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

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9t8z28

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#1
I Am about to purchase a left hand threading boring bar and inserts to do right hand internal threading using the reverse helix method. I need to purchase a boring bar and the inserts but I have some questions.
The thread boring bar I am looking at is a left hand bar that says it accepts ER11 inserts. I know that ER stands for external thread and IR stands for internal thread but when using the reverse helix right hand internal threading method do you use ER inserts or IR inserts? The bar I am looking at is in the link below:
https://www.ebay.com/itm/SNL0012K11...e=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649
 

Ray C

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#2
EDIT: Please see the diagram.

If you have a screw-on chuck, be careful that it does not unscrew.



Threading.JPG

Ray
 

Ray C

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#3
BTW, the boring bar you show does indeed take an ER insert.

Ray
 

petertha

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#4
I've been eyeing some Asian insert thread tooling myself. Haven't committed yet. For the most part I've had OK success with offshore clones & generally great success with their inserts. But every once in a while, a low quality dud tool arrives. Impossible to tell by a picture. I call those 4140-ish bar stock models. LOL

Anyway, what I think I noticed is they seem to be adopting Carmex type tooling & insert standards. But the problem is you may not see the full compliment of tooling/insert combinations, meaning left/right/inside/outside. I've attached an excerpt from Carmex catalog specific to your question (disregard the highlights). I'd suggest checking Carmex catalogs to at least try & figure out what the cloners were attempting to clone. To complicate matters, sometimes they use different designations. Some are sneaky & either embed or use similar designations to help you cross reference.
http://www.carmexusa.com/default.aspx?Page=Home

Another grey area aspect is shim/anvils. Carmex has a very complete selection & shows which ones in which applications. Clones might be anywhere from 'no information given', to 'comes with anvil - but no other details'. I noticed some vendors like Shars adopts what I assume is a medium range anvil but I'm not sure if they even stock sizes on either side. Hope this helps. Let us know how it performs,
 

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9t8z28

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#6
I've been eyeing some Asian insert thread tooling myself. Haven't committed yet. For the most part I've had OK success with offshore clones & generally great success with their inserts. But every once in a while, a low quality dud tool arrives. Impossible to tell by a picture. I call those 4140-ish bar stock models. LOL

Anyway, what I think I noticed is they seem to be adopting Carmex type tooling & insert standards. But the problem is you may not see the full compliment of tooling/insert combinations, meaning left/right/inside/outside. I've attached an excerpt from Carmex catalog specific to your question (disregard the highlights). I'd suggest checking Carmex catalogs to at least try & figure out what the cloners were attempting to clone. To complicate matters, sometimes they use different designations. Some are sneaky & either embed or use similar designations to help you cross reference.
http://www.carmexusa.com/default.aspx?Page=Home

Another grey area aspect is shim/anvils. Carmex has a very complete selection & shows which ones in which applications. Clones might be anywhere from 'no information given', to 'comes with anvil - but no other details'. I noticed some vendors like Shars adopts what I assume is a medium range anvil but I'm not sure if they even stock sizes on either side. Hope this helps. Let us know how it performs,
Thanks for the info. Hopefully someone on here has done the reverse helix internal threading and can chime in on what we need. I originally found the idea from Joe Pie on youtube. He didnt explain what bar or insert he used
 

magicniner

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#7
To cut a right hand thread with the lathe in reverse and the tool moving left to right you use a Left Hand Tool.

Tool.jpg

For work with bores from 8mm up I use Iscar MGCH 06 and MGCH 08 bars with appropriate holders and partial profile LH inserts

Using the terminology "right hand internal threading using the reverse helix method" will throw a lot of people off as it's not in particularly common use, cutting "away from the shoulder" / "away from the headstock" / "away from the bottom of the bore" and a few variants are far more commonly used amongst machinists.
 
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Bob Korves

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#8
To cut a right hand thread with the lathe in reverse and the tool moving left to right you use a Left Hand Tool.

View attachment 263181

For work with bores from 8mm up I use Iscar MGCH 06 and MGCH 08 bars with appropriate holders and partial profile LH inserts

Using the terminology "right hand internal threading using the reverse helix method" will throw a lot of people off as it's not in particularly common use, cutting "away from the shoulder" / "away from the headstock" / "away from the bottom of the bore" and a few variants are far more commonly used amongst machinists.
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...
 

mksj

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#9
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

Carmex Example.jpg
Laydown Threading inserts 16 AG60 .jpg
 

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9t8z28

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#10
To cut a right hand thread with the lathe in reverse and the tool moving left to right you use a Left Hand Tool.

View attachment 263181

For work with bores from 8mm up I use Iscar MGCH 06 and MGCH 08 bars with appropriate holders and partial profile LH inserts

Using the terminology "right hand internal threading using the reverse helix method" will throw a lot of people off as it's not in particularly common use, cutting "away from the shoulder" / "away from the headstock" / "away from the bottom of the bore" and a few variants are far more commonly used amongst machinists.
I know that I need to use a left hand bar but I still dont know what insert to use, one for internal threading or one for external threading and whether the bar can accept either external or internal inserts

I looked up the Iscar tool you posted and see that it is a different style of toolholder. I'm not sure of how its described but the insert mounts vertically on the very end of the bar. This is different from the laydown as Im sure you know. This now makes 3 different style insert type thread boring bars that I am aware of. Joe Pie uses a top notch style which are also very common for grooving or trepaning.

Your right about my wording. It does seem to be confussing now that I re-read it after you explained it.
 

9t8z28

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#11
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...
What kind of threading insert tool holder and insert do you use?
 

Ray C

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#12
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

View attachment 263192
View attachment 263197
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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#13
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.
 

magicniner

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#14
I looked up the Iscar tool you posted and see that it is a different style of toolholder.
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
 

Jimsehr

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#15
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.
 

9t8z28

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#16
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!
 

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#17
If you'd started with budget constraints I'd have suggested making a tool from Silver Steel or HSS
 

Bob Korves

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#18
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.
 

9t8z28

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#19
If you'd started with budget constraints I'd have suggested making a tool from Silver Steel or HSS
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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Ray C

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9t8z28

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#22
If you'd started with budget constraints I'd have suggested making a tool from Silver Steel or HSS
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.
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
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?
 

9t8z28

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#23
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?
 

Ray C

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#24
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?
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
 

Ray C

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#26
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?
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
 

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#27
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.
 

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#28
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
 

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#29

petertha

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#30
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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