Threading Question

[LVLAaron]

Decoding and understanding carbide inserts and tool holders is one of lifes more frustrating tasks.

 

[Dave in WI]

I just use the shim that comes with the holder... some holders don't have them...

I'm almost positive it didn't come with a shim.

 

[Randfal]

I'm gonna make some of my fellow machinists roll their eyes but bear with me. I'm gonna talk about what works great for home machinists and budget minded folks that still want nice quality results. You do not need expensive holders to use carbide threading inserts for gun work. There is production machining in a workplace and there is gunsmithing.... 99.9% of any gunsmithing is not taking 12" od heat treated material and plowing off .200-.400" depth of cuts off it. Small 1/2" TCMT style toolholders with decent thread inserts (carbide) like the ones in the attached pictures from ebay work very well on small lathes like the 4003g and you don't have to buy 10 at a time or spend $200.
Look back 2 pages to the thread pictures I posted a few days ago. They were all done at home, with Single Phase Power, on a 2hp, chinese, Grizzly 4003g lathe. I bought that lathe new for my home work shop 12-13yrs ago and have used the heck out of it since. Still a great machine for its intended purpose. I manage an all manual-machine machine shop in the mining industry and Do I buy Grizzly machines and chinese tooling for our industrial shop? No; the Neanderthals would destroy them in 2 weeks. but we're not talking about that here; that is heavy work, this is gunsmith talk.
I know toolholders and inserts are complete alphabet soup to home hobby machinists. Trying to figure out each manufacturer's "code book" is a real pain. So, I'll attach some short cuts here to maybe get you started.
Search Ebay for: 5 pc 1/2" Lathe Indexable Carbide Insert + Turning Tooling Bit Holder Set (this is $32)
The inserts included with these are junk for gun work and light finishing. You need sharper, less tool pressure inserts for the small, less rigid parts. For threading get a few 16ERA60 Inserts(the ER stands for External RightHand). They will cover everything from 16-48tpi and that's most of your Gunsmithing threads. Get a AG60 to do up to 8tpi but the A60 will get you closer to shoulders so they're the better way to start (unless you're doing Mausers). When you feel frisky jump up to the full profile inserts. I keep 8,16,20,24,28, and 32tpi on hand for my gun hobby work at home and use A60 and AG60 inserts for everything else. They are the bomb and once you use them, you'll never go back. But you do not need them to make a quality thread.
For general turning, get TC"G"T16T308 inserts not "M" inserts. Those 1/2" holders above will use both the thread inserts and TCMT16T30.. size inserts TCMT and TC"G"T interchange in the same holder. Think of the "G" as "Ground-like ground sharp" and the "M" as "Molded-not so sharp but heavy duty for big cuts". Most work can be done with a TCGT16T308 . A .......304 has a finer nose radius and you'll need a couple of those around too. (they're also called TCGT32.51 when you're shopping ebay.) TCGT32.52 is the bigger nose radius and the 308 size. I won't get into what those numbers really mean, not enough room/need here for that right now.
I'll use Ebay again to illustrate examples. The following would be a good start for threading inserts:
Search Ebay for: SECO CARBOLOY 16ER A60 S25M CARBIDE LAY-DOWM THREAD INSERTS (9Pieces) ($51/9inserts)


Search Ebay for:
SECO CARBOLOY 16ER A60 P30 CARBIDE LAY-DOWM THREAD INSERTS (3 PIECES) ($21 shipped)


Here are aluminum inserts, Inserts for Aluminum are generally very sharp with a high rake. While not necessarily recommended for steel, they do work really well on 416SS barrel steel and most normal steels. They just do not last as long. But most threads and cuts for gunsmithing are not very long unless you're profiling a barrel. And for the cheap cost of the inserts($1.50each if you shop hard), who cares if they do not last as long! Buy 20 at a time(60tips) and go to work. They also leave nice finishes and can usually shave a .0005" off a part if you need to. Don't overlook them.

