threading 304stainless

[dudesmpd]

I am trying to thread some 304 stainless tubing
I have to thread each end of 4300 pieces(8,600 threads)
its a 3/4 x 16 thread in an .875 tube
right now I am single point threading them and getting around 20 pieces per tip
(3 tips each insert=60 pieces)
does anyone have any suggestions to increase my tool life ?

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[PixMan]

First I need to be clear on what you're actually doing.

Are you single-point threading an INTERNAL thread in these 7/8" (O.D.?) tubes?

What machine are you using, how are you holding onto the parts, what tool holding systems are available for use?

If threading the I.D., there are some taps that would definitely out-perform the single-point threading.

[dudesmpd]

Thanks for replying...I'm getting desperate
Yes...the thread is an ID thread
Yes....I am single point threading it with a Vargus threading bar and inserts
I started by using a Citizen swiss lathe with no luck on tool life
I switched to roughing the parts in the Citizen and putting the parts in an Okuma lathe and threading them end for end.I am chucking on the end of the piece with about an inch protruding from the jaws.There is no chatter problems but a lot of chip build up.We have an abundance of tool holding options,but the problem is not there,but in the insert breaking down.
I am lucky if i get 10 to 20 pieces per insert tip(over the course of 4300 pieces-that means a lot of sorting for bad parts)
I appreciate any help i can get

[PixMan]

If you can use a tap with a Ø.590" (15mm) shank and have either a floating tap holder or rigid tapping on the machine...

Call Walter USA to find out who your local distributor is if you don't already know. There's a Protoyp (a brand sold under the Walter Tools umbrella) tap that comes up using their "TEC + CCS" software that I have that shows it'll do approximately 1453 holes per tap. The taps are most definitely NOT cheap with a $131 list price, but I've used themn with that software and they work.

You can order through your local Walter/Titex/Prototyp distributor on a guaranteed test order. It should make that many holes, and they'll guarantee it within 10%. Would you be still making more parts faster (and hence, more money) if you only got 1300 holes per tap?

The tap spec from the software is:

Prototex ECO-HT AE2326002-UNF3/4. EDP#5582470

Run it at 214rpm, 13ipm, 13.2 seconds per hole, needs about 37 lb/ft of torque. Your Citizen can't hold a shank that size unless you make something up yourself, and even if you did I don't think it would have enough torque. I threw a depth of 1" into the software, and a $100 per hour rate to give me the time per hole and cost per hole (at full list price) of $0.58 each.

BTW, the tap drill size that the software is calling for is a .689" diameter. That's a 17.5mm, and the Titex "TEC" software recommends A1149XPL-17.5 EDP#5236398

[leggazoid]

YouTube - AdventTool's Channel

[PixMan]

I had considered suggesting thread milling, but the fairly large-diameter solid carbide mill needed for an internal thread would be several hundred dollars and a bit risky with indefinite tool life. Also, those cutters are usually a coolant-thru design which feeds through the end of the tool. I a long tube application the coolant wouldn't be able to flush the chips out as well as it would in a blind hole. recutting chips shortens tool life immeasurably.

If the machine has the capacity to do it, it would be faster than tapping and require much less torque.

[dudesmpd]

My citizen doesnt have live facing tools so i cannot use thread milling
I am going to try the tap you suggested
In the mean time,I had a cobalt tap that i was going to see how many parts i could get.The tap got pulled out of its sleeve after 3 pieces and I got a nice crash when the next tool tried to enter the part.not sure if the tap stuck from heat or the collet nut got loose....Anyway,my headaches with this job continue!
I greatly appreciate the advice and time you have given me.I dont get any support in my shop when it comes to issues like these,just "where are my parts?"