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ug
10-05-2005, 05:49 PM
Since I'm just getting into a lathe and am learning as much as I can, I was wondering if most folks here sharpen and shape their own HSS lathe tools or if you buy the indexable stuff?

I ask because I prefer to do as much as I can myself yet at the same time I prefer to enjoy making parts and wonder if I'd be better off just buying preshaped indexable stuff.

FWIW, this stuff will be used in my Fimms q/c post.

Nutter
10-05-2005, 06:14 PM
Absolutley learn to sharpen your own HSS blanks. The cost savings is well worth it. The ability to custom make any tool you need is indispensable some times.

I have some carbide insertable tool holders, but I reserve the carbide inserts for things like blanking out an axle shaft to be shortened. I cut those while still hard. If I had them annealed, I'd use HSS on them. Anything soft enough for HSS sees the HSS.

I'm working with older equipment in a home shop. I'd guess that you are in the same situation.

If you were a pro where time=money, you probably wouldn't need to ask. The answer for that situation seems to be carbide for most jobs just to speed thinsg up.

3 Phase Lightbulb
10-05-2005, 06:18 PM
In my machine shop class, you had to grind your own HSS lathe tool bit. I used the same HSS bit that I made at the beginning of the class all through out the entire class. That's the only one I've ever made. At home, I just buy the Carbide inserts, or tons of the Carbide brazed on bits from ENCO. If I ever need a special bit, I'll grind it (If I still remember how), otherwise it's cheaper to just buy them pre-made.

-Adrian

ERBenoit
10-05-2005, 06:27 PM
[QUOTE]Originally posted by Nutter:
[B]Absolutley learn to sharpen your own HSS blanks. The ability to custom make any tool you need is indispensable some times.

True. A special shape or form for which there is no insert, you'll have the knowledge of how to sharpen your own lathe tools.

The cost savings is well worth it.

Inserts cost money. If you have sufficient income for pay for them, it becomes a bit different.

Get youself a guide on how differnt lahte tools are ground for specific operations. Practice grinding lathe tools from square key stock, less expensive than tool blanks.

SGW
10-05-2005, 06:31 PM
HSS for home shops, no question. The only time I use carbide is when I absolutely need to -- a hard spot in a casting or something.

Tin Falcon
10-05-2005, 06:51 PM
Books have been writen about the humble subject of cutting tool selection.Much of the choice is based on your needs and your equipment.
By all means learn to grind your own lathe bits. Most basic machining books as well as the machineries hand book will explain tool geometry for various metals and cuts.ie left hand right hand roughing finishing shouldering grooving etc. also this will help with learning nomenclature.
Look for blanks with cobalt added they will last longer.
HSS advantages easy to grind with regular wheel you can make any shape or angle as needed. Excelent finish at slow speeds.Disadvatage They take TIME to grind.
Inserts advantages saves time. Repeatability on CNC lathes.Increased productivety. Carbide likes speed(higher rpm) lasts longer on hard material. Disadvantages hihger cost limeted shapes.Bottom line? on a production cnc lathe inserts are the way to go on my 1936 south bend I lean more to HSS.
Jim

Your Old Dog
10-05-2005, 08:01 PM
I concur! Learn to grind your own. For instance:

Anyone tell me in 10,000 words or less how to grind a flycutter bit out of HSS for aluminum? The one I made gnaws the surface and leaves a horrendous mess! No doubt, I'm doing something wrong http://bbs.homeshopmachinist.net//biggrin.gif I've not been able to locate an example in any of the referance books I have.

A close-up picture and I'd be your little-web-buddy for life http://bbs.homeshopmachinist.net//biggrin.gif

[This message has been edited by Your Old Dog (edited 10-05-2005).]

Paul Gauthier
10-05-2005, 08:40 PM
I don't use HSS at all, mostly brazed carbide tool bits, and some inserts. HSS is more work that it is worth. The brazed carbide tools are cheap and will by far outlast HSS.

------------------
Paul G.

Mcgyver
10-05-2005, 09:36 PM
Its HSS for the home shop. Its easy, cheap, better workmanship because the geometry produces lower cutting forces AND you easily get the geometry you need, and most home shop machines really can't take full advantage of carbide's advantages. yes, you have to learn a tiny bit of stuff to sharpen a cutter, a few angles and what they are called, but you should really know this fundamental knowledge even if you are using carbide. Then again, imo unless you enjoy learning, this is not the right hobby – you should switch to woodworking or something while there’s still time http://bbs.homeshopmachinist.net//biggrin.gif

I disagree with the comment hss doesn't last as long. with a hss blank and a carbide insert, I guarantee my hss blank will remove a lot more metal than the insert.

