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vdisney
08-04-2008, 04:53 PM
I have SBL 9, V-belts with a one horse motor. I have been using HSS forever. I decided to buy the five piece set with the 3/8" three sided inserts. Before I order it, what is the advantage in using this tooling? I have a Aloris AXA holder that will take the half inch holders. The set on sale with 10 inserts (USA made) was only 100.00 Am I wasting my time or is it a good tool for what I do? This will be my first shot at Carbide, so I am open to suggestions. I turn quite a bit of cold roll, and wanted to take a shot at them. Also, how do they work on cast iron? Thank you in advnace, any advise is appreciated. Respect, Verne

paulx
08-04-2008, 04:59 PM
I like them mainly because I don`t have sharpen anything.

mark61
08-04-2008, 05:36 PM
Advantages are that you always know what the rake is and where to set for enter line. Every time you grind the HSS you have to re set for center line if you grind the top. Also we regularly cut course threads over 1" diameter using a tip instead of changing to threading tool. Dis-advantages are it can get expensive fast if you keep breaking them for some reason.
They are almost all we use at work. Lots of cold rolled gets plowed thru and they survive if you keep them cool. I am talking up to 1/4" depth of cut on a 6" dia. with a 15 hp machine! Watch out though even with coolant those chips are hot!

mark61

BadDog
08-04-2008, 05:55 PM
On a 9" SB, I think you'll be far more happy with HSS. Inserts like rigidity, speed, and power; none of which the SB9 can offer. They are no where near as sharp as HSS (even ground inserts, much less formed and/or coated), so cutting forces are higher and you'll likely see more chatter; which in turn eats carbide.

I sometimes used them on my 11" Rockwell, but only when required for highly abrasive (mill scale, cast iron) or hard material. And even then I generally prefered brazed carbide tooling, though I do have some TPG-32x Kennametal holders that I've been known to use...

Forrest Addy
08-04-2008, 06:06 PM
You can use carbide tooling on a small cone pulley lathe but you can't really take advantage of its productive potential. You need spindle RPM and HP plus overall rigidity to get the surface feet per minute, depth of cut, and feed per rev that makes carbide worth using.

I don't know why small lathe owners use carbide but they do and with some satisfaction. Anytime I borrowed a carbide equipped lathe I use HSS tooling in it and generally out-performed the carbide in the same class of work.

And yes carbide doesn't last forever. You still have to sharpen it especially if you are running it at near HSS speeds. Look at the edge of a carbide tool used for some time at too low a speed under 10X magnification. Note the crumbled edge and the smeared metal. This limits size and geometry holding and results in higher tool forces and deflection of slender parts.

But people will use carbide in these low speed not especially rigid machine tools possibly to avoid having to sharpen HSS tools.

My suggestion is for these carbide users to devote some time to gaining sharpening skills, tool setting, and feed and speed calculation and the simple decision process for using carbide Vs HSS by assessing the conditions and the goals. The lessons learned pay off at compound interest as home shop workers gain competence and confidence as they venture into more complex work. As in playing the piano, basketball, flying an airplane, performing surgery, or any other activity, the time devoted in learning the fundamentals and practicing the basics pays lavish dividends over a litetime.

My advice to vdisney is to stick with HSS on the SB 9 except for the very few jobs where carbide is called for, to learn the fundamentals and basic technique, feeds and speeds etc. You will not only get better size holding and finishes, but become quicker and more economical task execution. Practice the basic on remnents and scrap until you become proficient.

ERBenoit
08-04-2008, 06:44 PM
Advantage: New cutting face quickly.

Disadvantage: Under less than ideal conditions, your $10.00 inserts can become worthless very fast.

I'm with BadDog & Forrest on this one. I have had far better performance from HSS than carbide on my 9 1/2" South Bend. I have used carbide at home, when appropriate, with somtimes very good, and other times very limited, or no success.

Carbide gets far more use at work than home, but the lathe at work will run under contidions that suit carbide, namely in machine mass and spindle speed and H.P.

Carbide while quite tough is brittle and chips very easily. Set-ups that are not ridgid will contribute greatly to chipping.

