View Full Version : turning morse tapers
07-11-2001, 09:25 PM
I'm having a helluva time trying to turn a #2 morse taper that fits. Machinist Handbook shows tables for taper per foot, etc., so I have the basic idea. Is practice, practice, practice the ONLY way, or does someone out there have a shortcut I should know? TIA.
You are not the only one. I have used a taper socket reducer(#) 6mt to 2mt to "Dykem" spot blue (*) check and then file the durn thing until it does fit. polish with care. There are ways of setting the compound,taper attachment,or tail stock offset with Jo blocks and/or a dial indicator. Still have to check fit on the first one! One of the guys at work made a small ball ended center for a small import boring head and uses that in the tailstock for tapers.
More ways than machinists.
# saves tearing the setup you labored at from the tailstock. You may have gotten one for the headstock spindle of your lathe.
*similar to spot blue at your local auto parts store but stronger but, that will work.
Thanks John, should work good.
[This message has been edited by toff (edited 07-12-2001).]
You know of course that the tool has to be exactly at center height.
If you're doing it via tailstock setover, the center doesn't really fit the hole anymore and leads to error, I think. Although I've not tried this, I've heard of using a female center in the tailstock and interposing a ball bearing between that and the center-drilled hole in the workpiece, so you get more reliable contact when the tailstock is offset.
If you're using the compound or a taper attachment, set up a #2 Morse taper between centers in the lathe, put a dial indicator at center height, and run it along the side of the Morse taper until you get "0" from end to end. Then you know the angle is right.
But, as Toff says, you'll probably have to spot and "adjust" the fit the best you can do.
07-12-2001, 06:51 PM
Quickest way I've found for short tapers like morse etc is to first set the compound to zero. Then chuck a stiff piece of decent parallel bar in the chuck, something like a test bar or a pice of drill rod or silver steel. Clamp a piece of square bar in the toolholder so it's sticking out and parallel to the test bar. Take care to get this so it just touches all the way along and nip the toolpost. Don't touch the compound at this point. It helps if you place a piece of white paper on the lathe bed so you can see that it's parallel.
Next change the parallel bar for the pattern or in the case of a morse taper use a reamer or drill, gripping on the plain part with the taper sticking out. Now slacken and twist the compound so that the square bar is now parallel to the taper. Lock the compound and you will now have it set to the taper you require. Sounds a bit long winded but after a couple of goes it becomes quck. You don't need dial gauges or even need to know the angle concerned.
07-27-2001, 10:49 PM
The easy way to get a taper to match an exisiting taper, is to make a taper cut with your lathe, then hold up a NEW (commercial) taper shank horizontally next to the turned workpiece, but backwards, so they nest together. Now mike ( 1 to 2") the two parts together at the start and end of taper !
If the tapers match, both readings on your mike will be the same !
Any difference is double the amount to be removed.
Put a mag base indicator on the cross-slide (!) and zero it at one end. now move the carriage with indicator to the other end and it should stay at zero, cause you are running it at the same taper as your bit travels. Once confirmed 0 to 0 , then just turn the taper attachment UNTIL the indicator gives you half the mike reading !
You can then make your next cut, and remeasure the difference again or finish to the right diameter
Since the tool must be on the centerline, in order for the same taper setting (once found) to be used again and again, it is important to get the exact point. Do this by turning a diameter (smaller is better) on some scrap stock, then stop the lathe, pull the cutter back and insert a 6" aluminum scale vertically flat against the workpiece and bring the cutter up lightly against the scale. If the scale leans out toward you, the toolbit is too low. If it leans away from you, the bit is high. When it is straight up and down, you are "deadnuts on center"
A small straight piece of aluminum can be substituted or even a steel scale, but don't push too hard, or you will mark the scale or dull your bit.
07-30-2001, 10:24 PM
Thanks for all the help, guys. My tapers still suck, but at least I'm getting closer.
07-31-2001, 07:10 PM
Turning a taper to given dimensions IS a trial and error effort. But you should be able to get it right on the first piece.
1. Face the round to length and center drill for turning between centers.
2. For a short taper, as in the short end of a drive center, just set the compound for the angle. Then use the compound wheel to cut, move the tool in with the crossfeed. You'll get a good taper.
3. For the longer tapers, ie. the Morse taper, set the taper attachment or offset the tailstock some amount. Calculate the amount to give the best taper per foot or taper per inch. Now, set the round between centers and make some cuts.
4. After you have made enough cuts to get an inch or so of taper, blue it and mark two lines. Measure with a mic at the two lines, calculate the difference in diameter. That is your taper per inch.
5. Now just adjust the tailstock or taper attachment in the proper direction to correct for too much or too little taper and cut some more.
repeat 4 and 5 until you get it right, then cut to the given dimensions.
You can also use a surface plate, gage blocks and drill rod to measure a little more precisely.