Lathe tool inserts

[Shiseiji]

Which are the ground inserts.?

I've found I can get 'acceptable to me' finishes on mild steel with DCMT inserts that are intended for aluminium with small nose radii like 04 or 02 (which to be fair, are the only ones I use now, apart from one teensy one that I think is a CCMT in a boring bar that I've been using on brass).

I mean, it's true that trouble arises with the finish for anything more than about a 0.010" DOC.

I can get up to about 0.020" if I don't mind a bit of ugliness to the finish (So the mini lathe equivalent of roughing out on steel ) but that's at a pretty slow manual feed (mini-lathes with the change gears supplied don't really do fine feeds) or else it's howlin' cow in chattersville.

A.R. Warner company makes HHS inserts that are easy to keep sharp. Another option. "may" be tangential tool holders. Shop made or available from Eccentric Engineering
I say may because I don't know what size tooling your lathe uses. The tool is sharpened in a jig, very easy to sharpen. A crobalt tool will last years and typically only need a honing after they have been ground.

Yes, lots, if not most, operators of hobby lathes use inserts because they want to make chips. But the lathes aren't made to use them for the reasons given. HHS inserts may appear to be more expensive, but in my experience they aren't because they are easily re-sharpened.

Just my $.02

 

[Jimsehr]

Put your turning tools on center.
boring tool can be on center or a little bit higher,
you can sharpen carbide brazed tools to work on light duty lathes.
high positive back rake really helps on light duty lathes.
i use hss or carbide on my logan lathes it does not matter to me.i can take a 1/4 inch depth of cut on my Logan on 1 inch leadloy with no problem if I use lots of back rake.
i have been machining for 70 years.

 

[SouthernChap]

A.R. Warner company makes HHS inserts that are easy to keep sharp. Another option. "may" be tangential tool holders. Shop made or available from Eccentric Engineering
I say may because I don't know what size tooling your lathe uses. The tool is sharpened in a jig, very easy to sharpen. A crobalt tool will last years and typically only need a honing after they have been ground.

Yes, lots, if not most, operators of hobby lathes use inserts because they want to make chips. But the lathes aren't made to use them for the reasons given. HHS inserts may appear to be more expensive, but in my experience they aren't because they are easily re-sharpened.

Just my $.02

Unfortunately, the Warner HSS inserts aren't available direct from Warner outside the US, so I have had to order via LMS which is a little extra expense on top.

Also unfortunately, the nose radius on the Warner HSS inserts I mistakenly ordered from LMS (0.8 mm) are just too large to use comfortably on a mini lathe. I really should get round to ordering a couple of the 0.4mm radius Warner inserts and see how those go.

I have the tangential tool holder from Eccentric Engineering but I've yet to use it, as the shank of the holder doesn't quite fit in my 1/2" toolholders. It will fit in the four way holder I got with the lathe but I just haven't got round to swapping out my Aloris style toolpost and trying out the Eccentric Engineering in the four way.

I have thought about milling the shank down to 12mm but eh, I worry that, given Eccentric Engineering definitely know what they're doing better than me, I might be dropping the rigidity of the shank a mite too far.

The other issue with the Eccentric Engineering toolholder is that the design of the shank limits the diameter of the work piece I can machine on my little 7x14. At some point I'll modify my cross-slide to increase the travel but that's for the future (thankfully replacement cross-slides for my type of Chinese mini-lathe are cheap and plentiful, so I can afford to mess up a few practicing!).

Since, right now I'm mainly working in brass, I'm using HSS tools that I've ground myself (even with my clumsiness, I can manage a right hand turning tool for brass!). The carbide inserts I've got, I have tended only to use for steel (and, of course, aluminium, for which they were really intended).

 

[VicHobbyGuy]

I have the tangential tool holder from Eccentric Engineering but I've yet to use it, as the shank of the holder doesn't quite fit in my 1/2" toolholders. It will fit in the four way holder I got with the lathe but I just haven't got round to swapping out my Aloris style toolpost and trying out the Eccentric Engineering in the four way.

I have thought about milling the shank down to 12mm but eh, I worry that, given Eccentric Engineering definitely know what they're doing better than me, I might be dropping the rigidity of the shank a mite too far.

I have an EE tangential tool holder with an 11mm shank, so it fits easily in the 250-001 toolholder for the QCTP in my 7x14 lathe.
Milling down that shank might be a challenge - I don't know if it is hardened. A user posted a video of milling a toolholder in the Sieg X2 mini mill group on Facebook the other day. Carbide insert face mill and the red sparks were flying off the workpiece.

The other issue with the Eccentric Engineering toolholder is that the design of the shank limits the diameter of the work piece I can machine on my little 7x14. At some point I'll modify my cross-slide to increase the travel but that's for the future (thankfully replacement cross-slides for my type of Chinese mini-lathe are cheap and plentiful, so I can afford to mess up a few practicing!).

Extending the cross-slide travel on a 7x is a worthwhile project. The easiest method is to just move the leadscrew nut attachment point, as Ted Hansen has mentioned. I made a new leadscrew and extended the 'block' at the dial end of the cross slide as one of my first 7x projects - there was no need to alter any of the stock parts, which was good because I don't like doing that much anyway.