Carbide also does not like thermal shock, which means keep it cool or leave it be.

This link has quite a bit of information about carbide inserts / tooling.

http://www1.mscdirect.com/CGI/NNPAGE?PMPAGE=/solutions/kennametalProducts.html

Mcruff
08-04-2008, 06:47 PM
Well I'm gonna be the nay sayer again.
I use carbide all the time on my lathe, 9" SouthBend.
I don't use it for form tools and I don't use it on aluminum or brass, but my little machine will rip .040-.060" per side off quite nicely with a small Kennametal tool I have and do it all day long on S7 or A2 tool steel. Never had a rigidity problem and no chatter. As far as sharpening tools, thats fine I know quite well how to sharpen tools as I build molds for a living and run a lathe daily and have for 25+ years.
A small lathe like the SouthBend will not be able to take full advantage of the benefits of carbide but I can rip more material off with it than HSS can do, and not need lube or coolant to keep it going. HSS will hold up nicely for mild steel but not very long in good tool steel. Cobalt tools take to long to sharpen and the carbide is convenient at that point.
Carbide will dull thats true, it can also be honed very sharp with a ruby stone or a diamond hone.

This is an age old argument just like old timers and the rocker posts vs Aloris style tool posts.
I suggest you try it yourself and form your own opinions!!!
For me it works great and is money and time well vested!

aboard_epsilon
08-04-2008, 07:54 PM
Only four years experience under my belt ...but i learn quickly .

This is what I've found ......my opinion ...not necessarily everyone else's.

Carbide is for taking large cuts...........DEEP AND FAST

and the large cuts end with a large finishing cut ..

That means you got to work super accurate ..

You cant take mincing cuts with carbide until you end up with your finished diameter ...like with hss

You have to more or less take a few large cuts to get you down to a position were you have one more largish cut ..(thats compared with hss )...to finish with ..

This is because a carbide tool deflects the work, if set up for a mincing cut ....its blunt and rounded .relies on aggressive cuts.

Also its not very good at all for intimitant cuts ...it will chip and bugger up.

I have found carbide really comes into its own with cast iron and stainless and other hard or abrasive metals.....very good for brake rotors/disks ..that are impossible with hss

If you have a DRO..that's when you will see the benefits ...it will also work out sucessfully....as you can then do those very few cuts without guessing and measuring and stopping all the time...you know your tool isn't wearing .........and you can get away with no lubrication..
add to this a quick change tool post .....and you have repeatability .

you'd be able to churn out item after item .....all bang on .

southbend nine ...i dont know yet ...

but it works on my 2.5 hp lathe .


all the best.markj

smiller6912
08-04-2008, 08:50 PM
My experience (limited as it is) on my 1-1/2 HP 13x24 3in1 has been less than great. I have a friend who is a Kennametal salesman and, fortunately, he sampled me a few that I promptly destroyed. There is a little learning curve involved in the proper use. For me, the time was better spent learning to grind a good HSS tool (and that I practiced with some 3/8 square wooden dowel on my belt sander). I do use some brazed carbides for cast iron and real hard stuff but, I feel way more comfortable with my good old HSS.

But hey, that's just me...............;)

PS.
I just notice that Enco has a 3/8" set of 5 on sale for $19.99 (SC250-1400), if you just want to try some out on the cheep.........

clint
08-04-2008, 09:48 PM
I tried some HSS on my lathe, and had a few tool holders modified for my aloris AXA 3/4" kennemetal tool holders using the tpg 322 inserts, and a Manchester 5/8" parting tool holder. I have never looked back to HSS, and parting was a nightmare with the aloris tool holder using the HSS blade, if I could only use one carbide it would be the Manchester parting tool. I have had problems with finish on some materials, and changed to another insert to correct this, on cold roll I will have to use some oil for a nice finish, but never had any of the problems I read about so much using carbide. I'm still very new to machine work, so I do not pretend to know everything, just my experience. Also I'm not sure how much the lathe has to do with what type of tooling is use (carbide verses HSS) I have a Clausing 4912. Another note I have had poor results with brazed carbide other than the brazed carbide radius tools.

