Tuesday , February 20 2018
Home > Shop Tips > Shop Tip: How to cut a Morse Taper … the Easy Way!

Shop Tip: How to cut a Morse Taper … the Easy Way!

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″? One degree 26 feet and 16 inches? What? … Just kidding.

Center Drill Holders

Then it occurred to me that I could use my compound to cut a Morse taper since it has plenty of travel. I needed about 4″ of travel to cut a number 3 Morse taper (also known as a MT3, MT#3, or a 3MT). Excited, I set to work.

Here is an image of all the dimensions of a Morse taper (click the image to go to the Wikipedia article on Morse tapers). But you don’t have to calculate a single dimension if you follow my process for creating a Morse taper – it is very simple.

675px-morse_taper

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.

Holding an Arbor Between Centers

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.

sweep-dial-indicator-along-taper-to-set-angle

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! Frank Ford built a special dial indicator holder that helps ensure that his indicator is reading exactly from the centerline of a taper. Franks special indicator holder can be found here. If you plan on making a lot of tapers, Franks tool would definately speed up the process and help make it more precise.

Here’s what 1° 26′ 16″ (one degree 26 minutes and 16 seconds) looks like on my compound – pretty precise … right? Which is exactly why it would be impossible to set up this angle using only the graduations on the compound – they’re not nearly precise enough.

1° 26' 16" on the compound

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.

check-taper-size-using-sleeve

Here’s what I mean by using a drift to separate a taper from a sleeve. Get my drift? …

using-a-drift

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.

using-ink-to-test-the-fit

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.

Polish the Taper

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. Feel free to put a tang on your taper if you like.

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.

live-center

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! The long one on the left will be used to make a die holder. The third one from the left will probably become a slitting saw arbor. And the 3 on the right became the center drill holders shown at the very beginning of this article.

Blank Morse Taper 3MT Arbors

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!

Update: There have been several comments on this project posted on the Machinist Workshop Forum. Feel free to visit the forum for more information and insight from others.

Update #2: Here’s a picture of the completed Steve Bedair style Die Holder.

Morse Taper 3 Die Holder 1.5 inch

It’s actually pretty similar in design to one that you can buy from LittleMachineShop.com. However, the LMS die holder fits smaller dies (13/16 and 1 inch). I made mine so that one end can hold a 1″ die and the other end can hold a 1.5″ die.

Morse Taper 3 Die Holder 1 inch

Also, the shaft is slightly longer than the sleeve, so you can pop the dies out easily when the set screws are loosened. Here’s a pic of the 1.5″ die being pushed out.

Morse Taper 3 Die Holder 1.5 inch

I’ve been thinking about trying my hand at CAD and drawing up a set of plans for the die holder with the dimensions I used. I haven’t seen plans for one anywhere else. If anyone is interested please leave a comment. If there is enough interest I’ll draw them up.

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About Tyler

Tyler is a hobby machinist and 3D printing aficionado. He teaches computer programming and web development at Highline College near Seattle. Tyler founded Projects In Metal in 2008 because he was frustrated by the lack of free plans available for hobby machinists.

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13 comments

  1. Here’s a picture of the die holder from LittleMachineShop.com – click the image to visit the site.

    lms-die-holder-4802314

  2. I would really like to see a copy of the plans for the die holder, even if just scanned copies of hand drawn plans. fortunately i have access to a CNC Haas tool room lathe so this would be a breat project to whip out. thanks, Tim

  3. Actually, I’ve posted the plans for the MT3 Die Holder in the forum section. I’m planning on doing a more formal write up soon on the site, but until then you can find the plans via this link. Please post a few pictures on the forum once you complete your die holder!

    http://www.projectsinmetal.com/forum/metalworking-projects/new-project-plans-for-a-mt3-die-holder-for-10-15-dies/

  4. Great job on the taper “puzzle” and in documenting your work.  I'll need to start out by making some tooling once I get my shop up and running and to get back in practice.  I always use center drills for everything on my drill press.  When I worked in machine shops they used to have a couple of chucks, or a couple of chuck keys laying around to change back and forth. 

  5. Thanks Fabrickator!

    I'm actually thinking about setting up for another round of taper turning because I've got a tool post grinder now, and a new (new to me) Atlas mill in need of MT2 end mill holders. But I think I'm going to hold off until I have the ability to harden the shanks. That way I can turn the end mill holders between centers and leave the taper .001 or so oversized, harden, and then grind the last .001 down to size. I can't believe how one project leads to another … and to another … and to another.