Of course in the privacy of your garage you can use anything from marshmallows to diamond, but hopefully the number of experienced peeps advocating hss at least compels you to check it out http://bbs.homeshopmachinist.net//smile.gif

C. Tate
10-05-2005, 09:54 PM
Learn to sharpen HSS. Once you have mastered it switch to brazed carbide. You will be able to sharpen them and they are cheap. $3.50 for a 3/8 shank. I agree with Mcgyver that one piece of HSS will move a larger volume of chips in its life than one insert. However; the insert will move 4 or 5 times as much in a given amount of time. Carbide is more porductive than HSS without question. If it were not they would not sell as many as they do. Ever see a HSS both at IMTS?

spope14
10-05-2005, 09:54 PM
In the home shop, grind them, but have some carbide sintered or a couple of different indexables handy for harder stuff.

In the school shop, I have this strange philosophy. The students use carbides at first. They also use pre-ground tools for forming and threading - tools I grind up and test.

Then, they make their own. The theory is this. My students have learned proper chip formation from different tools, and know the feels and sounds of the tool when it is right. I also teach the angles and such during this part. They know surface finish, and effects of nose radius on wear. Basically, they know the way things SHOULD BE. Then, as they grind tools, they instantly know if the tool they ground is junk or good. I do not have to teach the proper chip formation and such. They know good or not. They take to grinding the tool better, and take less time figuring out the problems - solutions, and the best tool. They also get into some very complex form grinding as well - much faster, and do it with the highest of quality.

I base this on 18 years of teaching, the first 10 spent doing the "grind first", and having moderate success getting this down. Now I can teach tool grinding in one week, and get the students making very fine turning left and right hand, profile tools, thread tools of a great variety, chamfer tools, and radiusing and even little specialty tools. And they work great!!!!!! before, I was lucky to get a turning and thread tool that would pass muster and make the projects without looking like bevers attacked them.

This goes against all that past apprenticeships teach - including mine, but it has been proven to my industrial supporters, and they love this method now.

It also helps that I consider tool grinding of all types the highest art of machining, so perhaps my love of this, and my desire to take it to the next level is passed on.

C. Tate
10-05-2005, 09:57 PM
Just read spope's post sounds like a good way to learn. Might work well for the homeshop guys. Makes perfect sense to me.

Junk
10-05-2005, 10:09 PM
I'm planning on buying a few preshaped and doing my own mostly but want the preshaped around as a reference to compare to mine so I know when they are spot on.

I can definitely see the value in doing it yourself.

[This message has been edited by Junk (edited 10-06-2005).]

Mcgyver
10-05-2005, 10:24 PM
<font face="Verdana, Arial" size="2">Originally posted by C. Tate:
However; the insert will move 4 or 5 times as much in a given amount of time. Carbide is more porductive than HSS without question. If it were not they would not sell as many as they do. Ever see a HSS both at IMTS?</font>

what you say is true but needs qualifying - firstly, IF the machine is capable. work is cubic units of removal per time - a lot (most?) home shop machines hit the wall either rigidity or horsepower before they can take advantage on these higher removal rates. wont' see a used Harrison, used Colchester or shaper booth there either, but they might the best thing for the home shop

Don't forget, they are not purely interchangable - the angles hss is capable of are much better for cutting resulting in lower cutting forces which is farourable to our lighter/older home shop machines. Carbide has its place, but not as frequently as it does in industry, imo.

Old dog, here's a sketch of how I grind a fly cutter. this ones ready to drop in run counter clockwise. Its the same as any other cutter, needs rakes and clearances. These ones are almost the same as a facing tool - the radius is put in with the edge of the wheel and is exaggerated in the sketch

http://i20.photobucket.com/albums/b201/michael0100/Assembly2.jpg


[This message has been edited by Mcgyver (edited 10-05-2005).]

charlie coghill
10-05-2005, 10:26 PM
YODThis is the way I do it, not nessceraly right. I grind it close to the way that I would if I was going to use it for the lathe. I do grind a fairly large radis on the nose say maybe 1/8 inch.

It would be mounted in the flycutter at apporx a 30* angle.

