Morse taper arbours in drill presses

[atunguyd]

@dick what did you end up doing?

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[Sean KZN]

Dick's gone quite on it so I'll tell my story.
I had to split a petrol generator, oil seal leaking. They are normally close coupled with a Taper, male on engine, female on armature, some time a key way as well. The male taper is threaded.
So we know a taper responds well to pressure and or shock, so it's best to use those.
Armature has a long 10x1,25 mm bolt through and the through hole is 10,5 mm
Step 1) drill armature to 11mm and tap 12x1,5 mm thread.
Step 2) Turn 10mm EN8 round down to 9mm for 50mm so it can clear the male taper threads.
Step 3) Cut 10mm EN8 round bar to length so that the thread tapped 12x1,5mm will push on it once a bolt is screwed in.
4) Insert 10mm shaft with 9mm end, screw bolt into 12x1,5mm tapped hole, tighten up, off it pops, nothing broken.
So there we are, this thread sowed the seed for my project and certainly sped the process up.

[Dick]

@dick what did you end up doing?

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I made an extraction tool. A bit heath robinson but it worked on it's first and second tests. If you can imagine a 40 wide x 20 thick x 280 long bar with a hole in the centre that fits around the exposed portion of the arbour between spindle and chuck. If supported (restrained) at one end by tying down to the drill press table with threaded bar, a smart smack on the other end loosens the arbour from the spindle. The catch which I'm sure you've all noted, is that it could loosen the chuck but not the arbour. Fortunately, both arbours are tighter into the chuck and tapping head than into the spindle.

There is of course no way of fitting a solid bar in the required position. I made it from two 20 x 20 bars offered up to each side of the arbour and bolted together. The hole through which the arbour passes was drilled with the assembly bolted up so that there's half of the hole in each bar. Drilling a 19mm hole was a mission even on that big drill press.

Originally I had drilled a 12mm hole near the end of the bar to tie it down to the press table with 10mm threaded rod and nuts. That was to restrain that end from jumping up sharply when the other end was struck with the hammer. It worked well enough but was a bit unstable. So I fitted a short T piece across the end so it could be tied to the table with two rods. Like I said, its a bit heath robinson and takes fifteen minutes to install. There must be better methods but it works well enough.

But it did throw up another issue. Morse taper arbours don't always stick firmly in the spindle without a light tap on the nose of the chuck. And so it is with my tapping head, but the business end of a tapping head is too delicate to hit with anything. The only part that can safely be struck is the body, but only the thin exposed outer part can be hit and it won't be easy to make some sort of circumferential punch. In the meantime, the only part we can hit is the circular rotating plate the covers the bottom of the body. I made up a wood punch for the purpose and can only hope that it won't damage the R7000 tapping head. I will attempt to make something better but the components for which the tapping head is needed are due to arrive soon so my time might run out. In which case we'll have to use what we have.

[Sean KZN]

Great Dick, that's progress. At least you are better off now than you were a week ago.