Indexable boring bar.

[dobbslc]

I need a 12mm shank indexable boring bar for my lathe, I've had a look on Ebay etc but there's so many to choose from I don't no what to get!
I have small one (8mm?) but it's no good as I can't get it to centre height, the tungsten one I have was cutting ok but screeching badly until I tried sharpening it and now it's quite but don't work anymore
So I think to save me from myself I need one with replaceable tips.
Any suggestions on makes or type? I've got a Sandvik tool for normal turning jobs and it's very good but they are expensive, are the RDG tools ones any good?
Thanks.

 

[mike os]

One with readily available inserts , I went ccmt because I use a lot of them

 

[Kram]

Edit - ignore that I missed the words boring bar..

One of these,
www.ebay.co.uk/itm/S12M-SCLCR09-12-150mm-HOLDER-CNC-turning-tool-for-CCMT09T3-CNC-INSERT/303193884544

But you will want the 8mm one for small bores, either shim it or get a QCTP. Deep bores both will chatter I have a 20mm

Rdg are just expensive chinese imports I prefer to buy direct.

 

[Agroshield]

As mike os says, it is helpful to choose a bar that takes the same inserts as your turning tools.

If CCMT are your thing, you would not go wrong with one from JB cutting tools. Look also at Chronos and ArcEuroTrade.

...One of these,
www.ebay.co.uk/itm/S12M-SCLCR09-12-150mm-HOLDER-CNC-turning-tool-for-CCMT09T3-CNC-INSERT/303193884544

That one uses 09 inserts which are overkill on a 12mm dia. bar. The 09 inserts are also more money than 06 ones. The only reason to buy that is if everything else you have uses 09.

 

[Steveblade]

Why cant you pack it up to centre hight? Regrind on a green wheel.

 

[slim_boy_fat]

I have small one (8mm?) but it's no good as I can't get it to centre height

Shims are your friends.

 

[Brad93]

Korloy are real quality at not too expensive prices

 

[dobbslc]

Why cant you pack it up to centre hight? Regrind on a green wheel.

Even when its hitting the top of the tool post it's still under centre.

 

[dobbslc]

I think the inserts I have are TPMT no idea what they are or if they'll work in a boring bar

 

[brightspark]

Even when its hitting the top of the tool post it's still under centre.

isn't there enough meat on it to mill a bit of the top of the tool

 

[Steveblade]

Even when its hitting the top of the tool post it's still under centre.

Sounds like the top at the cutting end has been ground away to much or you have a tool post problem/miss alignment. If its the latter a new bore bar aint going to help

 

[Kram]

That one uses 09 inserts which are overkill on a 12mm dia. bar. The 09 inserts are also more money than 06 ones. The only reason to buy that is if everything else you have uses 09.

Nope I have about 20 holders and most types of insert. Both sizes are cheap enough but 09 is far more durable. I ordered one of these yesterday after getting through 4x 06 inserts on one en19t part.

www.ebay.co.uk/itm/SCLCR1212H09-12mm-Lathe-Holder-Turning-Tool-Boring-Bar-CCMT09T3-Inserts/174227681330

 

[northwest]

I buy from two places generally unless it is something specific, Jenny at JB Tools: http://www.jbcuttingtools.com/epage...ctPath=/Shops/es461493/Categories/Boring_Bars because most of this stuff is made by Brian in his workshops from decent tool steel or I buy from APT here: https://www.shop-apt.co.uk/

I also buy Iscar tooling at every opportunity.

APT are having a bit of a sale on at the minute so some good discounts. I tend not to mess about with cheap and nasty tooling as it can waste both my time and materials.

I have small one (8mm?) but it's no good as I can't get it to centre height,

I would like to see a pic or two of your setup.

 

[MBB]

Lift the whole tool post with shims under it.

 

[zx9]

I buy from two places generally unless it is something specific, Jenny at JB Tools: http://www.jbcuttingtools.com/epage...ctPath=/Shops/es461493/Categories/Boring_Bars because most of this stuff is made by Brian in his workshops from decent tool steel or I buy from APT here: https://www.shop-apt.co.uk/

I also buy Iscar tooling at every opportunity.

APT are having a bit of a sale on at the minute so some good discounts. I tend not to mess about with cheap and nasty tooling as it can waste both my time and materials.



I would like to see a pic or two of your setup.

I second the call for JB Tools, Jenny is great to deal with, on the one occasion that things went slightly wrong she was very apologetic and sent a couple of free DCMT holders to make up for the inconvenience.

 

[Brad93]

Nope I have about 20 holders and most types of insert. Both sizes are cheap enough but 09 is far more durable. I ordered one of these yesterday after getting through 4x 06 inserts on one en19t part.

www.ebay.co.uk/itm/SCLCR1212H09-12mm-Lathe-Holder-Turning-Tool-Boring-Bar-CCMT09T3-Inserts/174227681330

Cheap inserts and holders you’re just throwing good money after bad.

cheap holders fair enough but buy decent inserts and they’ll last months and months unless you’re doing production machining.

 

[dobbslc]

Sounds like the top at the cutting end has been ground away to much or you have a tool post problem/miss alignment. If its the latter a new bore bar aint going to help

The tool post is fine, the 8mm tool I'm talking about is an indexable ones, it's not been ground down. It's just that the lathe is designed for 12mm tools.

Lift the whole tool post with shims under it.

That would be a ball ache. I just need a 12mm tool that will fit with a couple of shims to get it on centre.
I'll have a look at the links above.

 

[dobbslc]

@northwest thanks for the link.
I've just had a look at that and think I've bought some inserts from her before, does she go to the autojumbles? The tool in the link has a round shank but mine are all square, will it still work?
I'll get a photo later of the set up as any advice it very welcome.

Edit: I've just thought. Round shank tools are meant for QCTP are they not? Mine is just a 4 way job.

 

[dobbslc]

Thanks mods for moving this thread to the correct place, I didn't notice there was a machining section!

 

[Agroshield]

Even when its hitting the top of the tool post it's still under centre.

So how is a bigger bar going to help if this is the case?

Let us assume the top of the insert coincides with the top of the bar on both 8mm shank and 12mm shank. If the top of the 8mm one hits, the top of the bigger one will also hit, just the bottom of the bigger one will be lower.

If we assume the top of the insert is level with the centreline of the bar, a bigger bar will make the situation worse: the 8mm one will be 4mm below its top, the 12mm one will be 6mm below its top, so 2mm lower.

How do you make all your turning tools work as I have not seen many where the cutting edge is above the top of the tool shank?

All indexable bars have flats ground on the round shank so can sit on a flat surface. You might need to pack the back as well as the bottom so the clamping screws are close to the centreline of the bar.