# facing the end of a pipe



## ARC-170 (Jul 6, 2019)

I have a 4.5" dia x 0.25" thick steel (type unknown, but it's nothing fancy) pipe I'd like to square the end on. I cut it with a reciprocating saw so it's a bit crooked. I grinded it down a bit. My question is *how I should go about squaring it up on the lathe*? 

Here it is mounted on the chuck. You can see where I've tried to cut it:



Here is the cutter I'm attempting to use. It's cut like a cut-off tool:



I thought I might try using this cutter in this orientation when I get the end smoother:



Here is an end-view of the pipe:



I'm getting lots of chatter. The lathe is on low speed (164/500) on the spindles and medium speed (1140) on the motor. Back gear is not engaged. If the motor I have is similar to the original and I'm using the speed chart in the MOLO correctly, then I'm at 500 RPM. I tried it on low (164) and it really chattered. Higher speed gave a smoother cut.

Cutting speed for carbon steel is 80 ft/min. 3.82x80/4.5=67.91 RPM. I'd use the back gear drive for that speed, correct? 

Because the end is crooked and the pipe wobbles a bit in the chuck, the cutter will contact the material, then be in the air, then contact the material, on so on. I've grinded it such that the tool doesn't contact a blunt end; instead, it contacts a "ramp"/inclined surface, but at some point, the cutter will break thru; then what? Whenever I've used a parting tool before, I've always stopped before it broke thru. I may not have that option here; it may break thru in one part. 
Here's a sketch to illustrate what I'm talking about:



One option may be to grind this down as square as I can, then finish it on the lathe. However, it's a lot of grinding. I thought using a cut-off type tool would be quicker and look nicer. I didn't count on the pipe wobbling, either, but didn't think that would matter since I don't need the end perfect, just somewhat smooth and straight.

I'd like some guidance on how to safely do this. Thanks!


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## matthewsx (Jul 6, 2019)

I just did something similar today but with a much smaller tube. You will need to get it chucked up with as little runout as possible, I had to file and sand the end I planned on cutting so I could use a dial indicator to get it aligned. Then light taps with a small hammer should allow you to true it up. I used a rounded HSS bit and cut back from the center with the tool at ~29*.

I'm sure someone else has a better insight but that's what I did and it worked for me.

Cheers,

JOhn


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## mattthemuppet2 (Jul 6, 2019)

smack it a bit until it's running true, put the lathe in backgear then use a RH cutter (like the brazed carbide cutter in your 2nd pic) to face it with the carriage locked to the ways. I'd start off with light cuts otherwise the interrupted cut will lever the pipe out of the chuck.

If you want to hold it a little more solidly, hold it in a 4 jaw, that'll be a little more secure than a 3 jaw.


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## T Bredehoft (Jul 6, 2019)

John has it right. Before you cut, get the outer surface of the meterial running without wobble, to be consentric. Then cut toward the center, a bit at a time. use, under 100 RPM, slow to get the correct surface feed. Until you have one continuous cut you must take so little cut that it doesn't disturb the security of the piece in the chuck.


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## ARC-170 (Jul 6, 2019)

Thanks for the input! Just to clarify:

1. Use a hammer and dial indicator to get the pipe running true. Light taps.

2. Use the RH cutter or a rounded cutter to cut from the center of the pipe out. In other words, cut away from the center and toward me. Take light cuts until the cut is continuous.

3. Cutter bit should be angled a bit in relation to the pipe. In other words, don't cut with the whole length of the cutter (as shown in 3rd picture above), cut with the point.

4. Lower speed. Use back gear.


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## markba633csi (Jul 6, 2019)

Agree with all above.  Always risky when you hang a workpiece out farther than the diameter, but we all do it and (usually) survive to tell the tale.
Be careful, try to stand off to the side somewhat in case the pipe decides to fly out in your direction


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## ARC-170 (Jul 6, 2019)

markba633csi said:


> Agree with all above.  Always risky when you hang a workpiece out farther than the diameter, but we all do it and (usually) survive to tell the tale.
> Be careful, try to stand off to the side somewhat in case the pipe decides to fly out in your direction



Thanks! It's already come off once. It was very slow speed, so it was fine. I think the bits are dull as well.


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## MontanaLon (Jul 6, 2019)

Run your tail stock up and extend the quill inside the pipe so if it does come out of the jaws it can’t get loose and create chaos.


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## MontanaLon (Jul 6, 2019)

Also, if you turn down the thickness away from the ragged edge the interrupted cut will be less of an issue as the thickness isn’t so great. 

interrupted face cuts place a tremendous amount strain on everything where interrupted turning cuts are less stressful.


