Help with machining Titanium

Hi,

My wife lost her Titanium wedding ring on our trip to Wales and I would like to make her a replacement on my lathe. Has anyone had experience with machining Titanium?

I would like to know what is the best grade to get and also what type of tooling is best.

Thanks in advance for any help!

Stu

Stuart

I don't have vast experience with machining titanium but found best to treat it like 316 stainless, don't let the tool rub and I found with a small cnc lathe light cuts at low feedrates worked best using the G type inserts designed for non ferrous materials, turning 12mm rod 800rpm .20mm@80mm/min. No doubt others with more experience with Ti will be along with more info.

Take care with the swarf build up in the chip tray, it can be a fire issue.

Emgee

Hi Stuart,

I have tried machining titanium (an Ti alloy used to make bolts), and I too have found it best to do much the same as with stainless steel (like 316). If you have a flood coolant system, use it. As Emgee says, titanium may catch fire and burn. A metal container with dry sand underneath the lathe might be an advantage if the swarf catch fire. Good luck.

Thor

Hello Stuart,

Sorry to hear your story, your wife will take keen interest in your work to replace the loss.

There are Damascus grades of Titanium alloy that take on multiple swirling oxidation colours with heating after the machining work, otherwise the straight grades [available oddly enough from HPC gears] will still colour up but not in the attractive mixed form that jewellers achieve with the Damascus grades.

I did the machining work on two wedding rings for one of my grandson's and his wife, a dummy sizing run in the straight grade HPC material and then the proper rings in the fancy grade that Chris had found.

I think an intense localised flame like oxi/gas with immediate quenching gets the best colouration but there are also electrolytic methods I believe that might give deeper and more durable colours. Not a field I have any experience with.

As others have said, take care with the swarf; I fired mine outside later. As for tooling, ordinary tipped tooling will make as good a job as any other, nothing fancy is needed; Ti machines in a very similar manner to the stainless steels

Enjoy the challenge

Brian.

Edited By Brian Wood on 04/07/2021 10:18:21

For a ring Grade 2 would be my choice - it’s reasonably available. I’d get a piece in bar form unless you can find a tube.
Tools need to be sharp and the cut made without hesitation.
Rubbing in the cut will work harden and then your done for.

Making a ring a swarf fire is unlikely, but be aware of heat buildup.

Dave

Thanks everyone, that's some really helpful advice! Much appreciated as always!

Stu

Stuart,

I machine quite a bit of titanium for engine parts such as valve spring retainers, cam wheels, various spacers and also special bolts. I use almost exclusively Ti614 (6% aluminium, 1% manganese, 4% vanadium) which is a very tough and versatile alloy. I always machine it with HSS - carbide can be a pain as it will tend to rub rather than cut especially if light cuts are taken.

I endorse all that has been said about treating it in a similar fashion to Stainless. I too have seen the Damascus alloys and can vouch for their appeal - would make an interesting wedding ring.

The fire issue is overstated here I believe, only an issue if you have very fine swarf and a rubbing tool, which is not the way to machine titanium! In 40 years I have never had a titanium fire and only once with magnesium which was insignificant at the time (a bit of a sparkler on the tool!)

Martin

Some years ago a chap asked if i could make some rings out of titanium (8 in total all different sizes) he supplied the material 2 “ dia by 12 “

it machined very well only lost 2 due to work hardening problems..

they were to give to parents grand parents and god parents to his first born child.

after doing them to his satisfaction i tried very hard ( as an experiment) to set fire to the swarf to no avail..

Fast forward a few years and my niece brought a new suitor round for a family meal.and the chap had one of my rings on…he was a god parent to the child….small world

As already mentioned, sharp tooling is the way to go. If you are intending to use carbide, then the polished inserts made for aluminium, often called H01 grade will work well. If you have to drill a bar, a sharp drill, slow speed, high pressure and plenty of lubricant, soluble oil being preferred. Titanium conducts heat slower than most metals, so you must not allow it to get hot if possible. After drilling a pilot hole, let it cool down before enlarging the hole. Tube would be the best option if you can get some of the right size. If you can get tube, make a plug to go in the part within the chuck jaws so you can get it nice and tight without distorting it.

Sharp tooling also minimises the generation of heat on cutting, which I think may be due to its toughness and the reluctance with which the chip parts from the parent material.

Given sharp tooling, it's quite straightforward to machine much as you would medium-carbon steel as far as speeds and feeds go.

I'm interested to hear about the Damascus grades - I didn't know of these and have generally used grade 2. It blues nicely:-

Edited By Mick B1 on 04/07/2021 14:59:21

That's some great feedback, thanks again everyone!

One thing though, we had matching wedding rings and they are a polished silver finish, I'm presuming that is the natural finish of Titanium once it is polished up?.....

Titanium is naturally silver colour, but can be anodised at different voltages to give lots of different colours.