These Kennametal examples are decent for steel too:



Hope that helps some of you get an idea of what to look for. I am not associated with anyone of those Ebay sellers, just using them for examples as to what to look for. Those little 1/2" toolholders work just fine and are plenty heavy duty enough for anything that you should be putting in a 12x36 etc. lathe. I only check in every couple days so if I don't respond to a reply right away, I'm not ignoring you. Thanks and happy smithing.

 

[WSnyder]

I'm almost positive it didn't come with a shim.

If it didn't come with a shim its probably set to the default helix angle of 1.5°. I'm guessing that with holders with no shim that you can buy inserts for different helix angles incorporated into the insert for that particular tool insert combination. If not then that tool isn't universal for all situations.

 

[Randfal]

I have an inexpensive Grizzly lathe, a G4003G. I've switched to an inboard spider to keep the workpiece as close the headstock as possible. I use a laydown full profile threading insert and make threading passes as prescribed in the Standard of Depth of Cut document for American UN external threading.

There does not appear to be a problem with the threading work except for the way it looks. I used to use an on-edge HSS threading tool with similar results. I thread at the slowest speed my lathe will run - 70 RPM. I use Viper's Venom on the last few passes but not the first ones lately.

I am guessing this is some kind of chatter. You can see what looks like ridges in the valleys of the threads. What is causing this?

View attachment 1430972

Thank you,
Hank

Hank,
I miss read you first post. Sorry for high jacking you thread with a long tooling blog since you're already using lay down tooling. Tooling isn't your issue. If your part is supported both sides of the headstock and working close to your spider chuck, that shouldn't be a problem either. I'm assuming you are using the compound to adjust the depth of cut? If not, and you are only using the cross-slide, I would quit doing that and try make the transition to using the compound. And if you are using the compound, I would bump the compound feed angle down(On your particular lathe. If following Old US "How to Run a Lathe" guidelines, they tell you 29.5degs. That won't work on your Grizzly and often overlooked. The degree wheel is positioned differently on asian machines. We use 29degrees on our old Monarchs at work.) to 57-58degs and give it a try. Sometimes it helps to keep the right side of your insert dragging a little to help stabilize it. My Grizzlies sweet spot is 58degs. It won't make a difference to the thread profile in the end.

 

[LVLAaron]

I'm gonna make some of my fellow machinists roll their eyes but bear with me. I'm gonna talk about what works great for home machinists and budget minded folks that still want nice quality results. You do not need expensive holders to use carbide threading inserts for gun work. There is production machining in a workplace and there is gunsmithing.... 99.9% of any gunsmithing is not taking 12" od heat treated material and plowing off .200-.400" depth of cuts off it. Small 1/2" TCMT style toolholders with decent thread inserts (carbide) like the ones in the attached pictures from ebay work very well on small lathes like the 4003g and you don't have to buy 10 at a time or spend $200.
Look back 2 pages to the thread pictures I posted a few days ago. They were all done at home, with Single Phase Power, on a 2hp, chinese, Grizzly 4003g lathe. I bought that lathe new for my home work shop 12-13yrs ago and have used the heck out of it since. Still a great machine for its intended purpose. I manage an all manual-machine machine shop in the mining industry and Do I buy Grizzly machines and chinese tooling for our industrial shop? No; the Neanderthals would destroy them in 2 weeks. but we're not talking about that here; that is heavy work, this is gunsmith talk.
I know toolholders and inserts are complete alphabet soup to home hobby machinists. Trying to figure out each manufacturer's "code book" is a real pain. So, I'll attach some short cuts here to maybe get you started.
Search Ebay for: 5 pc 1/2" Lathe Indexable Carbide Insert + Turning Tooling Bit Holder Set (this is $32)
The inserts included with these are junk for gun work and light finishing. You need sharper, less tool pressure inserts for the small, less rigid parts. For threading get a few 16ERA60 Inserts(the ER stands for External RightHand). They will cover everything from 16-48tpi and that's most of your Gunsmithing threads. Get a AG60 to do up to 8tpi but the A60 will get you closer to shoulders so they're the better way to start (unless you're doing Mausers). When you feel frisky jump up to the full profile inserts. I keep 8,16,20,24,28, and 32tpi on hand for my gun hobby work at home and use A60 and AG60 inserts for everything else. They are the bomb and once you use them, you'll never go back. But you do not need them to make a quality thread.
For general turning, get TC"G"T16T308 inserts not "M" inserts. Those 1/2" holders above will use both the thread inserts and TCMT16T30.. size inserts TCMT and TC"G"T interchange in the same holder. Think of the "G" as "Ground-like ground sharp" and the "M" as "Molded-not so sharp but heavy duty for big cuts". Most work can be done with a TCGT16T308 . A .......304 has a finer nose radius and you'll need a couple of those around too. (they're also called TCGT32.51 when you're shopping ebay.) TCGT32.52 is the bigger nose radius and the 308 size. I won't get into what those numbers really mean, not enough room/need here for that right now.
I'll use Ebay again to illustrate examples. The following would be a good start for threading inserts:
Search Ebay for: SECO CARBOLOY 16ER A60 S25M CARBIDE LAY-DOWM THREAD INSERTS (9Pieces) ($51/9inserts)
View attachment 1432645

