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the kid
04-11-2015, 05:09 PM
As the title says, I'm seeking an internal thread tool, I want one with a carbide insert and small enough to do down to 1/2-13 it needs to be usable in a lantern type tool post and suited to machining hard metals such as titainium and stainless, and be of an appropriate size to fit my 9 or 10 inch lathes. There are so many options with regards to inserts that I don't know where to begin! I don't use carbide much, mostly hss tooling is what I'm used to. Price isn't a major concern here, I need quality above all else. Thanks in advance for your help.

LKeithR
04-11-2015, 05:40 PM
The issue you're going to have for a 1/2-13 internal tool is min. bore and thread pitch. I looked at a couple different toolholders which use 1/4" IC inserts. Both had a min. bore of .500" and neither had inserts that size as coarse as 13 tpi. Reach depth was limited as well. If you step your min. size up a bit it gets easier. For anything 3/4" or smaller I'd just use good taps and leave the single-pointing to anything larger...

iMisspell
04-11-2015, 06:08 PM
Is there a reason you want to single point something that small and not use a tap ?

the kid
04-11-2015, 06:14 PM
I see what your saying, the only reason I need the 1/2-13 is to do a left hand nut for a grinder, but I can grind a hss tool for that, the primary purpose of needing the carbide tool is to do some custom muzzle breaks and flash hiders for a friend and possibly some to sell as well, so nothing on those is as course or small of diameter, I used the 1/2-13 figure as it was the first to come to mind, I kinda need to make that but soon, but certainly not in Ti or stainless.

Forestgnome
04-11-2015, 06:22 PM
If you're not hooked on using inserts, a Micro100 carbide threading tool would be the ticket. Otherwise check out the Carmex kits. Pricey though. I've wanted a Carmex for a while, but now have a building colection of Micro100's. Either way you'll probably need to make a sleeve for your boring bar holder.

Ron of Va
04-11-2015, 06:44 PM
First, I don’t think any muzzle brake should be custom. Most correspond to the standard sizes for suppressors. Stick with those sizes. Make sure the threading is concentric to the bore of the gun, and not to the outside of the barrel. (But that is a different conversation)

Now in my opinion the best value out there is the Grizzly 5/16” internal threading tool H8302, which will go into a .433 size hole ($33). It uses a 08 size internal insert which can be had in a full profile, or an insert that will do a range of thread pitches. If you are going to do mostly the same pitch, get the full profile. You can get inserts on ebay in the $6-$8 range.

A smaller internal threading tool uses a 06 size, but the holders and inserts are much pricier. My favorite is the Carmex. I recently snapped a Carmex solid carbide holder in half ($200) in a blind hole. Made me sick. Check out page 945 in the MSC big book, under Ultra Miniature internal toolholders.

the kid
04-11-2015, 08:07 PM
Pardon my ignorance on insert tooling, I think I have holders that will work, I've got a criterion boring bar that I use often and I really like it, it's a ta500btxx 10118 whatever that means (from the wording on its plastic case) and also an enco 377-7010 boring tool that I've never used (forgot I had it, I never used it on my 9" or 10" lathes, it was just too large for the tool post but will fit my new 13" south bend nicely) both of these holders look to take the same insert, so, if the little criterion bar will be suitable the question becomes; what is the best insert to purchase? Any inserts I have or have used, including the holders, have been ones that came in a package deal (buying a box of tools) so I really don't know much at all about the various sizes and interchangeability, all I do know is that the one I've been using has lasted far longer and preformed far better than any hss boring bad Ive used. I wish I knew exactly the insert that's in the criterion bar, it's quite sharp, and cuts very nicely anything I've thrown at it, though mostly steel, I've not tried it on Ti.

Edit: I don't plan on making them custom oddball threads, I've yet to get the exact specs on the pitch ect.. That will be required on these, I simply know at this point I'll be tackling the project soon and need the appropriat tool to thread them, the barrels afaik are already threaded.