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## benmychree (Jul 6, 2019)

If you were doing this very much, I would make a "spider", a steel disc that would fit inside the pipe with perhaps 1" total clearance, with 4 holes tapped into it radially for 3/8' square head setscrews, on the back of it I would weld on a piece of pipe that would fit through the spindle with cross drilled holes that would mount a pin at various distances that would bear against the spindle end so that tailstock thrust would not push it back, and of course, on the front end there would be a center drilled hole (in the center) for the tailstock center.  In use, it sits inside the pipe enough to clear the tools used for facing or parting, and would be used to center the part up, much like a 4 jaw chuck.  This is standard shop practice, often used.  As you have already seen, it is all too easy to knock long unsupported work out of the chuck.  As to extending the tailstock into the work to prevent the work being tossed out at long range, why risk scarring up your tailstock quill?


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## Illinoyance (Jul 6, 2019)

You don't have much grip on the pipe so you are going to have to take a lot of shallow facing cuts.


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## tcarrington (Jul 6, 2019)

I would go for minimum stickout of the tool. That might be the source of chatter. With the work piece so long, taking light cuts is required. I prefer a honed HSS tool with a good rake and other geometry appropriate for the material. Approach slowly, feed slowly, celebrate for a long time when complete.


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## Tozguy (Jul 7, 2019)

MontanaLon said:


> Run your tail stock up and extend the quill inside the pipe so if it does come out of the jaws it can’t get loose and create chaos.



Although I too would suggest protecting the quill from damage somehow, like slipping a piece of ABS pipe over it or by using a drill chuck in the quill.
This job is a good excuse to buy a 6 jaw chuck  

On second thought there is too much doubt about the possibility of the work slipping in the 3 jaw so do not proceed.
A 4 jaw would be much better than the 3 jaw but even then its iffy. The work is too long to face unsupported, do you have a steady rest or a follow rest?
Or rather than cut the pipe square using a 3 jaw chuck I would grind it by hand (with angle grinder) using a try square to get it close. Then maybe take a light facing cut with a very sharp tool on the lathe to finish.


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## ARC-170 (Jul 7, 2019)

The pipe is 5" long. Is that really too long to be unsupported? What's the rule of thumb for this type of thing?

I thought I might get the pipe running true (no wobble) then use a cut-off tool to trim off a ring from the end. I'll take light cuts.

I've got the back gear engaged so the cutting speed is nice and slow.


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## mattthemuppet2 (Jul 7, 2019)

ARC-170 said:


> The pipe is 5" long. Is that really too long to be unsupported? What's the rule of thumb for this type of thing?
> 
> I thought I might get the pipe running true (no wobble) then use a cut-off tool to trim off a ring from the end. I'll take light cuts.
> 
> I've got the back gear engaged so the cutting speed is nice and slow.



First part - yes, but you can make it work with light cuts

Second part - don't even think of using a cut off tool. The cutting force is way too high for that much unsupported work. The pipe will climb up onto the tool and break it or spring out of the chuck.

Shallow facing cuts from outside in, using the same type of tool you would use for turning down the diameter. You only need to make sure that the tool is angled so that there's enough side clearance. Or you could use a LH tool (for cutting left to right) mounted in line with the pipe/ bed. Doesn't matter.

Shallow cuts, get rid of the uneven bit, then face the pipe. It's pretty simple, no need to reinvent the wheel.


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## Illinoyance (Jul 7, 2019)

The real issue is the very short length of chuck jaw engagement.  Too heavy a cut will pull the pipe off the chuck.  HSS will work better than carbide.  The sharper edge and proper rake will generate less tool pressure than carbide.


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## MrWhoopee (Jul 7, 2019)

A parting tool (cutoff tool) is the wrong way to approach this, too much tool in contact with the work. Use something like a threading tool or chamfering tool with a sharp or almost sharp point (point facing towards the chuck) and face the pipe off taking light cuts and slow feed. HSS with positive rake will generate less pressure than carbide.


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## f350ca (Jul 7, 2019)

Second on facing it with light cuts. I wouldn't use the tailstock to catch it if it comes out of the chuck, beter to hope it goes away from the cutter.
Was facing these spacers, had just welded them, think it cooled and shrunk thus coming loose in the chuck.



When it came loose it jammed against the compound and moved the probably 4 or 500 pound carriage.
The results.



Greg


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## matthewsx (Jul 7, 2019)

Another thought, although it might get some grit on your lathe you could use an abrasive cut-off in an angle grinder.


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## ARC-170 (Jul 7, 2019)

mattthemuppet2 said:


> 1. First part - yes, but you can make it work with light cuts
> 
> 2. Second part - don't even think of using a cut off tool. The cutting force is way too high for that much unsupported work. The pipe will climb up onto the tool and break it or spring out of the chuck.
> 
> ...



1. That's what I thought. Is there a rule about how far out something can stick before it's considered too long? 

2. Thanks. That's what I wanted to know.

3-4. Got it, thanks! The hardest/most dangerous part for me was figuring out how to deal with the uneven end. I knew that it would hit the tool and possibly cause problems. Thought I'd ask those with more experience. I needed more detail than I was getting and you've all provided it.