Search Ebay for:
SECO CARBOLOY 16ER A60 P30 CARBIDE LAY-DOWM THREAD INSERTS (3 PIECES) ($21 shipped)
View attachment 1432642

Here are aluminum inserts, Inserts for Aluminum are generally very sharp with a high rake. While not necessarily recommended for steel, they do work really well on 416SS barrel steel and most normal steels. They just do not last as long. But most threads and cuts for gunsmithing are not very long unless you're profiling a barrel. And for the cheap cost of the inserts($1.50each if you shop hard), who cares if they do not last as long! Buy 20 at a time(60tips) and go to work. They also leave nice finishes and can usually shave a .0005" off a part if you need to. Don't overlook them.
View attachment 1432648
These Kennametal examples are decent for steel too:
View attachment 1432650


Hope that helps some of you get an idea of what to look for. I am not associated with anyone of those Ebay sellers, just using them for examples as to what to look for. Those little 1/2" toolholders work just fine and are plenty heavy duty enough for anything that you should be putting in a 12x36 etc. lathe. I only check in every couple days so if I don't respond to a reply right away, I'm not ignoring you. Thanks and happy smithing.

Good info here. I ended up getting a bunch of KC5010's and love them. (I find they need about 600rpm on 1-2 inch stock) Same deal with the polished inserts... they leave a fabulous finish on stainless and cast iron. I use them for tenon and smaller work. They're nice because you can use a slow to moderate speed and not sling hot chips all over the place.

Nothing will give you a nicer finish on your crown than a little 21.51 polished insert on a carbide bar

 

[luckyshot52]

I’ve been using the grizzly 14x 40 gunsmith lathe for 10+ years. Been around all types of heavy manufacturing since I was 14. I don’t agree single is an issue. Tooling dead on center for threading carbide inserts, good coolant, and medium speed. I thread straight in and don’t ever get any waves or chatter. Gunsmith machine work is nothing compared to real machinist work.
It’s too bad Mesa is not making their tooling anymore. Best bang for the buck for a gunsmith or home shop work. At least they are still going to sell the inserts.
I’ve used them as well as formed carbide and high speed. All can do a great job if you hit the basics.

 

[SKWERLZ]

Decoding and understanding carbide inserts and tool holders is one of lifes more frustrating tasks.

It’s a big pool of choices and yes it’s a pain, as a tinkerer I kinda like researching stuff but For a professional environment time is money.

 

[SKWERLZ]

Good info here. I ended up getting a bunch of KC5010's and love them. (I find they need about 600rpm on 1-2 inch stock) Same deal with the polished inserts... they leave a fabulous finish on stainless and cast iron. I use them for tenon and smaller work. They're nice because you can use a slow to moderate speed and not sling hot chips all over the place.

Nothing will give you a nicer finish on your crown than a little 21.51 polished insert on a carbide bar

Polished carbide parting inserts are awesome,

 

[Dusty Stevens]

I go by @Walt Krafft spreadsheet for tooling. Im revamping my selection now. All ive been using is stuff left over from long term cnc machine runs.