Take light cutts and use plantey of cutting fluid. For the cutting fluid I use cutting oil or some stuff that comes in a green can(dont remember the name at present). It is made for cutting aluminum. Just keep the chip from welding back to the parent metal.

Hope this give you some help.

Tin Falcon
10-06-2005, 06:54 AM
YOD:
Never gave a lot of thought to grinding a fly cutter for facing aluminum just looked at how it needed to cut and ground the tool to the right geometry. If you are not familiar with grinding lathe tools learn that. Like McGiver and charlie said it is basicly the same as a lathe tool make sure you have good clearance so you cut rather than rub.And radius also effects finish. i think the green stuff charlie is refering to is A-9 I keep a can in the shop.
Jim

Your Old Dog
10-06-2005, 07:19 AM
UG, good topic for us rookies. Keep in mind when you see diagrams of the various angles of the bits it's not usually as critical as one might think unless you're blessed/cursed with a machinist mindset. It's okay to be off or vary a little bit in the demensions and it will still work. I grind my HSS bits freehand on a Sears & Roebuck grinder and they work fine. A Master Machinist want's to know that it's dead nuts on because they spend their lives chasing a .0001 of an inch. I don't need that same confidence for the things I do. That's why I'm not a Master Machinist ! If I walked into their shops looking for work (dragging my gloves behind me) they'd likely hurt me before they let me out http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif

The flycutter bit has escaped me because I haven't been able to locate a picture or drawing of one. I can't visualize the grinds on it unless I weld on a glob of metal to have something to grind! Mcgyver your pic isn't showing on my system, just a checked box. Any chance you could email to me? Thanks for the extra effort. Do that for me and I'll send you a before and after of the result!! Just don't post it.

dicks42000
10-06-2005, 07:45 AM
Good topic & replies guys.

Spope, I like the teaching method you outlined. I wish some BCIT instructors had used your method in the early 80's....

Anyway, I pretty much agree with most if the others. If you have a not-so-rigid or worn machine or limited HP (eg. my little Atlas lathe), use HSS. (Also why not learn tool grinding ???) HSS is also invaluable for form tools, one off shapes and makes cheap parallels...I even use gauge plate & drill rod to make gear & sprocket cutters for occasional work.

If your machines can handle & power it,
for production use carbide, also obviously for machining hard materials. Use inserts for the convenience...even the Chi-com type stuff at Busy-Bee etc. works & is cheap. Insert-type face mills rock in the mill for large, flat surfaces. Even my Rockwell likes its insert face mill.

My .02 (Cdn) worth, anyhow....

ricksplace
10-06-2005, 08:49 AM
I'd have to say hss too. If you are new to grinding, buy some cheap hss and practice on that rather than key stock. That way, you can try your grinds to see how they cut.

Try the cheap 1/4" stuff from enco. It's Chinese hss, and it really is crap, but it's cheap, and good to practice on. It cuts the soft stuff OK, but it loses an edge fast (that way, you will have to resharpen often, and get more practice!). I have also tried the cheap stuff from KBC tools. Their cheap hss is from india (Bipico), and in my experience, is much better than the chinese enco stuff. It's pretty much standard m2 hss. I'm not prejudiced about where the hss comes from, just talking about my experience with the different brands.

Spope -great idea with your students

Rick.

PBMW
10-06-2005, 09:54 AM
I guess I'm going to be the odd man out...I use Carbide for almost everything.
I do manual mill an dlathe and CNC mill and lathe work. I use which ever material that allows me to take the cut in the least ammount of time. Time is money and I have a backlog to get through.
If I can cut at 5 or 6 times the SFM with carbide, I'm going to save time and make money by spending twice what I would have spent in tooling if I had used HSS... It's really just that simple
I use HSS on plastics (and I cut a lot of them) but carbide will outperform HSS at LEAST 3 to 1 every time
Here's another thing...Carbaloy came out with the cemented carbide cutter as a flycutter first and HSS just can not do the SFM that a flycutter in steel requires. You can't turn it slow enough
Jim

ERBenoit
10-06-2005, 10:06 AM
<font face="Verdana, Arial" size="2">Originally posted by ricksplace:
I'd have to say hss too. If you are new to grinding, buy some cheap hss and practice on that rather than key stock. That way, you can try your grinds to see how they cut.
</font>

The suggestion of the key stock was the way I learned it. Not saying it is/was right. We would sharpen the key stock "tools" and compare them to properly shaped HSS tools. I see your point with the "cheap" HSS where you can at least try your grinds.

