PDA

View Full Version : How to cut a Morse taper - the Easy Way!



tyleryoungblood
10-17-2009, 12:39 AM
I ‘ve wanted to make a set of center drill holders for a long time. No matter what project I was working on, it always seemed like I spent half of my time with a chuck key in my hand swapping out center drills with drill bits. However, the thought of cutting a Morse taper (with no taper attachment) had always seemed daunting. After all, how in the world was I going to accurately cut a taper at 1° 26′ 16″?

Then it occurred to me that I could use my compound to cut a Morse taper since it has plenty of travel. I only needed about 4″ of travel to cut a number 3 morse taper and my compound has nearly 6". Excited, I set to work.

I set things up using a MT3 drill chuck arbor positioned between centers (the center in the 3-jaw chuck is a sacrificial center that I re-cut at 60° to ensure that it was perfectly centered). I didn’t have an extra arbor sitting around, so I removed the arbor from my lathe’s drill chuck and used that.

Using a dial indicator (attached to the compound with a mag base) I adjusted my compound to about 1.5° and began sweeping the indicator from one end to the other, making adjustments as needed until the indicator read zero across the entire length of the taper. The Picture below is my attempt at a double-exposure to illustrate the process of sweeping back and fourth along the taper. Make sure that the point of you dial indicator is on the centerline of the part, if it’s high or low you’re taper won’t come out right!

http://www.projectsinmetal.com/wp-content/uploads/2009/10/sweep-dial-indicator-along-taper-to-set-angle-300x225.jpg

Once you’re satisfied that your compound is set at the correct angle you’re ready to start cutting your taper. It’s a good idea to have a way to check the size of your taper occasionally. I used a Morse taper sleeve (4/3) for this purpose. Keep test fitting until the taper fits into the sleeve to the right depth. Be sure it fits far enough into the sleeve so that it can be knocked out with a drift, but not so far in that it bottoms out.

Here’s an image to illustrate how to use a sleeve to check your taper for proper fit. The taper on the top is still too large and doesn’t penetrate the sleeve far enough to be knocked out with a drift. The taper on the bottom has enough of the taper exposed to be knocked out by using a drift in the slot.

http://www.projectsinmetal.com/wp-content/uploads/2009/10/check-taper-size-using-sleeve-300x225.jpg

Once you’re satisfied with the size of the taper and the depth of the fit, you can fine tune the angle using layout die (or a Sharpie) and emery cloth. To test the fit draw a line along the taper and slide the sleeve over the taper giving it a few full rotations. The ink will be removed wherever the two tapers make contact.

http://www.projectsinmetal.com/wp-content/uploads/2009/10/using-ink-to-test-the-fit-300x225.jpg

Here you can see that my taper rubs in the middle more than at the ends, but it’s making contact along about 2 inches of the taper. With a little fine tuning (polishing with fine grit emery cloth reinforced with a flat backing) I should be able to improve the level of contact even further.

You’ll notice that my taper doesn’t have a tang. This is because my tailstock doesn’t have a slot in it so tangs are useless for my lathe - they just get in the way.

However, if you decide to forgo the tang, be sure to turn down the first 0.300 so that you’ll have a protective “button” (for lack of a better term) at the end of the taper. This button is intended to absorb any abuse the arbor might experience over it’s lifetime (from being dropped or deformed by a drift). If the taper were to extend all the way to the end, any damage would cause the taper to not seat properly in the tailstock. Here is a picture of a manufactured live center with a black (hardened) protective button on the end.

http://www.projectsinmetal.com/wp-content/uploads/2009/10/live-center-300x174.jpg

I decided to cut several blank tapers while I had the angle set up. I’d advise you do the same. You can always think of uses for the tapers later!

This was my first time cutting my own Morse taper, so If I missed anything please leave a comment. I’m sure there are several other methods of accurately cutting a Morse taper, so if you have one, please share your experience!

tyleryoungblood
10-17-2009, 12:43 AM
Here's a picture of the completed tapers. The long one on the left will be used for a die holder. The third one from the left will probably become a slitting saw arbor.

http://www.projectsinmetal.com/wp-content/uploads/2009/10/100_0199-300x225.jpg

The three on the right were turned into my center drill holders.

http://www.projectsinmetal.com/wp-content/uploads/2009/10/100_0208-300x225.jpg

Walter
10-17-2009, 12:50 AM
Very nicely done Tyler. Classy touch with the knurls.

tyleryoungblood
10-17-2009, 12:55 AM
Very nicely done Tyler. Classy touch with the knurls.

Thanks!

The little buggars are hard to hold on to without the knurl. I dropped one right off the bat with a center drill already seated. Luckily it bounced off my rubber shop mat without breaking the center drill or dinging the taper.

So I decided that a knurl would make them easier to hold on to when swapping them in and out of the tailstock.

