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Thread milling tool recommendation for Job shop environment

cgmaster

Cast Iron
Joined
Jun 9, 2008
Location
Ocean Springs, MS
I am looking for a recomandation for a thread mill. Right now I need to cut 1"8un internal threads 1.5" deep however I have another job that I do fairly often that is 1" -8un internal thread 2" deep.

I have been using Xact Form thread mills TMH0075-88-21 with kc20c grade inserts but it seems like I am constantly chasing tolerances having to adjust tool comp every few holes and having problems with inserts holding up. I have not had much luck with Tech support either. I have just been given info already in the catalog.

For example the job I am on now I am cutting AR500 plate 1.25" thick. I am only getting about 10 holes per insert. I am running 1700 RPM = 330sfm and 2.5 ipm = .0014" per tooth. I have gone down to 1.7 ipm = .001" per tooth. Speeds I have tried have been from 1018 (200sfm)- 2200 (431 sfm). My stepover is .0153" and 3 passes.

In standard 4140 holes 1.75" deep I am getting about 20 holes per insert. I finally settled on 1440 rpm/ 282sfm and feed in at 3ipm and increase to 8ipm after a full revolution.

The inserts don't always chip at the front sometimes they chip at the back like it is rubbing.

To throw another curve someone put an insert in backwards yesterday morning somehow it held up and cut 15 holes in the AR500 before I caught it. ???

I have also had 2 of the screws for these holders break while they were in the hole destroying the thread mills.
 
I just always go with the recommended speeds and feeds the tool manufacturer recommends and go from their. I haven’t mastered threadmilling yet to say I use it without having to adjust the comp from time to time. Taking spring passes helps a lot but it does add cycle time. I hope someone can respond here to share some secrets that works for them.[emoji3]


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I don't have experience with your brand. We use Iscar (tools are made by the same manufacturer as Carmex threadmills too)

Googled your threadmill number, found the catalog. It says the minimum internal diameter is 1". What isn't clear is, does it mean the minor diameter? I think so.

Your threadmill is the same diameter as the drilled hole for your 1"-8, and I'd say that you do not have enough clearance. Try the smaller 3/4" diameter version of the tool
 
For pure job shop work, I have had good luck with the Harvey Tool single point tools. I think I bought three different sizes and the have covered everything I need to do from little to big. Some of them have run production for years on end in an endless variety of materials.
 
For pure job shop work, I have had good luck with the Harvey Tool single point tools. I think I bought three different sizes and the have covered everything I need to do from little to big. Some of them have run production for years on end in an endless variety of materials.
This! Ive done about 200 holes worth so far of m12x1.25 3/4" deep in 8620 and another 100 external m30x1.5 threads on 1215 parts with the same single point Harvey thread mill. Obviously it's slower than a multi flute thread mill, but as G00 said, 2-3 tools will cover all your internal, external, English, or metric threads instead of an entire drawer full of multi flute mills.
 
I do have a few Melin single point thread mills and agree they are good for short runs. But I have started using insert thread mills for some regular jobs since it speeds it up significantly.
 
when we thread mill harder materials, like Inconel, we use 2 threadmills, a rougher and a finisher. Cuts down on having to adjust comps after every part.
 
I've wanted to try the Harvey thread mills, but I've been very happy with Carmex stuff. I was thread milling Austempered Ductile Iron at 48Rc a few weeks ago with a solid carbide Carmex and no issues after 100-150 parts. After that we were cutting them in the as-cast state and just comping for the Austempering.

We've also used the Carmex insert blanks and EDM'd custom thread profiles for higher production stuff.
 
For pure job shop work, I have had good luck with the Harvey Tool single point tools. I think I bought three different sizes and the have covered everything I need to do from little to big. Some of them have run production for years on end in an endless variety of materials.

Harvey Tool rules![emoji23] I have yet to experiment with single point thread mills. I’ll have to dive in on my next project with the single. I’ve always used the scientific multi tooth ones.


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when we thread mill harder materials, like Inconel, we use 2 threadmills, a rougher and a finisher. Cuts down on having to adjust comps after every part.

Do you use an optical pre-setter to get a length offset to the crest of the first pitch or are you finding that the end to crest dimension consistent enough to just set off the end of the tool?
 
I've wanted to try the Harvey thread mills, but I've been very happy with Carmex stuff. I was thread milling Austempered Ductile Iron at 48Rc a few weeks ago with a solid carbide Carmex and no issues after 100-150 parts. After that we were cutting them in the as-cast state and just comping for the Austempering.

We've also used the Carmex insert blanks and EDM'd custom thread profiles for higher production stuff.
Where are you getting those? I'd like to try them as I've been very happy with their lathe threading tools.

Maybe Exkenna has them...

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From everything I’ve heard about AR500 it sounds like you’re getting exactly the tool life you should be getting.
 
Where are you getting those? I'd like to try them as I've been very happy with their lathe threading tools.

Maybe Exkenna has them...

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I can get them from my normal tooling guy (DXP Enterprises) or from MSC. With MSC I often have to call up my MSC tooling rep and have them do a quote for any of the specialty stuff like the insert blanks, and then from there I can click the quote to add them to our cart and usually have them next day since they drop ship from Carmex (who is local to me).
 








 
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