Nice thing about the TPG inserts is the wealth of them on ebay and many grades etc, I use a ceramic insert for a super nice finish on Titanium 6AL-4V, and I work with this material a lot. I'm not sure how HSS would hold up on the Titanium, I use cobalt hss drills and have no problems.

Clint

Clint

JRouche
08-04-2008, 10:22 PM
Well now.. I love carbide. I use it for everything from aluminum, steel, hard steel, stainless and plastics.

I use inserts mostly. I dont pay any more than about .25 cents per insert and I have thousands. All ebay buys over the years. I use CCMT, TCMT, VCMT and DCMT and their variants. All positive rake.

I also use brazed carbide bits when I want a really fine knife edge. I hone them on a accu-finish hone and can get just as fine of an edge as I can with HSS.

I use HSS for formed shapes and some threading.

My machines are a SB 10L, Monarch 10EE and a lil Emco 120 cnc. I spin them up as high as I can before the HP gives up the ghost. I turn for purple to blue chips as much as possible.

HSS???? Ummm. I guess for the home shop guy there is a HUGE advantage. And even for the Job shop guy. HSS will do everything the carbide will do for the majority of turning. I just use what I have on hand and with a hundred pounds of new carbide on hand I use that. JR

BobWarfield
08-05-2008, 01:48 AM
the insert really matters. I like the ccmt's JRouche mentions. If you cut aluminum use ccgt's. They can be had razor sharp. Also try round inserts for a fantastic finish if your work will take the big radius.

Best,

BW

PS. This is all working ok a oil Asian lathe that I spin fast as JR describes!

heidad01
08-05-2008, 01:58 AM
I just started using carbid inserts (DCGT) on plastics and aluminum and think I will stay with the ground positive inserts. At about $5.00 each from Travers (you can get them much cheaper if you shop. ebay, etc) there is no way I want to pay about $15 for a good HSS bit and spend an hour grinding. I can not even think of how to grind such a nice sharp tool with the radius to match the carbide insert. I got the best finish on the work and never did with hand ground bits. I will keep my hand ground ones for mashining rebar!! DavidH.

NickH
08-05-2008, 05:22 AM
There's always someone who'll tell you it's great, and someone who will say that you need to learn to sharpen HSS, I'm saying both :D

I started with HSS, learned to create my own tools, then to make my own brazed tip carbide then started using inserted carbide, provided I use the correct speeds they all work great for me and I still use HSS parting blades in 3 sizes, some hand groung HSS and some hand made brazed carbide, but for most jobs mainly inserted carbide.

Being in the position that I still work & don't have infinite time in the shop, (and if I did the point of being there is to make the things I want to make) I use inserted carbide tooling for all "off the shelf" jobs because it gives me the choice of 20 tools on quick change holders where I can just get on with the work and not have to waste time and mess about sharpening & shimming.

You will have to buy at least one tool to experiment with and reach your own conclusions, just dont listen to anyone who tells you carbide is the magic bullet or that it has no place in your shop, they're both more than likely dead wrong,
Regards,
Nick

Evan
08-05-2008, 05:34 AM
I use carbide extensively on my 9" South Bend with original motor and belt drive. I don't use carbide inserts though as I have solid carbide tooling in sizes and shapes equivalent to HSS sticks. I sharpen my own in the same manner as HSS tools but the difference is for the carbide I run the lathe at top speed. It will take advantage of the carbide if everything is in order. Don't make me post my pic of hard turning with chips on fire again.

DR
08-05-2008, 05:53 AM
Today's carbide is much different than your father's.

Positive and high positive rake inserts will work well at low speeds and in small machines like the SB 9".

And anyone who says the high positive ground polished inserts aren't as sharp as HSS can be made hasn't looked closely at them, they are literally razor sharp.

I don't know enough about these "bargain" sets with triangle inserts to comment. I have heard negative comments about some of these sets, but possibly those were off shore variety. Myself, I don't like triangle inserts, an eighty degree diamond (CCMT,CCGT)is a much more versatile insert because it'll both turn and face with the same setting..

