Lathe tool inserts

[VicHobbyGuy]

Eccentric Engineering suggest that 7x lathe users buy the left hand toolholder and mount the toolholder on the front of the toolpost.

As I said in Post #21, I don't understand this advice. To clarify: I think this is very unwise advice. I have both RH and LH holders and I think the EE advice only applies to facing operations. If that's all you plan to do with the EE toolholder, or if you never want to cut close to the chuck, then the LH one should work just fine for everything.

 

[VicHobbyGuy]

It looks like Eccentric Engineering have raised their price about 30% since I bought my turning tools 10 months ago. That moves them into the 'sizeable expenditure' (almost $300 CAD for the RH+LH tools and shipping) category for me.

 

[Shiseiji]

It looks like Eccentric Engineering have raised their price about 30% since I bought my turning tools 10 months ago. That moves them into the 'sizeable expenditure' (almost $300 CAD for the RH+LH tools and shipping) category for me.

I know Gary was forced to get some of his processes done in NZ after his customary shop closed down and he was very unhappy with the remaining Australian place.

FWIW the Logan is a 10" and I rarely have to alter my QCTP from 90. The times I have needed to, I just move it to what ever is needed. Unlike the second picture VicHobbyGuy posted, I have my tool holder choked up as close to the tool holder as it will go.

Anyway these discussions are always good, hopefully will save someone from bitter disappointment if they can't use the tool holder like they expected to.

 

[VicHobbyGuy]

Unlike the second picture VicHobbyGuy posted, I have my tool holder choked up as close to the tool holder as it will go.

It's hard for me to get pictures at the right correct angle to show the relationship of the tool and work on the lathe; my apologies if the pics weren't clearer. The tool tip is over 30mm from the front of the OXA toolholder, when it is 'choked up as close as it will go' (as it was when I took those pictures...)
BTW, I also have a 10" lathe and it is a completely different situation. Part of the discussion here has been about the specific advice that EE gives for 7x lathe users; that's why I took the pics with the tools in action on my 7x lathe.
.

 

[SouthernChap]

As I said in Post #21, I don't understand this advice. To clarify: I think this is very unwise advice. I have both RH and LH holders and I think the EE advice only applies to facing operations. If that's all you plan to do with the EE toolholder, or if you never want to cut close to the chuck, then the LH one should work just fine for everything.

Sorry completely missed your post #21

I think EE are suggesting the LH toolholder be mounted the other side of the toolpost; the side closest to the work; the aloris style QCTPs don't have a mounting position where you show the tool mounted in your four-way.

The position that I've interpreted their advice to mean, will garner a bit more room to manoeuvre than using a RH tool in the standard position. Absent doing an 'extra cross slide travel' mod, the 7x mini-lathes are not blessed with tons of space in the 'surge' DOF whatever tool you're using so any extra will be a help.

That said, for doing 'squaring' up on larger rectangular work via facing operations (for those who, like me, don't own a mill), your idea of mounting on the side farthest from the work could be quite handy when working in harder materials like steel, given that the 'for aluminium' carbide inserts that many mini-lathe owners use for steel, don't like interrupted cuts. I'd have to use my four-way rather than my QCTP but that kind of messing about is the price of not being able to yet afford a mill.

 

[gard]

Back to the original, question for a moment. I don't use much carbide but generally do put it on center. The book from South Bend called "how to run a lathe" states to set the HSS cutter slightly above center except when turning tapers or threading. There needs to be enough front relief ground into the bit. Lots of info showing the recommended angles for various materials. The book dates from the 1940s which is about how old my south bend lathes are. Using the lantern post and armstrong holders. I tend to move the bit up and down a little if I don't like the way its cutting, this is quicker than regrinding it, which I also do a lot of.

 

[SouthernChap]

Honestly, the reason I asked the original question was that I'd never heard of anybody suggesting any position other than centre and from what I know about the physics of the cutting action (assuming the expected reliefs on a tool) being on centre would provide the best cutting with the least tool pressure.

But eh, what works for people is what works for people.

 

[VicHobbyGuy]

The book from South Bend called "how to run a lathe"

Many of us have a copy (printed or electronic) that book; it's often recommended for beginners and that's when I read it. As you point out, the advice about cutting tools in the 'How to Run a Lathe' assumes the use of a lantern toolpost and the holders which hold the tool at an angle.

 

[Janderso]

Diamond brand? $150 USD for one or two tools?

One

 

[Janderso]

Many of us have a copy (printed or electronic) that book; it's often recommended for beginners and that's when I read it. As you point out, the advice about cutting tools in the 'How to Run a Lathe' assumes the use of a lantern toolpost and the holders which hold the tool at an angle.

I haven’t used a lantern style since 1974. I can’t for the life if me come up with a reason to set the tool a bit high???
John??