Rich Carlstedt
04-11-2015, 08:37 PM
Two items to think about
Can you do a 1/2-20 instead ?
You get better clearances and it is much easier to cut in hardened metals

Beware of carbide inserts for threading, as you mentioned doing a LH thread.
The reliefs may be wrong for such a thread

Rich

PS, I see you say the barrels are threaded already...too bad, not the best thread for the application IMHO !

the kid
04-11-2015, 08:51 PM
No no! The barrels are not threaded 1/2-13 left hand! I'm sorry, I had in mind when I wrote my original post the smallest thing I would be doing internal threading on and that's for a grinder nut that was lost, 1/2-20 and larger would be perfectly suited to my main intended application of this tool, my thinking was If it could do 1/2-13 than it could do the finer threads also needed for this application, I don't know the exact threads on the barrels in question yet, but I know they aren't going to be anything too exotic, in fact they should be all standard, but I don't know what exactly is standard on those, 20 to 24tpi sounds about right but I'm not sure at this time, I've not yet got the barrels in hand to measure.

vpt
04-12-2015, 07:13 AM
I needed an internal threading tool some time again as well. What I did, and it works just fabulous, is took a tap that had a few chipped starting teeth and ground off all but one full profile cutting tooth (just on one side to save the others for the future).

It works absolutely amazing! The relief is already there, all the cut angles are right, and the thread profile is perfect!

PixMan
04-12-2015, 08:15 AM
For short length of internal threads that can't be easily done with a tap, it's hard to beat the Micro 100 solid carbide tools. They last a good long time and can be resharpened on a diamond wheel.

That said, I have carbide insert threading tools that can get into holes as small as .280", and that one I've yet to use. In fact, I so rarely cut internal threads without a tap, only two of the 5 internal carbide insert threading tools I own has been used.

BTW, I thought the vast majority of threads on guns were 28 threads per inch, regardless of diameter. Is this wrong?

Forestgnome
04-12-2015, 08:46 AM
Pardon my ignorance on insert tooling, I think I have holders that will work, I've got a criterion boring bar that I use often and I really like it, it's a ta500btxx 10118 whatever that means (from the wording on its plastic case) and also an enco 377-7010 boring tool that I've never used (forgot I had it, I never used it on my 9" or 10" lathes, it was just too large for the tool post but will fit my new 13" south bend nicely) both of these holders look to take the same insert, so, if the little criterion bar will be suitable the question becomes; what is the best insert to purchase? Any inserts I have or have used, including the holders, have been ones that came in a package deal (buying a box of tools) so I really don't know much at all about the various sizes and interchangeability, all I do know is that the one I've been using has lasted far longer and preformed far better than any hss boring bad Ive used. I wish I knew exactly the insert that's in the criterion bar, it's quite sharp, and cuts very nicely anything I've thrown at it, though mostly steel, I've not tried it on Ti.

Edit: I don't plan on making them custom oddball threads, I've yet to get the exact specs on the pitch ect.. That will be required on these, I simply know at this point I'll be tackling the project soon and need the appropriat tool to thread them, the barrels afaik are already threaded.

Generally boring bars aren't interchangeable with threading bars. They hold the inserts at different angles.

Doozer
04-12-2015, 08:53 AM
.... but will fit my new 13" south bend nicely....

If you mean NEW as in bought from Papa Grizz,
please post a pic so we can drool over it.

Thx.
-Dooozer

Forestgnome
04-12-2015, 09:14 AM
Also note that you will spend more time dealing with springing cuts when threading if you use a steel-shanked tool. Threading has a higher cutting load than boring, so the bar will flex more. I always go for the carbide shanks.

Doozer
04-12-2015, 09:19 AM
...I always go for the carbide shanks.

Yes. This. And if you don't absolutely have to use inserts,
Micro 100 is nice way to go for that reason.

--D

PixMan
04-12-2015, 09:43 AM
I don't know if carbide shanks for internal threading tools makes a whole lot of difference in larger sizes with short depths of thread (and inherently shorter threading bars.)