Rather than a set, I suggest one turning tool, a boring bar or two, a threading tool for lay down style inserts, and possibly a grooving/cutoff style holder. Of course, this basic set will be far more than $100. Many of the online tool houses have the Pafana (Polish?) brand of insert holders which are reasonable in price and quality.

Timo
08-05-2008, 07:29 AM
About 50 years ago I tried to teach myself how to play the guitar. I spent quite a few years at it, even took lessons, but in the final analysis I sucked at it. About 40 years ago I got my first lathe, a 6 Atlas. I spent several years trying to learn how to sharpen those HSS tool bits. Occasionally Id get one right but often than not Id end up with scorched finger tips and a stubby piece of junk. As a tool bit sharpener I sucked at that too. 30 years ago I got my Jet 12 x 24 lathe and discovered the Aloris system with the carbide inserts, and Ive never looked back. Not everybody is born with equal talents or the ability to develop certain skills, try as they might. Carbide works for me. My suggestion is that if youre not having much success sharpening tool bits, give carbide a try.

pcarpenter
08-05-2008, 11:41 AM
And yes carbide doesn't last forever.

The advantages of HSS have been hashed out so I will avoid that. I will however tell you about my experience with the typical "5 piece set". I don't know from that description for sure just what you are buying, but the triangle inserts on all tools is a clue.

1. I think I paid like $30 for that same set...so if you insist on it, shop around.

2. With regard to carbide not lasting....the set that uses the TT inserts like that is especially prone to insert chipping. Carbide is relatively brittle while hard and those inserts have an 11 degree positive point, making for a weak tip on those little inserts. Usually, those inserts can be more expensive than some others, too, so you may want to go with more conventional tooling if you want to use carbide. This is the voice of experience....I wish I could get my $30 back.

When I bought carbide tooling for my mini-lathe, I bought one of the Plastools holders. One may argue that negative rake takes more horsepower, but these work very nicely on small lathes. The maker explains how with a standard TNMG insert you can get a positive presentation with a depth of cut that gets the chip to the chipbreaker. The set of three is in the same neighborhood price wise as the set you are looking at and they are not third-world quality. Their turn and face tool holder is pretty neat in that it presents one point for turning and another for facing on the same tool. The web site is clumsy, but poke around and you can find a good bit of information. I think I called to order...that's how bad the web site is...but Dr. Hackler is a nice guy.

www.plastools.com (http://www.plastools.com)

heidad01
08-05-2008, 12:01 PM
I got a Micro100 turning/facing tool holder for the DCGT inserts. It is very well made and about $35.00 in 3/8" shaft and 4" length size. Once you see one up close, you can make your own ones for the future from any piece of steel scrap square stock. That is if you want to spend the time making it, and believe you me, it will come out much nicer than any imported set of 5 for $30.00. That is not to put down the imported set by no means. It takes a lot of time to make a nice one and it is hard to beat the set, but I am picky and like tools to be nicely made and polished. DavidH.

Mcgyver
08-05-2008, 12:50 PM
At about $5.00 each from Travers (you can get them much cheaper if you shop. ebay, etc) there is no way I want to pay about $15 for a good HSS bit and spend an hour grinding

yes but you'll get maybe 100 sharpenings from that $15 bit so there is no comparison in home shop economics. if it takes more than 2 minutes to grind and stone you're doing something wrong.

If you like using carbide, by all means do so. If the question is what's the best tool for the job, well, obviously depends, but most of the time in a home shop I think hss wins for two reasons...1) economics - we aren't covering overheads and even if we were aren't using machines that can take advantage of its removal rates and 2) cutting angles. Carbide is more brittle so for any given job you generally would be able to use a more acutely angle tool and maintain the same strength at the cutting edge. Up to a limit, a more acutely angle tool will create a shear plane of shorter distance hence less cutting force. Less cutting force is good. It's meaningless to anecdote how deep a cut you can take with such - if hss would let you take a deeper cut or the same with less force (less deflection etc) then from the geometry aspect it least its a better choice.

