How to Modify a Lathe and Restore a Used lathe

Now and again a job will come along that’s just a bit beyond the capacity of your lathe. For want of a couple inches of swing, you end up modifying the entire project to make the one turning slightly smaller. One way to get around this problem is to increase the swing of your lathe. As long as the headstock is a separate piece (not cast as part of the bed), you can unbolt it and interpose a couple of wood blocks to raise it up. You’ll have to find a longer bolt or bolts to hold it down, and there is a definite limit as to how much you can raise things up-typically about 1 in. on smaller lathes and up to 2 in. on larger machines. Swing is increased by double these amounts. You may also have to find a longer belt. If you need to use the tailstock, block it up in the same way. (A word of caution: Make sure you run your new blocked-up lathe at low speed.)

It’s also possible to stretch a lathe so you can turn long work such as porch columns and canopy-bed posts. Bench lathes are quite easy to stretch. Simply bolt the bed to a plank of suitable length, then bolt the tailstock to a block at the end of the plank that raises it to the proper height. For floor-model lathes, bolt a suitable wood extension to the bed, or bolt the tailstock to a bench or table nearby. Remember that exact center alignment is of no great importance in spindle turning. With either setup, stretch a wooden tool rest from the tool base to the tailstock. You can also tum the piece by halves, turning it around in the lathe to do the second half. This way the standard tool rest is always over the bed of the lathe.

Freeing Rusted and Seized Nuts, Bolts and Parts

When restoring machinery, you are often presented with a truly seized bolt, nut, or other part-usually due to corrosion. No amount of twisting, prying, or pounding will get the offending parts loose. The solution is to use a “fine wrench,” more properly called an oxi-acetylene torch. The trick is to heat the part in once place, as described for removing seized faceplates on p. 159. A student of mine brought in a tool base from a classic Walker Turner lathe with the tool rest seized in the tool base, an excellent example for the following photo essay.

TROUBLESHOOTING LATHE PROBLEMS

ProblemCauseSolution

There is harmonic chatter in the work.

• The work is too thin for the length.• Cradle the work in your hand, use a heel cut with your skew, use a gouge, or employ a steady rest.
• Bearings have failed or have insufficient preload.• Adjust the preload or replace the bearings.
The knob or control is hard to turn.• There are wood chips and dust in the thread.• Clean the threads. If necessary, run a tap into the internal thread and run a die over the external thread.
• The thread is stripped.• Replace parts; helicoil the internal thread (kits are available at auto parts stores).

The motor will not run.

• The motor is not plugged in.• Plug in the motor.
• A circuit breaker or fuse has blown.• Reset the breaker or replace the fuse.
• The thermal switch in the motor has tripped.• Reset the thermal switch (usually by pushing a button).
• A fuse has blown in the AC or DC variable-speed drive.• Replace the fuse.

 

• There is a brownout or no electricity.• Check with your electric company.
• The motor winding has burned out.

• Rewind or replace the motor.

The tailstock and/or tool rest slides on the bed during turning operations.• The bed has grease or finish on it.• Clean with the appropriate solvent.
• The hold-down mechanism needs adjustment.• Adjust the hold-down mechanism.
The tool does not move smoothly on the rest.• The tool rest is dry.• Wax the tool rest.
• The tool rest needs dressing.

• Dress and wax the tool rest.

Work slows down when you apply a tool.• The tailstock is loose.

• Tighten the tailstock.

• The belt is loose.• Tighten the belt.
• The key has come out of the motor or headstock pulley.• Replace the key and tighten the grub screw, which locks it.
There is vibration.• The work is out of balance.• Round the work better with a bandsaw and/or drawknife; change speed.
• A part is loose. • Find and tighten the loose part.
• A belt is worn. • Replace the belt.

 

• The motor or headstock pulleys are dirty or not concentric.• Clean or replace the pulleys.
• The pulleys are not in alignment.• Adjust the pulleys.
• The pulleys are out of balance.• Have the pulleys balanced.
• There is a defective motor or a• Repair or replace the motor.
 bent motor shaft.

• The stand resonates.

• Put sand bags in and/or on the stand.

Finding Missing Parts for Classic Lathes

FINDING A MISSING PART for an otherwise great classic lathe can present a problem, since the manufacturer may have gone out of business long ago. The Internet has become a great resource for searching for parts. Also, want ads in woodworking magazines and club newsletters can yield results. The problem is you’ll often have to buy an entire lathe to get the part you need.

1. Clamp the part in a vise and adjust the torch to a hot flame with a tip big enough to give plenty of heat. Heat one point on the periphery of the assembly (for nuts, heat one flat) until it is dull cherry red. (Reducing the room lights often helps to see this color change.) The flame should contact the work just above the inner blue cone, which is the hottest part of the flame. To prevent melting, always keep the torch moving, even if it is only an inch or so.
1. Clamp the part in a vise and adjust the torch to a hot flame with a tip big enough to give plenty of heat. Heat one point on the periphery of the assembly (for nuts, heat one flat) until it is dull cherry red. (Reducing the room lights often helps to see this color change.) The flame should contact the work just above the inner blue cone, which is the hottest part of the flame. To prevent melting, always keep the torch moving, even if it is only an inch or so.
2. Once the assembly is dull cherry red, start working the parts free from one another. In the case of this tool rest, I placed a brass drift against it and pounded it out of the tool base. Be careful not to burn yourself.
2. Once the assembly is dull cherry red, start working the parts free from one another. In the case of this tool rest, I placed a brass drift against it and pounded it out of the tool base. Be careful not to burn yourself.
3 The freed parts.
3. The freed parts.

Having the part made at a machine shop is often the best alternative, and prices can be quite reasonable-$100 to $200 for a part such as a spindle, pulley, or tailstock wheel. If you’re considering buying a lathe that’s missing major parts, such as a tailstock, check around before buying. Such a lathe is not worth much unless the manufacturer is still in business and parts are available.

Restoring a Used Lathe

Corrosion can be a chronic problem with lathes, and chances are that if you buy an old lathe it will have some rust. To restore the machine to its former glory, you can use Klingspor’s Sandflex blocks, emery paper, and steel wool. All are good weapons in the war on rust. For extremely heavy rusting with pitting, various proprietary preparations, often referred to as “naval jelly,” work well. They loosen the surface rust and change the chemical nature of the rust in the pits, thereby preventing further rusting.

The buffers described on p. 89 are also useful for restoring metal parts. A spiral-sewn wheel with emery compound will make quick work of light rust on the exterior surfaces of small parts that can be carried to the buffer.

For the best finish for your used lathe, brush on one or more coats of machinery enamel, which is available at any hardware or paint store. It’s best to remove any bolts and screws possible and to mask areas such as nameplates and bed ways with masking tape. Once the paint dries, remove the masking tape, replace the bolts and screws, and you have a classic restoration. To maintain your newly restored lathe (or any lathe) and prevent future rusting, get into the habit of wiping down the exterior surfaces with a rag on a regular basis, and always apply a thin film of paste wax to the bed after a turning session with green wood.

Support Us By Sharing

Leave a Reply

Your email address will not be published. Required fields are marked *

*

code