Threading Question

[urbanrifleman]

I know everybody is ate up on vipers venom, but I have found the best cutting oil to use in threading, especially if you use HSS tools, is Rigid Black Sulphurized Pipe Thread Oil.

But I do not think that is your problem. Get a quality insert holder and crank up the surface feet per minute.

Also, there is no law against single Point claiming a center and using your live center While threading.

I like the Rigid special. And I add STP oil treatment to it and it works even better.

 

[SKWERLZ]

Two other things I’ve learned with carbide threading, also mentioned above was the use of spring passes and a big one I learned on a YouTube machining video is on the last pass or adjustment pass I feed in with cross slide instead of the compound.

 

[PatMiles]

+1 to Rigid over V.V.

I recommend Carmex BCX grade inserts. They're designed for slow speeds and cut beautifully. The partial profile inserts are sharp and have high rake angles on them so they cut well.

What tool holder do you use with these inserts?

 

[LVLAaron]

What tool holder do you use with these inserts?

Take your pick of laydown threading insert toolholders. I use 5/8 or 3/4

 

[10XSHOOTER]

Mesa tool.com makes a tool holder for upside down threading. Got to have a lathe that will run in reverse.
feed straight in! 115 rpm to start. 2 cuts @ .005. 2 cuts@ .004, 2 cuts @ .003, 2 cuts @ .002. increase speed to over 200 rpm. .001 cuts to fit. Even on a geared head lathe. this will give you very smooth cuts.
make sure your insert is very sharp!

 

[Carl S]

If your set up isn't rigid you will get chatter.you won't put as much load on your tennon thread by using your compound as you will your cross slide feeding straight in.running on 3phase is just better all round for machining practices.more power and torque.single phase does get the job done though.

 

[Mudcat]

The 4003 will do a good job, IF you stay within its limits.

 

[Dave in WI]

If you choose to use a live center as Jackie suggested don’t overlook the part about single point claiming the center after you have it properly indicated

Sorry for stupid question, what is "single Point claiming a center"

 

[paperpuncher]

Sorry for stupid question, what is "single Point claiming a center"

Once the barrel is indicated where you want it use the compound and a single point boring tool to re cut the center in the end of the barrel. If you stuff the center in the in the original hole/ center it could move the barrel from the position it was indicated

 

[Dave in WI]

Once the barrel is indicated where you want it use the compound and a single point boring tool to re cut the center in the end of the barrel. If you stuff the center in the in the original hole/ center it could move the barrel from the position it was indicated

Thanks!

 

[shortgrass]

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...........

 

[Walt Krafft]

Depends on the size of the hole and the cutter. A single v small diameter, I always went top down. Multi v thread specific, I would go down as much as the cutter allowed then around, repeat if needed. Depending on the size, for thrue holes, taps were the first choice.

 

[Spotshooter]

On the threading insert tools - some come with a “shim seat” that is supposed to stay under the cutting insert … and some guys think they are blanks and pull them and just put an carbide cutter insert in there place…

The shim is supposed to set UNDER your carbide insert and it provides the carbide tip more stability and it provides it the right angle of approach so if you pull it out the edge of the carbide insert is off and can easily chatter… and cause that gray thread surface you are seeing.

not sure why I never hear anyone say this… but since you just changed cutting tools..

You can see one here on the Carmex thread cutter insert tool.. it’s the gray triangle under the carbide insert.

if you pulled it - just put one back in or go get a replacement… all good.

 

[SKWERLZ]

On the threading insert tools - some come with a “shim seat” that is supposed to stay under the cutting insert … and some guys think they are blanks and pull them and just put an carbide cutter insert in there place…

The shim is supposed to set UNDER your carbide insert and it provides the carbide tip more stability and it provides it the right angle of approach so if you pull it out the edge of the carbide insert is off and can easily chatter… and cause that gray thread surface you are seeing.

not sure why I never hear anyone say this… but since you just changed cutting tools..

You can see one here on the Carmex thread cutter insert tool.. it’s the gray triangle under the carbide insert.

if you pulled it - just put one back in or go get a replacement… all good.

View attachment 1431324

My Carmex threading insert holder has that.

 

[Randfal]

I don’t have time today to give full write up but I have that same 4003g lathe. It’s a great machine for gun work. All the threads in the attached pictures were done one one. All using Ridgid Dark, Mobil Omega, Oates Dark Thread cutting oil. (You don’t need fancy oil… period).
Full profile laydown insert are the easy way to go. Not enough time in the day anymore to be messing around with high speed steel tooling. I’ve got more productive things to do with my time and I imagine most people do too. Carbide inserts are very affordable these days. You just got a look for them.
Make sure the insert tip is on centerline of spindle.
Speed up the spindle to your 220 or 270rpm speed. Threading up to shoulder at 16tpi is still very manageable at that speed, just do it and don’t look back.
Keep practicing you’ll get there.

 

[Jesswil61]

Before you go out purchasing additional tooling, I had the same lathe you mention. Check your half nut dial and make sure it has minimal slop, its drive gear engagement is adjustable, I had this issue and found when I made an adjustment the threads cleaned up somewhat. I quit threading with my compound and just feed straight in, even with the cheap inserts that came with the machine the thread are perfect using rigid dark.

 

[Henryrifle]

A lot of good suggestions. Thank you all. Guess I'll grab a junk barrel and perform several of these recommendations.

Thank you all again,
Hank

 

[Dave in WI]

A lot of good suggestions. Thank you all. Guess I'll grab a junk barrel and perform several of these recommendations.

Thank you all again,
Hank

I need to clean up my threading as well and will work along with you @Henryrifle if you don't mind. We have very similar lathes and the same problems!

 

[Dusty Stevens]

I need to clean up my threading as well and will work along with you @Henryrifle if you don't mind. We have very similar lathes and the same problems!

Is yours single phase as well? Makes threads look just like that.

 

[Danny1788]

I have the same lathe, I use cheap carbide inserts at 70rpm. Dark ridgid cutting oil and compound set at 30-29.5 but the last few pass I go strait in with the cross slide to clean up both sides, also I thread at 200RPM the last few passes.

I also put vibration dampers between my motor and lathe, do the 1phase motor doesn’t transfer to the lathe.