What left hand boring bar and inserts for reverse helix right hand internal threading?

magicniner said:
If you'd started with budget constraints I'd have suggested making a tool from Silver Steel or HSS
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It can go both ways. If I said the sky is the limit then I would have everyone telling me to call Kennametal or Sandvik, tell them what I need and they would sell me 8 bars for internal, external small to large threads left to right and then all of the grooving and trepaning inserts to go along with it. Oh and not to mention it would have to have through coolant as well. Lol
I have a piece of Mo-Max set aside for my last resort. I don't want to use HSS. I want to use carbide and inserts.
Ray C said:
Mark,

He's got a left hand tool and in post #3, I told him he needs an ER type insert. Depending on what company you're dealing with, the terminology is different but anyhow, ER (external right) is the same geometry as IL (internal left). In post #7, Mcingineer, zoomed-in on the cutting diagram from the picture I posted. The boring bar he showed does not accommodate a shim -it's just a simple LH bar. I think he said it takes an ER11 size insert which are the little small ones like this: https://www.ebay.com/itm/10-16ER-11...660631?hash=item283c516b17:g:yrEAAOSwa81XSPi7

If he lived nearby, he could drop over and I'd hand him a couple... In my original post, I started to describe how all the orientation works for threading but, I ran out of time.

Ray
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Sorry for questioning you but I want to be clear. In post #3 you said the bar I posted a link to takes ER inserts and above in your post# 12 you said I need ER inserts. But then you said ER is the same geometry as IL. Do I need ER or IL inserts and if I need IR inserts will they work with the bar I posted a link to? Or,, should I forget about the bar I posted a link to and go with something else?
 
Ray C said:
Here are a few choices. Could not find a 12mm (1/2" equivalent) but found some in 10mm (3/8") and 16mm (5/8").


https://www.banggood.com/SNL0016Q16...-p-1161645.html?rmmds=search&cur_warehouse=CN

https://www.banggood.com/SNL0016Q16...-p-1153642.html?rmmds=search&cur_warehouse=CN

https://www.banggood.com/S10K-SCLCL...-p-1129429.html?rmmds=search&cur_warehouse=CN

Ray
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The Bar in the first link uses ER inserts. The bar in the second link uses IR inserts. The bar in the third link is not even a thread turning bar or insert. I saw these on bangood but I still don't know what will work for reverse helix threading away from the headstock. Were you just giving me options to try or you were recommending a bar and insert that will work?
 
9t8z28 said:
It can go both ways. If I said the sky is the limit then I would have everyone telling me to call Kennametal or Sandvik, tell them what I need and they would sell me 8 bars for internal, external small to large threads left to right and then all of the grooving and trepaning inserts to go along with it. Oh and not to mention it would have to have through coolant as well. Lol
I have a piece of Mo-Max set aside for my last resort. I don't want to use HSS. I want to use carbide and inserts.

Sorry for questioning you but I want to be clear. In post #3 you said the bar I posted a link to takes ER inserts and above in your post# 12 you said I need ER inserts. But then you said ER is the same geometry as IL. Do I need ER or IL inserts and if I need IR inserts will they work with the bar I posted a link to? Or,, should I forget about the bar I posted a link to and go with something else?
Click to expand...

Here's another way to answer the question...

Please look closely at this picture of the Shars tool: http://www.shars.com/products/index...rs/1-2-x-7-lh-internal-threading-boring-bar-1

It is a left hand tool very similar to the one you posted in your original link. You'll notice that Shars tool takes a 16er ag60 insert. I've got no less than 4 different LH boring bars and they all take ER-type inserts.

Also look at post #7. To use a LH threading bar, this is the best way to make the cut. I've done in many, many times. You will need to make a starting groove inside the bore. Since you're starting-out and don't have grooving tools, just use the tip of your threading insert to dig a groove.

Ray
 
9t8z28 said:
The Bar in the first link uses ER inserts. The bar in the second link uses IR inserts. The bar in the third link is not even a thread turning bar or insert. I saw these on bangood but I still don't know what will work for reverse helix threading away from the headstock. Were you just giving me options to try or you were recommending a bar and insert that will work?
Click to expand...

The bar in 1st link would work but it has a 16mm diameter (maybe too big for what you need).

The bar in the 2nd link has a typo. It is a LH bar and therefore needs an ER insert.

The 3rd bar... Sorry, I must have cut/paste wrong. Forget that one.

Ray
 
Yes I have that bar and yes used it like you want. it comes with both left and right handed inserts. One of each. you can also get grooving inserts for it.
 
Anyone still in doubt, please go here and read the wealth of information in the section about Thread Turning Inserts. You will see the relationship between EX-RH, IN-LH and IN-RH, EX-LH spelled-out in black and white. http://www.carmexusa.com/content.aspx?file=customerpages/inch_catalog2018.htm

They only fit one way and there's only 2 combinations for flat type inserts. The main difference between various styles is if they're full or partial profile. Some also have different top angles for chip-breaking purposes etc. For manual machining, you don't need to get too fancy...

Ray
 
If you end up getting insert & anvil overwhelmed (as I became), these might be an option.
https://www.carbideanddiamondtoolin....Threading.Tool.060.to.490.Min.Bore.Series.30
From what I can visualize, should work right to left in forward rotation or upside down left to right as you are wanting - so long as your toolholder / tool post can re-position it vertically which is another thing to watch out for. A thicker shank tool upside down means the toolholder must be able to compensate 'up' sufficiently so the cutter tip is on center bore. Check your setup that you can do this. Bigger lathe + smaller shank shouldn't be a problem, but the revers may not be true

Homebrew variation
http://madmodder.net/index.php?topic=3523.0
 
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