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

[savarin]

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.

 

[jdedmon91]

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

Sent from my iPhone using Tapatalk

 

[mikey]

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.

 

[T Bredehoft]

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.

 

[Tozguy]

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

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

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.

 

[macardoso]

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.

 

[bill stupak]

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

 

[wildo]

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.

 

[pontiac428]

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!

 

[Larry42]

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.