fixing a pinion gear temporarily on a shaft to cross-drill for a pin?

If hot melt glue is strong enough, that should do it. If not I'd try some other glue that breaks down with heat. Cyanoacrylate may be the trick.

However, I'd avoid the roll pin. It doesn't have a lot of shear strength. I'd go for a solid pin.

-- Ed Huntress

Loctite? Heat to remove the gears after drilling.

Before you "repair" that "screwup", you may want to make sure that the machine wasn't designed correctly in the first place, then made a victim of poor maintenance.

Not knowing what the rest of the story is I can't say, but are you sure that the shaft, gears and pins weren't right from the factory, then made wrong by some major maintenance that put some _other_ pieces in the wrong spots? Could the shaft have been put in backwards, or it's locating hardware put in wrong, or the shafts that it runs against done wrong, etc.?

"Tim Wescott" wrote: (clip) are you sure

^^^^^^^^^^^^^^^^^^^^^ The simplest possibility is that the gears are 180 degrees around from where they should be. When a gear or collar is pinned to the shaft, the hole doesn't line up in both positions.

Beyond that, I suggest lining things up as well as you can, and then reaming for the next larger size taper pin. The reamer will line things up, so there will be no need to position the gears.

If it's a decent fit, blue Loctite -- Loctite #242. Car parts stores carry it. It will hold well enough for drilling, a bit of heat will pop it loose. The red stuff #271 is stronger, but it can be tougher to get loose.

Hear ya, but this can only go together one way .. - GWE

"Don Foreman" wrote: (clip) The red stuff #271 is stronger, but it can be tougher

^^^^^^^^^^^^^^^^^^^ If you are going to drill it and pin it. why would you need to get it loose?

To assemble it. You have to take the gear off, stick the shaft through a bearing, and put the gear back on.

Grant

Weld it on with a good BAP with a MiG.

Loctite? You can always heat it afterwards, to get it off.

One way to manage the Straight Through part is to rest the exit hole on a center facing upwards under the spindle, with the drill stop set just short of it.

Hand-reaming for a taper pin would be easiest, but if you want to hold both in a mill, can you make a clamp? Bore a through hole in scrap for the shaft, widen the hole half-through for the pinion collar-part, hacksaw a slot, fit the shaft/gear and close the mill vise on the scrap so as to close the saw kerf and hold it all still. It sometimes helps to kerf across so the two diameters are independent (and use a mill vise with some flexibility in the moving jaw, or put a rocker scrap against that jaw).

Superglue breaks down at 250F or so. I super glued some shimstock to a gib and it proved too thin. A bit of time in the oven at 250F and the shim came off.

Wes