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Tips/Techniques Tapping Head Morse Taper Question

Tips/Techniques
whydontu

whydontu

I Tried, It Broke
Premium Member
I’m working on a project that requires a whole bunch of 3/8” UNC holes in 3/4” thick mild steel plate. I recently acquired a Big Daishowa ACCU412 tapping head.

Tapping head has a JT6-MT2 tanged shaft. My mill is MT3. So I’ve ordered a JT6-MT3 shaft for use with a drawbar. Snag is I can’t get the existing shaft off the tapping head, and I’m worried about trusting a tanged MT2-MT3 sleeve under the forward and reverse load under power tapping.

Am I safe using a sleeve, or should I bite the bullet and spend the money ($40) to get the proper JT6 removal wedge so I can use the drawbar arbor?

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I would get the wedge set:

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I have wedges for each of the JT tapers I have (just in case).

Or make a pair or mill slots in a pair of these:

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Personally, I’d bite the bullet and get the proper tool.
 
whydontu said:
Am I safe using a sleeve, or should I bite the bullet and spend the money ($40) to get the proper JT6 removal wedge so I can use the drawbar arbor?
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You might be safe with the sleeve, but I wouldn't. Assuming it's not an integrated arbour, I'd swap out the old MT taper for the bigger one in a heart beat.

I agree with @ChazzC, the tapered wedges work great. I even made a few CRings out of washers to take up the space that existed on a few of my tools. It would be great to buy the right arbours for all my tools, but my ancestors brought a few red headed Scottish Girls home with them and I'm pretty sure I have a little Scottish blood in my viking veins, so I share arbours when I can. The wedges get lots of work. They are great tools. I don't use a hammer - I just put the wedge and arbour assembly in my shop vise, squeeze them together, and off they come!

In general, we all know tapers can slip without a compressive load. Bigger is always better when it comes to Morse and Jacobs Tapers.
 
trlvn said:
Proper wedges are hardened steel so they can be used repeatedly.
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I was gunna mention this but didn't. So I'm glad Craig did. For the first time I needed them, I made my own out of plain steel washers. The wedge Jaws simply spread apart. The steel has to be high strength. This is not a time to cheap out with the steel. After my first failure, I simply bought the high strength wedges and smiled. I did make a constant thickness C - style spacer out of a washer though and it worked fine because it sees no spreading forces.
 
trlvn said:
Proper wedges are hardened steel so they can be used repeatedly. For limited use, you can make your own! Mill (similar) tapers on each piece and have at it.

View attachment 52423

Craig
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Yes, I was concerned about the plastic wedges, but the width of the Echo ones may be worth a try, my wedges are hardened and purchased long enough ago that they reasonable so I think I also have some for arbors I don’t (yet) have.
 
Ok, suggestions? I bought a proper Jacobs JT6 wedge set, but there is nothing to wedge against. The slot in the wedge is wider than the MT3 arbor. I cut a steel washer down to a snug fit in a groove in the arbor, but all the wedges do is bend the washer and I can’t get the arbor to release.

I’ve tried the factory idea of using a pin and hydraulic press, but all that did was destroy a pin punch.

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Ouch. Those two tapers are too close in diameter. You might have to grind flats on the washer so you can put a clamp on them to stop them from splaying. Or go all out and machine something that has a fatter end on it to take a screw and nut to hold it together. The fatter end will have to be installed before the wedges.

If you have some freeze it, you could spray some of that to the head of the taper. Liquid propane works too.

That head doesn't look like it could take much heat but judicious use of a regular propane torch on the head might help too.
 
quitereal said:
Then the wedges can be used between the chuck back and the
cross pin.
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Makes some sense.

But it might be better to drill the hole at the thickest part of the MT instead of through the neck and use the washer. The washer won't spread against a pin.
 
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