HSS indexable tooling?

[danski26]

i have been making chips and learning as much as i can with my south bend lathe. I have found that at the slow speeds that i normaly run i like HSS better than carbide. Better finish and control i think are the reasons i like the HSS. The problem is grinding the tool bits is definitley an art form. I f i take a tool bit to an old machinist friend he grinds me what i need "like magic" and then i can keep it sharp and use it well. I run into problems trying to grind my own from scratch.

Not to run away from a shortcomming but, I was introduced to indexable HSS tooling. It's not cheap but it is cheaper than carbide. Does anyone have experience with this tooling? it it worth using? This is the company I am looking at.

http://www.arwarnerco.com

[S.R.Custom]

Depends on how closely the inserts fit. If the fit's not real close and they rely on the screw tension to keep them still, they may move around under load.

Seems to me that they're aimed at production work, where changing out the spendy inserts would be cheaper than paying a machinist to grind tools every time a tool got dull.

Sharpening tools is not the voodoo it seems to be once you understand the how & why of all the angles involved. Once you have that down, tool grinding becomes intuitive. And it allows you to modify the standard grind for specific, custom applications, which is at least 50% of gunwork anyway.

[arjacobson]

Just spend the time and learn what it takes to sharpen the hss. It will be WELL worth your time involved. I remember when I finally got sharpening twist drills by hand down.. I still use this skill today and people are amazed I can get any drill to work right without a"drill grinder"

[Bret4207]

I have to agree with the others. Take the time to learn to sharpen the HSS tools. Carbide on light lathes is the wrong choice.

[andremajic]

http://smartflix.com/store/video/58/Grinding-Lathe-Tools

10.00 to rent this video is well worth the info. Included are plans to make an adjustable rest which you can use to grind compound angles.

I learn by watching, and some by reading but you really can't beat seeing it done and explained to you and the ability to rewind and play over and over again until you understand it.

Andy.

[John Taylor]

The advantages of running carbide is the much higher speed. HHS can run at about 50 surface feet per minute, carbide is good at 250. Like the rest said, learn to sharpen your own. I have a special grinder for sharpening both carbide and HSS using a diamond wheel. If I had to send out for getting a tool sharpened I would never get any work done. Part of the learning experience is grinding different points stiles and seeing how they cut. What point stile will cause chatter and which will cut with the least amount. I was told by an old gunsmith years ago that using carbide on barrels would set up stress in the barrel. I have found that there is no problem using carbide on barrels. If I used HHS on a Douglas barrel blank I would be there all day.

[theperfessor]

I use both carbide and HSS tools on a lathe. Its all in the grind. Negative rake carbide tooling on limited horsepower machines is not so good, but positive rake carbide tools work just fine. On higher powered machines and on parts that are rigidly mounted nothing beats indexable negative rake carbide for taking off a lot of material in a hurry with good tool life. There are some positive rake carbide tools available, check out some holders that use clamp in TPU style inserts.

Its not the cutting tool material so much as the tip radius and top rake angle. In a small shop, learning to grind your own tools is a valuable skill to develop.

[Bret4207]

I've used real lathes in the past- Clausings and LeBlonds. But with light home shop lathes like the Atlas or South Bend tool post rigidity is lacking. Carbide is a mistake in those set ups.

[JIMinPHX]

Those HSS inserts look REALLY handy. Some people will flame me for saying this, but HSS will outperform carbide in some applications. HSS takes shock better than carbide. HSS can be sharpened to a finer edge than most carbide without the edge getting brittle. HSS has better natural lubricity than carbide in some materials.

Knowing how to grind your tools is a very valuable skill & you really should learn it, but those little inserts will get you going in the mean time.

[JIMinPHX]

I was told by an old gunsmith years ago that using carbide on barrels would set up stress in the barrel. I have found that there is no problem using carbide on barrels.

I concur. I have done a lot of single pointing with carbide. Some of it is in aircraft. some is in printing presses. Some is in firearms. None of my carbide cut threads have ever failed. I haven't seen any unusual warping during heat treat either.

[S.R.Custom]

Some people will flame me for saying this, but HSS will outperform carbide in some applications...

Not me; it's true. And I would say as far as gunsmithing is concerned, HSS works better for most applications.

What I've noticed about carbide is that it bears harder on the part because it won't sharpen as well. While I agree, that does not cause "stress in the barrel," it does cause more deflection as I cut, which makes for a poorer turning.

[leftiye]

The rounded edge on carbides smears the stteel at the point of parting. At highspeeds this produces a polished finish. Many small machines flatly won't use carbide, or not unless it is hand sharpened. HSS -- if COOLED (so it remains hard) can be awesome in slow heavy load, heavy cut situations (within reason, not the modern fast hogging situations), and also in surprising speeds with lighter loads. I hand sharpen both HSS and carbide with a diamond lap after grinding. Luv the cobalt HSSes.

[Cap'n Morgan]

Today there's an absolutely staggering number of different carbide insert types. The same insert type may be had in three different carbide qualities with four different cutting angles (and as many different rake angles) Add to that, maybe three or four different coatings, at least three different nose radii - and don't get me started on the myriad of different chip breaking profiles.

I guess what I'm trying to say is, that you can find a carbide insert that will work on even a skinny lathe, but you'll need to ask the supplier for advice.

[trevj]

The HSS inserts work, but you are just as buggered, once you have gone through all your inserts and they are all chipped or dull, except that you've paid a bunch for the holders and for the now useless inserts.

Think of them as a luxury item, not a way to avoid having to learn to grind tools.