    For example, over a year ago started building a flame eater engine designed by Jan Ridders. It's taken me over a year to get just past 50% completed because of all the tooling I've needed to either buy or make. But that's what's fun about this hobby!

  6. colbra said
    Hi Tyler I have been reading your article on How to cut a Morse Taper … the Easy Way! I am going to have a go at it; I generally work with wood but have always liked the idea of working with metal and your idea seems like a worthwhile and challenging project to start with

    You have done a great job with the layout of the instructions I find it quite simple to understand, although it would be great if you could explain about the recut on the dead centre to my way of thinking you have turned a parallel shaft on the rear of the dead centre? is the 60deg that you re-cut the point of the dead centre I am not the sharpest tool in the shed so that would be good if you could let me know if I’m going in the right direction with my thinking.

    When I get through making the 3MT I intend to have a go at the Die holder for the tail stock. Would it be possible to get a copy of the drawings if you have made any please! 

     I had a look at   Frank’s special indicator holder but that is a bit more complicated for me so I will wait till I get more proficient with the machining. I will keep in touch with the forum as I find this method a great confidence builder for myself as I’m sure other would as well Happy Easter to All

    After thinking on things overnight I believe I can see why you would turn 60deg on dead centre it is to keep it true in a 3 jaw chuck. Could you confirm this with me please!

    Just an add to my questions is it difficult to hold the dead centre in the 3 jaw chuck when turning the shaft on the rear of dead centre given that its tapered there may be a technique to holding tapered objects in a 3 jaw chuck possibly a four jaw chuck would be better as I said this is only the start of my journey in machining sorry if my questions are a bit over the top all help is really appreciated thanks

                                                                                                      Col Smile

  7. Great tutorial, Tyler.  I’ll add one small thing.  All of the Morse tapers are different.  That is, the angle of taper of an MT2 is different from an MT3, which is different from an MT4, etc.  This was done intentionally, so that if one were to accidentally slide an MT2 male into an MT3 or larger female, the MT2 would not be locked in so deep that the to parts would be ruined (the smaller taper would not leave room for a drift key).  You can find all of the different taper angles here: http://en.wikipedia.org/wiki/M…..aper#Morse

     

    -Chris

  8. ironring1 said
    Great tutorial, Tyler.  I’ll add one small thing.  All of the Morse tapers are different.  That is, the angle of taper of an MT2 is different from an MT3, which is different from an MT4, etc.  This was done intentionally, so that if one were to accidentally slide an MT2 male into an MT3 or larger female, the MT2 would not be locked in so deep that the to parts would be ruined (the smaller taper would not leave room for a drift key).  You can find all of the different taper angles here: http://en.wikipedia.org/wiki/M…..aper#Morse

     

    -Chris

    I didn’t know that. But it makes complete sense. Thanks Chris!

  9. @colbra,

    I’m glad you liked the writeup and found it easy to read. I try really hard to make things as clear as possible, while still being terse and to the point (although I often fail on the second part and end up with long novellas).

    The dead center is a “sacrificial center” that can be made from any piece of scrap (steel, aluminum, etc). 

    I created a writeup here about the sacrificial center. But yes, the main purpose is so that you can chuck it up quickly and take a quick 60 degree skim pass off to true it up for use. That way it’s perfectly concentric with the spindle rotation, just like a true MT3 dead center would be if you inserted it into the spindle taper. On my lathe you have to remove the chuck to use a traditional dead center, so using a sacrificial center saves you the hassle of removing the chuck.

    And I turned the smaller shank to size first, and then flipped the sacrificial center end for end to turn the 60 degree point. Keep in mind that I’m not using it with a lathe dog or anything since I’m not rotating the taper that I’m holding between centers. I’m simply holding the taper stationary between centers and using it as a template for setting the angle of my compound. 

    As for the die holder, the plans are already posted on the home page under “Lathe Projects” but here’s the link just in case.

    Good luck with your project. Let us know if you get stuck. We are here to help!

  10. Please disreguard the PM I sent. I finally noticed the link to leave a comment by going to the forum post. Excelent job!

    Chuck

  11. No worries. I replied to your PM before I saw this message. Thanks for the kind feedback!

  12. Tyler, What is the best material to use for making Morse Taper tools? 4140? 12L14? CR Bar?

  13. I used unkown stock originally (probably CRS). It was fine – but the fact that I used HSS probably helped me get a good finish. If you have 12L14 I’d try that. It’s sure to be easier to machine a nice smooth surface on. I have a Dumore tool post grinder but I didn’t use it for my tapers. I was able to get smooth enough results with HSS and a little fine grit sandpaper.