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

Bob Korves said:
I use that method most of the time doing internal threads, especially when threading close to an internal shoulder or hole bottom. Saves using the foot brake, and keeps my anxiety level down...
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What kind of threading insert tool holder and insert do you use?
 
mksj said:
I do not see that that the OP's question has been answered, and it still seems conflicting as to the the insert/anvil to be used. According to Carmex and a few other references one would use a LH (left hand) internal threading bar with an internal IL (left hand holder) type insert. The EL insert would be for an external left hand thread. The anvil needs to be changed to a negative anvil, the anvil sets the angle cutting into the thread (positive) or away (reverse) from the thread (negative). I would suggest you call one of the manufactures and ask what specific tool holder and anvil would be appropriate for the type/size of threading you want to do. Most of the inexpensive threading tools do not have an anvil under the insert, so I am not sure if they would work for doing reverse internal threading. Carmex is made by Iscar, I have the Carmex IR lay down holder and it works great. I went with a size 16 insert "AG60" type which has a much wider threading capacity than the size "11" "A60" insert (I have both size bars). The smallest size 16 insert holder left hand internal thread is a SIL 0500 M16 which has a 0.625" shank and the threading shank section is 0.50" with a minimum bore of 0.620". I like the Carmex, but I also find TMX tooling to be very good and 1/2 the price. Which ever you decide, I would call TMX or Carmex for the correct anvil part number for what you want to do before you purchase anything. Also Carbide Depot is a great alternative for both information and to purchase holders.
http://www.carmexusa.com/content.aspx?file=customerpages/inch_catalog2018.htm
https://www.toolmex.com/itemdetail/6-SIL-500-M16
http://www.carmexusa.com/default.aspx?page=item+detail&itemcode=SIL0500M16

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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
 
If you use a lay down insert tool, then you need an insert specific to the holder you are using. So the four types of inserts and holders indicated by manufactures would be left and right hand, external and internal. So for a left hand internal threading bar, you would use a left hand internal insert. The left hand internal holder for lay down inserts has a different shim depending on if you are threading into the the work or away from the work. So if you use a lay down internal left hand boring bar threading threading outward, you would need the negative shim plate and you would use an 11 IL A60 or 16 IL AG60 depending on the size insert that the boring bar takes. With lay down insert holders you need four different bars and insert types to cut all external/internal and left hand and right hand threads.

The top notch and other vertical inserts (on edge inserts) use just one insert for all four scenarios, so something like a TNMC insert can be use in an internal or external holder. Also you can look at Mesa Tools which sells there own variant where both insert and holder can be used for any of the above scenarios for $44.
http://www.mesatool.com/products/threading-tools/

Ray, you may be able to interchange inserts as you mentioned, but it doesn't follow with what is indicated by the manufacture. I am aware of the difference between the internal and external insert, say right hand insert is the direction of the cutting tip. But the lay down inserts that I also have a cant to the vertical cutting edge in addition to the seat angle which tilts into the direction of cut. All I am recommending is that he call one the manufactures (or Carbide Depot) and see what they recommend. I understand that a right hand external insert may work in an internal lay down threading tool holder, but it may not be ideal. My Carmex right hand internal threading holder does not have a seat, but the left hand internal does so the insert seat angle also may be a factor. Bottom line is I do not have a clear answer and I am only pointing out what is indicated by the manufactures.

Also, I find a lot of misinformation and pictures on the posted specifications, so when in doubt, I have called the manufacturer or in this case I would check with Carbide Depot specific to the lay down threading tool holders, inserts and shims if needed. One can also use an on edge type of insert, although I find the TNMC type can be a bit more fragile and there are some limitations as to the size of the holder. The Top-Notch are more robust but also a wider insert.
 
9t8z28 said:
I looked up the Iscar tool you posted and see that it is a different style of toolholder.
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I mentioned it only as many seem unaware of the tooling and that it can be used for LH & RH threading, grooving and boring on the lathe and for grooving on the mill, it can also be used for thread milling on a CNC Mill
 
I would not even have to think about buying that tool . For that price it is a throw away if it don't work. When I was in business the insert used to cost that much. Buy it and try it. And if you can hold part in a collet and don't worry about chuck unscrewing.
 
Thank you to all who have posted and been patient with me. I am catching on to the different types of inserts and insert holders that can be used. I am looking for the cheapest way to go about this and that may not be possible or practical. I may be better off with one of the other types of bars and inserts mentioned here. I was hoping that I could put together a bar and insert for under $30-$40 and that may get the job done but I also may be better off spending more for a better tool that can not only be used for threading but can also be used for grooving and or maybe trepaning.

I am unemployeed right now and just started going back to school for machining. I am taking a government funded metal working training program. Its designed to get more people (high school students all the way to seniors) back into the manufacturing industry. I was skeptical at first but now that I am just going on 4 weeks in, I have come to realize that it is a very in depth program that gives you the tools and a hands on experience into all aspects of the trade. So far I havent learned a whole lot more than what I have already taught myself. I do need to touch up on my Trigonometry but I get the basics on where its used. Sorry for going on like that! All I wanted to say was I was on a tight budget and I went on to give you guys more info than you needed!
Thanks again to all who commented. This forum and the people are really helpful and patient. Its a pleasure to be here and ask questions and read your comments. Even if my issue isnt always solved I get different outlooks on what I am seeing and a different way to look at my issue or what it is I am trying to do. Thanks!
 
I have many boring bars and threading tools, of all types, most ground decades ago by unknown machinists. Got them dirt cheap in tool lots. Why start from a square blank when you can find one in a couple minutes that is very close to what is needed, and the grinder is nearby to modify them as needed. I find the good old USA HSS better than new imported stuff today. I have not seen any new high quality HSS, but I am sure it is available if you have enough money. Why bother when there is so much good used HSS for sale cheap. Most everyone has gone to carbide, which is good stuff, but I like to keep my quiver full of arrows for all circumstances, expected or otherwise.
 
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 inserts.
 
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