This video will show you a technique for setting up your lathe compound for precision angle cuts. This is an excellent way to get your angle settings within minutes of the desired spec.
source
Setting the Lathe compound to precision angles

This video will show you a technique for setting up your lathe compound for precision angle cuts. This is an excellent way to get your angle settings within minutes of the desired spec.
source
Retired now, I worked for many years in Jig Boring shops. Just about every job that came across my desk involved tolerances in tenths of a thousandth. Angles usually were no exception. We came up with a method using the side of the compound to set the angle with an indicator in the spindle. First set the compound angle as close as possible to start with using the graduations. Then consider the side of the compound as the triangle's hypotenuse, pick an even number like 3" or 4" for the side, then calculate the other two sides of the triangle for the desired angle. set the indicator to zero just touching the compound. Use the lathe readout for the distances in the X (cross slide) and Y (long travel) axis to set the opposite and adjacent sides of the triangle. You will need to double the X cross slide number as it reads in diameter! Just as with Joe's method, it's possible to set angles within seconds of arc!
Joe, I used this technique last night in order to set my compound cut an precise 8-degree taper for an ER11 collet cavity for a holder I made. Worked like a charm! Here I thought I would need to go and buy a sine bar to do this but with a little math and your technique I saved some much needed dough! Much Thanks and keep up the videos. This is priceless knowledge that you are choosing to share and I greatly appreciate it.
Thanks
You lost me at hellow…..
this method is unreliable if the tailstock isn't accurate. i know even a better way
Great learning technique. Thanks joe
Simply brilliant!
Hey Joe, love your videos.
I have a small JET lathe at work and I have a question about it (I'm also very inexperienced so forgive me). The cross side angle indicator plate looks almost identical to what your's looks like in this video. Is there an indicator mark you have scribed onto the plate or something? I'm not certain on how to determine a precise angle if there isn't a reference point. Is it as simple as measuring the slide and using a punch or a scribe to mark the center to use that as a reference? Hopefully this doesn't sound like a bunch of gibberish…
I was trying to part off a piece yesterday and managed to get the parting tool parallel with the chuck face (by some miracle, and I mean that we don't have a tool post mean for the parting tools we have, they're just three capscrews you tighten down onto the tool itself) and whenever I came to measure how far back I needed to go I noticed that the distance travelled on my slide did not match actual distance and I determined it was due to someone (probably me at one point) cutting an angle and most likely didn't get it centered on zero whenever they were finished (due to the lack of an indicator).
P.S. As a submarine veteran I thank you for your work. I'm also from Texas and continue to work on Submarines (now as a civilian) in Washington state at a naval shipyard. Keep Austin weird!
That's a great tip, I'm sure I will use it. Quit hating on Engineers though!
I used to use a small sine bar with gage blocks, set up with a flat surface to create the triangle and indicate straight. your method is close if your cross feed and compound slide screws are not worn. checking the diameter is a separate issue.
NIce to see you use a box wrench, I see so many using open end wrench like they never been taught
Excellent. Such a simple solution I wish I would have learned years ago! Thank you!
Oh my – so simple when you know how! so many thanks Joe for passing on this invaluable knowledge – Going to try this on my 70 year old Myford ML7
Also thinking of trying to make some angle gauges, we will see. Again many thanks and best wishes to you and you family.
So, I see 38 thumbs' down votes, as I write this. I was hoping to find 38 better videos on this topic, but found none that come even close. What do those 38 people want? Perhaps they didn't like your shirt? Just guessing here. Or perhaps not enough special effects? Beats me! Well, I gave you thumbs' up. Thanks.
Hi Joe, put your method into practice and replicated your figures however, two important points
1. had to convert to decimal degrees, (No printed trig book handy)
2. Tail stock must be precisely inline with Lathe center line.
then it worked like a charm.
Worked amazingly as you indicated used your method for the expanding arbor Nut.
Thank you again.
I clamp my 2.5" MiniSine to the side of the compound after setting it with gauge blocks, shims or adjustable parallels and just dial by rolling the carriage with indicator in the tailstock drill chuck. The MiniSine is a self-contained sine bar with its own magnetic base. Sine angle X 2.5 = shim thickness. I'll try your plan next time. Good video. Thanks
Have you ever met a person that called himself a machinist that did not know right angle trig? I make my movements using the two legs of the triangle (not the hypotenuse) and arrange it so that the indicator touches the same spot when finished (many ways to do it). I use similar technique to set angles on a mill. Where do you show how to measure the depth (diameter) of the taper?
This technique came in very handy. I had to make bevel gears on an old Cincinnati universal miller. Great job Joe!!
Another great lesson.
Brilliant, thank you!
Excellent.
Thanks
Very nice, i will try, thanks.
We need more like him, with experiance and history to teach our youth. Because those who have potential will instantly understand what he is talking about and soak up the knowlege. And i'm not talking about machinist class, i talking about math class
I had to watch this a couple times to get it but I got it and thank you.
I got a Hardinge lathe and made my own cross slide and compound so I had no graduated marks for the angle and needed to cut a backing plate for a chuck with the Hardinge 4 degree taper. I failed three times trying to use protectors and digital angle fingers and a few other items to double check the angle. I had one that would work but wasn't true. Only hit at the very back of the spindle nose taper. I just got done setting up using this method and I believe it's going to work great. Thanks for all the knowledge you are giving away and keep up the good work.
Should do a video on how extreme acurate tolerances are important to function
Joe. I just noticed you never did do a video on how to measure the size of the hole after cutting you angle.
I'm ashamed to admit this, but I'm still going to… I did not know this method. It's so simple!
To those people who are having trouble grasping it, watching the video while standing in front of the lathe is a good suggestion that someone else mentioned.
Thank you, Joe!
U make me feel like i no nothing
Why, when I do the trig on this, do I get a different answer to you. I get 1.5549. While you get 1.5615?
Trig the machinest savor with out it we would be in a hole heap of trouble lol
Would love to see this written out to save me watching this video a dozen times. I'm looking forward to using it though as I have some tapers to cut and no taper attachment. Is it documented somewhere ? Will I have to set my computer up on my lathe and hit pause a few times ? Thanks for posting this. I thought I was in a hopeless situation.
Another fantastic video by if I may " Joe " , Always a great and informative master of description, process and understandable direction. Joe you are what Yoda is to Luke. THANKS MAN im thank full for your expertise and willingness to share. From an appreciative old hobbyist .
can you cover different methods and techniques to cutting tapers? id and od
Holy shit, I've been in Toolmaking for years and all the guys who i've worked with don't know this. Fantastic!
Joe, an unusual question, who was the machinist who did things you didn't think possible!? (in your youth).