Greg/f350ca: Wow! That's just incredible. Thanks for sharing. You've scared the ---- out of me, but in a good way. I think I will grind this down as much as possible.



matthewsx said:


> Another thought, although it might get some grit on your lathe you could use an abrasive cut-off in an angle grinder.



I was grinding it on my workbench and the sparks caught a piece of steel wool on fire. I need to take this outside and grind it, but I need to figure out how to hold it properly. I also cleaned up the workbench, but sparks still fly everywhere, even when I grind in such a way as to direct the sparks down and/or out of the way.


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## mattthemuppet2 (Jul 7, 2019)

ARC-170 said:


> 1. That's what I thought. Is there a rule about how far out something can stick before it's considered too long?



you'll hear it - the work or cutter (or both!) will sing, even with light cuts. Lots of chatter and squealing. To be honest, it'll be a fairly miserable job and take you a while, but as long as you take your time and don't try any short cuts you'll get it done just fine.


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## Tozguy (Jul 8, 2019)

ARC-170 said:


> since I don't need the end perfect, just somewhat smooth and straight.





ARC-170 said:


> It's already come off once.





Illinoyance said:


> The real issue is the very short length of chuck jaw engagement.


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## mickri (Jul 8, 2019)

I had a similar problem where the end of the work was about 5" or so out from the chuck.  It was wobbling around pretty bad when I tried to make a cut.  I finally set it up with my steady rest and that solved the problem of the wobble.


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## ericc (Jul 8, 2019)

There was an accident some time back at Techshop.  They made the people pull the photos off the web.  Anyway, I heard that it was very predictable.  The pipe deformed and came loose at a high speed.  It didn't hit anybody, but looking at how deformed it was when it hit the wall, it could have lead to a fatality.  Use a plug.  It stabilizes the piece and allows for higher gripping pressure.  The problem is that it is too easy to skip this step, since they wouldn't let you turn wood at Techshop, and it is expensive to make a plug out of delrin or polyethylene.

Be careful out there.


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## mickri (Jul 8, 2019)

Looked more carefully at the pictures.  I would place the end of the pipe against the chuck and if you have them I would use what I probably mistakenly call reverse jaws so that you have more contact against the pipe.  Look at the jaws in the picture in post 18 above for an example of what I am talking about.


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## gjmontll (Jul 8, 2019)

If the pipe is just 5" long, 
   1) maybe use a faceplate instead of a chuck, using some angle brackets.
   2) or do it on a mill.
      Greg


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## ARC-170 (Jul 8, 2019)

I grinded/ground (I've always used "grinded" when referring to grinding metal, but isn't "grounded" correct?) it down, then used a belt sander to get it a little more even.

I'm getting ready to put it back on the lathe, use the dial indicator to eliminate the wobble, and make light cuts to true it up. Here is a quick sketch of the set-up:


Is this correct?


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## MrWhoopee (Jul 8, 2019)

You ground the pipe down.

Yes, that will work.


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## mickri (Jul 9, 2019)

Ground is the correct past tense of grind.  Grinded or grounded are incorrect.  I'm not being picky here.  Just answering your question.


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## Tozguy (Jul 9, 2019)

It all depends on how solidly it is held in the chuck. 
Once you have eliminated the wobble using the dpi, yank on the pipe by hand and recheck for wobble. If you can pull the pipe out of alignment by hand then beware!


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## MarkM (Jul 9, 2019)

Jeez guys!  Doing this kind of stuff in a three jaw is a good way to ruin your day and then some! 
That should be in a four jaw.  No way will you have the support you need in a three jaw on larger diameter stuff especially using the inside jaws with its little contact.
Throw it in a four jaw Please!!!!!!


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## ARC-170 (Jul 10, 2019)

gjmontll said:


> If the pipe is just 5" long,
> 1) maybe use a faceplate instead of a chuck, using some angle brackets.
> 2) or do it on a mill.
> Greg



I thought about using my mill, but the vise doesn't open side enough.


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## ARC-170 (Jul 10, 2019)

mickri said:


> Ground is the correct past tense of grind.  Grinded or grounded are incorrect.  I'm not being picky here.  Just answering your question.



Ha! I really was curious. For some reason I got it in my head that it was some sort of jargon to use "grinded" for metal. It is "ground". That concludes today's English lesson.


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## ARC-170 (Jul 10, 2019)

MarkM said:


> Jeez guys!  Doing this kind of stuff in a three jaw is a good way to ruin your day and then some!
> That should be in a four jaw.  No way will you have the support you need in a three jaw on larger diameter stuff especially using the inside jaws with its little contact.
> Throw it in a four jaw Please!!!!!!



I got a brand new 4-jaw that came with the lathe. It's still in the original grease paper. Might be time to whip that bad boy out.


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## pontiac428 (Jul 10, 2019)

I think they say "done grinded" in West Virginia.  "I done grinded them valve seats.  You check them points, uh-hrr?"

Most 4-jaw (independent) chucks have reversible jaws, so you done best get to degreasing that chuck!  If you can hold it, you can machine it!


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