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Thread: Making titanium pens
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5th Sep 2018, 08:34 AM #16Senior Member
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Baron,
trefolex is still sold as a paste (which melts quickly) - it is sold in a plastic container, but I heated mine up and poured it into an old anti-seize tin (the type with the brush as part of the lid) and use that .
in summer, the paste is a liquid about the consistency of cream, in winter it is a paste the consistency of toothpaste.
I will admit I've never used it on a hacksaw blade - I will now - thanks.
Des
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7th Sep 2018, 10:14 PM #17Most Valued Member
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I ordered one each of a 5mm and a 5.2mm solid carbide drill bit. I also ordered a mist coolant system to help keep the heat buildup down. I should be in a position to test it all out in a week or so.
Chris
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11th Sep 2018, 10:48 AM #18Most Valued Member
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While I'm waiting for my titanium, carbide drills and mist-coolant system to arrive I thought I'd make some practice pens in easy to work materials. I decided to make an aluminium body with a brass end cap. The pictured pen is my second effort. It's surprisingly heavy. A little too heavy. Wall thickness is 2mm. And the brass rear cap makes it tail heavy. It's very noticeable when you write with it. I find 10mm about as thick as I would want to use. My wife reckons it's too thick. It's really a desk pen as there's no cap, no pocket clip and it can't be retracted. Baby steps!
The manufacturing steps were:
1. Turn ali to 10mm diameter
2. Drill 6mm to appropriate depth to accept a Parker G2 refill.
3. Drill and tap M8 for end cap.
4. Part off, and flip pen body in chuck.
5. Drill 2.5mm for pen nib.
6. Set compound to 12 degrees and cut taper.
7. Cut grip grooves at 5mm centres with a 1.2mm wide round-ended grooving cutter. Remove pen from chuck.
8. Turn and thread brass end cap.
9. Using brass cap as a mandrel, screw pen body onto cap. Mount 2.5mm drill bit backwards in tailstock (shank sticking out). Insert drill shank into tapered end of pen. Drill bit supports end of pen.
10. Turn pen body and brass cap in one operation for seamless fit. Sand & scotchbrite.
11. Part-off brass end cap, flip pen in chuck (protect with electrical tape) and finish end cap.
I've been doing more research on titanium and I'm having my doubts about tapping it. Apparently it 'closes up' as you tap it and it jams the tap in the hole, even if you drill oversize. Some people suggest form taps instead of fluted taps. It may be OK hand tapping it though. Most of the discussion I've read has been about machine tapping. I've ordered some 10mm carbon fibre tube and 8mm titanium tube from eBay. The 8mm pens would need to use a D1 refill which is 2.5mm diameter for its full length.
One idea I have is to use the CF or Ti tube for the body and make threaded brass inserts which would be glued in each end of the tube. Then make a Ti tip and rear end cap to screw into the brass insert. The brass would be easy to tap and wouldn't be seen.
Pen 2 (2).jpgPen 2 (1).jpgChris
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17th Sep 2018, 03:40 PM #19Intermediate Member
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A friend of mine used to run a business making dental implants from Ti, generally grade 5 but some grade 2. All on one of three(!!) Schaublin 70s. He used exclusively HSS tooling, which he took great care to keep VERY sharp, sometimes giving them a lick with a stone half way through a cut if he felt that the edge was going away. He also used coconut oil when generating threads, at room temp (unless it's Summer!) this is solid, so he used a cup warmer to keep it runny.
He was very good at what he did.
cheers
Bill
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17th Sep 2018, 08:19 PM #20Most Valued Member
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Thanks for the info Bill. I wouldn't have thought of coconut oil. I think I'll start with the Trefolex paste first though!
A few previous posts mentioned using a larger tapping drill for less thread engagement. I found an online calculator that calculates drill size for any given % thread engagement.
OSG | Taps | End Mills | Drills | Indexable | Composite Tooling | Diamond Coating | Die ProductsChris
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28th Sep 2018, 04:07 PM #21Most Valued Member
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Here's my first titanium pen. Very basic- no cap, no pocket clip and not retractable. Basically it's a desk pen. It's 8mm solid Ti, peck drilled from each end with a 13/64" (5.16mm) solid carbide drill then tapped M6 each end. I used the mist cooler to blow the chips off the drill point with each 'peck' and to cool/lube the tip. It worked really well. It was flame coloured with a MAPP torch. I was aiming to get bronze fading to dark blue, but I overheated it in a few spots and it went lime green.
Tapping the M6 was nerve-wracking. I used Trefolex paste (geez that stuff stinks!) and started with taper taps. It would tap OK and then suddenly seize. I was able to back the tap out but there was no way the tap was going to cut any deeper. I'm going to order a form tap.
It's quite hefty despite being Ti. I can get 8mm Ti tube with a 0.9mm wall thickness, but tube is considerably more expensive than solid (no idea why). The 0.9mm wall wouldn't leave much metal for tapping either.Chris
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28th Sep 2018, 04:51 PM #22Golden Member
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I like the colours
Well done on the colours.
Was it easy to control the colours - ie stop and freeze the current colour by taking the flame away ?
BillLast edited by steamingbill; 28th Sep 2018 at 04:58 PM. Reason: added question
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28th Sep 2018, 10:52 PM #23Most Valued Member
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It was fairly easy Bill. It took a while for the initial bronze colour to appear. Once the colour started to appear the colour changes were fairly quick. I think I had the pen too close to the flame or too large a flame. Next time I will keep the pen further from the flame to slow the colour changes down.
I don’t think the colour continues to change after the flame is removed. I could polish the colour off and start again, but I’m happy with the result.Chris
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