South Bend Lathe

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Lathe history:

This is a 1927 South Bend lathe. It was originally purchased by a German immigrant to the US named Karl Nilson, who ran a blacksmith shop in the Schenectady, NY area. On his death, his widow sold it to Frank Mossey, it then went to his eldest son, Gerald, and then to his oldest son Kevin, who is sick of lugging it around the country. Kevin donated it to Denhac and hopes it will find many more years of love and use.

Info:

11” swing over bed
4’9” between centers
1/3hp reversible electric motor
Self threading attachment
3 jaw and 4 jaw chucks
Spindle Speeds*:

Without Back Gears
High (left) Medium (middle) Slow (right)
885 558 362
Back Gears Engaged
High (left) Medium (middle) Slow (right)
149 94 61

* Speeds are approximate, based on counting rpm with the back gears engaged, then counting gear teeth and multiplying by the back gear ratio. Back gear speeds may be off +/- 2 rpm, and non-back gear speeds may be off +/- 12 rpm.

Safety information:

This lathe was built back when safety advice was “Don’t kill yourself, and if you do we’ll just find someone else to do the job”. If you use this tool you must be aware of your surroundings and mental state at all times. You should not wear loose clothing, jewelry, or hair while using this machine. If you have long hair it is recommended you tie it up while using this machine.

Do not change the direction of the motor while it is running! Ensure the machine is fully stopped before reversing the motor direction!!!

There is an on/off switch located at the front of the machine on the leg of the base. There is an emergency stop button similar to the one on the laser cutter on the power strip that you can leave by your foot to stop it. This will not stop like the sawstop, there will still be angular momentum and it will continue spinning until friction stops it, but it will stop fairly quickly.

Before turning it on ensure that:

  • The motor is set to the direction you want (99% of the time you’ll want it in the “forward” mode).
  • The work is securely fastened in the chuck, the chuck is securely fastened on the spindle, and the chuck key is NOT in the chuck. A good rule of thumb is if the chuck key is in the chuck your hand is on the key. If your hand is not touching the key, the key should not be in the chuck. Put it another way – if you let go of the chuck key, it’s only to put it away where it belongs.
  • The tooling is appropriate for the material to be cut, and is not touching the work piece.
  • You have verified the threading gears are disengaged on both the head stock and the carriage if you are not cutting threads (easiest way to do this is spin the chuck by hand)
  • If you are cutting threads you have verified that the thread gears are configured properly
  • The drive pulleys are disengaged (throw arm lever pulled forward)

When cutting, don’t be greedy. Depending on the material you can get away with more material – aluminum and brass you want to limit yourself to .020” (20 thou). Delrin, teflon, and other plastics you can get away with 0.030”, but steel you may not want to do more than .010” per pass. If the tool catches because you got greedy, stop the lathe and back the tool away. Reassess the situation and proceed cautiously from there.

Changing the chuck/chuck jaws:

The 3 jaw chuck has outside jaws and inside jaws. The chuck teeth are numbered, and will come out in the order of 3, 2, 1, and go in in the order of 1, 2, 3. Keep the teeth together and don’t get them confused with the chuck jaws of the other lathe.

Place a flat wooden board on top of the bed before removing the chuck. Lock the gears in place and use a breaker bar in the chuck key hole following the rule of lefty loosey righty tighty. The wood is to protect the bed in case you lose your grip on it.

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