Machining Ti

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KC2IXE

KC2IXE

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Ok, I've seen threads here on drilling Ti, and milling Ti, and turning Ti, here's my question

For the first time, I want to make a couple of small parts out of Ti - I have a choice of Grade 2 (CP-2) or Grade 5

The parts are small. The larger part needs to be drilled and internal threaded the fit smaller - probably 5/16-24 or 3/8-24 (Interesting that the UNF for both is the same TPI - never dawned on me till just now)

The thing is, it'll be a blind, fairly short (say 1/4") internal thread (yuck - the works thing to do in any material)

Can Ti be tapped, or am I going to be stuck attempting to single point this? If it can be tapped, can someone recommend a tap? Will standard HSS taps work, or should I look for one of the exotic coatings (BTW the whole run is maybe - maybe 4 pieces, probably 3)

Thanks
Charlie
(It's good to be healthy enough to get back into the shop for the first time since last fall :twothumbs )
 
I would start out with grade 2, as it's a little easier to machine. You can tap the holes, but I would seriously recommend getting a thread forming tap instead of a cutting tap. I tap 1/8" deep blind holes with a 4-40 tap alot more than I care to. I started out using cutting taps, first HSS, then cobolt. This was ALWAYS a nail biting experience. After breaking a few taps in a Ti part I just spent 8 hours making, and having to spend $50 to get one of them wired out, I decided to take Barry's advice from here and try a Balax thread former. I should have took his advice sooner. The tap is MUCH stronger because there's no flutes. It raised my confidence so much that I actually enjoy tapping the holes now. I'm still using the same tap after ~40 holes. For titanium, the best tap coating is steam oxide/nitride. No one stocks this coating. Find an online Balax distributor, order online and Balax will drop ship it to you. I receved mine 3 days after ordering, but Balax is only one state away from me. For example, the part number you would want for a 3/8-24 bottoming tap would be 13624-016. The first 5 numbers is the tap part number, the last 3 are options. The 0 is no grooves, the 1 is to removed the front point for closer bottoming and the 6 is the coating. The part numbers and options are in the Balax catalog. If you're only drilling a few holes, you can get away with a cobalt bit, but be prepared to re-sharpen or have spares. The best thing would be to get a solid carbide bit. You can find them cheap on Ebay. Drill slow & hard...
 
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Heh, I wouldn't have thought that Ti would thread form, so...

I tlooks like MSC does stock steam oxide taps, but not in thread forming.

Drilling "slow and hard" has always been the way I was taught, so that won't be a problem.

Rumor has it that it's a lot like working 316 stainless
 
Both CP titanium & the alpha alloys are the easiest to machine (much like a difficult grade of stainless steel). The beta alloys are the most difficult to machine, and the alpha-beta alloys (like Ti 6-4) fall in the middle.

Can Ti be tapped
Click to expand...
Both CP Ti and Ti 6-4 have been tapped for many years. Balax recommends their Thredshaver Series BX400, which is a powdered metal, slow spiral tap designed specifically for difficult to tap metals (Inconel 625, Waspalloy, Ti 6-4). See page 28:

http://www.balax.com/catalog.pdf

Suggested tapping speeds for Ti are on page 67. They recommend about 5 - 7 sfpm for a cutting tap in a bline hole, about the same as everyone else, with as much coolant or lubricant as you can keep on the tap. For the sizes you mention, that's about 50-60 rpm.
 
precisionworks said:
Balax recommends their Thredshaver Series BX400, which is a powdered metal,
Click to expand...

That's strange, I spoke with Matt Finger at Balax several times about my requirements and he recommended the BXB series with the options I posted. Maybe this was the best option for me due to the small size I am working with. I would suggest giving Matt a call and tell him what you want to do. He'll tell you your options and recommend the best tool for the job. He can be reached at 262-966-2355 - Extention 114.
 
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KC2IXE said:
How are the OSG threadformers?
Click to expand...

I just tried one of the OSG taps I got on Ebay. It worked just as good as the Balax tap I have. It seemed to require the same torque and the threads look just as good under magnification...:thumbsup:
 
Mac,
For 4-40, I use a #39 bit. I haven't had a single problem. I start a couple of threads in the drill press turned by hand for guidance, then finish tapping by hand with a small tap handle. I rock back and forth, advancing ~1/8th rotation until the tap bottoms. I only use one drop of motor oil. I had 50% success with cobalt cutting taps. Broke quite a few. I'm still using the same thread forming tap after 75+ holes. The taps I have are a little different than the ones you got. Mine do not have a necked down shaft. PM me your address and I'll mail you one to try.

Jeff
 
JHanko said:
Mac,
For 4-40, I use a #39 bit. I haven't had a single problem. I start a couple of threads in the drill press turned by hand for guidance, then finish tapping by hand with a small tap handle. I rock back and forth, advancing ~1/8th rotation until the tap bottoms. I only use one drop of motor oil. I had 50% success with cobalt cutting taps. Broke quite a few. I'm still using the same thread forming tap after 75+ holes. The taps I have are a little different than the ones you got. Mine do not have a necked down shaft. PM me your address and I'll mail you one to try.

Jeff
Click to expand...

Jeff thanks for the offer. Does MSC carry the tap your using? I'd like to order a couple today for tomorrow delivery.

BTW your PM inbox is full.

Mac
 
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Sorry about that... PM box cleaned out now. The numbers on the tap are:
OSG 4-40 NC H3B HSS USA 093993, and they were advertised as having steam oxide coating.
Seeing how I got these cheap on Ebay, It may be a discontinued part number.
 
The drilled hole size was .1015.
Click to expand...
The size is correct ... the problem is that OSG does not recommend any of their formers for Ti :shakehead

Balax says that their standard Thredfloer forming tap will work if nitride steam coated & used with a tapping oil. The steam coating is somewhat porous & retains enough oil on the tap to overcome the friction of the tapping forces. The nitride coating is extra hard (70 HrC, about the same as industrial hard chrome) and is used in both abrasive & tough to tap materials.
 
it appears MSC does not carry what I need? That would be a first.
Click to expand...
Balax has half a dozen in stock at the factory. Call MSC, tell them you need Balax part #10723-016 (4-40, nitride steam coated, H3). Ask them to call Balax & have Balax drop ship today. Retail is $12.80 each.

That's a Series BXB bottom chamfer Thredfloer (pn10723) with nitride steam coating (-016)

MSC stocks only the bright finish 10723:http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1907381&PMT4NO=75030032
Or the TiN finish 10723-T:http://www1.mscdirect.com/CGI/NNSRIT?PARTPG=IMLMKD&PMPXNO=2623661
 
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I just ordered
MSC P/N's

02770782 Emuge 6al-4v tap $35 Emuge said these are good for 450-500 holes. 15sfm in and out.



64181688 OSG $19


Over $50 for 2 taps but there *for* Titanium.

Mac
 
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I spoke with Matt Finger at Balax several times about my requirements and he recommended the BXB series with the options I posted. Maybe this was the best option for me due to the small size I am working with. I would suggest giving Matt a call and tell him what you want to do. He'll tell you your options and recommend the best tool for the job. He can be reached at 262-966-2355 - Extention 114.
Click to expand...
Small world, Jeff. That's the same person I spoke with today - twice. Same recommendation, the -016 nitride steam coating.
 
WOW!

MSC #: 02770782

Emuge Rekord C-Ti

Cut's 6al-4v titanium like a regular tap cuts aluminum! Price of entry $35

Mac
 
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