The keystock was good for a laugh at times though, one underclassman spent all day trying to use keystock "tools" on the shaper.

From shaper to grinder to shaper to grinder for a whole day.

Michael Az
10-06-2005, 10:26 AM
I agree with everybody else about learning to sharpen your own but I will have to disagree about using the cheap asian tooling. I have never had good luck with it. A well made cobalt high speed tool will give me a lot of service but my experience with the asian is a crapshoot. Since I got a bigger, more rigid lathe, I have been using carbide a lot more than ever. Cobalt can't come close to keeping up with it. Here is a roughing cut in 4140 prehard I did today. Stock is two inch dia., depth of cut .100, feed .012, spindle speed 200 rpm.
YOD, are you sure you know the kind of aluminum you have? Unless it is alloyed, it doesn't machine well at all. I use wd40 when cutting aluminum.
Michael
http://myweb.cableone.net/michaelaz/4140-2.jpg

spope14
10-06-2005, 10:54 AM
Like I mentioned before, I consider tool grinding one of the highest and finest of the machining arts. This because without the best sharpened tools, no program, fixturing, or skill level can overcome the issue of a poor cutting tool.

This said, I do have some cheap bits for use in quick aps., but for the students, I use the good Cobalts that hold edges, and are harder on the wheel when grinding. I understand the practice idea, but with what I do when they already know what good is, if I go cheap at this level, they would figure that out rather fast (yes, they did the last time when the cheap bits were donated, and I was dumb enough to try to slide one by). Kind of boxed in to the higher quality.

tomb
10-06-2005, 11:13 AM
I guess I'll throw in my $.02 here. I learned to grind my own HS bits and I think it's a valuable skill. That being said, I use the cemented carbide bits 90% of the time. I just find it quicker to grab a pre-made bit then having to sharpen and resharpen. I have a 12 x 36 asian lathe which seems to be fine for carbide.

Every now and then a job comes along that needs a special shape, has interrupted cuts, etc. that I go with HSS.

Something no one has mentioned yet - you can get HSS inserts. I've seen them advertised in H.S.M. Except for my boring bar - I never use inserts at home. No particular reason - just have plenty of carbide bits lying around and even more HSS ones if I run out.

Spin Doctor
10-06-2005, 11:17 AM
The old debate between the appropriate use of HSS and Insert tooling still rages. Fortunately they both have their uses. For specialized shapes, chamfers at specific angles, general machining and threading for the average HSM is well served by learning to use HSS. But that said Carbide Inserts do have their uses. Most HSms have lathes far too light to take advantage of the negative rake inserts but the positive rake inserts are something that lighter machines can use when used with discretion. But then when I was working I always cheated. Ground most of my HSS bits on a surface grinder after roughing them out on a pedestal grinder. Not because I couldn't grind them off hand but because with the tooling set-ups I used on lathes it was easier to maintain the angle relationships I wanted for threading and chamfers. I'd link pics of the fixtures but P'Bucket is down.

ricksplace
10-06-2005, 07:40 PM
erbenoit -I learned on keystock too. Funny to watch it smoke and squeal trying to cut. We'd swap the keystock for the real hss just to see if the class doofus would notice. It seemed to happen to me a lot.....

Tin Falcon
10-06-2005, 08:30 PM
Here is a goodbasic link on lathe tools.
http://www-me.mit.edu/Lectures/MachineTools/lathe/intro.html
The recomended geomeries are the results of much experiment and represent the Ideal geometry for a particular job on a particular metal. You can grind general purpose bits thay will cuta variety of metal but just not as efeciently.
JIM

R W
11-06-2006, 10:38 PM
The Sherline web site has some good information on grinding HSS.

dp
11-07-2006, 12:16 AM
Frank Ford has some pages that show why it's useful to be able to make your own cutters, grinding or otherwise.

http://www.frets.com/FRETSPages/Machining/Projects/RopeKnurl/ropeknurl.html
http://www.frets.com/FRETSPages/Machining/QuickTricks/ToolPostFile/toolpostfile.html
http://www.frets.com/FRETSPages/Machining/Products/ClampFeet/clampfeet.html

I grind my own but also buy cheapy brazed carbide cutters from Harbor Fright and I frequently find carbide insert grab specials at the local tool shop. I've made all the holders not that it's rocket science. I have done some exotic grinding on HSS using old pre-war designs as well as shapes that have stood the test of time.

