remove next time.
Install the set screw that engages the slot in the quill. What I do is advance the set screw until it seats on the bottom of the slot. Then I back it out about a half turn, hold it in place, and tighten the hex nut.
Turn the handwheel and run the quill over its full range of motion. Hopefully the motion will be free and easy all the way. If it binds at a certain point, back the set screw out another half turn just to be sure the set screw is not binding.
Sometimes it just doesn’t work. I was working with a friend in an attempt to free up his quill assembly which would run free for most of its travel but would then bind up. I was confident that a good cleaning and oiling, as described above, would solve the problem. But it didn’t.
After at least two complete procedures, the whole works, we substituted my quill for his in his tailstock, and it ran free – smooth as silk, all the way. Something had gone wrong with his quill, and we could not determine what it was. It was clean, the threads looked good, it rolled smoothly on a flat surface. Nevertheless, it would bind up in the bore of the tailstock. He installed a brand new quill and life was good again.
Parts are available from:
Preventive Maintenance: No turner I know schedules the times when the quill assembly is to be taken apart, cleaned, and lubricated. It just doesn’t happen.
The next best thing, however, is to do it promptly when you first notice that the handwheel is “a little stiff.” If you do it sooner rather than later, the disassembly will be much easier, there will be less gunk to clean, and the whole procedure will be much easier. Further, scoring of the sides of the slot is more likely to occur when the handwheel is stiff and hard to turn.