# A style/usage question about QCTP - how do you run yours? (question #2, less dumb)



## dbb-the-bruce (Jun 16, 2019)

I'm moving to metal work from wood work - although I've got a lot of experience using my Southbend 9 for making mechanical wooden models, I've only done a little metal turning on it.

I recently bought a QCTP - mostly because I want to be able to quickly change out cutters and have them setup exactly where I want them when I swap them in. My observation is that a QCTP is almost always setup square to the lathe axis, however, most of the cutter tool geometry descriptions I've seen assume an angled tool approach to the work. (yeah old books).

In the little messing around I've done with my new QCTP, I've already encountered cases where it gets in the way or requires huge unsupported tool bit overhang unless you rotate it. 

So none of this is a big deal: geometry wise, if the bit is set square to the lathe, the shape can just be modified to provide that same approach - as if you are coming in from an angle. If the tool post is going to get in the way, then you just rotate it and go back to a profile that works with that approach.

So I'm looking for comments and advise on how people handle this:

- Is there something like a "standard" set of tool shapes to use when the bit is going to be held orthogonal or parallel to the lath axis?
- How often do you find yourself changing the mount angle of your QCTP?
- How often do you use a spotting drill and tail stock support when turning? (this seems to be mostly when the QCTP gets in the way).

I'm sure I'll come to my own preferred work process given enough time and trial.... but would prefer to start with more "common" practice.

- Dave


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## RJSakowski (Jun 16, 2019)

Maybe coming from the old school, using the lantern style tool post, I modify the angle of the tool post to best suit the work that I am doing and the tool that I am using.  There are times when I have to use multiple tools on a part and am making multiple parts where I set the tool post (not necessarily square) and leave it though.

The short answer is do whatever is expedient to the work you're doing.  Don't box yourself in by someone else's convention.


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## Tozguy (Jun 16, 2019)

Many tool sets have a variety of angles to the cutting edge so that we can choose the appropriate one for a job. Designed to be held either square to the spindle axis or parallel to it, in a QCTP but with the possibility of rotating the QCTP to some extent to maximize performance if necessary. I have no hesitation to rotate the QCTP either to create clearance for the tool or to tweak the cutting angle.
I don't understand your third question.


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## Ulma Doctor (Jun 16, 2019)

since the name is Quick Change, i quickly change the angles and heights to accommodate any tooling needs i have for the job.
you can change the angle of the compound to the lathe axis too, it doesn't all have to be done at the QCTP


Q1: yes, there are some "standard" shapes of tooling, and grinds for tooling for turning parallel to the axis- Right Hand, Left Hand, and straight tooling exists
even sub-groups like roughing and finishing tools.
there are also tools and grinds for tools that run transverse to the axis as well.
it can be a study upon itself

here is a pic of common tools:



Q2: only occasionally do i find myself changing the angle of the QCTP. i usually have my compound at 30° to the axis for threading or turning
if i change the compound angle, i then change the QCTP angle back to 90° to the axis.

Q3; i use center drills all the time, i have not had much problem there-
but sometimes, when turning, you may need to leave extra length in the stock you are turning to avoid interference of the work, the live (or dead center), and the tooling.


if you are doing it right,
you'll learn something every time you turn some work


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## Canus (Jun 16, 2019)

You mention using a spotting drill and tail stock support.  A spotting drill has a 135 degree angle and the hole drilled will not allow the live or dead center to seat properly.  You want to use a center drill for this.  Spotting drills are great to start a hole that you will be drilling.


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## Mitch Alsup (Jun 16, 2019)

dbb-the-bruce said:


> So I'm looking for comments and advise on how people handle this:
> 
> - Is there something like a "standard" set of tool shapes to use when the bit is going to be held orthogonal or parallel to the lath axis?
> - How often do you find yourself changing the mount angle of your QCTP?
> - How often do you use a spotting drill and tail stock support when turning? (this seems to be mostly when the QCTP gets in the way).



