In defense of the four-way lathe tool post

[mickri]

When I got my lathe it came with the typical lantern and a 4 way. I really liked the 4 way. I was looking into making another 4 way when I ran across plans for the Norman QCTP. I made one and have been very happy with it. Lately I have been doing some drawings of 4 way and 3 way tool holders for the Norman. Still working on some of the details. It may never happen.

The 4 tool bits that I use most of the time are a right turning bit, a facing bit, a threading bit and the parting bit. It would be nice to have those available by simply rotating the holder.

 

[mac1911]

Im very new to lathe work.
I like my Aloris clone better thsn the 4 tool post…. BUT I did set up my 2 Four Post with tooling to avoid buying more holders
My two , four tool post tools are set up
1: has my cheap Brazed carbide for roughing and breaking scale
2: set up with threading tool and a facing tool.

4 post or qctp I can see tool posts/holders accumilating quickly. Eventually Im sure I will have holders for most of my cutting tools

 

[marka12161]

It is a little like @tcooper27 diamond tool holder but at 5 degrees. (or similar - I'm an hour away from the shop right now)... It is the lower picture in post#39 of "Lathe Tool holders" :

Lathe Tool Holders

Ah, thank you. That's a great explanation. I've just ordered some 02 and 04 DCGT inserts to see how they go. As I said, I currently have 04 and 08 (the latter due to me not paying attention on amazon) DCMT inserts and the 04 radius inserts seem to be fairly forgiving of my clumsiness (not...

www.hobby-machinist.com

Gotcha.

 

[Dabbler]

Bottom tool is a tangential tool holder, did you mean the upper image?

Yes, the bottom picture. I was referring to the method of setting the tool height.

 

[benmychree]

In my opinion, square turret tool posts are the very best for a turret lathe, but a QC tool post such as the Aloris is best for an engine lathe due to having every tool normally used ready to drop on and go to work, a rack to hold them solves the "clutter" issue; for my 19" Regal, I have 17 tool holders, that cover nearly all possible functions, including a threading die head, they are all original Aloris type CA and were accumulated when they were much cheaper than nowadays; when I was in business for myself, I also had a Warner & Swasey #4 ram type turret lathe and used it quite often, it had a 4 way turret that worked well for manufacturing our products, it also had a 6 position ram turret to work in conjunction with the square turret. The new owner has gone to CNC for most work, but still has the W&S for work requiring it's larger swing.

 

[Huub Buis]

I glued shims to the bottom, top and side of all my tools so they are always on center and I only have to release the nuts half a turn. Later I made a stop at the back for accurate repositioning (to use a tool offset). Later I changed the top plate so I can lock a tool in seconds with just one handle.
Because there is no tool holder that sticks out, the rigidity of the lathe isn't reduced. That is important for my not so rigid desktop lathes.
A (not edited, incomplete) video of my old version.

The new version doesn't require to rotate the top to change from outer to inner turning.

 

[Ultradog MN]

I know this is a much discussed topic with, perhaps strong opinions, but I've recently changed my thinking on these and would like to share my thought process (for whatever that may be worth). Like many, when I first started using my lathe, I quickly got frustrated with the lantern tool post that came with the machine. The need to constantly set tool height when changing tools and lack of rigidity, particularly when parting, were my main sources of frustration. I then did a bit of study and quickly converged on an import multi-fix quick change tool post system as the solution for me. When I took delivery of the QCTP system, i was very happy with the build quality, rigidity and versatility of the system. I predominately use high speed tool bits with the occasional brazed carbide tool bit. I do not use carbide insert tooling. In order to better accomodate the various HSS tool bit blanks i use (5/16", 3/8" & 1/2") i made some simple tool holders (picture attached) from cold rolled bar stock and i was in business. I used this system successfuly for many years and really didn't give it a second thought.

However, after a bit of time, i found myself wanting more tool holders to accomodate the various tool bits (my multi-fix system came with three standard tool holders and a boring bar holder). I looked at pricing and at about $80.00. holder I paused to really think through this. After a bit of reflection, i realized that the thing that bugged me most about the QCTP system was not necessarily the lack of an adequate inventory of tool holders, but was the clutter all those tool holders caused when they were not on the machine. Getting more tool holders would just lead to more clutter. At about this same time, i bought a second, smaller lathe that came with an import piston type QCTP set. Again, more clutter.

So, after a bit of additional pondering, I decided to change both machines to four way tool posts. Both of which are Enco brand (3 1/2" & 4 1/2"), with 12 indexible positions. For my use, the main down side of the four way system is not the need for shims, rather, it is the need for seperate turning and facing tools required to avoid interference when facing by swigning the turning tool 30 deg. I got around this on the small lathe by grinding a suitable tool to avoid this intereference (picture attached) and on the large lathe by fabricating a tool holder that holds the HSS tool bit at an angle of 15 deg (pic attached). I'm very happy with this change as it has cleared up all kinds of clutter. I sold both QCTP systems which more than offset the cost of the four way tool posts. I hope this helps others who may be thinking about this.

I use an Aloris and have at least a dozen tool holders for it. The tool holders are in the cabinet drawer that you see open.
When that drawer is closed - and it always is because I would bump it with my arm while working, there is no clutter.
Photo also shows the advantage of setting a lathe perpendicular to the wall instead of parallel to the wall.

 

[gard]

Interesting discussion, I have and use both a shop made 4 way and the lantern tool posts. I set up a dedicated cheepo HF magnetic base and dial indicator to measure the height of the tool point, I found center by turning a scrap to a very sharp point using a magnifier to see if the cutting tip was above or below center. I then set the dial indicator to zero. Now it is a simple matter of putting a cutting bit in the 4 way and I get a direct measure of how much shim is required. I have a small box of shims that are labeled and cut to the correct size so it is very quick to change tool bits. The indicator and base lives on the shelf behind the lathe.

I currently set the magnetic base on top of the cross slide which requires rotating the 4 way tool holder so the bit of interest is under the indicator. I have also considered mounting the indicator to a base that sets on the ways. This would make it useful for setting heights with the lantern tool posts.

I do not have any kind of rotational stop for the 4 way, I just loosen it and rotate it to the angle needed then fine tune the angle as needed.

I have a related question, some of the older books like the South Bend "How To Run A Lathe", fig 51 pg 28 says for ordinary strait turning the bit should be set 5 degrees above center or 3/64" for each inch of part diameter. Is this still common practice for HSS? How about carbide?

 

[Steve-F]

I have 2- 3" 4 ways in my cabinet and will never use them.

 

[Huub Buis]

I have a related question, some of the older books like the South Bend "How To Run A Lathe", fig 51 pg 28 says for ordinary strait turning the bit should be set 5 degrees above center or 3/64" for each inch of part diameter. Is this still common practice for HSS? How about carbide?

If you turn, the turning forces will press the tool down. Depending on the flex in the tool, tool post, cross slide, head stock, lathe bed, etc the tool will get lower. So if you start on center, you will definitely be below center. Nevertheless, to get reproducible results, I always set the tools on center, regardless of the tool type (HSS, carbide).