Can someone recommend a good aloris type holder, and a good cutter for various materials (SS, mild steel, Alum).

I'd really appreciate it.  I think I'm doing ok with machining and turning, but parting on the lathe, especially SS is a nightmare.

What machine are you using

Grizzly gunsmith lathe

IME, slow RPM, heavy cutting oil, and making sure your tool is on center, are necessary for parting off on a manual lathe.
Manual lathes usually aren't rigid enough for heavy parting or wide part off tools.

I did some experimentation today, and tried various speeds. parting tool widths, etc., and had a hell of a time. Best I could do was about 240rpm with a fresh ground 1/8" cutter, but it wouldn't last long, and got hot quick. Lots of smoke with lubrication, was terrible. Probably took 1/2 hour to part 1" SS with 3 regrinds.

This can't be normal.

ETA: I should add that sometimes if if can get the rpm and feed rate kind of working I can get it cutting, until the holder starts letting the cutter slip out.

Smoke and heat sounds like your bit is too high, or you don't have any relief, and your speed is too high.  Especially until you know what you can get away with, take that speed down to 70.  As the poster above said, on center, lots of lube, and I'll add, make sure your bit is perpendicular to the stock.

ETA, with stainless, Anchor Lube works really well.

Thanks. I'll order anchor lube.

90 degrees?   Maybe that is it. My holder is at an upward angle.

I have the same lathe and a terrible cut off tool too.  

On center or a tiny touch high but not low.   The tool I have tends to work loose in the holder.  Thin blade, slightly wedge shaped.  Might be the wrong style tool for the holder too.

Aluminum it works great.  Steel it howls unless its just been sharpened.


https://www.grizzly.com/products/grizzly-parting-tool-holder-series-200/g5704?adlclid=80744c4e495b18830f902c5860038450&msclkid=80744c4e495b18830f902c5860038450&utm_source=bing&utm_medium=cpc&utm_campaign=%5BADL%5D%20%5BPLA%5D%20%5BShopping%5D%20-%20%7BGeneric%7D%20-%20Tablet&utm_term=4585788123778985&utm_content=%7BGeneric%7D


this holder but under a differnent Wuhu factory name

No, I meant coming into the work square.  You are diving the bit into a channel it is cutting.  If it is off even a little bit it will rub, flex, and possibly break.

OH, and lock your compound.  Anything you can do to make things a little more rigid will help.

Yep.

I think I've tried high/low slow/faster fast-feed/slow-feed lotsa-lube/ no-lube thin-cutter/fat-cutter.

I suck at parting.

The funny thing is sometimes the stars have aligned, and I've had good luck, but mostly sadness.

Ahh.

I do dress the end of the part, and square the cutter to the part. I feel like I'm pretty square.

How close to the chuck are you parting?

I was a couple inches out, and did wonder if chatter from the part being that far out was the problem , so I did try it within an inch or so.

As a general rule, you want to be as close to the chuck as you are comfortable getting.  That bar stock is deflecting when you put the cutter into it, even if you can't see it.  A couple of inches is way too far without support.

If you’re parting 1” SS with HSS back the RPM off to about 100.   I prefer to run cut off tools a touch below center.  About .003-.005.  

And as stated above when parting keep it close to the chuck.  Like 1/4” or so.

For years I had trouble parting. My 10x22 lathe just wasn't rigid enough and my tool was too thick. I changed to a 3/16" blade with some relief ground into it and with a good cutting oil I was getting ok results. Then I started setting the cutter upside down in the holder and running the lathe in reverse. What a difference that made. Now I rarely have trouble parting.

That's interesting.

My aloris holder holds the cutter at an upward angle. Are you running your cutter the same way you did before? Just above centerline?

I'll give it a try today.

If the holder is letting the cutter slip that's a problem. Is the cutter slipping while it's chattering? The harmonics of chatter can do weird things like move cutters that are otherwise rigid enough.

That being said, it sounds like you aren't feeding heavy enough in-feed. Parting takes a heavy in-feed. Too light and it will chatter, especially on stainless. You should be running your rpm very slow (to the point that you feel it's "way too slow"). And you should be feeding very heavy into the cut (to the point that you feel like you're going to break the cutter right off the tool holder). When it starts to chatter don't back off the feed rate, increase it. Increase feed rate right through the chatter and as long as you have a rigid setup it will settle down and cut smooth as butter.

Maybe that's it. When I feed heavy, the holder lets it slip back and then usually the rear end of the cutter will start walking out from the holder so that the cutter is not square to the work any longer. The holder only has a wedge at the front to hold it in place.

I took the wedge out and tried to file the surface a bit to see if I could improve its hold on the cutter, but it didn't seem to help.

I think I need a new holder.

I much prefer parting tools with replaceable carbide inserts over the HSS blades. The inserts have better geometry for chip control and hold their edge much longer. Look into an Iscar blade and holder that you can clamp in a turning tool block, get it set on center - Very important step! - and it will outperform anything you have been trying. I get excellent surface finish on parts with one as a bonus, carbide can run at much higher surface speeds without burning up like HSS. I usually use an insert with a slight angle on it but on a small hobby machine it would probably have a tendency to drift, the angle minimizes the size of the pip.