I run my post square to the axis most of the time.

I change the post angle when turning/boring tapers to minimize the excess cut on the unturned stock due totheuse fo CNMG inserts. I could get away without doing this is I had Dxxx or Vxxx tool holders with appropriate holding angles and inserts.

I support the part being turned whenever it is longer than 4 times its final turned diameter.
I spot using center drills.


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## dbb-the-bruce (Jun 16, 2019)

Canus said:


> You mention using a spotting drill and tail stock support.  A spotting drill has a 135 degree angle and the hole drilled will not allow the live or dead center to seat properly.  You want to use a center drill for this.  Spotting drills are great to start a hole that you will be drilling.



My bad - wrong term for the drills I use. They are the correct ones for matching the 60Deg center.


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## dbb-the-bruce (Jun 16, 2019)

@Ulma Doctor - that's pretty much the same as what I've been looking at ~pg 34 of "how to run a lathe" After taking another look at the book, the only tools that don't approach the work at 90 deg are the facing tools.

So the issue is really just the facing bits.
If the work is unsupported by the tail stock, then I can see how a RH facing tool could be ground and mounted parallel to the axis.

For work that's supported on the tail stock end, looks like you have to change the approach angle of the toolpost, possibly by changing the compound angle, but more likely rotating the QCTP. (seems like no matter how much I try to think a head - something is alway in the way when I'm using the tail stock for support!)

@Tozguy - exactly, if it's a QUICK CTP why am I having to rotate it? 

The third question was more about supporting work - do people regularly us dogs and/or a center in the tailstock? 

Starting as a wood turner, I'm quite aware of dealing with flex, vibration and thin stock (however we just wrap our finger around the work). I also understand the beauty of the geometry of a lathe - driving work between two points a cutter has to (in a perfect world) cut on a plane that is 90 deg to the axis.

That said, I've never setup a dog to drive a piece of work.

Tailstock center support is clearly needed for anything that starts to get thiner/longer. Almost all of the parts I've made to date (either wood or metal) have been stout enough to not require it.

Thanks for all the input.
-Dave


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## francist (Jun 16, 2019)

I had occasion recently to turn between centres again, I hadn't for quite a while. And I kind of surprised myself, it was oddly "peaceful" for lack of a better word.

I know that probably sounds goofy and maybe it is, but there was something weirdly relaxing about not having to tighten the chuck, not having to dial in, not worrying about if it was still on centre, yadda yadda. I could take the part in and out as many times as I wanted and it went right back in the same way, beautifully true. I can hardly wait to have occasion to do more of it!

So I would encourage you to at least try it, if for no other reason than to know how to set up if and when you really do have no other options. Who knows, you might be surprised too!

-frank

Edit: oh yeah, ex-wood turner here too.


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## dbb-the-bruce (Jun 16, 2019)

francist said:


> I had occasion recently to turn between centres again, I hadn't for quite a while. And I kind of surprised myself, it was oddly "peaceful" for lack of a better word.
> 
> I know that probably sounds goofy and maybe it is, but there was something weirdly relaxing about not having to tighten the chuck, not having to dial in, not worrying about if it was still on centre, yadda yadda. I could take the part in and out as many times as I wanted and it went right back in the same way, beautifully true. I can hardly wait to have occasion to do more of it!
> 
> ...



My mentor, Jon Siegel, is a woodturner, machinist and all around amazing guy. One of the things he does (and demos) is turning cue sticks. He uses a dog drive and centers. I've learned a hell of a lot from Jon.

We recently ground the threads on a refurbished dividing head - between centers, with a dog on an absolutely beautifully restored Hendey.

So, I've kind-a done it.  
Sooner or later, I'll be doing something on my small Southbend 9 that warrants it.

-Dave


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## savarin (Jun 16, 2019)

I change the angle of my qctp whenever I feel it needs it to suit the job.
The first thing I did was remove the spring loaded pawl that I felt restricted some angles.
As without the pawl the qctp "can" spin if not savagely tightened or has not been relieved sufficiently  underneath.
I use a thin brown paper shim that prevents this without loosing any intentional movement.