If you find it easier, more convenient, whatever, have at it and power to you....but I don't think an economic or tool geometry argument is to be had - with the caveat that we're machining soft materials (steel, AL) on a light machine.

To guys who aren't using HSS because they can't grind a bit or are intimidated to so, I say don't sell yourselves short. Its really no worse than tying a shoe - a task that once confounded all of us :D. The guys that have a machinist level skills and choose to use carbide, well that's a lifestyle choice :), but if your just going there because you hss skills are less than top drawer, well, like any shop skill that is deficient, work on it. Maybe you didn't have the right teacher, info at hand or even a good grinder but i think it is a task that is doable by all.

I have both but mostly I gravitate to hss. I want it sharp and the right shape. I can probably grind and stone a tool before you'd be able to find an insert in the drawer and the right sized Allen key. I do use some boring bar inserts, mostly because boring bars are a pita to grind out of hss so i'm not adverse to convenience either in extreme circumstances

BobWarfield
08-05-2008, 01:03 PM
And anyone who says the high positive ground polished inserts aren't as sharp as HSS can be made hasn't looked closely at them, they are literally razor sharp.

Absolutely true.

BW

heidad01
08-05-2008, 01:26 PM
Mcgyver, you are absolutely right Sir. I do admit that my grinding skills are poor at best and to make it worse, I am very fussy. It has never taken me less than 20 minutes and some burn blisters on the finger tips to grind a bit ( I use 5/16" bits) and I have a few grinders in the home shop. How do you get the material removed so fast? It takes quite a while just for the material removal, at least on my HF grinders. DavidH.

lazlo
08-05-2008, 01:58 PM
Today's carbide is much different than your father's.

Positive and high positive rake inserts will work well at low speeds and in small machines like the SB 9".

And anyone who says the high positive ground polished inserts aren't as sharp as HSS can be made hasn't looked closely at them, they are literally razor sharp.

Yes, but those high-positive inserts like the CCGT's are sold specifically for turning aluminum, because even with modern micro-grain carbide, they're very fragile.

That's why commercial inserts are usually negative -- they're much more durable.

HSS is much tougher than carbide, which is why you can grind a razor-edge on HSS and use it on steel, cast iron, ...

Mcgyver
08-05-2008, 03:00 PM
Mcgyver, you are absolutely right Sir. I do admit that my grinding skills are poor at best and to make it worse, I am very fussy. It has never taken me less than 20 minutes and some burn blisters on the finger tips to grind a bit ( I use 5/16" bits) and I have a few grinders in the home shop. How do you get the material removed so fast? It takes quite a while just for the material removal, at least on my HF grinders. DavidH.

David, being called on my few minutes claim, i guess i better come through eh :D

In claiming I can do it in minute or two, quicker than loading an insert, I was thinking resharpening not the initial grind. I touch a face to the wheel and then stone with a combination 200 & 1000 water stone (water stones cut very fast) that is wet and in a bucket beside (on the floor) the grinder....in a minute or two you are back to machining. As any woodworking knows, those water stones cut so quickly that often a resharpening doesn't involve the grinder, just the coarse side followed by the finer side and you're back in business

The initial grind takes longer but not much. Here's some ideas to speed up grinding time

One thing you should do is get rid of the wheels that come with the grinder, those grey ones that come with it are brutal. That's another reason to get an 8" vs 6" grinder - more choice in available wheels. Use a quality fast (friable) wheel...it breaks down constantly exposing fresh (sharp) edges - I'll go have a look at what i;m using and report back, cant remember off hand. Short life yes, but in the home shop maybe we're talking 10 years instead of 20 so no big deal. They tend to cut cooler and faster. keeping the wheel dressed also keeps it cutting its maximum rate

I also keep a cup of water handy and try not to let the tool change colour through grinding heat. I know there are differing opinions on dunking the hss to keep it cool but i think most do so and it seems to work for me.