Thank you sir.

The only thing I will add is that these parting tools have higher cutting forces and require a more rigid setup. OP's grizzly lathe may be questionable on being tight enough and rigid enough to run one without chewing through inserts.

Rigidity is paramount to longevity with carbide but in this instance I disagree with your assertion, it is a better match for a light machine because the carbide can withstand more heat. Run the spindle faster, I usually start around 200 SFM and go up from there, and light feedrate of about .002 IPR. That combination results in very low cutting forces as opposed to low speed/high feed that has been recommended.

And you're doing that successfully on an import lathe parting stainless? I've never seen that amount to more than a squealing, chattering train-wreck that chips the insert every time you part when running the machine & material combination mentioned. Granted, my experience trying carbide is with another brand of import machine but similar size.

HSS parting tools can be resharpened and profiles changed easily. Carbide inserts get costly when chipped from chatter every time you part something.

Even on a rigid machine like my Leblond I still prefer HSS parting tools due to lower cost and superior cut quality.

Proper technique is the key, you can't compare 2 different types of tools by using a technique designed for one on the other. I outlined the proper parameters for the insert tooling, it's up to you to adapt to newer technology and methodology - or not. Faster and lighter on a light machine will win you over if you do it the right way.

Your "proper technique" doesn't get you under a work-hardened skin on stainless. The carbide can handle cutting the hardened layer but NOT on machines that aren't rigid. Rigid machines, those often found with ball-screws and servos or very heavily built, can take the light cuts and burn right through that skin, but an import machine will often push hard, flexing back, until the force becomes high enough to start cutting and the flex drives the cutter beyond the work-hardened skin into soft material where it bites hard and chips the cutter. There is no "light cuts will stop that", light cuts are what CAUSES that.

Same happens for other work hardening non-stainless alloys and hardened alloys.

OP, don't take my word for it though. Buy $1000 in carbide tooling and try it for yourself! You will either learn that your import lathe is rigid enough, or you'll learn a valuable lesson.

It was a hell of a conundrum until you said $1000 :)

That's way out of my price range.

Your word is worth exactly what anyone has paid for it. I have noticed a trend with you, you tend to jump into a thread and proclaim yourself to be the expert in all things with no validation of your experience or qualifications. I'll put mine on the line, I am a Mechanical Engineer and Journeyman machinist with almost 50 years experience. I have stayed current on advances on technology and have written several peer reviewed articles on machining technology. I taught machining technology for several years in the local technical college and currently own and operate a manufacturing company. What I am sharing here free of charge is knowledge gained from years of experience that you seem keen on finding fault with for some reason. Open your mind, whatever you have been taught in the past is now obsolete. If you want or need to stay current in the technology related to this field you need to be more open minded and not lead others astray with your outdated thought process, losing the know it all attitude would be a bonus too.

On light duty lathes I have better luck with grinding a hss blade than a carbide insert blade.  Usually a insert needs a chip load to function properly.

Same as yours


If you actually paid attention you would see that I only post when I have actual expertise. I am not the expert of all things. The fact that you're projecting your narrow band of expertise onto me is your downfall. I am very lucky to have an expertise much more broad than the vast majority of others. It has just happened that way, my upbringing, my career & position, as well as my life outside work have all brought me down a path that has given me said experience. I didn't necessarily choose, or pursue it, but I'm sure glad life brought me this direction. Did you want my resume as well? It's pretty long...


The bolded, underlined part explains your attitude. Engineers are the worst at holding the attitude of "my way is the only way". And the really ironic bit here is that you've called into question my expertise then laid out your qualifications and experience that nearly mirror mine, right down to teaching machining technology. I teach for a high level employer intro machining classes and CNC machining. And I can point out the flaws in engineers because I am one.


Is any of that experience on the class of machines we're talking about?

I have thousands of hours both running and teaching on this class of machine (as well as true industrial class machines).

I have found through those thousands of hours that import machines do not have the necessary rigidity in the feed mechanism (screws, nuts, journals, etc) and spindle/chuck to handle the pressures of parting hard materials.

The beauty of my instructional environment is that there is no budget limit, we use carbide tooling (mostly Sandvik) for consistency in the classroom environment and it isn't impactful when inserts are broken. We've tried every possible way, and we encourage the students to experiment with feeds and speeds. We instructors also experiment with feeds and speeds. We have found that running parameters similar to those suggested by you yields a great deal of chatter, gouging, breaking of inserts, poor finish, and much frustration. This isn't an outdated way of thinking or a taught knowledge this is true, boots on the ground experience.


Not necessarily finding fault with, only expressing that my experience, equivalent to yours in depth, yet most certainly different in detail, has shown me that your suggested way likely won't work in this particular case. It might work, but it carries risk that OP buy expensive tools to find out if it works.

