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- From: Lawrence London <lfljvenaura@gmail.com>
- To: machinist@lists.ibiblio.org
- Subject: [machinist] Setting Lathe Compound For Tapers
- Date: Sat, 16 Nov 2013 21:42:50 -0500
http://www.practicalmachinist.com/vb/general/setting-lathe-compound-tapers-174133/#post1054386
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Setting Lathe Compound For Tapers
This made a good stable way to do it for me. Gib on compound has to be snug. Since compound travels along Hypotenuse, the Sine of the half angle is used, not the Tangent. The huge Federal indicator is marked off in tenths and has over .400" of travel, so three full turns and a bit to get .0624" in an inch of compound travel (for 1.500" per foot on diameter).
http://smg.photobucket.com/albums/v3...eering%20Ball/
John Oder -
Mr.Oder,
Thanks for the pics,little ideas like this are where I learn the most.
I came up with 1.49688 for the taper,are you sure you could not get it
a little closer. just kidding. -
Hi Mark - you have to consider that going along the angle (the Hypotenuse) is a little different than heading directly towards the chuck.
So the 1.0000" along the angle is really only .9980" directly towards the chuck
If we projected this out, it would be 12.02341" along the angle for the foot of distance directly to the chuck.
12.02341 X .06237 = .74989998" for the half side and 1.49979997" for the taper on diameter.
John Oder -
02-05-2009, 12:59 PM #4
- Join Date
- Oct 2005
- Location
- Charlottesville, Virginia
- Posts
- 563
Thanks for posting this, hope you won't mind a couple of questions:
1) Did you make your own cylindrical square?
2) It's really nice that your chuck has t-slots. Mine doesn't. I guess I could use a faceplate and it would still be quite accurate.
3) I have been making some tooling for the Van Norman 12, which has that steep "C" spindle taper. Have been chucking a solid Van Norman dividing head center in good shape to indicate the compound. Trouble is, I can't accurately set the center height of the indicator...
Many thanks, Charles Morrill -
No, bought it from a retired toolmaker now 81. He was smart enough to make it with a 5/8" thru hole. Most of his stuff he made for himself is heat treated D2, which must of been fun to grind.Did you make your own cylindrical square?
As to center height, I oil stoned that left front saddle wing on the old CW 16 Monarch until it felt good with the vernier height gauge sitting on it, then with gauge blocks on flat way, I came up with center height of 9.003" from flat way. A handy standard to refer to for that particular lathe.
John Oder -
02-05-2009, 01:25 PM #6
- Join Date
- Aug 2006
- Location
- Hesperia, SoCal
- Posts
- 4,222
Thank you for that John, gage blocks on the way under the cylindrical square, done right, pretty much removes the critical question, is it centered? and complete with photos!
For set-up I assume some version of, indicator close to dead horizontal and centered on the spindle. Gage stack to center of the indicator ball tip, with the top block of the stack, half of square diameter, remove same and rotate square to stack?
Should cut way down on the blue/fit, blue/fit sequence, just to achieve a good fit only with your try taper, not necessarily to the ideal.
Thanks again John, another great one mentally filed away...
Bob
Edit; shoulda' waited, your post #5 pretty much clears it up. -
02-05-2009, 02:57 PM #7
- Join Date
- Apr 2006
- Location
- Montreal Canada
- Posts
- 896
John,
I have allways done this as follows: Center up a bit of steel bar in the chuck and face it off square. Then drill a good clean center in it. Then mount a dead center of the size you want to duplicate ( this must be a good precision piece in excellent condition ) and mount it's point in the center hole with the tailstock with another good dead center in it. It is prudent to make sure that the tailstock is exactly on the lateral center.
Then mount a good indicator, preferably with an elephants foot tip, in the tool post and
sweep the top slide parallel to the side of the taper.
Of course this is only usefull if you have a male of the taper you wish to cut handy, but I seem to be making morse taper shanks most of the time.
Charles. -
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"Thank you for that John, gage blocks on the way under the cylindrical square, done right, pretty much removes the critical question, is it centered? and complete with photos!"
Slick indeed. The benefit of this setup is that the exact centering of the indicator
tip on the cylinder is not critical. The problem with it of course, is well you need to
know trig.
This approach will give a very accurate taper of any size but it will take longer.
In my example (taper standard to go in a collet) the centering really is vital as small
deviations there directly affect the taper angle. The bonus is all you need to do is
null the dial gage and you are good to go. No calculations needed.
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- [machinist] Setting Lathe Compound For Tapers, Lawrence London, 11/16/2013
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