CCWKen
10-17-2009, 01:02 AM
Great job and nice detail too! Me, I'm too lazy or have less free time. I buy MT-to-JT tapers when they're on sale and cut them up for my needs. I keep a stock on hand for special purposes. (Headstock and tailstock sizes.)

abn
10-17-2009, 03:45 AM
Very nice. Your work looks excellent.

gnm109
10-17-2009, 04:10 AM
That's an excellent use of the compound. I once asked my journeyman machinist friend what to do to make a taper. He was doing something else at the time in his shop and he said over his shoulder without even looking up.."Just set your compound to match a taper".

Now I know what he meant. Nice work!

Gary Gill
10-17-2009, 07:13 AM
Nice write up and great looking parts. What make and model lathe are you using in the pictures?

RTPBurnsville
10-17-2009, 09:20 AM
A very interesting and educational post, thanks!

Robert

andy_b
10-17-2009, 10:33 AM
great post and nice work! i think i need to make a few of those center drill holders (and some #2 taper shanks). :)

andy b.

Evan
10-17-2009, 10:46 AM
Super post and good photography and markup. It's also a subject that a lot of people are afraid to try. One thing to point out is that even if the compound doesn't have enough travel to do the cut in one setup it isn't difficult to reset for a second cut since the angle won't change.

wierdscience
10-17-2009, 10:50 AM
Very nice work,do you intend to blue them or leave them as is?

J Tiers
10-17-2009, 11:24 AM
Very nice. I like to see someone DO that instead of wussing out*!

I cut them pretty much like that myself.

A couple points:

1) the accuracy of the taper setup is equal to the accuracy of alinement of HS and TS centers. They should be in line at the beginning or the measurement using DTI will be "off". There is compensation, as the compound path will generate the same surface the DTI followed, and theoretically should still make the taper, but some small errors can remain due to the centers being angled in the center holes of the setup piece (looseness). If you used ball centers I think the compensation at small angles would be essentially perfect for any sensible purpose.

2) The poster has a very long-travel compound. But if yours is shorter, it is NOT necessary to cut the whole taper length. In many cases, especially where you are going to pull it in with a drawbar, you can leave the small end as an under-size cylinder, without any problems. That may be better than trying to re-set, although there is nothing wrong with re-setting aside from the hassle.

Even if you will not use a drawbar, you are likely fine. After all, the large end has the most frictional resistance to turning, it has the largest lever arm.

*I've seen all sorts of complicated means for grafting pre-made tapers onto other sections, for milling machine arbors, etc. Most look twice as hard as doing it right to begin with.

tyleryoungblood
10-17-2009, 12:47 PM
Great job and nice detail too! Me, I'm too lazy or have less free time. I buy MT-to-JT tapers when they're on sale and cut them up for my needs. I keep a stock on hand for special purposes. (Headstock and tailstock sizes.)

I've thought about just using a pre-fab arbor like the one from my drill chuck that I put between centers (its an MT3/JT33) to make center drill holders out of, but I needed a long one for the die holder I'm planning to make (similar to Steve Bedairs design (http://www.bedair.org/Die/Die.html) - pictured below).

http://www.bedair.org/Die/DIE2.JPG

http://www.bedair.org/Die/DIE3.JPG

So after cutting the long shank for the die guide I figured I'd cut a few more blanks. However, in the future I'll probably start buying them. Grizzly sells them for about $5 each. Pretty hard to justify making your own if you can adapt a $5 arbor that's ground and perfect.

Your Old Dog
10-17-2009, 12:52 PM
Nice job! Great post. Thanks for your efforts, I know many will find it useful.

tyleryoungblood
10-17-2009, 01:04 PM
Nice write up and great looking parts. What make and model lathe are you using in the pictures?

It's a Grizzly G0602 10x22 lathe (http://www.amazon.com/gp/product/B000M67TJ2?ie=UTF8&tag=amaterobotres-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B000M67TJ2). One of the best lathes you can buy for 1k (in my humble ... totally biased opinion). :)

The only thing I didn't like straight out of the crate was the turret style tool holder. So I added my own QCTP (http://www.youtube.com/watch?v=_r2finp1RCw). A much needed upgrade. Otherwise the lathe has been perfect for me.

tyleryoungblood
10-17-2009, 01:09 PM
Very nice work,do you intend to blue them or leave them as is?

I thought about hardening them, but then I decided to leave them untreated. That way if they were off by a bit they would "wear-in" with years of use in a hardened tailstock or headstock.

If I could figure out a way to harden just the end without hardening the taper, that would be ideal. I wonder if I could somehow shield the taper and heat the end hot enough to quench harden the "button"? Thoughts?

tyleryoungblood
10-17-2009, 01:25 PM
Super post and good photography and markup. It's also a subject that a lot of people are afraid to try. One thing to point out is that even if the compound doesn't have enough travel to do the cut in one setup it isn't difficult to reset for a second cut since the angle won't change.