Parting & grooving is most certainly the test by which many machines can be measured, it takes a very rigid machine to to do it effortlessly with good tool life. Anything less and it becomes a challenge, all the way to the bottom where it is a fight to find anything that will work.


Haha, umm...taught, obsolete? I'm not expressing anything taught, I'm expressing my first-hand experience from teaching and using carbide insert parting tools on import machines. And I highly doubt those experiences are obsolete, they're all current (within the last decade).


It seems it is you who is being closed minded here. But hey, I'm not one to think I can't learn something new. Do you happen to have one of those peer reviewed articles about parting on less-than-rigid lathes? I would certainly read it...



Ironic coming from a guy trying to show everyone how much he knows by bringing out his resume as if his experiences in this matter are somehow more valuable or given more consideration than others.



STOP IT! You're not allowed to have those experiences they don't align with the expert's experience so they must be wrong!

fwiw, I did try to cut this stuff with with a standard blade on a Milwaukee handheld bandsaw, and it ate up the blade pretty quickly. I do have some new blades down there, and will give it another try. I'm not opposed to sawing it off just to avoid having to part this.

ETA: Blades don't fit :)

Story of my life.

What grade of SS you are working?

I knew someone was going to ask, and I hate to say it, but I can't remember :)

I bought it about two years ago when I got my form1 stamps back, and research what stainless to make my can from :)

Tell me about your cutter and holder if you would.

Does the holder angle upward?  Did you simply flip the blade over?  

Did you contact just above centerline?

The reason I ask is some SS is gummy, other grades cold work harden really fast.  It changes your plan of attack.  If it work hardens easily and you are not aggressive, life gets more interesting.  With gummy SS it is the opposite.  You can get away with light, fast cutting as opposed to hogging in.  Just something to keep in mind.  Know you material and how it reacts to being worked.

Thanks. It is definitely not gummy at all.

Best advice I was given for parting is to zero your tool with a dial indicator.  Adjust until it is feeding in close to perfectly straight. Deviation from that puts a side load on the tool creating chatter & broken tools.

Parting was the slowest rpm I ran except for maybe drilling multi inch bore holes

What a thread

1.  Don't be afraid to use a hacksaw or a sawzall

2.  Ive had decent luck with cheap Chinese insert parting tools from EBay.  They are built for mini lathes so max DOC is around .75 inches.  

3.  Part from behind.  I've never tried it but some guys swear by it on small lathes

4.  Build a plinth and ditch the compound.   Again, I haven't tried it.  The internet says it's a game changer on small lathes.  I was surprised how much deflection I could generate on my 12x36 with just my thumb pushing on the tool holder.   It's on my short list of projects this year.

From the aspect of what the tool is doing when met with cutting forces (especially on a less rigid lathe) , parting in reverse with an upside down cutter is nearly the same as parting on the back side with an upside down cutter. It offers many advantages. Namely, as cutting forces increase the cutter flexes away from the stock instead of into the stock. This more naturally balances the cutting forces because when the cutter flexes away from high cutting force the force then instantly decreases.

I also use the same technique when threading barrels with no thread relief. I run in reverse with an upside down cutter going from "tight to the shoulder" into free air, then reset and go again. It's a little more tedious but it yields a factory looking barrel bc the vast majority of factory barrels don't have thread reliefs.

On my South Bend Heavy 10 (which is a small lathe), I use carbide inserts almost exclusively for parting and turning without issue.

Could you post up what you use?

I ordered another holder and HSS cutter today, but wouldn't mind grabbing a carbide cutter if there is something reasonable out there.

IM me your address and I'll send you an Iscar holder and a pack of inserts gratis. It was used for a special project that will never come back around, I had to modify it slightly to fit in a custom holder to get it on center. You won't have any issues with that in an Aloris style holder assuming you can hold 3/4" shank tooling - it was milled down to a little less than 0.75".

I use this to good effect.  https://www.latheinserts.com/3-4-PARTING-GROOVING-TURNING-TOOL-4310000738.htm

Biggest deal for me was to choose a proper feed rate, engage it and let fly.  The steady, even pressure made all the difference.  Even on my 12" Monarch, parting 304ss will make the toolpost wiggle if you're not setup dead square with minimal extension.

Interesting thread.

My $0.02:

Manually/uneven feeding is the problem.

I have a Prototrak 1630. I can part with a program using .0008-.0011" per rev and an insert will last 100 parts in stainless with coolant (max RPM of 1000 if set on SFM cutting).

I can try parting by hand just once and chip the insert. In fact, I bet I've broken 10-20 carbide inserts before just trying to part off something manually in the Prototrak (especially in stainless).


Also, the guy who mentioned turning upside . . . for sure. I've had parting tools last months on a CNC lathe with a traditional turret where the tools are upside down anyways.

Below is exactly what I use. Something I learned from (I think) Abom79 is if it starts to squeal try pushing harder into the cut. That always seemed counter-intuitive to me, but it does work.