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## jdedmon91 (Jun 16, 2019)

I never move my angle. Since the majority of my turning is done with a CNMG 432 insert. The tool holder is dovetailed to direct mount. Here is a video link to my tooling set up just in case your haven’t seen it. A picture is worth a 1000 words so this should be a novel 






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## mikey (Jun 16, 2019)

Dave, what kind of tooling are you asking about? If you mean inserted carbide tools then most are meant to be used with the shank of the tool perpendicular to the work so the tool post doesn't move. However, you can often improve how they cut by altering the angle. 

For HSS tooling, the tool post angle is frequently changed to engage the desired edge. Lots to discuss about that.


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## T Bredehoft (Jun 16, 2019)

dbb-the-bruce said:


> For work that's supported on the tail stock end, looks like you have to change the approach angle of the tool post, possibly by changing the compound angle, but more likely rotating the QCTP. (seems like no matter how much I try to think a head - _something is always in the way when I'm using the tail stock for support_!)



It appears that you are concerned with tail stock overhang. I do not change my QCTP, but extend my tail stock quill so that it supports the work as needed.  Stick that quill out until you can support the work and begin the cut without turning anything.


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## Tozguy (Jun 17, 2019)

dbb-the-bruce said:


> exactly, if it's a QUICK CTP why am I having to rotate it?





mikey said:


> the tool post angle is frequently changed to engage the desired edge. Lots to discuss about that.





savarin said:


> I change the angle of my qctp whenever I feel it needs it to suit the job.



To my mind the quick change term is relative to lantern tool posts or ones that require shimming the tool in the holder. For example it is much quicker to adjust the thumb nut on the QCTP holder than to fiddle with shims in a four way holder. 

The QCTP does not have to be rotated just as it does not have to remain square to the spindle axis. As Mikey and Savarin implied, rotating the post is an option that some of us might use while others might not.


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## macardoso (Jun 17, 2019)

I also subscribe to not moving the QCTP. Mine is set square to the chuck by squeezing a 1-2-3 block between the side of the toolpost and the face of the chuck. Most of my tooling is import grade indexable tools. I don't buy them because I believe carbide necessary for most things in the home shop, but rather to save time on grinding (I refuse to grind in my basement so I have to carry the grinder outside) and to know I always have the right tool geometry.

The only time I need to loosen the toolpost is when I change my compound angle.


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## bill stupak (Jun 17, 2019)

I move my QCTP all the time, to get the tool bit close and not interfere with the chuck, to allow room for a boring bar not to rub the side of a deep  bore, to get close to a tailstock center, etc, etc. Realigning for single point threading or parting is a simple task. I feel it's the same with a mill vise, tramming it back in is so simple I never hesitate to move it to get a better setup.  Stu


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## wildo (Jun 17, 2019)

I haven't read this whole thread, but I agree with a couple who have indicated that they move the toolpost depending on what they are doing. For me, I am not usually making a basic turning cut but rather trying to create some interesting and artistic angle or facet. Therefore I move my compound (and thereby also the QCTP) constantly. That wasn't exactly the focus of this video, but I think that in the video you can see just how often the tool approaches the work from a myriad of different angles.


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## pontiac428 (Jun 17, 2019)

I move my QCTP rotation to present the tool to the work in the manner that best suits the job.  It's a "feature" of the system.

I also slide my QCTP across to the furthest-from-center points on the compound slide to bring it further toward me (imagine compound slide set to 45) in order to accommodate larger work, understanding that I will have less rigidity in this position and working accordingly.

I have a snug-fitting and overkill robust T-nut holding my QCTP along with a ball nut and washer combo on a stud from mcmaster to help keep things tight.

Edit:  I don't bother with insert tools unless the material calls for it.  HSS is king!


