Thread: Titanium Bolt-action Pens

Wow

Firstly I’m not really into bolt action pens.
But there amazing how,were did you get all the pieces.
Are they a kitless pens or a kit or a hybrid.

Cheers Matt.

That’s taking your penturning to the next level up Jack, well done Mate. There’s attention to detail everywhere I look.
Just one question, why did you go with anodised barrels and not heat the titanium to get that multi coloured look ? I am not saying there’s anything wrong with going that way, and it has the benefit of making each pen alike and more uniform looking, and probably gives them a more high-end look.

I have got a length of titanium tube that I bought years ago with the intention of making some pens with it, hopefully I will get around to it one day.

Thanks Gents.

The barrels are 10mm OD x 8mm ID Ti tube. The ends are bored to 8.3mm with a solid carbide boring bar then tapped M9x1.
All the other parts were made from 8mm and 10mm round Ti rod and 11mm round Damasteel rod.
I went with anodising rather that heat colouring for exactly the reason you suggested Ironwood- a classier look. I've done heat-coloured Ti pens too and they look great. Just not the look I was after this time.

Some more pics.

Sorry about the multiple posts. The forum is giving me grief tonight.

Thanks for the extra info and pics, I find it very interesting. Did the titanium give you any trouble with machining it ? I see you mention carbide tooling.

With my tube, I had intended to take the simpler route. I was planning to use a commercially available pen kit, and machine the inside diameter out to match the kit components, the OD is 12 mm and is close to the size needed for the kit I had in mind.

Originally Posted by Ironwood

Did the titanium give you any trouble with machining it ?

Yep! It can only be drilled successfully in the home shop with solid carbide drill bits. It just destroys HSS and Cobalt drill bits. You will need a solid carbide boring bar to bore it out and even then you will only be able to bore to a relatively short depth. This is what I used: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I got it cheaper than that when it was on special.
The problem is Ti has only ¼ of the thermal conduction of steel, so the cutting tool ends up taking a lot of the heat.

That’s good to know, thanks.
I see they have similar tools for single point thread cutting, did you use one of those also ?

I have a range of solid carbide straight fluted drill bits, from 1/8th up to half inch, but there are some big gaps between the sizes , the boring bar you linked would be a better option to do what I wanted to do.

Nicely done. When I saw the title I almost didn't look because I'm not a fan of the bolt action kits but I'm glad I did.

I've never worked titanium but had the opportunity to pick the brains of the machinists that did. The one thing I came away with was that you had to be cutting metal and not rubbing. When that happened it would instantly work harden and destroy the cutters. So no creeping up on the dimension like we do with steel or aluminium.

Pete

Originally Posted by Ironwood

I see they have similar tools for single point thread cutting, did you use one of those also ?

No, I used an M9x1 HSS tap I bought on Amazon. It worked well because the starting hole was 8.3mm which is a little larger than normal for a 9mm thread. That's no problem for a pen though. The tips screw in nice and snug.

Originally Posted by QC Inspector

Nicely done.

I've never worked titanium but had the opportunity to pick the brains of the machinists that did. The one thing I came away with was that you had to be cutting metal and not rubbing.

Thanks Pete. That's certainly true if using HSS. I machined the concave in the rear end cap with a HSS form tool I ground up and it cut really well. The trick was a sharp tool, cutting fluid and keep it cutting, but not too hard. The solid carbide is much more forgiving. I was able to creep up on the dimension when I bored the tube out to 8.3mm.

It could have been the alloy we used (Ti6Al4V) but they only used carbide and I've seen enough solid and insert cutters completely destroyed to know that it does happen. When it happened during roughing they were sometimes able to salvage the part by recutting under with a new cutter as long as there wasn't much imbedded carbide.

Sorry for the hijack
Pete

Not a hijack at all. Thanks for the input. From my experience external cuts aren't too bad because the swarf can carry some of the heat away and you can apply some form of cooling. It's drilling and boring that are more demanding. Both require frequent withdrawal of the tool to remove the swarf and apply lube/coolant.