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P.A.R.
09-22-2011, 01:27 PM
I have a tube 11.5x1.25x.065 wall Ti 3Al-2.5V I need to put a 28 tpi end to end.
My thoughts are mount it on my lathe and use a boring bar between centers to cut it.

TGTool
09-22-2011, 02:00 PM
I've used something like that and it can work. Plan for a way to either measure the amount of advancement of the tool with each resetting, or some way to advance it with precision. This is one approach from an article in Model Engineers' Workshop. Two different bars so parts don't match but the basics are the same.

http://i48.photobucket.com/albums/f244/TGTool/BtwCntr2.jpg

http://i48.photobucket.com/albums/f244/TGTool/P1010124.jpg

P.A.R.
09-22-2011, 02:21 PM
Design of tool feed was next thanks.I was thinking of using a 15%cobalt HSS with flood coolant.Thanks

franco
09-23-2011, 11:37 AM
Design of tool feed was next thanks.I was thinking of using a 15%cobalt HSS with flood coolant.Thanks

An interesting and easy-to-set-up way to feed a between centers boring bar using a boring head in the headstock spindle is mentioned in post #4 here:

http://www.woodworkforums.com/f65/using-between-centres-boring-bar-129635/

I have not yet tried it myself, but cannot see why it would not work for boring if there is not a lot of material to remove. For cutting a thread the disadvantage would be that the angle at which the tool is presented to the work will change very slightly slightly with each cut, but this would probably not matter with a thread as fine as 28 TPI unless great precision is required. If the tool is in the center of the boring bar it should advance by about half the reading on the boring head for each cut.

franco

P.A.R.
09-23-2011, 01:00 PM
No super precision its a suppressor tube "Legal" I'm glad I have found this sight Being a Machinist and Gunsmith I like to hear how to not cant do.

DICKEYBIRD
09-23-2011, 03:27 PM
An interesting and easy-to-set-up way to feed a between centers boring bar using a boring head in the headstock spindle is mentioned in post #4 here:

http://www.woodworkforums.com/f65/using-between-centres-boring-bar-129635/Here's a link to a thread on this forum where I did a similar process. It worked great! I've been itching to use it again but the opportunity hasn't presented itself yet.
http://bbs.homeshopmachinist.net/showthread.php?t=46359&highlight=LINE+BORE