Pneumatic Motor Freeze-Up

Air-powered motors need regular oiling, or they stop working. October 11, 2007

I have a relatively new Kreg Foreman pocket hole machine, and when I went to use it today, the drill didn't work. When I pull the handle down, the clamp comes down, but the drill doesn't turn on. I disconnected the air and tried to manually turn the chuck and drill bit, but couldn't. The humidity may be playing a role - it's been extremely humid here lately. Anyone had a similar problem or know of a fix?

Forum Responses
(Cabinetmaking Forum)
From contributor L:
Is your oiler working? Is there oil in it? Do you have a water elimination system on your air supply? Can you turn the drill by hand? If you disconnect the air line to the motor, is there air coming out of it? It could be the air valve/switch.

From the original questioner:
- Not sure what an oiler is.
- Where do I oil it?
- No water elimination at that station.
- Disconnected air line to the motor and there is air coming out of it (it seems to be blowing out the back of the unit when it's connected).
- Would this mean it's the air valve?

From contributor L:
If you have an oiler it will be inside the machine on the right side near the fence. It looks like a small water separator. You may not have one. If you don't have one you should have been putting 2 drops of oil in the airline before using the machine. If there is air coming out the back of the motor, then it seems that it is getting air, so I doubt it is the air valve. Can you turn the motor by hand; does it spin? Or is it jammed? Is there a water separator on the air system at all? Sounds like one of two things, rust or motor burn out because of lack of oil. Do you have the required 5 CFM of airflow? Is there a pressure regulator on the line that has been turned down?

From the original questioner:
I can't turn the motor by hand, it does seem jammed. There is plenty of air to the unit.

From contributor D:
The electric one doesn't have that problem.

From contributor L:
A properly taken care of pneumatic motor will last decades without problems. Electric motors will start to weaken in about 5-7 years.

Sounds like your motor is locked up. Contact Kreg and ask for assistance.

From contributor F:
Oil... Air turbines need oil. A drop an hour of use or a drop a day in an air motor is necessary for trouble-free use. Lubricant can be introduced through the air line at the tool.

From contributor T:
Same machine. I let it sit for years after I bought it. It would not turn. Took the motor apart and oiled, it works fine now. Last time I checked, anyway. It does now leak air, so I did something wrong, but it does work.

From the original questioner:
I put some penetrating oil into the air inlet of the drill, inverted the machine so that the oil would drain into the drill, and let it sit for awhile today. After a few hours I was able to unfreeze the spindle by twisting the chuck with a pair of channel locks. Seems to be okay. Lesson learned. It will be oiled daily from now on. Thanks for the help.

From contributor L:
I think you may have a problem with water in your air. It should not lock up that tight in that short of a period from lack of oil. If water gets into the motor and hangs around, it will rust any steel parts and lock the rotor. So along with oiling your machine, I suggest you get a 5 micron (or smaller) water filter for your air supply. Locate it as close to the machine and as far away from the compressor as feasible. This will make it more effective. You should also think about getting an auto oiler for the machine. You might be able to get one from Kreg. The Db-55 comes with one installed already.

From contributor F:
It is true that water isn't good in air tools or the lines that feed the tools, but oil is usually the answer. I have repaired many air sanders that run on lines with driers that were frozen. Once a discipline of regular oiling was adoted, the problems stopped. For best results, use oil that is prepared for air tools, not WD-40 or something that should be in a crankcase. Filters will also extend the life of air tools.

From contributor R:
The only thing to weaken an electric motor is if it has permanent field magnets, which lose power in time. Most fields today are electro magnetic fields. Freight trains are powered by electric motors.