Setting A Lathe Compound to a Nearly Perfect Angle

hey guys joe pi here at advanced innovations welcome back to the shop today's demonstration is inspired by a component for the mini lathe that i did off camera that i had hoped to share with you but the detail was just so small it was ridiculous it was like doing a colonoscopy on a mouse sure you can do it but you can't get a camera in here right pretty much the same exact thing that just happened i had to bore a 4-0 taper and a piece of 3 16 diameter steel a 4-0 taper tapers approximately five thousandths of an inch per side per half inch so that is not a whole lot that is 21 000 total change per side over two inches 21 000 that's really slight now you can buy a reamer for that and just spend 35 bucks to do it put it in your box and good forever or you can learn how to single point something like that bore it and i board mine with an o 80 diameter two millimeter diameter carbide boring bar i'll show you the bar it's pretty small it's pretty cool anyway the technique i've already covered this on this channel and it's it's setting your compound to precision angles so if you haven't had the opportunity or desire to sit down and watch 260 videos jesus i don't blame you uh this is a good refresher course so let me show you what it did i know on my machine that i have three inches of usable stroke on my compound let's use a 30 degree angle because i know that's what my machine is currently set to i'll draw that nice and big so you can see it 30 degrees now 30 degrees as compared to the center line of the machine first thing we got to do is do a little bit of math 30 degree triangle and i'll bet you that's pretty close to 30 degrees three inches here on the hypotenuse because that's what i'm going to do with the compound i'm going to articulate the compound three inches so we need to know this distance right here and whatever angle that you're using calculate that for the height of the triangle and on a 30 degree triangle that is one and a half it is very important to mention right now that you need to know what kind of dial you have on your machine and believe it or not i bet you have two different kinds of dials on your machine and didn't even realize it first style being the main dial the cross slide dial that when you dial in 10 the part that you're working on gets 10 smaller well that is called a diameter reduction dial diamond reduction now that's what i know it as if it's called something else put in the comment line let me know diameter reduction dial gives you exactly what you think you have coming off the diameter so technically the cross slide dial on your machine let's say one revolution of your dial is 200 the carriage or the cross line did not just move 200 it moved 100 because it's removing 100 off the front and 100 off the back because the parts spinning so the diameter gets smaller by 200. the compound dial if it was still 200 and most of them are 100 minus as you spin that handle one complete revolution and it goes all the way around to 100 and back to zero it will have actually moved that distance so that is a radius reduction dial if you turn your compound perpendicular to your work and use that for turning it will cut off twice as much as you ask for so if you dial in 10 it's going to cut 20. that's the difference figure out what you have it's really important to know what you have for this particular thing right here i am going to put an indicator on my top of my compound and rest that indicator against my tool post when i move the compound three inches without moving the carriage i should be able to dial in one and a half inches on my cross slide and have the indicator come back to zero so just to illustrate further indicator sitting right here connected to the compound it's on zero when it slides all the way back here and i move it in that indicator should come back to zero and if it doesn't keep smacking it with a wrench a hammer or whatever you need to do to tweak it to move it until you get your numbers to line up and you're going to have the tightest angle you can possibly imagine now use a large number use the largest rod that you can use on your machine because it'll it'll help you to dial in the error now the angle error will always be the same like oh i'm off one degree over a course of a mile well a mile out it might be 100 yards across but at a foot out it's only going to be this big because you use the mile as your standard same thing here ranges let's take a walk out i'll show you the compound i'll show you the indicators i'll show you the movement and make this perfectly clear let's take a look okay this is a solid center it can be applied and used as a dead center a live center whatever now if the center spins it's considered a live center but the movement should be contained within the unit itself so technically any day of the week this is considered a dead center it can be used as a live center but it's a dead center now let's take a look at how small the dead centers are for the latham building and believe it or not that's a tapered center it really is i will do everything i can because i'm doing this with one hand right now so bear with me all right there is the spindle for the mini lathe that is the hole that i had to bore and this is the little center of the head to fit in there there you go big difference in the two and i can guarantee you that that angle is spot on let's take a walk over to the lathe and review that setup i just showed you on the board that's pretty small i think it is very important to demonstrate exactly how precise this setup can be so to do that it's really important that you know something about angles a one degree angle at one inch long will rise seventeen and a half thousands approximately point four five millimeters it's a little bit less than point four five but it is really close now it's easy to remember this number for me anyway because 17 4 is a very popular surgical grade heat treatable stainless steel so one degree at one inch equals 17 4. great what if this isn't one inch how does that play out what do you do is this three degrees now no it may be or you could look at it this way take a bunch of those little one degree triangles and just add up the stacks for every inch that you get okay three inches long three stairs three times oh seventeen four fifty two thousandths of an inch three inch long one degree error projected 52 thousandths of an inch that's about a millimeter and a half almost knowing this exactly what do we have here what is this that is one degree at three inches but let's break it down one degree error at three inches is o fifty two two now half of one degree 30 minutes that's half of one degree most prints that you get are not going to take you beyond this as a tolerance for an angle 30 degrees or excuse me 30 minute a 30 minute error at a 3 inch projection on an indicator will give you a 26 000 total range when you try to set your compound split this in half again 15 minutes that's a quarter of a degree that is incredibly tight 13 000 showing up on that indicator i'm not saying no i'm just saying there's the needle moving around 13 000 13 000 on that indicator and believe me you won't have a problem hitting that you take one degree is composed of 60 minutes right here one minute one of those 60 minutes 1 60 of a degree at our three inch projection eight and a