Pre-ground tools are good for providing examples of what you could do with a little practice. I'm no expert, having been at this for just over a year, but some of the stuff I've done has been very serviceable.

I'm dp and I approved this post.

ahidley
11-07-2006, 11:19 AM
Your OLd Dog,
For some reason I cant see pics here. But I would bet its "speeds and Feeds" that is causing your problem.

Alistair Hosie
11-07-2006, 12:43 PM
I use both Carbide and hss but am leaning towards making my own carbide tipped tools with steel shanks, making a screw thread to hold it.I also have the capability to silver solder them using spare tips I got in my local toolshop in Glasgow .Buying new tungsten carbide tipped tools is expensive but there are the times it is worth it.I recently bought an expensive tipped boring tool then made just as good a one from copying it,using spare tips I had.Alistair

BillH
11-07-2006, 12:44 PM
LOL, this thread is from 2005, hehe.

Alistair Hosie
11-07-2006, 12:56 PM
Only buy good quality spare tips from ebay or wherever cheap asian chinese carbide is soft as a cookie.Alistair

Spin Doctor
11-07-2006, 01:09 PM
HSS for threading, form tools and those special projects. Carbide is great for general turing operations and facing cuts but ONLY if your machine is rigid enough and can handle the speeds required. Also for home use IMO the only inserts to use are the ones with a positve rake and chip breaker built in. Negative rake tooling requires too much HP

PaulT
11-07-2006, 01:28 PM
Even in a home shop, I think you will be more productive with insert tooling. If you really enjoy hand grinding HSS tools that's a different story, but if you like to cut metal fast, go with carbide. Here's some notes I posted on a different forum on using carbide tooling in the home shop.

Paul T.

Don't waste money on inserts and holders using the common TPG type inserts. Since those were designed long ago some newer designs have come out that work better and if you shop around the prices aren't much more for the better ones.

I'm assuming you have home shop sized machines and this means you want tools that use positive rake, meaning they cut the metal more like an HSS tool rather than "rubbing it off" using a negative rake insert, which requires much more horsepower and rigidity.

On a lathe I would recommend tools that use the CCMT type insert. This is a positive insert with built in chip breaker that cuts really well on small machines (much better than a typical TPG insert) and since its an 80 degree insert the same tool holder can be used for both turning and facing in the same mounting, so you only have to buy a single holder to get started. I like the Hertel holders, they're made by and just as good as the Kennametal ones and all the parts are exchangable. J&L Industrial often has the Hertel tools on sale, but you'll find these from many other manufacturers like Micro 100 also.

The industry standard listing for a CCMT holder that allows both facing and turning is SCLCR. They're available in a variety of shank sizes and generally 2 insert sizes are used. In the larger ones like the 5/8" shank I have (full model # SCLCR103) the CCMT3251LF insert is used, in smaller shank sizes they go down to the CCMT2151LF size, both work well.

As mentioned earlier you can get good deals on this standard insert on Ebay. www.carbidedepot.com also has good prices on these inserts.

If you have a small shop, rather than stocking insert types for both steel and aluminum you can get away just buying an insert designed for steel and using it on aluminum also. It won't last quite as long on aluminum but will work very well. The CCMT3251LF and CCMT2151LF inserts I mentioned above are good all around inserts for both light roughing and finishing, and have a small radius to provide good surface finish. For more aggressive roughing you can buy some MF inserts also. Make sure to buy the inserts in a carbide grade rated for mild steel, in the Hertel series that would be grade HC210.

You can also buy boring tools and endmills that use this same CCMT insert. I haven't used the endmills but I would expect they probably work pretty well.

For my endmills (on the wise recommendation of tmngcarbide from this forum) I went with tools that use the APKT style inserts. This is a highly positive insert that was designed for efficient cutting on smaller machines, ie BP sized machines. After switching to these type end mills I got the best surface finish on 6061 parts that I had ever seen on my BP clone CNC machine. The endmills come in style that accept either the 1003 or 1604 size insert, for smaller machines the 1003 size is the way to go and they're a little cheaper.

Endmills using APKT type inserts are available from a variety of vendors and also on Ebay. Keep in mind that the smallest endmill size that uses at least 2 inserts is 5/8", if you go below that you go down to one insert which slows down the feed rate.

