Help with #3 MT Angle?

Old Iron

Old Iron

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Ok I've been working on cutting a #3 MT on some scrap steel, And I just can't get it right so need a little help.

I've worked out the degree and the angle but when I cut it it is just not right. So I guess I'm not figuring it right:nuts:

Paul
 
On critical tapers, I usually check my angle with indicator drop. With a known taper per inch, I zero an indicator on a known straight bar, running true, then advance the taper attachment or compound exactly an inch, making sure the indicator is on center, and move things until I get the drop correct. For mt 3, the tpi is 0.0502.
 
Thanks Bill. Yours as well. The angle in dd is 1.4377, from center. You also can mount a known good sleeve or shank, and indicate along it to get the drop correct. It would then indicate a zero drop, of course.
 
Paul,

You can also scribe a couple lines on the part in one inch increments and measure the diameters at the lines with a micrometer. Use the taper per inch figure that Tony provided to check the reading. You can also check the taper with a sine bar. The included angle for a #3 Morse taper is 2 deg, 52 min, 32 sec. and the taper must be set on axis with the sine bar.

Tom
 
Paul,
Where is your problem occurring?
A #3 should taper 0.60235" per foot, or 0.05019" per inch.
The minor diamater of the contact area of the taper should be 0.778" and the major diameter at the final contact area should be 0.938" which if measured over the length of the taper, should be 3.250" for the contact area.
You need the major diameter to finish larger than 0.938" (so it wont disappear down its own orifice) and the minor to finish less than 0.778" so that the taper extends far enough to facillitate removal.
Hope this helps.

Cheers Phil
 
are you doing this with the compound , tail stock offset method, they have a jig for the tail stock which works great, and if my math is correct the offset on the tail stock will be .157:biggrin: mac
 
Thanks for the help, I even tried to put a #3 MT in the chuck and run a Dial indicator along it and set the taper attachment to that. But it just isn't working out. There know slop to worry about I took all that out before I starting cutting.

What I want to do is make a die holder anyway thats what I hoping to do. I'll just keep trying till I get it right. Thanks for all the info and the links.

Paul
 
On most taper attachments, there is a bit of slack that has to be allowed to squeeze out before the cross-slide will actually begin to move. It makes cutting a precise feature a little more challenging. If you don't engage the feed far enough off the part in Z, all the slack won't be taken up before the cut begins, and the first bit of your taper will not be correct.
 
Tony It was far enough back to take the play out but I'll check it again tomorrow.

Thanks

Paul
 
irishwoodsman said:
...and if my math is correct the offset on the tail stock will be .157
Click to expand...
??
Mac, Depending on how far the tailstock is from the face of the grip point will give you a different angle of taper.

Cheers Phil
 
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