Hi Evan, you and "J Tiers" both make the same good point. You could definitely cut the taper in two passes. I had to extend a taper slightly and had a bit of trouble getting the two passes to line up perfectly without a transition that needed to be polished out.

I would think that if you were to reset for a second cut and you could overlap the cuts in the middle and then hollow the taper out by .005 or so in the middle where they overlap. That way if your two cuts didn't overlap perfectly, you could cut out the transition in the middle. I've seen tapers with the middle carved out a bit (so that only about an inch at each end of the taper are to size and making contact). Here's a pic of an arbor from Grizzly with that design.

http://grizzly.com/images/pics/jpeg288/h/h1126.jpg

Frank Ford
10-17-2009, 03:25 PM
After I'd made a few tapered tooling items, I figured I'd want to eliminate one source of error. So, I made up this little indicator holder to fit my QC tool post:

http://www.frets.com/HomeShopTech/Tooling/IndicatorHolder/indicatorholder13.jpg

It has a spring loaded plunger with a vertical face, so there's no possibility of missing the exact center as I take readings.

Here's the full deal:

http://www.frets.com/HomeShopTech/Tooling/IndicatorHolder/indicatorholder.html

Peter.
10-17-2009, 03:55 PM
That's a nicely thought-out tool Frank!

S_J_H
10-17-2009, 04:12 PM
Excellent tool Frank! You sure come up with some great ideas!

Steve

tyleryoungblood
10-17-2009, 05:35 PM
Excellent device Frank!

I wish I had seen it before I cut my tapers. Then again I would have spent an entire evening building a tool to hold a tool ... to build a tool holder. My wife says thats all I ever do anyway, make stuff so that I can make other stuff... She's right.

If you don't mind I'll include a link to your indicator holder when I post this project to my site. Thanks for sharing!

The Artful Bodger
10-17-2009, 06:20 PM
I must be the only one who turns Morse tapers the lazy way, but I am only a beginner and quite possibly doing it wrong?

I start at what will be the small end and turn a short length as near as I can guess to the required taper. Then I take my hand MT reducer and try it for size, by carefuly wiggling I can determine if the taper is too steep or too flat and can tap my compound around accordingly before taking another test cut.

By the time I have the taper angle exact it is usually almost finished and just requires a few more cuts until I have a taper of the required length.

OK, this would be more clumsy if I was using centres but I am not, it is just done in the 3-jaw. When I get the taper made I dismount the chuck and put my 'new' taper in the spindle to turn whatever it is I am making, arbor or whatever.

wierdscience
10-17-2009, 10:52 PM
If I could figure out a way to harden just the end without hardening the taper, that would be ideal. I wonder if I could somehow shield the taper and heat the end hot enough to quench harden the "button"? Thoughts?

Depending on what steel you used it's very possible to harden just the tang.Flame heat treating would be the simplest.

Arcane
10-17-2009, 11:01 PM
Hi Evan, you and "J Tiers" both make the same good point. You could definitely cut the taper in two passes. I had to extend a taper slightly and had a bit of trouble getting the two passes to line up perfectly without a transition that needed to be polished out.

I would think that if you were to reset for a second cut and you could overlap the cuts in the middle and then hollow the taper out by .005 or so in the middle where they overlap. That way if your two cuts didn't overlap perfectly, you could cut out the transition in the middle. I've seen tapers with the middle carved out a bit (so that only about an inch at each end of the taper are to size and making contact). Here's a pic of an arbor from Grizzly with that design.

http://grizzly.com/images/pics/jpeg288/h/h1126.jpg

If two cuts do not overlap perfectly, one of the two cuts won't touch the inside of the taper socket.

Don Young
10-17-2009, 11:12 PM
Very nice work. I don't know personally but I have read that turning the center of a taper slightly undersize can help the ends fit closer and thus make the overall fit more accurate and secure.

Ken_Shea
10-17-2009, 11:35 PM
A great post Tyler, as usual, had to read it about 3 times before it made sense, while the task of turning a taper seems a bit time consuming it is none the less pretty straight forward.

Frank, that is a winner of a tool holder !

J Tiers
10-17-2009, 11:42 PM
You can do what Frank's tool does much more simply if you use a plunger indicator instead of a DTI...... All it takes is a different point on the plunger......

lugnut
10-18-2009, 01:17 AM
Thanks for the great post Tyler. I think you took the fear out of trying to turn a MT for me. Would the same type of procedure work to make the taper for a a R8 tool holder? any one?
Thanks
Mel

J Tiers
10-18-2009, 03:09 AM
Much simpler, a shorter taper.

Easy pie.

