Proper way to use lantern tool post

Mike,

One thing I have seen the lantern toolpost used for is as a ball turner. Since the cutter is in line with the
center line of the lantern you can swing your compound to make curves. With a QCTP since the cutter is
offset from the pivot of the compound I think you will get more of an ellipse if you do this.

I have to say that I have not actually tried this myself.
 
Thanks! It seems to me that arrangement would be a bit chatter-prone.
 
My favorite is the 4 way. But they vary so much that some are decent, others are a pain. Mine has the click stops that make switching from one to the other super simple. I also like the armstrong style tool holders, along with the HSS cutters that are easy to shape the way you want. I have the BXA QCTP, for my 12", bur would not spend the money to get them for my 6", just not enough benefit over the 2 way, to justify the cost.
 
The lantern tool post is far easier and faster to use HSS tooling on.

It is a little less rigid than a 4 way toolpost. Results vary for Aloris style, but really good ones are very rigid, and some offshore ones are not rigid at all.

It reaches into grooves easier, but not necessarily better than other tool posts. I have all types: 4 way, lantern, Aloris AXA and Aloris BXA tool posts. they all work well. For parting, I prefer the BXA. For wood and aluminum, I mostly use the lantern. I have my carbide setup so that every holder is already on centre on the 4 way, so using inserted tools the 4 way is king for me. The Aloris is best for easier setting height on unusual or new tool holders. It is also very convenient for parting.

Hey guys I'm not religious about these things. Everyone's setup will vary, and there's no one-solution answer.

If the OP is planning on using HSS home-ground tools, then his lantern will work very well indeed.
 
Dabbler said:
The lantern tool post is far easier and faster to use HSS tooling on.
Click to expand...

Just trying to understand. Why or how is it easier and faster to use a lantern tool post with HSS vs using that same HSS tool in a QCTP holder? It seems to me that the QCTP is more rigid, easier to adjust to center height, quicker to change tools and allows 360 degrees of rotational freedom. How does the lantern tool post do this better?
 
OK. this assumes that you are proficient in each discipline, not the time it takes to learn it. This is a slightly touchy subject for some, so please put away the pitchforks...

First - some people call Aloris tool posts QCTP, but there at least 4 different types of QCTPs out there. My comments pertain to Aloris only - I have virtually no personal experience with other types.

An Aloris holds the HSS bit parallel to the ground, without extraordinary measures to change that. Your grind and angles cannot be changed easily, but if you get them right one bit can serve very well - in one type of material. If you get them wrong, you go to the grinder and change them until they are right. Sometimes diagnosing tricky heat treats of a usual material, or an unusual or unknown material can take loads of time to get a good cut or finish... So you want to cut brass with your HSS tool ground for steel, and you'll gall the heck out of it.
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Now on the the lowly and sometimes maligned lantern (sometimes called American, or Anderson) toolpost. you do a grind with 5 degrees in each direction - normal for mild steels. If you get a bad finish, you adjust the angle of the cutter until you see a better result, which takes seconds. this is your indicator that you need a shallower or steeper cut angle, or whatever. you can adjust your grind for optimal results and go for it, again adjusting this new tool in subtle ways to achieve your goals.

BONUS: I have two tools for cutting wood in my lathe. they look similar, but by adjusting the angle of the tools I can use my softwood bit to accommodate differences in the wood grain, texture or moisture content. If that doesn't work well, I use the stteper cutting angle tool (hardwood tool) and adjust again. I get really good results because of this angle adjust ability.

Caveat: Unless you have a honking big lantern toolpost, don't bother taking a really big chip with it. It just isn't meant for those pressures.
 
I don't own a lantern tool post so I am speaking from ignorance. I do own a Sherline rocker tool post and understand exactly how to use that. It is similar in principle and use to a lantern post, although not nearly as versatile since it only uses the post and not arms with different angles on them.

I can see how the rocker feature allows you to get the tool tip on center and this would alter the rake angles but I don't see how you can alter rake angles independently, without altering center height. I know that there are accessory arms that hold the tool at different lateral angles and some that allow you to alter lead angle so maybe that is what you're referring to.

My Square Tool will cut almost anything, although it won't do that well in hardened steels. It will cut aluminum, brass, plastics, mild steels, medium carbon tool steels and stainless and it will do it with a single tool geometry. Perhaps if I did not have this tool then I might see the value of a tool post that can change tool angles, I dunno'.

With all of this said, I think I will be content with my Aloris post. Maybe one day I'll get to use a lantern post and come to my senses on my own.
 
the armstrong tool holders telescope in and out. This helps to make centre height adjustments after changing rake angle. Hard to explain even in pictures, but only 20 seconds to show in person.
 
You can also place shims under the tool holder, or better yet, You grind the bits for the tool holder, and lathe it will be used on.
 
The two posts above, combined, explain how it is easy and quick to change tool angles with a lantern tool post arrangement. The Armstrong style tool holders are relatively massive and rigid while also narrow in width, and tool bits are typically installed in them with very little stick out, often the ground tool angles are partially recessed into the holder. The lantern post is the weakest link WRT rigidity (though certain models are better than others.) With the tool holder also installed in the lantern post for minimum stick out, you have a small, compact, and reasonably rigid setup that can get into tight places. By sliding the tool holder out farther, it is even better at getting into tight places, at the expense of less rigidity with more stick out. That system of lathe tool holding was ubiquitous for many decades, without much serious competition from other lathe tool holding systems. It worked well for what they were doing, and what they were doing then was often more similar to what is done in hobby shops today than in production shops today. Can you get along without one? Yes! Is having lantern tooling for occasional use an asset in your shop? Sure, but there is no pressing need to rush out and buy them ASAP...
 
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