LATHE TOOL BITS - Shapes & Geometry #710 tubalcain atlas

hello again this mr pete your youtube shop teacher and this is tips number 710 all about the geometry and shapes of lathe tool bits now hopefully you've watched the preceding four chapters or videos on making this little grinding jig well i'm continuing to beat the subject to death here and i want to talk a lot more about tool angles and tool shapes in this video so this is optional and actually it should have been before the one where i demonstrated how to use the grinding jig but didn't work out that way so this is a little out of sequence as i said but uh you might get some benefit out of it so let's take a look there will be lots of still pictures at the end of this video so watch for those as well let me talk about some of the resources available to you people out there you can get these as reprints a lot of them or on ebay or places like that but you're not going to find them at kmart but let's take a look first of all if you have an atlas craftsman these two books are identical they just have different covers but there's great sections on tool bits and tool angles and all of that stuff in these books the south bend how to run a lathe book has been around for 80 or more years printed in many languages and millions of these printed it is one of the best this is the exact one that i had in high school we had no other book then we just had this it was 25 cents we had to pay for that and it may appear in many different covers and you'll find that you can print it out one of the older versions on vintage machinery so this is really what i consider to be almost the bible of lathes and lathe tools and all of that so check that out now if you're over in england boxford and myford lays are very popular this is the boxford book and since they had a licensing agreement with south bend there's a lot of similarities between this and what you find here is in regards to the pictures that are inside of this book and then finally i don't believe logan ever printed a book at least not to my knowledge but here's a lindsay reprint of the sheldon book and it's similar to how to run a lathe it isn't as good but there's still great sections on tool bits and tool angles so if you have a sheldon lathe check that out but of course these two little bits and tool angles apply to all lathes regardless of manufacturer this is the atlas craftsman book notice that there's eight or nine pages in a chapter entitled cutting tools lots of pictures lots of angles definitions parts names they talk about tool holders and here's two more pages that are really really good on those angles the sheldon book also has a chapter on cutting tools there shows all of the shapes angles and they're a little bit different than what we see in the other books but these will all work and work well but i think for the sha the sake of clarity i'm going to stick with the south bend there's well over 10 pages in this book taking a look at south bend's book again a 10 page chapter and really i think the best pictures so this these are the ones that i will use for reference and have been using for that matter for 60 years [Applause] now remember this picture here real quickly as i go to the next book if you're in jolly old england you're really used to the box words and there's six or eight pages in this chapter as well on lathe tools now you're going to recognize these pictures because these are the exact same pictures that are in the south bend book because of their unholy alliance and there's the picture that i just mentioned in the south bend book okay this is the south bend book and here are all of the shapes that they specify and that i have been teaching for many many years and here are my old teaching aids you might have seen these in other videos but i really don't want to talk about the threading tool or the universal tool at this time or at all for that matter so i'm going to lay those aside we have here right and left hand turning and facing tools and this again is the tool that i showed in one of the other videos i actually showed how to grind it probably the single most useful tool matter of fact the tool that you will probably use ninety percent of the time if you're using high speed steel as opposed to carbide right and left-hand tools actually are mirror images of one another and we get the right hand name because this when we face the tool toward us the cutting edge here is on the right hand and of course just the opposite on a left hand the biggest difference between the turning and the facing tool and sometimes the facing tool is called a side tool according to the books but it doesn't really matter what we call them i guess but you look at the included angle on a turning tool it's about 80 or 85 degrees as shown by the arrow and the facing tool is less than 60 so that it can get in and do a little facing when you are holding the work between center something that you really don't do very often but the other clearance angle are about the same on these tools remember there are two things that you're doing when you're grinding tool bits one you're grinding it to shape such as a right hand turning tool and the other thing is you're branding the clearance angles so in review and i've talked about this in many other videos we start with a tool bit that is blank and the first thing that we do is to grind the side relief at about 10 or 12 degrees never mind that black spot secondly we grind it on the end and that gives us the end relief or front relief or front clearance they all mean the same thing and then we need some rake angle rake angles are always on the top of the tool so then we would grind this material away and you can see how the tool is now ground at an angle like that and that produces the angle of keenness remember that the actual area that the cutting takes place is right here and sometimes we grind a radius on the end if we want a good finish in a later video i'm going to make for your enjoyment one of these little south bend grinding gauges and we've shown this before it's pretty hard to see but this side is for the front clearance about 15 degrees i always say about because it does not have to be exact and this side 10 degrees for the clearance angle on the side so we got side and front and then the top one here is for the angle of keenness now i can show you that all right here but it's a little hard for you to see so i have taken the liberty of making an enlarged gauge to use on my large teaching aids remember these angles only need to be approximate but that little grinding jig will help you get the angle pretty close so using the gauge on our right hand turning tool for the side which is 10 degrees you can see that i'm right about exactly at 10. and now let's take a look at the front angle it calls for about 15 degrees you can see i'm not exactly at 15 degrees but remember that if you're using this type of tool holder it holds the tool at an angle as well so the tool would be held up approximately like that and then you would be pretty close to the 15 degree front angle and then finally for steel and they do not even specify the angle here but again this is the angle of keenness i'm not right on but it's pretty close you do not want this to be too steep of an angle or it can chip or wear very quickly that is it would become delicate let's take a look at a picture of that in the book here we are in the south bend book and they call it the included angle rather than the angle of keeness right there books will vary for steel it's approximately 61 degrees for cast iron about 71 degrees i will repeat that you do not want the angle to be too acute or it does become delicate from the south bend book that notice when they're checking the front clearance they are holding the tool in a tool holder here they're checking the angle of keenness or included angle and in this view a little gauge is being used to check the side clearance i forgot to show this booklet earlier in the video but this is a 1936 publication by south bend it was their bulletin 35 strictly on how to grind lathe cutter bits now when you look through here you're going to find that many of the pictures are similar to what you will find in the how to run a lathe book because i'm sure you won't find a copy of this and i don't know where i got this maybe it was vintage machinery real quickly without dwelling on it this is what this little bulletin looks like and you will recognize that picture and probably that i have a suggestion for you this is three-quarter inch square wood that you can buy at any hobby store hardware store or building center and that is what i have used to make some of these little models over the years just cut yourself off a six inch piece and practice and you can even do your practice on your belt sander of course you're not going to grind wood or your band saw and make these various angles until you fully understand them and then it'll be very easy to go to your high speed steel and grind your bit to the final shapes and angles well i hope this short video helped you and i didn't beat the subject to death too much but be sure and watch many of my other videos give me a thumbs up it would help me a little bit and i'll see you in the next video this is mr pete you

Channel: mrpete222

Views: 20,441

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Length: 13min 46sec (826 seconds)

Published: Sat Apr 30 2022