Make Your Own Gib Key Puller

Created from the scrap box

| October 2007

  • 10-07-012-puller3.jpg
    The finished gib key puller. Jerry notes, “Not a work of art, but very functional and robust enough for those stubborn keys that need to be tensioned and given a hard blow with a VBH (very big hammer).” Note the slot cut into the end – this allows the tool to be slipped over the head of the gib key.
  • 10-07-012-puller1.jpg
    Jerry found these bits and pieces in various scrap boxes. The pieces he used are marked in the photo. (A) A large piece of threaded rod and some nuts; (B) a piece of 2-inch gun barrel, which probably came from an anti-aircraft gun. It had been lying in the scrap box for years. (Any piece of heavy tube could be used.); (C) a big nut that became the spacer shown in the drawing opposite page; (D) a 1-1/2-centimeter-thick dropout salvaged from a profile cutter. It became Ring A also seen in the sketch.
  • 10-07-012-puller5.jpg
    The tool is placed over the gib key. The cutout slot in the face of the tool is slipped over the head and the whole tool is rotated 180 degrees. The adjusting cap screws are tightened (only finger tight) to align the puller to the shaft and seat the tool onto the gib key head.
  • 10-07-012-puller7.jpg
    This drawing shows possible improvements for making the puller into a universal-type puller to fit different shaft sizes. The tube could be a bigger diameter and instead of welding Ring A into place, a slot could be cut into the tube and a bolt fitted to hold a piece of bar stock into the slot, making it into an adjustable puller.
  • 10-07-012-puller6.jpg
    The tool in position and ready to remove the gib key.
  • 10-07-012-puller2.jpg
    The drawing Jerry made after making the gib key puller. The drawing took longer to do than the actual tool took to make. Note that a few details are missing from the drawing, but become self explanatory when looking at the photos.

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  • 10-07-012-puller1.jpg
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Removing a gib key, especially those really old stubborn ones, has been a topic of discussion on the Stationary Engine List many times and there are numerous ways of approaching the problem. They all involve two things: loosening the key (which is probably seized tight) by heat, penetrating oils or solvents, etc.; and removing the key with either a wedge and hammer, a puller of sorts or a percussion/impact/slide hammer to shock it loose. Of course, if all else fails, you can drill it out.

My little Ruston & Hornsby PT was leaking oil from the timing gear cover and the two bolts (1/4-inch countersunk machine screws) that needed to be tightened were directly behind the flywheel rim with no way of reaching them. The flywheel was going to have to come off.

I restored this engine two years ago so I knew the gib key would not be too tight or rusted and would be a simple matter to remove. But I was loathe to use a wedge or any method that involved pressure against the flywheel, as this could have damaged the paintwork.

The design for a gib key puller I came up with is very simple and can be made by anyone with very basic tools (welder, files, drill press and hacksaw - a lathe is a great help but not essential). The materials all came from my scrap box.



I have not put sizes to my drawing for obvious reasons. This one was made for my Ruston, but will also work on my Wolseley engines or any engine with a crankshaft diameter of 32 to 38 millimeters (about 1-1/4 to 1-1/2 inches). Just remember the inner diameter of the ring (Ring A) must be big enough to fit over the crankshaft plus the height of the key (not the key's head, the slot fits over that). The two adjusting bolts align everything for a grip on the gib head and a straight pull. Remember also that the big bolt that exerts pressure will work best with a fine thread. And don't forget to oil it before use. The tool is robust enough to take a hammer blow to shock the key loose, but also strong enough to exert steady pressure for a more gentle release. (Of course this depends on the materials you use as well as your welding skills).

Since making and using this one, I've had ideas for improvements. One is to make a universal one-size-fits-all puller. This would be easily made by not welding the front ring in place. Instead, just cut a slot through the pipe to allow insertion of a piece of bar stock and a means of holding it in place to grip the gib key head. Any ideas for improvement will be graciously accepted.