Because I tend to use compound infeed, the cutting pressures are less, and chatter can be counteracted with the cutting edge geometry such as chipbreakers on the inserts. I do know that the 3/4" and 1" internal threading bars I have would be far beyond my reach and financial justification for the extremely rare occasion where I might have to make an internal 1"-12UN thread over 3" deep.

paul463
04-12-2015, 10:05 AM
I needed an internal threading tool some time again as well. What I did, and it works just fabulous, is took a tap that had a few chipped starting teeth and ground off all but one full profile cutting tooth (just on one side to save the others for the future).

It works absolutely amazing! The relief is already there, all the cut angles are right, and the thread profile is perfect!

I did something similar last week for an internal thread, but without grinding the tap. I needed 16TPI, so I put a 3/8x16 tap in one of my tool holders, squared it up to the work and let er fly. Worked great, you just have to make sure to back out the cross slide before you kick out the halfnut.

Ron of Va
04-12-2015, 12:09 PM
BTW, I thought the vast majority of threads on guns were 28 threads per inch, regardless of diameter. Is this wrong?
Most suppressors are -28 in the smaller calibers, rimfire and AR15’s.
Most large caliber centerfire rifles are 5/8-24, with some being 9/16-24.
Large caliber centerfire pistols are frequently .578-28, or sometimes M13.5-1.0mm left handed if it is a European handgun.
http://www.silencerresearch.com/AAC%20Barrel%20Threading%20Specs.pdf

But if you are making your own silencer or muzzle brake, and threading the rifle, it can be anything you want. I would just stick with standard sizes. At first I thought the OP was going to thread it 1/2-13, but he corrected that.

the kid
04-12-2015, 03:51 PM
So the carmex seems like it's the best made, the carbide shanks make me a bit nervouse that I might shatter one and at the price, that would be a sad day, the micro 100 looks like a pretty good buy, I've always thought of enco as kind of a cheapy brand but I've not had any personal experience with thier products so can't pass judgment, the enco boring bar I have is made in the usa, and visually looks to be of reasonably good quality, but I've never made a single chip with that one. Would there be any problem getting an enco or micro 100 holder and a carmex insert? The insert sizes have me a little confused, but I'm sure it will all start making sense in short order and I'll feel like a dummy for not figuring it out sooner lol


If you mean NEW as in bought from Papa Grizz,
please post a pic so we can drool over it.

Thx.
-Dooozer


Well not exactly new, though I've heard nice things about the newly produced south bends. This one is new to me, and it was factory new in 1922, I may make it look new again but am thus far undecided on whether to paint, I just got it drug home 2 days ago after its 2 week stay at my friends garage while I rearranged the shop to make room. It's a model 34-C 6' bed 13" swing and I believe 44" between centers, I wasn't really in the market but I ran across it and I just couldn't resist such a good deal, it's very well tooled and very complete, in fact as I've been doing research on it I think it may be one of the most complete lathes of its model left in existence, a genuine antique, and a major piece of my antique machine shop I've been slowly collecting tools for over the years.
http://i60.tinypic.com/24whkt0.jpg
More pictures and info on this lathe can be found on this thread http://www.practicalmachinist.com/vb/south-bend-lathes/very-nicely-tooled-complete-13-ca-craigslist-301233/
And this thread http://www.practicalmachinist.com/vb/south-bend-lathes/my-new-south-bend-34-c-302329/

the kid
04-13-2015, 06:56 AM
Ok Ive been doing more reading and looking around, I think I'm going to get an enco holder and use a carmex insert in it. In reading about thier various offerings it seems that the HBA type is the one I want, but I can't seem to find them for sale anywhere, I found some ad material for them published by carmex but no price and nowhere to buy the damn things!

