[How do I?] Tapping 1.6mm thread in Grade 2 Titanium

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Mike Hulme

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Hi,
I have to tap 104 x 1.6mm threads through 52 pieces of Grade 2 Titanium. The pieces are 1.5mm thick and as yet have only pilot holes drilled through them., as they came from the makers.

Is it possible to tap these holes by hand and, if so what sort of tap should I use?

Any advice would be appreciated.

Thanks,

Mike
 
1.6 mm threads, tapped in 1.5 mm metal... that's not one complete thread. Or am I reading it wrong. (No experience in Titanium, so no help on the base question.)

For we retrograde Yanks, 104 mm diameter is just over four inches.
 
Sorry, I wasn't clear on what I meant!

54 pieces of titanium, with a thickness of 1.5 mm, need two 1.6 mm diameter threads tapping through them. They are the frames for concertina reeds. Here is a photo of them. The top of each frame is detached to form a clamp for the reed tongue, and has been pilot drilled. So the complete job is to drill the clamps to allow passage of 2 x 1.6 mm socket head bolt into a 1.6 mm tapped thread in the frame body (the larger sectionIMG_3228.jpg.534f0a85816010238ecd7d6b48eae0e7.jpg
with the slot in it)
I hope this is clearer.

Mike
 
Couple of issues. M104 x 1.6 doesn't show up in any of the thread charts I can find - M100 jumps to M105. Which make this some kind of special thread and implies a special tap (maybe possible but going to be expensive, not that a 4" tap wasn't going to be anyway). I too am titanium deficient, so tool life is unknown. I am wondering if faceplate and single pointing on a lathe wouldn't be an option. Most anything can happen for 1, 52 is another thing.
 
I think we have a communication issue (for us non metric guys). But to clarify, I think you want 2 tapped holes, per part, M1.6 - 0.35 (since by ISO convention if you don't specify a thread pitch we are to assume coarse thread series), in 54 parts - so 108 tapped holes total. I do know that small taps have a finite life before they break. In steel, a 10-24 tap will last for 52-54 holes before it is fatigued enough to break - it still looks good, but it is done. If you stop tapping at 50 and take it home because it still looks good, it will break in 2-4 holes. I would anticipate you will run into a similar issue - there will be a statistical life, stop a few short and toss the tap. You are trying to tap a through hole, which is good for chip removal and other things like being able to use a plug tap instead of a bottoming tap. Find the right tapping fluid, get a good setup to stabilize the tap handle, and count the holes to see what the structural limit of a tap is in titanium. Good luck, charge accordingly. I do wonder why the guys who made the pieces didn't tap the holes - maybe the knew something?
 
In my limited experience with that material outside work is rather simple, OD turning, OD threading grooving and so on is much like working on nickle alloy materials.

Inside work such as drilling, reaming and tapping are a different ballgame. I suggest taps made specifically for this application.
You will not like the cost at all. You may also have to go elsewhere to find the pitch that you require. This is merely a sample of products that are TI specific
https://www.emuge.com/products/taps/ti-taps/c-ti-metric
 
Thank you for your replies gentlemen. I should have been clearer in my earlier description!
The thread is 1.6mm x 0.35 coarse pitch, and I will be using a reversible tapping head to do the work. As the frames are already pre-drilled and are only 1.5mm thick I that I should be relatively safe from work hardening - I don't intend to "peck" as you might with drilling, and the clutch on the tapping head should kick in to prevent snagging (hopefully). I already have 10 of the correct size taps in HSS, so I can throw them away after a dozen holes each.
For coolant/fluid I was intending to use Moly D, but I have heard it mentioned that olive oil might be an option. Does anyone have an opinion on anything better?

GL - The guy who made them misread the worksheet. He was asked to make Aluminium frames!

Mike
 
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Tapping TI is not fun . Not fast . Damn near impossible ! Get the correct taps for the material , I suggest OSG or Guhring , and if using that tapping head , buy a lot of them . Acculube is what we used to use . Not sure if it's still available since it seems everything that worked got pulled off the shelves years ago . :)

Mike Hulme said:
The guy who made them misread the worksheet. He was asked to make Aluminium frames!
Click to expand...

That's an expensive " misread " . :grin:
 
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