HSS or Carbide for barrel threading

Noted above is a concern on ending the threading pass. When we thread a barrel tenon the cut pass must stop at a shoulder. Some advocate machining a groove to stop the cut in. With the tool retracted If you will move the threading tool to where you want it to stop the cut then, with a dry marker, draw a line on the bedway at the left edge of the carriage wing. Then when making the threading cuts, instead of watching the tool tip, watch the carriage wing as it approaches the mark you made, use that as to where to pull the cutter out.

Practice this method for a few passes, with the tool retracted, to see how this works for you.

Left hand on the cross feed dial, right hand on the half-nut handle.

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I can get this done with a dial indicator aginst the saddle on the ways; can usually stop within .005" or less. I thread with AR inserts and don't gotoo fast.
 
I received my new lathe in December and was lost with all the types so I ordered some hss blanks and carmex. The hss is another step and more equipment to deal with imo. With the carmex or iscar I start at .009 cut then .008, etc until it is almost right then a couple cleanup cuts. Aggressive is the key even if the speed isn’t high. At least it works best on my machine. Either way, good luck.
 
Ok, get out the flame throwers. I use the Warner inserts. I also have carbide. I thread to the shoulder without a relief. I have Trav A Dial and set it to zero for my stopping place. Dial is big enough that you can stop it within .002". I just disengage the halfnut, stop the spindle, retract the cross slide, and start over again. I guess you can say I have a relief now that is the size of the root of the threading tool. Just my way and I like it.
 
Ok, get out the flame throwers. I use the Warner inserts. I also have carbide. I thread to the shoulder without a relief. I have Trav A Dial and set it to zero for my stopping place. Dial is big enough that you can stop it within .002". I just disengage the halfnut, stop the spindle, retract the cross slide, and start over again. I guess you can say I have a relief now that is the size of the root of the threading tool. Just my way and I like it.

It could never be that easy.

www.youtube.com/watch?v=7dmE-emrrAs
 
Ok, get out the flame throwers. I use the Warner inserts. I also have carbide. I thread to the shoulder without a relief. I have Trav A Dial and set it to zero for my stopping place. Dial is big enough that you can stop it within .002". I just disengage the halfnut, stop the spindle, retract the cross slide, and start over again. I guess you can say I have a relief now that is the size of the root of the threading tool. Just my way and I like it.

I like the Trav A Dial on my 1236, but the 1024 is a lot more fun to thread with using the Proximity sensor. Push the forward switch, it stops on the mark, retract, push the bypass and reverse, stop, advance cutter...

Watch "Ken's Shilen # 2 Threading with Proximity Sensor" on YouTube
https://youtu.be/TJNiTXQ0imU
 
A lot of things are easier with a 3-phase motor.

Instant reverse, instant stop (though you can rig a single phase to stop by injecting DC).
 
I don't know why people dis on carbide so much. I've had nothing but good results with carbide threading inserts. I use full-profile inserts, mainly Carmex or Iscar at 100 or so RPMs.

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Alinwa, thank you for the thank you. I hope all can benefit from these discussions. :D

Butch Lambert, There's nothing wrong with cutting the relief like you do. I sure you already knew that , but I mentioned it as that particular step you use has not been spoken of here. :)

Gene Poole, Those are some good looking threads . They put a great face on this issue. :)

For those thinking of using "Full Profile" carbide, the prep is a bit different. With sharp V style tooling you should cut the finished major diameter first then thread. IE ~1.055 vs 1.0625

With Full profile you leave the tenon OD at full size or close to it. IE 1.0625 dia. versus ~1.055 that you turn to, prior to threading with a basic V tool. That way you have a proper full profile thread when you are finished. Also with carbide the full profile is much more durable than a sharp V that will chip or knock the tip off by just looking at them.

IMHO, Full Profile inserts are worth their weight in gold. If the FP thread is a bit tight, don't take a file to them!!!!..... take another spring pass or even a light cut to decrease the total thread profile.

Personally when someone talks of galling , my first thought is they V cut it and then filed off the top of the threads or cut the finish Major Diameter after they cut the threads. They may look and measure ok but all it takes a tiny burr and you are screwed.
 
Gents,

My old-school machinist father found out I threaded into a shoulder and about sh!t a brick.

"Turn that f@$king tool upside down and make a groove next to the f@$king shoulder. That is zero. Then thread the f@$k away from the shoulder, you f@$king dumba$$"!

He's always had a way with words...

I understand that the lathe is designed for the cutting force being directed downword, but with snug gibs and light cuts, prolly don't mean a bit-o difference.

The old man built a ton of aerospace quality parts on manual machines way back when, and there is no doubt in my mind that he could thread to a shoulder if necessary. But he didn't, if he didn't have to. I should probably pay attention to him on matters such as this.

Using this method, you could really crank-up the rpm's if using carbide.

Justin
 
My Dad kicked me out of the house early....... his reasoning was, "quick! Get out there and change the world while you still know it all!"
 
Threading

I vote Arthur Warner HSS that said you should explore some different setups and find out what the lathe and you like. Slower speeds typically like HSS as it cuts the steel vs. melting the steel. Some lathes you can successfully thread away from the headstock however this requires you to cut the relief. I MHO always preferred more steel in the area of the tenon were supposedly we want the most rigidity.
 
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