The harder thing with these tapers is grinding them. If you don't have a cylindrical grinder, you need a toolpost grinder. Grinding is not required (I didn't do it) but it does give a much smoother surface.

There typically is no power feed on the compound, leading to possible uneven turning and 'rings".

wlpier
10-18-2009, 01:26 PM
Nice work, Tyler... Some real classy work. Where there's a will there's a way. I'm curious tho'... why didn't you just off set the tailstock and use the longitudinal feed?

tyleryoungblood
10-18-2009, 02:15 PM
Nice work, Tyler... Some real classy work. Where there's a will there's a way. I'm curious tho'... why didn't you just off set the tailstock and use the longitudinal feed?

That's a good question. Basically I try to avoid messing with my tailstock at all cost. Currently it is perfectly centered and I don't want to mess with it. I also don't have a lathe dog (tho I've been meaning to make one) to drive the part when it's between centers. And lastly it would require a bit of math to calculate the offset. Sin, cos, tan oh my!

The compound had enough travel and it just seemed quicker and easier. But you're right, a power feed would have been excellent!

darryl
10-18-2009, 05:26 PM
Nice work! It occured to me that it wouldn't really matter if the ts center was off axis a bit- you'd be adjusting the compound angle to match that error, and any taper you turned using that setup would result in a taper matching your sample anyway.
I'm wondering about the steel you used- is it a stress relieved, or would there be the possibility if it warping over time- Just a thought, as these things are normally expected to be as accurate ten years from now as the day they were made.

Bill in Ky
10-18-2009, 05:50 PM
Nice work there and a very good write up and pictures.
Thanks

tyleryoungblood
10-18-2009, 07:48 PM
Nice work! It occured to me that it wouldn't really matter if the ts center was off axis a bit- you'd be adjusting the compound angle to match that error, and any taper you turned using that setup would result in a taper matching your sample anyway.
I'm wondering about the steel you used- is it a stress relieved, or would there be the possibility if it warping over time- Just a thought, as these things are normally expected to be as accurate ten years from now as the day they were made.

I'm pretty sure it was 1018 CRS - but I'm not 100% positive. I had some in the scrap bin and that's what I used. To be honest, I hadn't considered using stress relieved steel. I suppose I could have heated the steel and let it air cool, but I didn't. Besides, the tapers aren't made to that tight of tolerances anyway (I don't have a TP Grinder or any way to make them extremely accurate anyway).

Do you think it will distort enough to be a problem down the road?

darryl
10-18-2009, 08:45 PM
I'm wondering about possible distortions because I have had some bad experiences using CRS. I cut into one piece, and the cut splayed like an old clothspin- in about 3 inches of cutting into the end of a piece, the cut had expanded from the normal width of about 1/16 to nearly 1/4 inch. For the operation you're doing, which is removing an equal amount of metal from around the circumference of the piece at any particular point, it may not be a problem. But I do point this out because a stress-relieved steel would probably be a better all-round choice when you're making precision tooling.

dr pepper
10-19-2009, 05:32 AM
Good write up, thanks for the lesson.

wlpier
10-19-2009, 08:44 AM
Come on Tyler… live dangerously…. Move that tailstock…:D

First, lathe dogs are cheap. That’s one of those things you just buy. Cut a piece of copper sheet or brass to place under the dog screw when you tighten it to prevent marring the work piece.

Second the math is simple. Multiply one-half the taper per foot (in inches) by the whole length of the work piece (in ft). Let’s say you have a 6” piece of stock that you want to cut a MT3 taper. For the MT2&3 the taper is 0.602” per ft. Take one-half of that (0.301”) and multiply it 6/12 or 0.5' (0.301X0.5=0.1505”) and you get 0.1505” which is the amount to offset the tailstock. Basically the same setup with your dial gage only make it read from the tailstock arbor and move the tailstock toward you by 0.150 and a hair. When you're finished just reverse to procedure to get your tailstock back to center.:)

EVguru
10-19-2009, 08:54 AM
Come on Tyler… live dangerously…. Move that tailstock…:D

Or buy a cheap boring head with a MT arbor. Stick it in the tailstock with the slide horizontal and you can wind a centre mounted in it offset to whatever ammount you need.

wlpier
10-19-2009, 10:06 AM
Paul, you know I did consider that a one time and then the brain went into overdrive considering how to get and maintain the boring head center on the horizontal. :confused: Anything less or more is going to change the taper dimensions. Gauging the horizontal, fixturing, clamping the boring head from potential rotation during the cut seemed a bit much compared to a simple tailstock offset.

Of course, it’s all a mute point now that I have a taper attachment for my lathe.:)

J Tiers
10-19-2009, 10:21 AM
I tried it, and there seems to be no particular tendency for the boring head to go off of its setting. I was surprised.

Not to say it couldn't, just that it didn't.