Toolholders and Inserts - Help for the Novice
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  1. #1
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    Default Toolholders and Inserts - Help for the Novice

    I feel so bad having to ask this question, but I just can not sort it all out without prior experience. I'm in the middle of set-up, repairing, and restoring a South Bend 14 1/2. While I'm traveling along that journey, I'm also attempting to find out the basics and secrets of the cutting tooling. I have downloaded, printed and read through the Kennametal catalogs (and maybe this is my problem) and the overwhelming array of options.
    Even with their selection charts and advice (which I thought would lead me to the answer) I'm as confused as ever. Five holding methods (Screw-On, Ken-Loc, etc), 19 tool holder styles (configuration and lead angles), 9 Inset shapes, 7 Clearance angle choices on the inserts, AND the choice of right, left, and neutral turning. (Want was the formulae for the number of permutations on that set - just kid'n.) I have acquired an Aloris BXA quick change tool post that they recommend for a 14 inch and a few Dorian BX holders (1/2w x 5/8h). At first I thought, Oh hell just buy one of those el cheapo Asian 5 pieces carbide sets and make chips. But than I thought surely I'm not the only one that's in the same position, maybe someone would take the time to steer a boat load of newbies out here.

    So the question is, for a newbie that wants to learn all the types of cuts, threads, and bores, first in aluminum and then steel, what would be a recommendation for good collection of tooling?

    I assumed that going from Al to Fe would simply be a change in insert material without the need to change angles/shapes of inserts.

    I realize that this is asking a huge amount of time of someone if it has not already been compiled, so I do not ask lightly. Any pointers would be greatly appreciated.

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    My suggestion would be to ignore carbide and the extremes of choices.

    If a newbie wants to learn about cutting tools - what works and what doesn't, and also wants to build a knowlege base that will last him all his life and never be obsolete, buy a few HSS bits and a decent bench grinder with decent aluminum oxide wheels and learn to grind your own cutting tools.

    There is a very large amount of info to draw on here and in reasonably priced publications.

    That is what your 14 1/2 was intended to use.

    You can actually cut some metal without going into hock.

    Every time you grind a new cutting edge you will be adding to your understanding of the whys of cutting tools.

    Way on down the road, with more demanding work that can support the cost of carbide, and tougher, more rigid and more powerful equipment that can actually use what carbide has to offer, you will be ready to switch over - but you will have put yourself in a postion to know what is going on.

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    I agree 1000% with John Oder, and further suggest taking a look at the other thread here with much the same theme wherein I offer some suggestions about visiting Home Machinist, not to be confused with Home Shop Machinist, for dissertations from Harold V on this topic. He has some good ability in putting his knowladge into words that can be easily understood.
    Dave

    On edit: The thread I'm writing about is on "New General" and is titled "Basics on lathe tool bits"

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    I'm an old timer, but I'm not one of the "grind your own HSS tool bits and forget about inserts" guys. Insert tooling can work very well on smaller manual lathes, and with the right holders and inserts its very affordable. If you search these forums using the string "CCMT" you'll hit some good discussion on this topic, but here's a quick summary.

    Don't mess with the older TPG based tooling commonly used in cheapo import sets, since those inserts were designed many years ago some much better ones have become available. Most of the cheapy import insert tooling sets aren't worth messing with.

    I would recommend tooling using the CCMT insert, its a highly positive insert that works well on home sized machines for both steel and aluminum.

    Inserts are available in different grades, primarily a type for steels and a type for non-ferrous, but it turns out that the steel grades work pretty well on alum. and brass also, so you only need to buy a single insert grade, the steel ones.

    I would recommend a tool that uses the CCMT3251 inserts to start, this is a smaller radius insert. When you get comfortable with that and want to move to heavier cuts, you can get some CCMT3252 inserts, they have a larger nose radius. One thing about carbide is it doesn't like light feeds, both these inserts like at least 0.003" feed per revolution.

    The holders I use are type SCLCR, this is an industry designation describing the type of holder. My are made by Hertel, their part number HBO50900D, I got them from J&L industrial, the often have them on sale. This is a 5/8" shank tool that works well with a BXA type holder, and what's slick about this holder is it can be used for both turning and facing, so if you want to try insert tooling out without blowing too much $ you only need to buy one of these to start out. As far as I can tell the Hertel holders are made by Kennametal, who now owns Hertel, so the quality is very good, probably the best piece of tooling I have in my shop.

    This is like moving from LP's to CD's, once you do it you'll never want to go back. We'll maybe not totally true, HSS tooling has its place for super finishes, highly interrupted cuts and other specialized operations like special formed tools, but I just don't do that stuff very often, 99.9% of the time inserts get the job done faster for me, both the cutting itself and the setup.

