Threading Question

[boltfluter]

If that happens, you probably shouldn't be using a lathe.

Very good video. Using carbide on an engine lathe may or may not work depending on the mass and rigidity of your lathe. Generally speaking carbide is made for CNC lathes and mills that will smoke a HS tool in a few seconds. Carbide, generally speaking, relies on pressure and rpm/surface feed to cut. High rpm cuts down on tool pressure which in turn cuts down on the rigidity needed for a chatter free cut. It really is that simple. It can be made to work on an engine lathe, but you need the most rigid set-up you can come up with and higher rpm's carbide is designed to run at. I personally run the sharpest HS threading insert I can find in my engine lathe. If I were to try carbide, and had troubles, I would try running the tool upside down and crank up the rpm's. My chucks have cam locks. Common sense would dictate not doing this with a screw on chuck!! Good luck and happy threading.
Paul

 

[xr650rRider]

Not all carriages are on the ways with much more than the weight of the carriage. It's meant for downward pressure... so you lift up on it with an upside down tool and I'd say you're more apt to chatter than before.

You really need to reevaluate what your depth of cut is and what tool your using if this were to happen.
Man's gotta know his limitations.

 

[boltfluter]

I've got a question about threading. Is it better to feed a full profile thread mill into the hole, or start at the bottom and feed up? The CNC controller on this mill gives me the option of doing either way. Carbide, full profile, 4 flute, rotating @ 3325rpm (300sfm) in mild steel (A36). It's a through hole, goes all the way through the 'part'. I got NO info with this tool, with others there's been a 'thumb drive' or a link for programing. I haven't done much thread milling before. This thread was becoming so redundant...........

All of my thread milling is done with a single flute tool from Micro 100. To my way of thinking, which is very limited on this subject, if this is a right handed thread you need to start at the bottom and feed into the work and up and out of the hole. All my experience is with a single point tool so my comment may be of no value to you. Wish I had more to offer but nadda.
Paul

 

[shortgrass]

All of my thread milling is done with a single flute tool from Micro 100. To my way of thinking, which is very limited on this subject, if this is a right handed thread you need to start at the bottom and feed into the work and up and out of the hole. All my experience is with a single point tool so my comment may be of no value to you. Wish I had more to offer but nadda.
Paul

Only 23 more holes to go!

 

[SKWERLZ]

Very good video. Using carbide on an engine lathe may or may not work depending on the mass and rigidity of your lathe. Generally speaking carbide is made for CNC lathes and mills that will smoke a HS tool in a few seconds. Carbide, generally speaking, relies on pressure and rpm/surface feed to cut. High rpm cuts down on tool pressure which in turn cuts down on the rigidity needed for a chatter free cut. It really is that simple. It can be made to work on an engine lathe, but you need the most rigid set-up you can come up with and higher rpm's carbide is designed to run at. I personally run the sharpest HS threading insert I can find in my engine lathe. If I were to try carbide, and had troubles, I would try running the tool upside down and crank up the rpm's. My chucks have cam locks. Common sense would dictate not doing this with a screw on chuck!! Good luck and happy threading.
Paul

I’ve learned a lot from that guy!
Years ago he did a gun video and got harassed.

 

[xr650rRider]

I like Joe Pie, but I cringe every time I see that inverted reverse threading thing. Just learn to do threads correctly. My mentor rolls in his grave.

My mentor, said if you've been doing something the same way for 10 years, you've probably been doing it wrong.

 

[CNC-Dude]

I've got a question about threading. Is it better to feed a full profile thread mill into the hole, or start at the bottom and feed up? The CNC controller on this mill gives me the option of doing either way. Carbide, full profile, 4 flute, rotating @ 3325rpm (300sfm) in mild steel (A36). It's a through hole, goes all the way through the 'part'. I got NO info with this tool, with others there's been a 'thumb drive' or a link for programing. I haven't done much thread milling before. This thread was becoming so redundant...........

I thread hundreds of internal and external threads with a CNC weekly using single point and multi point thread mills. You typically need to make a roughing and a then a finish pass when machining tougher materials like 17-4 and titanium and higher grade steels. That has been my experience with CNC threading with threadmills....

