- Joined
- Apr 24, 2021
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Yes please. Apparently I have a lot more to learn.
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Threading 4140 troubles
- Thread starter FTlatheworks
- Start date
Thread depth to me is radius when using the compound and diameter when using the cross slide for threading, so just wanted to make sure I understood what you are doing.
The tool you linked should work fine for what you are doing. With the amount of chatter in your threads, there could still be something loose. Did you verify the insert is sitting flush in the tool and there is not anything preventing it from being fully seated? Use your finger and see if you can rock the insert at all in the toolholder. I had an insert screw in one of my toolholders with too much unthreaded section to firmly hold some of my inserts that caused some chatter problems until I replaced it with a better screw.
Well, we all started somewhere.
so, the pitch diameter is the most important feature of a thread in terms of tolerance and is where the functional part of the thread is. It’s what is taking the load.
So, first you need 3 pins, or as shown in the picture, 3 drills of equal size. For an 18 pitch thread the pins should be in the range of .0311-.0500” but a little over or under will still work. Let me know what size you come up with and i will give you the range when measuring over the pins as shown in my picture.
i would HIGHLY recommend the app i use. As i mentioned in my intro, even with over 30 years under me i still double check my speeds and feeds nearly every time, it’ most productive and least tool bashing. It was only $10 bucks when i bought it. Nope, not getting kick backs either Lol.
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- Joined
- Apr 24, 2021
- Messages
- 462
Yes everything is tight, but idk how to know if this piece under the insert is the problem, or what it does?
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It's a shim that sets the inclination angle of the insert. There's charts on when to change for what pitch based on the diameter of the part.
It does look like there is a gap between the shim and the insert. There should not be one. It's also hard to tell but the rear face of the insert doesn't appear to be flush with the pocket. I would take it apart and clean real good.
It does look like there is a gap between the shim and the insert. There should not be one. It's also hard to tell but the rear face of the insert doesn't appear to be flush with the pocket. I would take it apart and clean real good.
That’s the anvil, it is used to change the angle of the insert for different threading conditions. If you wanted to use this holder to thread left handed threads, you would need to change the anvil, and course threads, or small diameters may need a different anvil to ensure you are not rubbing on the flanks. This guide will help explain that.
- Joined
- Apr 24, 2021
- Messages
- 462
I took the screw out and turned it because it was hard to see the shim under the insert otherwise. It’s been cleaned and tightened down well.
- Joined
- Apr 24, 2021
- Messages
- 462
It’s crooked in the picture on purpose. It was hard to differentiate the shim and the insert with the lighting and with the insert tightened down. I will snap a pic of it back together.
Did some speed and feed experiments with facing this stock and the finish really cleans up when I run faster and feed faster for facing. Maybe I need to be threading faster? Or no?
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That view looks better.
For turning, carbide definitely likes fast speeds. For that diameter stock, I would be in the 1200+ range with the inserts I have. I use TNMC inserts for external threading, they are on edge style, but seem to work fine in the 200-300 rpm range. I started with the Arthur Warner HSS inserts mentioned earlier and recently switched to carbide since the holder I bought came with one, and it seemed to worked at the lower speeds as well, but did improve a bit more as the speeds got higher. You could try going faster, if your reflexes can keep up, and see if that helps. It could also be the insert from the kit, I’m assuming the insert is from the kit you posted earlier, is not that good and a name brand insert would work better.
If you have some larger diameter stock you can try on, that will give you a higher SFM without speeding up the machine to the point you can’t keep up and you will see if the higher surface speed helps.
For turning, carbide definitely likes fast speeds. For that diameter stock, I would be in the 1200+ range with the inserts I have. I use TNMC inserts for external threading, they are on edge style, but seem to work fine in the 200-300 rpm range. I started with the Arthur Warner HSS inserts mentioned earlier and recently switched to carbide since the holder I bought came with one, and it seemed to worked at the lower speeds as well, but did improve a bit more as the speeds got higher. You could try going faster, if your reflexes can keep up, and see if that helps. It could also be the insert from the kit, I’m assuming the insert is from the kit you posted earlier, is not that good and a name brand insert would work better.
If you have some larger diameter stock you can try on, that will give you a higher SFM without speeding up the machine to the point you can’t keep up and you will see if the higher surface speed helps.