Buy 10 1/4 inch HSS lathe tool bits and a good dresser for the grinder wheels. Practice. Buy an adjustable protractor and a fine tip marker, and draw your angles onto the tool blank, to get yourself started.

Carbide at low speed. Try some - -GT inserts. Last two letters are GT, available in various shapes. I like the CCGT's. Watch yourself around them when measuring. Cut myself a few times on them. Fragile? Not so much, once you learn how to use them. Carbide does not suffer being bumped against the work at all well. Lots of carbide around these days that works very well at low speeds, and holds up to a bunch of abuse. Gotta hit the catalogs and get sorted out on the what's what. If a fella thinks picking the perfect powder for reloading is a pain in the ...., this has it beat.

There are a couple outfits flogging HSS tooling. Most of the guys that buy them are the ones scared spitless of grinding tools, or thinking that hey can somehow buy the solution. They can't.
Guys that buy them as a convenience, are the rest, and I think, a minority. IMO price per edge is too high, for the average guy to benefit from them.

Cheers
Trev

[PatMarlin]

I have spent coming up to 2 years choosing carbide inserts for CNC that work the best for production in terms of finish and longevity, etc. and I'm pretty close to acceptable, but like Cap'n mentioned above- what a difference in performance between types, brands, etc. It is staggering.

I've gotten pretty good at grinding HSS for my manual lathes and they work great, but there is still indexable carbide that works very well on my 11x28 Logan.

A plug here for some darn quality tooling at a great price- and he makes them all in Oregon. His bits work very well in many apps as well, and you can't beat the prices.

I've modified many of his tools as you can't beat the price:

http://www.mesatool.com/

Jim's a US home setup manufacturer and great to deal with. I use a few of his bits and tools exclusively now.

[bowfin]

danski26,

Believe it or not, I used to grind high speed tool bits as a hobby on my lunch hour. (Something a little more relaxing than carbide step reamers and form tools.). I would rough the bit out with a Norton Aluminum Oxide wheel (an SG wheel for the more exotic high speed steels) and then finish it glass smooth with a Borazon cup wheel. Then I would do the same to the other end of the bit, making it double ended. They were almost too pretty to use, but the guys cutting bronze lead screws would come raid my stash. I told them to return them, and I would sharpen them up, though they would last forever with that particular type of bronze.

If I were rich, I would have me a tool cutter grinder, a Jones & Lamson optical comparator, a Rockwell hardness tester, and a pegboard full of wheels to go with my closet full of high speed steel...and Tantung, lots of Tantung!


I also collected different types of high speed steel blanks. It would make my day when we got a load of stuff in from Chicago and I would find a piece of T-15, M-42, or better yet, a piece of Tantung or Stellite.

Even though I have a fetish for high speed steels, I think the niche where they would outperform carbide inserts is narrow, and probably moreso every day, at least for machining in factory settings. Then again, carbide is losing ground with some of the ceramic and other "exotic" cutting materials.

What size of tool bits can your tool block accomodate, without a ridiculous amount of shimming to get it on center?

[jmh54738]

Oh no, I didn't think there was another person who had a fedish for HSS tool blanks. Other than the common Mo Max and Rex, some have interesting names...
Red Cut Superior
Atlax LXX
Co Co
Beaver
Dreadnought
Simonds Red Streak
Clarite
Braemow
Electrite Vanadium
Haynes Stellite J a bugger to grind half the way to carbide & non magnetic
Tantung also non magnetic.
I even have hand forged carbon steel bits. If you think that HSS is slow, you must cut the rpm in half again to use carbon steel bits. Well Bowfin, I got the Scherr Tumico 14" optical comparator, K O Lee Univ Tool and Cutter grinder and the wall full of wheels. I do most work with HSS bits and resort to carbide for hard materials or quick, heavy stock removal. I am not running production, besides, I don't like buying diamond wheels. It takes horsepower to run carbide along with a heavy feed to curl and snap the chip off. Some guys never catch on and have stringy chips winding around the chuck, grabbing the work light and even sucking all of the chips out of the pan and then the whole mess is spinning. I can determine a man's skill by just looking at his chips.

[PatMarlin]

What I did when I started out with manual machines is have a friend show me how he ground HSS bits, then I figured out what worked best for me. Then I bought a Harbor Freight tool grinder on sale ( the Baldor copy with green wheels) set the tables for the angles and left them there and was good to go. Repeatable tool grinding every time.

I would then finish the edge with few strokes of an eze-lap flat diamond hone.

[danski26]

Pat, that is the route I am also taking. It took a bit of work to get the grinder up and running but I should soon have a a/o wheel on it for HSS grinding. All of the "fixing" work is done to the grinder. It runs very smooth now. When I first bought it, it was so out of balance it would vibrate right off the table! Now smooth as galss.

I checked out Mesatool.....VERY interesting at VERY good prices! I think eventually I will order some.

Thanks to everyone who replied. Keep the good suggestions comming!

[PatMarlin]

Go head and use up those green wheels. Not optimum but they work.

Mine's fairly smooth. How did you balance it out?

[bowfin]

K O Lee Univ Tool and Cutter grinder

Yep, that would be the one!

The one I used to run is down in Mexico somewhere, since the Appleton plant moved from Nebraska to there. The drill pointer has been down there for more than five years, and they never even wired it up, so I don't think they will be grinding many carbide form tools with my faithful K.O. Lee.

[danski26]

I took the motor apart, put the shaft with all of the backing plated, bushings, washers and such between centers on the southbend and recut all of the faces true to the shaft center.