 

[shortgrass]

I thread hundreds of internal and external threads with a CNC weekly using single point and multi point thread mills. You typically need to make a roughing and a then a finish pass when machining tougher materials like 17-4 and titanium and higher grade steels. That has been my experience with CNC threading with threadmills....

I initially enter 4 passes, have reduced to 3. Standard 7/16"-14 thread, root to crest = roughly 1/32" . Conversational programing using Centroid controller. A36 steel plate, 1" thick, ,easy cutting. A short production run of parts the customer is not in a huge hurry for. We usually use programing software, but we wanted to see how this "conversational programing" would work for thread milling, as that feature is present in this controller,,,,,and then we'd have experience with it for other short runs where we didn't have the proper tap, and didn't want to buy one for some bastard pitch thread. Multi-point/full form cutter. "in the hole, thread up" seems to be working best. We've slowed to 275 SFM. less than a minute per hole. The Centroid controller allows many options in programing. And, the program is very easy to alter/modify. Seems it would only take a small inventory of single point cutters that cover many diameters and pitch for "job shop" type work. We just happened to have this full form cutter in tool storage.

 

[Bogusname]

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.

 

[Henryrifle]

@Bogusname: That looks great! I'd be happy if mine looked like yours.

Thanks,
Hank

 

[jackieschmidt]

Very good video. Using carbide on an engine lathe may or may not work depending on the mass and rigidity of your lathe. Generally speaking carbide is made for CNC lathes and mills that will smoke a HS tool in a few seconds. Carbide, generally speaking, relies on pressure and rpm/surface feed to cut. High rpm cuts down on tool pressure which in turn cuts down on the rigidity needed for a chatter free cut. It really is that simple. It can be made to work on an engine lathe, but you need the most rigid set-up you can come up with and higher rpm's carbide is designed to run at. I personally run the sharpest HS threading insert I can find in my engine lathe. If I were to try carbide, and had troubles, I would try running the tool upside down and crank up the rpm's. My chucks have cam locks. Common sense would dictate not doing this with a screw on chuck!! Good luck and happy threading.
Paul

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.

 

[Henryrifle]

@jackieschmidt: I've seen a small number of projects you work on and know of you skill behind a trigger. You are a master of many things and I, maybe, have enough experience/knowledge to appreciate what you can do.

Thank you for sharing what you know and what you've experienced--always impressive.

I am learning and getting incrementally better because of guys like you who share, teach and encourage. Will not make it to your level--not even close, but the journey is interesting, challenging and rewarding.

Thanks to you and several others like you who make this place meaningful.

Hank

 

[Dave in WI]

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.

@Bogusname I have that same setup and have the A60 ER inserts. How do I know what shim to buy?

 

[Bogusname]

Honestly, I don’t know. I’m not a machinist.
What I have done, lots of this and that.
You will figure it out. After that you will question yourself on everything you do.

 

[LVLAaron]

@Bogusname I have that same setup and have the A60 ER inserts. How do I know what shim to buy?

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

 

[SKWERLZ]

@Bogusname I have that same setup and have the A60 ER inserts. How do I know what shim to buy?

Sandvik Coromant

www.sandvik.coromant.com

 

[LVLAaron]

What I took away from that is... use the standard shim unless you're threading the direction opposite that the insert was designed for

 

[shortgrass]

Many times the shim/screw/clamp/insert is stamped or acid etched on the holder

 

[WSnyder]

@Bogusname I have that same setup and have the A60 ER inserts. How do I know what shim to buy?

Every tool holder I’ve seen that came with replaceable shims comes standard with a 1.5° shim which works for just about any thread you’ll do while gunsmithing. Now if you take a left hand tool and run it upside down towards the tailstock you’ll have to swap out for a -1.5° shim (assuming common threads and diameter). Aggressive multiple start threads? Yeah you’ll need a different shim. Very small diameter with very fine threads? Again you’ll need a different shim.

Side note: Both my Iscar and Vardex 1.5° shims are flat with no angle to them. I assume it’s setup like this because the 1.5° is the most common and therefore the standard baseline shim.

 

[WSnyder]

Many times the shim/screw/clamo/insert is stamped or acid etched on the holder

Every shim I own is marked. Each manufacturer has its own numbering system.