 

[SouthernChap]

I have an EE tangential tool holder with an 11mm shank, so it fits easily in the 250-001 toolholder for the QCTP in my 7x14

[sigh] Yeah, I bought the wrong one, should have paid more attention.

Oh well, just ordered the 10mm tool /11mm shank version.

I went with standard shipping so it'll be a while before it gets here.

Thanks for the heads up.

 

[David2011]

I recently saw someone say the following:

Is this good advice?

From my cursory knowledge of how a lathe tool cuts (HSS or carbide insert) that sounds off but eh, I'm greener than the fresh paintwork on a 1970s English park keepers shed!

You’ve had lots of good information on tool height. How big is your lathe and what’s its horsepower? I’ve had excellent results using ISCAR DCMT070204 IC807 inserts on my small lathe. It’s a Grizzly G9972Z which is an 11x26, 1 hp machine. The IC807 grade inserts don’t require the heavy depth of cut and higher feed rates typical of carbide inserts to get nice surface finishes. I recently got a 13x40, 3 hp machine and will continue to use the same inserts. I’ll also explore other insert options for the bigger machine.

 

[SouthernChap]

You’ve had lots of good information on tool height. How big is your lathe and what’s its horsepower? I’ve had excellent results using ISCAR DCMT070204 IC807 inserts on my small lathe. It’s a Grizzly G9972Z which is an 11x26, 1 hp machine. The IC807 grade inserts don’t require the heavy depth of cut and higher feed rates typical of carbide inserts to get nice surface finishes. I recently got a 13x40, 3 hp machine and will continue to use the same inserts. I’ll also explore other insert options for the bigger machine.

The lathe is just a little 7x14. The motor is 750 Watts but that almost certainly won't translate to a level of torque you'd find in a 'respectable' 1HP motor.

I'll take a look at the grades of my inserts. I can decipher the ISO codes mistly but I haven't spent any time on understanding the grading systems. ISCAR tooling do seem to be well-considered.

 

[Shiseiji]

Unfortunately, the Warner HSS inserts aren't available direct from Warner outside the US, so I have had to order via LMS which is a little extra expense on top.

Also unfortunately, the nose radius on the Warner HSS inserts I mistakenly ordered from LMS (0.8 mm) are just too large to use comfortably on a mini lathe. I really should get round to ordering a couple of the 0.4mm radius Warner inserts and see how those go.

I have the tangential tool holder from Eccentric Engineering but I've yet to use it, as the shank of the holder doesn't quite fit in my 1/2" toolholders. It will fit in the four way holder I got with the lathe but I just haven't got round to swapping out my Aloris style toolpost and trying out the Eccentric Engineering in the four way.

I have thought about milling the shank down to 12mm but eh, I worry that, given Eccentric Engineering definitely know what they're doing better than me, I might be dropping the rigidity of the shank a mite too far.

The other issue with the Eccentric Engineering toolholder is that the design of the shank limits the diameter of the work piece I can machine on my little 7x14. At some point I'll modify my cross-slide to increase the travel but that's for the future (thankfully replacement cross-slides for my type of Chinese mini-lathe are cheap and plentiful, so I can afford to mess up a few practicing!).

Since, right now I'm mainly working in brass, I'm using HSS tools that I've ground myself (even with my clumsiness, I can manage a right hand turning tool for brass!). The carbide inserts I've got, I have tended only to use for steel (and, of course, aluminium, for which they were really intended).

Didn't intend to put you through a writing exercise, but of course it may help someone in the future. Sorry. Always "something" isn't it?

Yes, Gary hardens the tool holder. "But" because the HHS tool is also adjusted in the tool holder to center on the work, narrowing the shank wouldn't matter. It was also suggested to me to purchase pre-ground tools to use as a reference. The result did not work out well for me because the tools I purchased are like old-school planer tools with the shaped tool ends. Nothing easily used as a reference for a square or rectangular HHS tool. Just an FYI for anyone else.

 

[SouthernChap]

Didn't intend to put you through a writing exercise, but of course it may help someone in the future. Sorry. Always "something" isn't it?

I'm guessing you haven't seen that many of my posts. I'm philosophically and psychologically incapable of being terse! So no apology required!

I've now ordered the correct size toolholder from Eccentric Engineering for my size lathe so I won't be needing to do anything to the larger one I currently have. I'll stick it in the back of the drawer for when I get find the Boxford I want.

Since I actually bothered this time round to pay attention to Eccentric Engineering's website, I noticed that Eccentric Engineering suggest that for little 7x14s like I have, it's best to get the left hand tool and mount it on the front of the toolpost to get the largest possible diameter of turning. So that's what I've ordered.

 

[verbotenwhisky]

I recently saw someone say the following:

Is this good advice?

From my cursory knowledge of how a lathe tool cuts (HSS or carbide insert) that sounds off but eh, I'm greener than the fresh paintwork on a 1970s English park keepers shed!

This has not been my experience, I center them.