Another insert thread

[Jim F]

I am thinking about pulling the trigger on insert turning tools.
I see I can get HSS inserts.
I am thinking about getting these while I hone my grinding skills.
Advise and opinions accepted.
Mind you I have a SB9C, I do have a QCTP.

 

[benmychree]

HSS inserts are generally more expensive than carbide, if you do not have a QCTP don't try insert tools --- learn to grind a HSS tool bit first, low power machines do not like carbide very much.

 

[Jim F]

HSS inserts are generally more expensive than carbide, if you do not have a QCTP don't try insert tools --- learn to grind a HSS tool bit first, low power machines do not like carbide very much.

I have a QCTP, and a bunch of HSS bits, mostly ground.
I was thinking that inserts will let me make stuff, until I get my grinding skills honed.
I am practicing grinding, but the temps are preventing that right now.

 

[Jim F]

And why are carbide so much cheaper than HSS ?

 

[MrWhoopee]

And why are carbide so much cheaper than HSS ?

1. There is MUCH more demand
2. They are pressed in molds and sintered (and perhaps finish ground) rather than ground from solid.

 

[Ianagos]

I recommend you grab a cheap pack of Chinese ccmt09 inserts (typically about $10 shipped) and a holder to suit your toolpost (should be maybe $10-$15) and run it. If you can’t figure it out let me know.

On another note I’ve seen lots of these threads and I’ve thought about bulk ordering from China a bunch of holders and inserts so I could sell them to members here for good prices. I wouldn’t be making any money but just as a service because I see so many of these threads and I think I could help some of y’all out. What do you think? Vtcnc you around? What’s your opinion.

 

[MrWhoopee]

I recommend you grab a cheap pack of Chinese ccmt09 inserts (typically about $10 shipped) and a holder to suit your toolpost (should be maybe $10-$15) and run it. If you can’t figure it out let me know.

 

[Downunder Bob]

Yes, whatever you do or don't do, learn to grind HSS. it is not difficult. The cheap inserts you refer too are chinese, and not really that good. Forget the Chinese rubbish get American, Australian, German British Swedish anything but Chinese. Carbide inserts are really only for rigid high speed machines, Sure many people get acceptable to good results on slower less rigid machines, but a well ground HSS tool will almost always give a better result.

 

[Jim F]

Yes, whatever you do or don't do, learn to grind HSS. it is not difficult. The cheap inserts you refer too are chinese, and not really that good. Forget the Chinese rubbish get American, Australian, German British Swedish anything but Chinese. Carbide inserts are really only for rigid high speed machines, Sure many people get acceptable to good results on slower less rigid machines, but a well ground HSS tool will almost always give a better result.

I am in possession of a set of @mikey 's examples, but the temps have limited grinding abilities.

 

[mikey]

I am thinking about pulling the trigger on insert turning tools.
I see I can get HSS inserts.
I am thinking about getting these while I hone my grinding skills.
Advise and opinions accepted.
Mind you I have a SB9C, I do have a QCTP.

Jim, if you want to try inserted carbide turning tools, the most popular tool holder is an SCLCR. For your lathe, an SCLCR06 would work well (3/8" shank, RH). Chinese tool holders like this are all over ebay for cheap or you can get a Dorian tool for under $60.00 retail. Other top brands are Iscar, Seco and Kennametal. If you are feeling particularly rich you can buy an AR Warner tool that comes with several HSS inserts and will also take CCGT and CCMT inserts.

The advantage of the SCLCR tool holder is that when the tool shank is held perpendicular to the work piece, you can turn or face without having to move the tool. The inserts that fit this holder will all be positive rake inserts so they will work okayish on a low HP lathe if you can get near or into the right RPM range.

The SCLCR tool takes CCMT and CCGT insert. For this 3/8" size, you would look for CCMT 25.50 or 25.51 finishing inserts for steels. Look for CCGT 25.50 or 25.51 AK inserts for aluminum; these are uncoated, ground to a sharp edge and have an extremely aggressive positive rake that will rival HSS in aluminum if you can go fast enough. As for brands, look for Seco, Iscar, Valenite inserts on ebay. Look hard for the 25.50 inserts if you can; they have a 0.004" nose radius that will allow you to take much smaller depths of cut without deflecting excessively.

If you wish to try a HSS insert, the same tool holder should take an AR Warner CCMW 25.51 insert. The advantages of these HSS inserts is that they will work better at the speeds your lathe can hit and they can be resharpened by honing the flat top on a diamond stone. In my experience, AR Warner inserts will deflect less (or cut more readily) at small depths of cut vs a carbide insert because of its very sharp edge. The same is true for CCGT-AK inserts mentioned above.

Note that SCLCR tool holders are RH. SCLCL holders are LH. The difference between good tool holders and cheap Chinese ones is the accuracy of the insert pocket and screw location. I own both Iscar and Seco versions and have tried a Chinese one; there is a difference. The same is true for inserts and I would go for name brand inserts if you can.

AR Warner is the only company in the US that grinds T-15 HSS inserts to my knowledge and their inserts can last for well over a decade if you keep them honed so they are vastly more economical vs carbide and will work better on your SB9, at least in my opinion.

There are times when inserts are the right tool for the job. While HSS tools will usually work better on a smaller lathe for most jobs, sometimes you just need carbide (think high carbon steels or tool steels). You have to try both carbide and HSS so you can learn which tool will work for you and your lathe. Just keep in mind that HSS that is ground well will almost always work better on a smaller, lighter, less powerful lathe for most stuff.