    Once you get hooked on insert tooling, you can buy specialized inserts (for example very sharp ones for good finish with aluminum) from www.carbidedepot.com .

    Good luck-

    Paul T.

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    Thanks gang! While I am VERY new to the lathe cutting sceen, I grew up with grinders and fine tool shaping and sharpening. I have three in the basement that I use regularly, two high RPM and a moderate RPM. I can hog out metal with the best of them or touch-up the dings from a fine plane blade. From all I can gather on grinding your own lathe tool bits is the critical nature of all the angles where the difference of 2 to 3 degrees means the difference between a great tip and junk. To do this properly I would need to set-up alignment jigs for practically all of the styles I see listed in the Machinists Handbook. (Yes, I even have my father's seventh edition with all the WM Sellers styles).

    I will indeed roll some of my own HSS for finishing as I have seen some impressive photographs of the difference HSS can make on finishing; cheap steel for example.

    But PaulT I am forever in your debt as you have helped me bridge the technology gap without spending a huge amount of $ and time. e.g. I was so clueless as to the difference between the TPG that I see flooding the market and that of the CCMT. Paul I will be emulating your recommendation when I throw the switch for the first time. Again, Thanks a million to all ... - Dan P.

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    Default Carbide Holders

    danielp,
    I know this isn't what you want to hear, go with what johnoder and dirty old man said. I have been there/ am still there. My 14 1/2 South Bend lathe is still relatively new to me so is machining. Yes, I have spent good money on piles of tool holders and inserts, with questionable results. I am good to .015 on a good day, I need to finish my new shop building and get good with HSS. With a South Bend like ours HSS works better than carbide. Am I going to quit using carbide, no. Am I going to use more HSS, you bet. If you grind HSS like Harold V says you will be better off, in my opinion.

    If you don't agree with us do what PaulT says, his advise is very good. With carbide you will find the spindle speeds limit your finish quality. You will find the spindle bearings may not hold up to the fast speeds you need with carbide. With 8 speeds on the old South Bend I just don't want to push the RPM up where it should be. With the worn cross slide it is hard to keep the insert pressure as constant as it should be.

    Does carbide work with the "old South Bend" yes, with limits. Can you live with the limits?

    Follow the advise as you see fit, we will be here if you need us.

    Thanks,
    Paul

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    I agree with the advice on following Harold's method. I'm utterly green as a machinist, but like you, with many years of semi-related skill development (fab in my case). I started with a small chinese lathe, and no knowledge about proper cutting tools, no mentor, no help, no clue...

    I figured the cheap brazed carbide sets were the easiest way to get started. Hey! I made chips. Had no clue good from bad, but I was using the lathe!

    Heard/read "noise" about HSS, fiddled with some blanks, had NO luck. Had some given to me, bits done by someone who knew what they were doing. Hey, not bad! But I still couldn't do much more than duplicate them, and that not well.

    So I continued with brazed carbide for a while. I used HSS bits too, but the results were mixed.

    I eventually read Harold's series of posts about hand grinding, chip breakers, importance of relief and clearance, and it finally started working for me. I now grind most all of my lathe bits from HSS unless I actually need the characteristics of Carbide. Between the pointers gleaned from Harold's posts, and the added time of practicing, I'm quite comfortable with HSS bits of any orientation now.

    A couple of additional points. It won't be any surprise to hear that the Chinese HSS isn't as good as brands such as MoMax. It only costs a bit more and is still "cheap", so get some good bits. No need to be dealing with more trouble than you need to be. Some better quality brazed carbide is also handy for certain materials, especially abrasive like cast iron. But you need special gear to keep them sharp. At a minimum, a diamond hand lap is needed for touch up or they generally fail pretty rapidly. I also have some modified (to fit my post) Kennametal insert holders. Common TPG-32x inserts (triangles of the cheapest most common variety) fit most of them and make it easy to use without worrying about the cost.

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    Here is a toolbit drawing to get you started.

    Jim

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    Default Grinding Jig

    Alisam Engineering makes a bit grinding jig the helps you set precise angles for grinding lathe bits. Supposed to be a reproduction of an old Southbend design.

    http://alisam.com/page/14g9f/Metalworking.html

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    I'll pile on another endorsement for HSS.

    When I bought my first metal lathe a few years ago (POS 9x20), I thought I just had to use carbide. My dad gave me some of his HSS cutters, and I thought, oh, that's quaint, the old man doesn't know what he's missing. Went out and bought a set of insert holders and carbide inserts. I struggled, got a few parts made, but was somewhat discouraged with it all. Sold the lathe after I made the parts I needed.