I also usually go for the 1/4 bits and use some packing, slightly reduces how much you need to grind away. Finally, once you've ground it, it only needs the odd resharpening and you' be using it for years and years. That longer initial grind time doesn't happen very often once you have a collection of common bits

hope that helps

Evan
08-05-2008, 03:59 PM
Carbide in stick form has a major advantage over HSS. It's about three times more rigid so it can be stuck out ridiculous distances that would never work with HSS. I can get away with having a solid carbide tool 1/4" x 1/2" sticking out over an inch or more and reach places that would be impossible without a completely new setup. The carbide I use most often is C1 carbide and it isn't the least bit fragile. It gives an excellent finish and is recommended for roughing cast iron with interrupted cuts. About the only thing I have found that it won't cut is a bicycle freewheel hub.

Mcgyver
08-05-2008, 04:06 PM
braze a bit of hss on the end of that Evan and you'll really be cooking with gas :D

Mcruff
08-05-2008, 04:07 PM
Evan has a good point about solid carbide. The best boring bars are solid carbide and use a carbide inset in them.
I do have some solid carbide blanks both round and square and use it occasionally.

lazlo
08-05-2008, 05:13 PM
Carbide in stick form has a major advantage over HSS. It's about three times more rigid so it can be stuck out ridiculous distances that would never work with HSS.

Yes, but the carbide boring bars also very fragile. I've snapped a 3/16" Micro 100 carbide boring bar just by catching a bit of swarf in the clearance rake.

At 3/8" and above the insertable carbide boring bars seem pretty bomb-proof. Either that, or my Clausing 5914 just isn't man-enough to break them :)

Evan
08-05-2008, 07:05 PM
I have never snapped any of my carbide sticks. They will chip if dropped on concrete.

DR
08-05-2008, 07:14 PM
Yes, but those high-positive inserts like the CCGT's are sold specifically for turning aluminum, because even with modern micro-grain carbide, they're very fragile.

That's why commercial inserts are usually negative -- they're much more durable.

HSS is much tougher than carbide, which is why you can grind a razor-edge on HSS and use it on steel, cast iron, ...

CCGT's work well on aluminum plastic, brass, stainless for finishing, and finishing on steel.

For steel I usually use CCMT.

I no longer use any negative rake inserts in my lathes.

lazlo
08-05-2008, 08:20 PM
On the top-right of this picture is the milling equivalent of the CCGT: an SEHW high-positive insert for aluminum. Compare the rake angle with the other SEHW and RA-245 inserts, which have rakes designed for steel and cast iron. Remember that the insert pocket is angled backward and inward (positive axial and radial rake), so the aluminum insert rake angle is especially extreme, like a CCGT.

That leaves such a thin line of material to support the edge, that the high-positive inserts shatter like glass if you try to take more than a whisper cut on steel. They leave a beautiful finish on aluminum though:

http://i164.photobucket.com/albums/u15/rtgeorge_album/SEHInserts023s.gif

In my opinion, high positive inserts are great on soft, highly machinable materials, but they're not a replacement for a shaving-sharp HSS toolbit.
For that reason alone, I tend to rough-out with carbide, and sneak up on the final dimensions with HSS.

LEOTECHCNC
08-05-2008, 08:48 PM
I make small stainless parts on small belt driven lathes.
I use carbide inserts with a very small tool nose radius , and I get very nice finishes at very tight tolerances. The smaller tool nose radius requires less horsepower and a small chip breaker on the insert gives more shear action. I especially like carbide for small bores. If you have a small machine get a tool holder with a neutral rake and small tool nose radius. .005 tnr tops. Coatings are also very important , uncoated inserts on stainless is a waste if time and money, for example. OFHC copper needs an especially small tool nose and incredible amounts of coolant.

Circle precision makes a beautiful set of carbide shank boring bars with 60 degree triangle inserts that are absolutley marvelous. They are on sale at MSC as a kit.Its a great deal. The diamond inserts on the 3/32nd bar are very brittle. 1/4 inch and up triangle bar are great.

If money is an issue the brazed turning tools and solid carbide boring bars are less expensive, but you'll need a diamond wheel to sharpen them.

