Machining titanium

I want to reprofile the heads of some existing titanium valves to fit them to a smaller head. Have never worked with this material. Any hints??

Titanium work hardens very easily. Light or fast cuts are not advised.
David from jax

chips have to be the same color of material.

If they come out different colors, youre doin' something wrong.

Whatever tools your using.Make sure to check some surface footage speed and feed guidelines before proceeding.As long as you stay in the proper parameters for feed and speeds you should have no problem.

I threaded some 2" pipe , type 2 not long ago and all went well...Not at all what I had imagined

Here is a link about its properties, since I must of offended someone with my previous post:
http://www.supraalloys.com/Machining_titanium.htm

I have been cutting titanium for 20 to 30 years, both milling and lathe. Great nmaterial and fun to cut. My rules are to use only sharp cutting tools and replace them the minute they get dull. Use coolant (brush if doing it manually)and watch the chips come of, thin chips similar to aluminum.

You cannot take of large amounts of material per tooth, but you can use the cutting diamter of the end mill same as in aluminum, only you need to go slow speed and figure .002 chip thickness per tooth.

The slow speed of cutting titanium may drive you nuts, and you may be tempted to push it when it appears to cut easily, but if you try to overcome it you will go home without having had a productive day. If you found a way that it cuts, leave it alone and don't try to improve it. Watch the process closely all of the time (don't walk away) and change tools immediately when they get dull.

I like cutting titanium the best of all the metals. absolutely no problems if you have sharp tools and go slow.

"Titanium work hardens very easily. Light or fast cuts are not advised.
David from jax"

Sounds to me you tend to use somehwat dull cutting tools.

When titanium work hardens, there is no way to cut it out even with a coablt end mill, you need a carbide end mill and then you can throw away that end mill and use th next new one to continue getting out the work hardened area.

Titanium does not work harden as long as you sue sharp cutters. You have SERO problems cutting titanium as long as you use sharp cutting tools.

The very second you have problem, you also have a dull cutting tools, and the very second you have a dull cutting tool you also have problems.

You should always take light cuts only. Even less than .001 or .0005 will come off with a sharp cutting tool. If it doesn't come off, you no longer have a sharp cutting tool.

Simple rules.

I forgot to mention: cobalt end mills seem the best to use on titanium, not to say the only thing.

On lathe carbide inserts are great. Trial and error will find you the best insert. Price has nothing to do with it. I always ground the round corner sharp on a diamond wheel. In these days, they may have some well cutting carbide inserts for titanium, I don't know what they have.

I worked on the F-14 wing pivots using 2by8ths, milled bulkheads for the space station using 2bysixes and wing spars for the latest fighter jet and did the first 500 radome rings for the phoenix missile (subcontractor) from titanium on the lathe for Hughes about 25 years earlier. Great stuff to cut when you are an employee and have all day. Now most of that can only be found in a museum. So, there may be better tools to cut titanium by now. But these are the basics, nonetheless.

Don't know if you are trying to re-cut the radius under the head or just reduce the diameter of the head. Valenite carbide grade VC-2 is what I have used to cut lots of Ti and watch the coolant to be sure it is working OK. DON'T use ceramic inserts. Good luck. -BW-