    Fast forward 5 years. Bought a better lathe (1956 Logan), but it came with a lantern toolpost. I wanted to cut some metal right away, so I pulled out one of dad's HSS cutters, had him show me why it had all those funny angles, and guess what, the darn thing cut steel pretty well, left a mirror finish on Al, and with a quick touch at the grinder, I had the right geometry for brass. Geez, what a great tool . What a bargain too! For $5, I've got a R-L cutter that I can resharpen 200 times. Need an Acme thread cutter? $5. Form tool to cut a rounded edge? $5. I'm out a whopping $50 or so for a what's probably a 5-year supply of cutters.

    I still use carbide for select tasks, like breaking through mill scale, roughing down big pieces, and leveling a weldment. My boring bar and ID threading tools are carbide, so it's not like I'm a HSS zealot. But I gotta tell you, I go back to the HSS as soon as I can. I find HSS is the "right tool" for 80% of my turning. Mind you, I'm not a production shop, I don't need indexability, I've got more time than money, and I'm not working anything exotic.

    Thanks for reading, and regards.

    Finegrain

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    Ah yes, I remember the old apprenticeship days of grinding HHS..The smell of grinder dust, the feel of a warm piece of steel in your hands and the constant dipping of the steel into the little cup at the grinder that either never had any water in it or was filled with some kind of purid liquid substance.

    I also remember my introduction to carbide, or manna from the machinist heaven it was to me.

    Now I grind only when necessary to obtain a special shape or touch up that old tool.

    I have cut all kinds of "stuff" with carbide including wood, plastics, and frozen rubber.

    The key to cutting succesfully with carbide of course is speed and horsepower. My old lathe doesn't have much of either but in most cases I can make do with what I got. But the real key to cutting with carbide is experience in using it. That experience can come with an expensive and flustrating price tag. A good carbide tool holder can be bought and last a lifetime in a home shop, but a 20 dollar insert can be destroyed in less than a revolution of the workpiece. I was lucky that I got to learn using someone else's nickel.

    I am retired now but still do a lot of hobby work. I like the aloris #16 quick change holder that takes the TPG inserts. This "old fashioned" carbide comes in a lot of grades and nose radius and can be had a fairly decent price. It works for me, so I guess thats all that matters.

    However, I think it is very important to learn to grind and use HHS as carbide is not a cure all or do all..

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    LOTSA good advise here so I won't reiterate.....but don't try to equate $ costs for carbide versus HSS. Tear up a $5 HSS tool and regrind it, tear up a $5 carbide insert (or brazed tool) and throw it away. Grinding is easy to learn and if you don't get the angles perfect, it will probably still cut. I am not crazy about carbide on my old, worn machines although I am perfectly aware of how efficient it is for certain jobs. If you will read the text and study the drawings in any of the old books, you can grind and hone very good tools from HSS in no time. The old books stress the importance of "back rake" but even Forrest Addy admits that he uses HSS tools with none. This is due to using HSS in quick change tool holders that induce no rake. Try it and ask more questions! These guys have more experience than you can imagine!

    Rick

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    Default hss is the way to understand cutting tools

    i agree with johnoder. i am graduating from the precision machining program this semester and when i first started the class they gave us High Speed Steel bits to grind our own cutting tools. this help me to understand the carbide inserts and different rake and relief angles a lot better, and why they were made the way they are. and too with the HSS you can experiment a little. Depending on the material you are cutting different rakes cut better. Each time u sharpen your cutting tool you can try different combinations to see what works better. then maybe move into som carbides, which i love now that i understand them.

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    There is indexable hss out there:

    http://www.arwarnerco.com/


    bb

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    Thanks for the information and links. Generally I have used carbide inserts for the lathe but grind my own Shaper tools.

    For someone who is starting to buy insert holders I would buy several tools that hold the same insert rather than buy what ever eBay has that week. Fine Finish inserts don't last when hogging so if you buy several boxes of inserts for each tool you will soon have a big investment.

    If you allow yourself a little delivery time a lot of money can be saved by buying from Salzburg, an eBay vendor, or on his web site ez-carbide.ecrater.com/

    I will explore the idea of a fine finish with HSS but I do like indexing which does not change the tool settings on the DRO.

    Working to leave Aluminum status again.

    Raymond

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    Quote Originally Posted by bikebuilder View Post
    There is indexable hss out there:
    http://www.arwarnerco.com/
    bb
    Who carries those?

    Clutch

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    Quote Originally Posted by clutch View Post
    Who carries those?
    Little Machine Shop carries them ($$$). I think you can also buy them direct from AR Warner.

    -DU-

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    a warner co is a great company. i have their HSS insert tooling, its the cats purr..

    mike warner is wonderful resource- i spent 10 minutes on the phone with him talking about pros-cons for my use.

    you can order direct from them too. they ship FAST!


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