For both turning and milling you have to change your approach when using carbide, cranking up both your feeds and your speeds. As a rough rule of thumb increase your SFM (and RPM) by 3 compared to your HSS SFM's. For feed you need to keep in mind that carbide doesn't like small feed rates and the insert will often chip if you use too low a feed rate. On the lathe tools mentioned above they typically spec a minimum feed rate of 0.003" IPT (inches per turn), with a max typically around 0.008" IPT. With an endmill you need a feedrate that yields a Chip Load per tooth of at least 0.003".

As I mentioned earlier, if you try to cut with feed rates that yields less IPT and chip load than describe above, the inserts will wear out quickly and your surface finish will be poor. On a CNC machine this is easy to implement, on a manual machine it takes more care.

Also remember that when setting up a cut with carbide tooling its much better to use a high RPM and feed rate and lower depth of cut than to use a lower feed rate and high depth of cut as your IPT and chip loads will end up too low with the latter approach. I always start with RPM's and feed rates pushed high with a small depth of cut and then carefully increase the depth of cut until the finish quality suffers or the machine starts to complain.

Insert tooling can be troublesome on interrupted cuts as the inserts are prone to chip. They make special tougher inserts in the CCMT size for this application.

The CCMT holders can also use CCGT inserts when you need light cuts, these are sharper, have even more positive rake and are designed to take lighter cuts. I find that with these positive inserts the sharp ones like CCGT will allow you make cuts very similar to what you could do with a sharp HSS tool (lowering the feed rate to get a better finish for example), and I never use HSS tooling in my shop at all anymore.

That's another good thing about the CCMT type inserts compared to a TPG and some of the other older types, the CCMT are available for a much wider variety of applications. But to be honest for the work we do (prototype, very small production run) 90% of the time I'll use the standard CCMT3151LF insert, its pretty flexible and gets the job done.

One thing I should have mentioned about carbide endmills is that you need to be careful to avoid chip recutting, this will wear the inserts quickly. This can be an issue when cutting pockets, to avoid it I used compressed air nozzles to clear the chips from the pocket or of course a coolant system will work. I don't use a full coolant system on my open BP clone machine so as to avoid the mess, we have a Trico Micro-Drop unit that both applies compressed air and a lubricant that's applied in small "micro-drop" quantities so you don't get a big mess. So far that system has been working well for us.

Good luck-

Paul T.

JimDobson
11-07-2006, 06:01 PM
One thing with a set of insert tools, is that relieves the necessity of having to pack shims under the cutting tool.

Norman Atkinson
11-07-2006, 06:09 PM
No one has mentioned honing lathe tools.
Now I have a microscope as many workers have on small lathes
Right, gentlemen?

Norm

Mcgyver
11-07-2006, 06:56 PM
Even in a home shop, I think you will be more productive with insert tooling. If you really enjoy hand grinding HSS tools that's a different story

Paul, I don't know why - sharpening a hss bit takes next to no time and is infrequent, wouldn't say i love it but it impinges so little on shop time i don't know why it would be a productivity issue. The biggy though is economics, there is a massive cost advantage to hss - how many dozens of easy touch ups can you do in a hss lathe bit compared to carbide inserts.

All that aside, there might be an argument to say carbides decrease productivity in the home shop. For a given removal rate, carbide takes more power than hss because of tool geometry. As our machine's rigidity and HP are generally constrained to removal rates less than what hss is capable of, switching to carbide would lower that removal rate further still.

lane
11-07-2006, 10:56 PM
Well I might as well add my 2cents worth . Looks like every one else did. I have 2 lathes a 10 inch S.B. and a 13 inch import. I use HSS and cemented carbide along with a very few carbide inserts. A piece of HSS cost may be $3.00 it will last a life time a brazed on bit will last untill you grind the the end off. A 2 or 3 edge carbide insert will last untill it chips or gets dull then you throw it away. at $2.00or $3.00 each The HSS i still have some that were ground up 30 years ago. PLEASE some one show me a carbide insert that has lasted 30 years with daily use. _Their aint one.

J Tiers
11-07-2006, 11:34 PM
I have yet another take on it....... I use HSS mostly.

But what I have done is to buy up cutters whenever they are cheap at sales. Not NEW ones, but ones that have been used......

Mostly they are useful shapes..... SOMEONE needed that shape, after all. I have about 6 drawers full by now, of HSS and some brazed carbide

Generally I can find a piece that is good for what I need, and just reshape it a little, or hone a good edge back on.

Just looking at them is an education, and I get to try out all sorts of shapes.