Carbide parting tools - iscar- are really worth it as well. HSS parting tools just dont compare. Kennemetal makes top notch inserts that you can turn as well as part and groove with(and thread with a different insert). If you can only afford 1 toolholder this is it, but you'll have to grind the insert as the toolnose is huge on all the inserts.

Then there is thinbit - costly but great for thin wall work or trepanning.
Matt


.

LEOTECHCNC
08-05-2008, 08:55 PM
Laso, great pic. Are those Milling inserts?

I use solid carbide em 's or hss em's. I use brazed carb in my fly cutters and my lathe boring bars go in the boring head...usually solid carbide or the circles I mentioned previously.

lazlo
08-05-2008, 09:28 PM
Yep, the bottom row are the Sandvik RA-245 (45 lead angle) milling inserts for this facemill:

http://i164.photobucket.com/albums/u15/rtgeorge_album/IMG_1641_edited-1.jpg


Circle precision makes a beautiful set of carbide shank boring bars with 60 degree triangle inserts that are absolutley marvelous.

Is that the TCMT set you like, or is it a Trigon (WCMT) set?

LEOTECHCNC
08-05-2008, 09:44 PM
MSC BIG BOOK PAGE 856.
Coolant thru the bar , very nice finish boring tool, especially in stainless. .002tnr great for small angles and odd features way down in a bore.

LEOTECHCNC
08-05-2008, 09:47 PM
Furthermore, if you have trouble with chatter in thin wall tubes, this is the way to go. GRANTED your cycle time is going to go thru the roof , you can't take much of a chip load with these but you can machine mirror finishes!

BobWarfield
08-05-2008, 10:23 PM
CCGT's work well on aluminum plastic, brass, stainless for finishing, and finishing on steel.

For steel I usually use CCMT.

I no longer use any negative rake inserts in my lathes.

These days you can get the ccgt's spec'd for nearly any material and they certainly work well on anything I've tried them on except interrupted cuts. For those I keep ccmt's on hand.

I'll also second the notion that circle boring bars are great!

Best,

BW

JRouche
08-05-2008, 10:32 PM
Oh, and I should have said I really love brazed carbide bits. I kinda hinted I use inserts more but in reality I use brazed just as much. I like them because I can resharpen them, many times, down to the point of being no point :)

The manufacture does matter also. I tried the inexpensive C5 variety from enco and they just dont hold up as well as a decent manufacture from the US.

I learned to use the brazed bits from my dearly departed friend. He had a job shop and mainly ran a large Reed Prentice lathe. 25 hp and plenty of swing. He would go to town on a large pipe that had been welded, cutting down the weld. Major interrupted cuts. I would cringe when he turned up the speed and dove the cutter into that ragged weld. I was waiting for the "crunch" sound. Didnt happen. He just set the feed and looked at me and smiled as that lil tiny bit ate the work. I was impressed. And he would have to grind them down from time to time. And being the frugal shop owner he was he would sometimes have just the smallest chip of carbide left there and would go to work on a really nasty piece of steel, just smiling the entire time.

I learned alot from that buddy!!!! Missing him still. He passed almost two years ago. His carbide outlived him. His boy is running the shop using the same carbide tooling :) JR

lazlo
08-05-2008, 11:02 PM
These days you can get the ccgt's spec'd for nearly any material

CCGT doesn't specify the high rake angle -- the specific style of chip breaker does (the suffix letters after the CCGT-xx). The CCGT's with the high rake angle are clearly indicated by the manufacturer as intended for aluminum.


You can use carbide tooling on a small cone pulley lathe but you can't really take advantage of its productive potential. You need spindle RPM and HP plus overall rigidity to get the surface feet per minute, depth of cut, and feed per rev that makes carbide worth using.

I don't know why small lathe owners use carbide but they do and with some satisfaction. Anytime I borrowed a carbide equipped lathe I use HSS tooling in it and generally out-performed the carbide in the same class of work.

But people will use carbide in these low speed not especially rigid machine tools possibly to avoid having to sharpen HSS tools.

What he said :D