So this is the holder I intend to get https://www.grizzly.com/products/Internal-Threading-Boring-Bar-5-16-Shank-Right-hand/H8302 And if I understand correctly then I'm going to need an 08 size insert for it. If I'm unable to buy the HBA inserts (made of unobtainium?) than which other inserts might I try for the machining of titainium? I've decided to rule out the micro 100, I didn't realize that they were a single piece tool (tiny picture on phone) I'd really like to use inserts as it just seems like a more practical way to go. Again please forgive my ignorance here, up untill now If I've needed a tool I just ground one, I never paid much attention to insert tooling and never bothered to learn much about it untill now, but I'm picking it up. One thing I find odd is that the inserts are rated for either right hand or left hand, with any hss tool I've had you could do either one with the same tool, is there a reason they make the inserts this way? Is It a gimmick to get us to buy more or what?

Ron of Va
04-13-2015, 07:54 AM
I understand carbide inserts will cut titainium, but I have never done it.

Carmex inserts are excellent, and so are Sandvik.
If you want full profile in 28 tpi, this is a good value for 5 inserts.

http://www.ebay.com/itm/5-Pcs-CARMEX-08-IR-28-UN-BMA-Carbide-threading-inserts-unified-/371236360811?pt=LH_DefaultDomain_0&hash=item566f69526b

If the description says 08 A60 BMA it means it will do a range of thread pitches.
08 is the size as in 5/16” (06=5/32; 11=1/4; 16=3/8; 22=1/2”)
A60 is the degree of the pitch
BMA is the coating that is for slow speed threading (not high speed as in a CNC machine)

Edit; The IR stands for internal right handed; IL stands for internal left handed.

Left handed threading is for the back side and the lathe would be run in reverse to cut right handed threads.

With inserts, I do not use 29-1/2 degree. I turn my tool post to 90 degrees and feed with the cross slide, not the compound. Especially true with the full profile, because when the depth is reached the inserts cuts the top off the thread. The crest and root will always have the same relationship, a perfect thread profile.

PixMan
04-13-2015, 08:26 AM
When you use the lay-down threading inserts there's a whole new world of terminology to learn. There are two basic styles, internal and external, and within those you can have left hand or right hand inserts. You cannot use a left hand insert in a right hand holder or vice-versa. The vast majority of holders and inserts will be right hand, as is the internal threading bar you are considering. On that bar you can use only 08IR inserts, though you can get several different options with them. You may use the generic 08IR AG60 or A60 inserts which are partial profile for a range of threads, or go with pitch specific full form "cresting" inserts for each thread pitch you cut. The latter gives you the highest quality burr-free threads.

The reason you can't interchange left of right is because of the orientation of the cutting tip in relation to the triangle. It may appear that an external left hand insert is the same as in internal right hand insert, but that is not so. The grind of the insert, height of the 60 tips isn't the same for internal versus external inserts. An internal left hand won't get a right hand external thread deep enough, and an external left hand insert on a right hand internal threading bar will rub in the wrong places.

I pulled out my internal threading tools yesterday and snapped a photo. You can see I have more right hand tools than left, and how the inserts on each would "point" differently. Does this make sense?

http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/IMG_20150412_201658_zpsqcpv8bqb.jpg

To complicate things further, once you get into larger sizes the holders have enough thickness below the insert to employ a carbide shim seat. The seat, or "anvil" can tip the inclination angle of the insert beyond the standard 1.5 to accommodate coarser or finer threads as helix angles change, and even tip the insert in the opposite direction so you can cut a LH thread with a RH tool. That is not doable without interchangeable anvils.

You can buy the pitch specific inserts for that bar in singles from several different sources, though Grizzly isn't one I'd use. I get the Vardex and Carmex brand inserts that way from KBC Tool or (for the 08IR) Travers Tool when I don't have the right one. You might start with 08IR-24UN and 08IR-28UN, for example, and get a couple of 08IR-AG60 for general purpose.

http://www.travers.com/miniature-ultra-miniature-threading-inserts?Category=cutting - indexables:298104||inserts:298111||threading inserts:298215||UserSearch=block id 106866 and class level3 id 298215||AttribSelect=Insert %23=08 IR 28 UN

Hope this helps.