I'd recommend it. They always go cheap, so much the boxful.

lazlo
11-07-2006, 11:49 PM
I use carbide inserts for roughing and hss for finishing.

Carbide really needs a 5 thou (or more) DOC to get a really nice finish, so it's hard to sneak up on a finished size like you can with a finely-honed hss toolbit.

Also, if you're using brazed toolbits, it helps a lot if you hone the edge, even if it's a brand-new tool. Green silicon carbide wheels leave a nasty finish on carbide -- if you don't want to invest in a diamond plate wheel, those $5 EZ-Lap diamond hones work wonders.

J Tiers
11-08-2006, 12:01 AM
if you don't want to invest in a diamond plate wheel, those $5 EZ-Lap diamond hones work wonders.

They sure do...... there is a coarse for roughing out and finer for getting a good edge finish. You can do quite a lot of re-shaping with them, actually.

Norman Atkinson
11-08-2006, 02:59 AM
It is worth repeating that the imperfections of the tool are transferred onto the work that it is doing.

A cheap microscope out of a child's toy box will soon show up what tooling is blunt.

So we are getting nearer to these endless postings about tool and cutter grinders- again and again.

However( arhhhhh) it doesn't take many replaced carbide inserts to equate to a very second hand T&C or a surface grinder which will do a lot of other exciting things

Cheers

Norm

Orrin
11-08-2006, 12:26 PM
I'm a HSM and have never had a need for carbide; but, I'm sure the day will come when I'll need it to cope with a hard spot in a casting.

IMHO, grinding HSS cutting tools is no big deal. All it takes is a little concentration. After obtaining a suitable shape, my HSS cutters will probably never see the grinder, again, for a year or so. I merely touch them up from time to time with a hone.

In a US Navy school the instructors taught us to always hone a keen edge, even on a freshly ground tool. Diamond hones are cheap and they remove metal, fast. If the diamond is followed up with an Arkansas or India stone, the edge will be almost razor sharp and will produce a beautiful finish.

A HSS cutting edge will last much longer and produce a better finish on steel if cutting oil is brushed on. On aluminum, use kerosene. Kerosene prevents aluminum build-up on the cutting edge; and, it produces a beautiful finish. On a facing cut my parts show a rainbow of colors, just like what you see on a CD.

If you are getting a lousy cut on aluminum, check your cutting edge. If there is an aluminum build-up, you've found the cause of your problem.

Not being a professional, I have no reason to work fast. The slower cutting speeds demanded by HSS set a nice, relaxing pace. If I used carbide and ran at the frantic speeds it is capable of, I wouldn't enjoy my shop time nearly as much.

Another thing that keeps me away from carbide is the confusing array of different nomenclatures assigned by the different manufacturers. You bet, I've read all about standard carbide designations, but they bear no resemblance to what I see in some tool catalogs.

Over the years I've concluded that very few people will change their habits based on what they read on line, so I don't expect to change anybody's mind. But, if you haven't formed your habits, yet, I hope my post will be of some use to you. :)

My 2¢

Orrin

Spin Doctor
11-08-2006, 12:59 PM
Perhaps my favorite insert tooling for lathe work are these

http://img.photobucket.com/albums/v19/markandannie/tool%20holders/MVC-003S.jpg
http://img.photobucket.com/albums/v19/markandannie/tool%20holders/MVC-007S.jpg

While both are negative rake insert holders but are fitted with positive rake tooling. These fit A series Aloris type tool posts and work like gang busters on a Hardinge. I'll have to see how they work on the new lathe when ?????? I finally get done with remodeling the house.

Spin Doctor
11-08-2006, 01:05 PM
Additionally these types of insert holders (1" x 1") can be modified to fit any of the wedge or piston type tool holder systems. Tread tool holders. Cut-off tooling, Grooving tools etc. But, a really large but, is you need a very rigid machine to get the most out of them.

hssmike
11-10-2006, 12:43 AM
Carbide is more porductive than HSS without question. If it were not they would not sell as many as they do. Ever see a HSS both at IMTS?

This year we had a booth (E-2470) at IMTS.
Everything I had in the booth was either High Speed Steel (HSS) or Tool steel. 85% HSS---15%TS. The response we got was overwhelming. It will take me well into next year to catch up.
Most of the interest was machining high alloy with HSS inserts, and then it would be Flat Ground stock.

Don't underestimate the production/economics of HSS.

Thanks
Mike Warner