 

[Dusty Stevens]

I have the same lathe, and had the same problem at first. I think tool hight was the biggest culprit. I also use a flood system when threading. I use the tool holders from Grizzly but use good tooling. Full profile carbide coated…… slow 80 rpm….
No polishing whatsoever.
Probably won’t win a machining award but I think they aight.

That is a carmex toolholder. The parts youre looking for is called an anvil. The one thats in there is fine for any thread we do, but carmex has an anvil selector guide if you want to get fancy.

 

[WSnyder]

That is a carmex toolholder. The parts youre looking for is called an anvil. The one thats in there is fine for any thread we do, but carmex has an anvil selector guide if you want to get fancy.

Might also be an Iscar, they are the same and Iscar uses the same numbering system as Carmex.
Vardex, Iscar and Carmex anvils are interchangeable. Vardex anvils use a different number system but you can use their chart. I use Vardex anvils in my Iscar toolholders.

 

[Irritant]

I bought a Griz G4003 . It chattered and just cut rough ugly threads. I tried everything. I decided to put a better grade of bearings in it but as I found out those bearings are used in trucks and thats the only grade there is. I bought brand name bearings and put it back together, better but not solved. I promptly sold it and bought a real 16x40 production grade lathe.

 

[boltfluter]

I am in the Machine Shop Business. We have no CNC machines. We have lathes all the way from a Monarch EE 12x36 inch to a twin carriage American that will work 38 feet between centers, and everything in between.

100 percent of our in shop tooling is carbide inserts. The only thing we use HSS on is our portable boring bars.

I have a little 14 inch Taiwan lathe in my home shop thatI do my barrel work on, I use nothing but carbide insert tooling and cemented carbides on It.

By your own definition you have high quality machines. Very good. I have manual and CNC equipment in my shop. Speaking in general terms, on most engine lathes,
which is not a Monarch or a 38 foot lathe, for the average person in a mostly engine lathe environment a HS threading tool will serve most people well. Most people don't have the ability to run a carbide threading tool at the surface feet that is needed when threading to a shoulder. Hence the thread finish, many times, is better with a razor sharp HS tool. Just based on my personal experience as a machinist as well, just like you.
Paul

 

[LVLAaron]

Carmex BCX inserts can be run at 50 RPM and still give a perfect finish.

 

[Walt Krafft]

Carbide tooling has been improved to the point they can be as sharp as HS and run slow if needed. Inserts generally come with chip breakers. The brazed carbide lathe tools are awfull with little rake and no chip breakers. HS lathe tools work fine but slow.

 

[6MMsteve]

Carbide tooling has been improved to the point they can be as sharp as HS and run slow if needed. Inserts generally come with chip breakers. The brazed carbide lathe tools are awfull with little rake and no chip breakers. HS lathe tools work fine but slow.

Mr Krafft does some fine workmanship, my barrel is shooting pretty small .3's very happy

 

[Randfal]

I have good machinists working in my shop today that don’t have the nerves or the reflexes to thread close to shoulders. In the past it always bothered me that they didn’t have the stomach for it. But they are really good machinists in every other aspect and as I matured I have just accepted the fact that some people can’t do it and I do not fault them for it. They make up for it in other areas. It’s just too nerve racking for some people. But most, once they try it and conquer their fear of it, wonder how they got by before. We’re competing with CNC machines these days and there isn’t time to waste. Home hobby work is other story. Do what you’re comfortable with and take pride in what you build.

 

[Henryrifle]

This is the setup I am using:





I believe this is a Carmex 16 ER 18 UN BXC -- Aaron, do you mean BXC or is there an BCX? I don't see that.

Is this the wrong lay-down threader for gunsmithing in stainless steel? I want to say, that I don't believe this is causing a problem, but as several people have asked me to chamber barrels for them, I'd like to produce threads that not only work but look good/great too.

Thank you,
Hank

 

[WSnyder]

Is this the wrong lay-down threader for gunsmithing in stainless steel?

I use the same holder in Iscar with Iscar inserts in the IC 908 coating. I can’t say how your inserts work but the toolholder should be fine.