er 11 inserts

i have a small lathe and i thread from the shoulder out i would like th buy a internal and external 11 sized laydown threading insert tool holder holders that way i can start the threads int or ext at the shoulder and thread right hand threads backwards but i cant figure out what 11 size inserts to buy 11er 11ir i just dont know any help would be appreciated

le3045 said:

i cant figure out what 11 size inserts to buy 11er 11ir

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11ER are for cutting external, right-hand threads. 11IR are for cutting internal, right-hand threads.

Generally speaking, you are going to need two toolholders. One for internal, and one for external. The toolholders for laydown size 11 inserts are frequently too small to take proper helix angle shims, but that's another part you should be aware of if you ever go to a larger size of laydown inserts.

Laydown inserts are available for practically any thread form used commercially in the last 40 years. So, what kind of threads are you cutting? Standard 60 degree threads? British (also metric pipe) 55 degree threads? Full ACME threads? Stub ACME threads? For now let's assume standard 60 degree threads.

You can buy inserts designed exactly for one pitch, or you can buy inserts designed to cut many pitches. The advantage of the single-pitch inserts is that you get both root and crest properly formed, so they are called "full profile". The advantage of the multi-pitch inserts is that you don't buy as many different types of inserts. The disadvantage of the multi-pitch inserts is that they cut a very small root (may not comply with customer requirements, may be bad for part fatigue life) and don't cut the crest at all. In fact, they are called "partial profile". If you want partial profile laydown inserts, look for "11ER A60" or "11IR A60". Those will cover the range of 16-48TPI (0.50-1.5mm pitch). You want coarser threads, you need a bigger insert size. You want finer threads, you need a full profile or a custom insert.

Really, I gotta say, if you know what thread you want to cut, the question of "what size 11 laydown inserts do I buy" practically answers itself. There are three possible outcomes:
1) Not possible to cut that thread with a size 11 insert,
2) Use the partial profile insert 11xx A60, or
3) Use the full profile insert 11xx yyyy.
That's pretty much the only choice you have to make, unless you want to fuss over insert coatings, chipbreaker styles, etc. But those fussy details aren't questions of size.

Threading small holes in a small lathe, use a tap. Way quicker and more reliable. I run taps in my manual lathe quite successfully. Drill it out, chuck up the tap in the tail stock and run it in. Don’t lock down the tailstock, let it float. Put some teflon tape on the tap to mark your final depth. When it’s close, stop the spindle to give it a chance to wind down, then reverse it out.

sfriedberg is right on! You will need different Laydown Size 11 Inserts for Internal and External Threads and for economy the A60 Partial Profile Inserts would be the way to go on the front end. They will allow you to thread 16-48 UN Threads (0.5-1.5 ISO) giving you versatility with 1 insert. If you have specific thread sizes in higher production then you can look at full profile inserts to top the thread.

What is the shank size on your lathe? The size 11 External Holders are only available in 5/16" or 3/8" Square Shank. If you need a shank 1/2" or larger then the best bet would be to go with the Size 16 inserts for you external turning. With the Size 16 you can get a AG60 Partial Profile Insert that goes from 8-48 UN Threads and there are Kits available that include a Holder and 10 Inserts to get you started both for internal and external, here is a link to them:
External Size 16 Laydown Threading Kit
Internal Size 16 Laydown Threading Kit

The Size 11 Internal Boring Bars are available in 3/8" Diameter x .470" Min Bore and 5/8" Diameter x either .580" or .640" Min Bore, would either of these work for you? If you are looking at smaller holes then a tap is the way to go as Spruewell suggested.

If you would like more information on any of these items let me know!

Mike

le3045 said:

i have a small lathe and i thread from the shoulder out i would like th buy a internal and external 11 sized laydown threading insert tool holder holders that way i can start the threads int or ext at the shoulder and thread right hand threads backwards but i cant figure out what 11 size inserts to buy 11er 11ir i just dont know any help would be appreciated

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fellas i understand but im using these for myself and making items that have not got a standard size i may make a piece that is .538 and need to thread it 24 or 28 or 32 tri and make the part it screws into along with it i just need to know what the tool holder for left hand internal threads is and what part number for the inserts for left hand and also need to know what the part number for left hand external thread tool and insert number also

le3045 said:

i just need to know what the tool holder for left hand internal threads is and what part number for the inserts for left hand and also need to know what the part number for left hand external thread tool and insert number also

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Well, then, get yourself a catalog and look those things up. Be aware that toolholder and insert numbers are only "mostly" standardized across the industry. Therefore, the numbers for Vardex toolholders and inserts might not exactly be the same as the number for Iscar toolholders and inserts.