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## Larry42 (Jun 17, 2019)

A lot of opinions here. My take on it is probably wrong, I only have a very few years as a hobby guy. BUT I rotate the QCTP to whatever seems to fit the work being done. When using a tailstock center and turning small work You will either have to leave a lot of extra stock to be removed later or extend the tail quill a lot. Even then you will be forced to go to too much tool overhang, change the tool post angle or change to a half dead center. Each causes some other limitations. Since I haven't opt for buying the very expensive US/Euro inserts I don't get a fine finish with my cheap imports. Part of that is due to me only getting a decent finish with the imports when running at higher speeds and deeper cuts. Which I'm often reluctant to do. So my normal practice is to change to hand ground HSS or tool grinder sharpened HSS for the finish. I find eyeball sharpening to work quite well. For parting off it is pretty easy to bring the tool back to square to the work. 
If I'm making a shaft that has to be a really good fit to another part, I mount the face plate, dead center, dog and have a go at it. That way I can test fit to my hearts content. That even works when turning a MT using the taper attachment. Live centers seem to have issues when they are cheap. I have a pretty good one that came with my PM lathe and a cheap not so pure long nose after market one. 
It may be possible for some to set their compound to exactly 30* so the  tool doesn't heal but not very likely. I find it a lot easier to just plunge with the tool mounted up side down and turn from chuck to tail. (See Joe Pie's channel) Turning metric threads is still a PIA but works.


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## Larry42 (Jun 17, 2019)

I should have added, buy a bunch of tool holders so every tool really is "quick change."


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## Creativechipper (Jun 17, 2019)

I find moving your tool position is done way more than I ever thought it would, for all kinds of reasons. Keep those wrenches handy to change tooling angles and positions.


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## Larry42 (Jun 18, 2019)

I made a "fixed handle" for my tool post so I don't have to fumble around with a wrench, faster and I'm lazy.


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## Creativechipper (Jun 18, 2019)

Laziness creates efficiency


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## MrWhoopee (Jun 29, 2019)

Fortunately, the lock nut for my tailstock is 7/8 and the nut for my QCTP is 22mm. I have a cut off 7/8 box wrench that lives on the tailstock nut. It's right there when I need it.


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## dbb-the-bruce (Jul 17, 2019)

A lot of good advice here - thanks for all the input!

I've gone full in on the QCTP, purchased a bunch more holders and will set them up with different tools as needed. I'm already appreciating it. All my tooling is HSS or brazed tips on some boring bars.

I need to get a dedicated wrench for the tool post so it's easier to rotate it when needed, right now I'm using a crescent wrench 
Once I've built up a bigger selection of mounted tooling, I should be able to reach most cuts with the QCTP. If I box myself into a corner with the tail stock center in the way, I can always fall back on my lantern style holder.


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## jdedmon91 (Jul 17, 2019)

I don’t rotate my QCTP often. However I keep a wrench I have the open end cut off so when I have to move it around it would be handy. For wrench’s like that I get them at Autozone or Advance because they are high quality 


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## savarin (Jul 17, 2019)

Why not make a new nut with a ball handle?
I soon got fed up with searching for the spanner.
I also got rid of the spring loaded stop from underneath and use a brown paper shim to stop any rotation.
I had to do that because I move it into many different positions depending upon what I cut.


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## mmcmdl (Jul 18, 2019)

Simple answer to the toolpost question. Set it at what you need . Most always it is set at 90 degrees because your parting blades / cut off blades / grooving tools are ready to part . If I need to swing the compound to a weird angle most of the time I will reset the post to 90 . ( unless I'm feeling lazy )


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## Buffalo21 (Jul 18, 2019)

I’m moving my QCTP constantly, to whatever angle is needed to get the job done.


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## magicniner (Jul 30, 2019)

A lot of good QCTPs (except the ones offering a fixed but semi-useless set of angle options) have a vertical through hole, it's to allow you to use a pin and a hole in the base, or a hole in a fixed base plate, to allow instant setting at a reference angle.


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