half tenths or 0.22 0.022 millimeters i believe if i'm wrong correct me on that so you can see based on the triangle that you decide to set up with your compound and the reading that you get with your indicator how close you really are to the angle you're looking for greater the distance the bigger this number will be the easier it will be to set that all right let's take a look at the machine my machine is set up for a three inch hypotenuse right here this is the same exact drawing from the board i'm going to use a three inch motion on my compound to do this looking for an inch and a half movement on my cross slide and i will set my zeros on my indicators here and look for it to repeat here if it does not repeat here that will tell me if this is larger or smaller if it's larger or smaller that will tell me if this angle is smaller or greater than the desired target let's do it to begin the demonstration i will show you that i have punch marks in the side of my compound that i know are three inches apart okay i'm using the end of the compound as my zero indicator as long as that dot is lined up with the end of the bottom casting i know i'm in line where i need to be my cross slide dial is set at zero imperial i know you're right watch this i might be sorry i did this but i'll flip it over here right make all you metric guys happy look at that oh metric tell how much i use that i might actually have to wash my hands or break out in the rash after seeing metrics like that close to my fingers the indicator pressed up against the tail stock also set at zero i'm just having fun with you metric guys that's just the language i never embraced so everybody that can do that god bless you compound set on zero indicator set on zero cross slide set on zero compound stroke set on zero looking at 30 degrees okay i need to back this compound off three inches that's the hypotenuse of the triangle so i'm going to back this off three inches i'm gonna hand hold this and go fast forward on it but i will return to that spot right there do not touch the indicator do not touch this dial back this one off to the second zero position right there bring it back i'm going to go beyond it and come back to it because that's how i zero the three inch position zero we are now at the very bottom of the hypotenuse the indicator is off the tail stock we now have to move the cross slide in an inch and a half knowing the dial setup on this machine i have to turn the dial equivalent of three inches to get this to move an inch and a half so 15 turns this is 200 around 15 turns now i'm going to pay attention to the indicator for now i'm going to turn the cross slide dial without even looking at the numbers and wait for this to come back around to zero all right if this is exactly 30 degrees my cross slide dial is also on zero which it is not so we turn this 15 times plus three thousands so this is three inches three thousandths what does that mean well that means that the compound has a larger than inch and a half drop because it didn't take three inches to get there it took three inches and then some to get there so this angle is larger if you travel farther it's a greater angle if you travel less it's a smaller angle now is this a big deal should i change that well you know i would change it but how close are you at three thousandths of an inch out let's go back to the cue cards here and find out right three thousandths of an inch out you're about four minutes four minutes that is about 1 15 of 1 degree out way within the 30 minute 1 15 of 1 degree about 15 minutes 1 15 of one degree four minutes or imperial or metric four degrees there you go should i change it absolutely not that is that is as close as you're going to want to get if you want to tap it in if you're doing a seat if you're doing some type of hydraulic system and you really want to tap it in on loosen the bolts tap it in either direction reset everything and check it it might take you two or three tries to get this but it is going to be well worth learning this technique let's pour a plug or let's say yeah let's let's make a plug turn a plug taper and bore a conical taper in a piece of material and i'll show you how to control where that plug sits in that table very much like i had to control the depth of the dead center i made for my mini tail stock i'll show you how that was done it's not nearly as hard as you would think first half of this operation i am going to make a 30 degree tapered plug that's 30 degrees on per side 60 degrees included and i'm going to show you a technique that you probably haven't seen before but if you've ever turned a plug and a tapered bore you know that you have to reset your compound to do both of them right the compound goes one way for one one way for the other well the only way to be sure that the angles are exactly the same is to not move the compound and to do that i am going to turn the od taper with the boring bar with the machine running in reverse this is my favorite boring bar it is a solid rock machine shop product and steve barton gave this to me at the bash out in california a couple years ago and i tell you just love it so look them up look them up on youtube look them up on the internet great bars i love them let's do it okay i'm going to put a bigger piece in do a 30 degree internal taper 60 degree included and then we're going to control the depth of that plug show you an easy way to do that [Music] all right so as i start the bore i am moving my cross slide out to get a larger diameter until the plug will sit in there and we'll figure out exactly how to get this plug at a certain depth right now i'm using the cross slide to control this cone [Music] i just zeroed out my digital readout i'm going to pull the tool out now don't move anything just the carriage now if you have a specific distance it's a very small land there so forgive the rocky nature if you have a specific distance from the face of your plug that you need to maintain or engage measure the height and when you want this to go a little bit deeper simply move the carriage in without touching the cross slat okay this looks like about an eighth of an inch more until this is tangent to the face let's see if that works [Music] do not move the cross slide now use only the carriage and the compound so the whole carriage out and if there's any merit whatsoever to this technique the edge of this plug should now be true to the face of this part and it seats like a rock okay this is exactly how i control the projection of the little dead center that i used for the miniature lathe i knew how far out i wanted this stick once i got a contact diameter that i was happy with i measured the projection and then i moved the entire setup using the carriage to get the projection that i wanted works well use them together and you'll have a lot less stress that's all i got for you guys thanks for watching joel pi here at advanced innovations in austin texas now i'm out okay wow

Channel: Joe Pieczynski

Views: 31,854

Rating: 4.9778218 out of 5

Keywords: Joe Pie, JoePieczynski, Advanced Innovations, advanced innovations llc, how to, machine shop, shop tricks, shop hacks, shop techniques, shop tutorials, turning tapers, setting a compound on a lathe, conical features, Lathe videos, Lathe tutorials, 4/0 tapers

Id: qwMX63_bPAA

Length: 24min 9sec (1449 seconds)

Published: Fri Jul 02 2021