The short version is that this is a reasonably straightforward DIY project, with a bit of patience and a vise, as well as a 3-56 hand tap, a tap wrench, and some oil.
First off, I can't take credit for the idea of altering Boye Needlemaster tips so that they can be used with the Knitpicks Options set. As far as I know, that honor belongs to Fleegle of the Knitter's Review forums.
After reading posts on KR by Fleegle and CalamityKat about converting Boye Needlemaster tips to take the Knitpicks Options cables, I knew I wanted a set. (The links go to blog entries detailing their adventures in needle tip alteration.)
Why do this? The Boye set has a number of sizes KP doesn't. It turns out that the Boye 6,9, and 10 tips are different from the KP equivalents, but more importantly, the Boye Needlemaster includes size 2 and 3 tips. I'm a loose knitter, so the fact that Options only go down to size 4 is a big downside to me.
More importantly, of course, I wanted to try it because it was there. :-) After reading the blog entries I Googled taps and discovered that (1) you can tap with hand tools and (2) taps and tap wrenches are actually quite cheap. This lead to that most seductive and dangerous of thoughts: "Hey, I could do that myself!"
Whenever I think that, I know I'm headed for trouble, but somehow that never seems to stop me.
I went online and after considerable Googling found an online store that sold both 3-56 taps and 2-56 dies. (Many thanks to CalamityKat for listing the sizes that her father used on her website. In case anyone is curious, the first number apparently refers to the size of the hole or screw, the second to the density of the threads.) Taps are the tools that you use to put threads on the inside of holes, and I planned to use the 3-56 tap to enlarge the holes in the Boye tips to take Knitpicks cables. Dies are the tools you use to put threads on the outside of cylinders, and I planned to use the 2-56 die to cut the threads on a Knitpicks cable down to fit into the Boye tips. The reason I wanted to try this is that both CalamityKat and Fleegle suggested not trying to tap the size 2 Boye tips, as the size 2 tips are only a tiny bit larger than the Knitpicks cable threads. As I mentioned, having the size 2 tips was one of the reasons I wanted to undertake this project. So, trying to cut down the cables to fit the needles seemed like it might be better than trying to enlarge the needle holes to fit the cables.
I bought myself a 3-56 taper tap (taper taps are used to start tapping), a 3-56 plug tap (a general-purpose tap), a 2-56 die, a tap wrench, a die handle, and a 2-56 plug tap and a few small drill puts to put me over the $25 minimum order.
Here is the die, the die handle, and the two 3-56 taps, one of which is in the tap wrench.
I ended up waiting to try my new toys until I was visiting my parents over Christmas: that's when I had the time, and it meant I could get suggestions from my engineer father. Also, my father has a lot more vises (as opposed to vices) than I do.
First, I took up a Knitpicks 32" cable and my die. Immediately we encountered two problems. First, no matter how tightly we clamped the vise, the cable insisted on rotating in its grip. Two, we couldn't get the die to start cutting. The first problem was easily solved by putting the Options key tool into the cable before clamping it in the vise, preventing the cable from rotating. The second was solved with more difficulty by using a Dremel tool to give the tip of the cable post a slight taper so it fit more easily into the hole in the middle of the die. (A file would work for this, too.)
After some effort, we had success, of a sort. The Knitpicks cable fit into the Boye needle tip, but it was hard to get the die started straight, and the die left a rough edge at the bottom of the post that needed to be ground down with a Dremel tool to obtain anything like a smooth join.
Discouraged, I got out one of the Boye connectors (chosen because they are cheaper than the tips) and tried the tap. I encountered the same problem with the connector wanting to twist in the vise, and solved it the same way -- by putting the key into the connector. Success! It turns out starting the tap is much easier than starting the die, and the taper tap isn't really all that necessary -- the hole in the needle tips are extra-large at the very top, meaning it's perfectly easy to start with the all-purpose plug tap. If I were to do buy taps again I would probably get either just the plug tap, or the plug tap and a bottoming tap (meant to cut threads to the very bottom of blind holes).
I guess I should have guessed from the fact that none of the people who knew what they were doing tried cutting down the cables instead of re-tapping the needle tips that re-tapping the needle tips was the way to go. Live and learn.
After this success, I moved onto the tips themselves. The tips don't have a place to put the key tool and I was uncertain how to keep them from rotating until I remembered what CalamityKat said about using a jar opener to protect the tips from the vise. My parents don't seem to have any jar openers, so I used the gripper that came with my Needlemaster with great success. The gripper kept the needle tips from rotating in the vise until the tap reached the bottom (at which point nothing could keep the needle from rotating -- which is actually useful, since it keeps the tap from jamming and maybe breaking when I hit the bottom of the hole). I will say, though, that while the gripper is still perfectly functional it emerged from its adventures quite a bit the worse for wear. I suggest being more patient than me and buying a jar opener.
I noticed that the connector I'd successfully tapped was really no larger than the size 2 needle tips and I decided what the heck -- I'd go ahead and try tapping the size 2s anyway. Besides, I had picked up a spare set of 2s at Hobby Lobby, so they seemed like a good place to start -- if I ruined the ones that came with my set, I had extras. I don't want to contradict Fleegle and CalamityKat, and of course I don't know yet how well they'll hold up in the long term, but in terms of the actual tapping I had no trouble tapping the Boye 2s.
I had been worried about breaking the tap off in the needle tips -- this is apparently a big problem with small taps and would ruin the tip as well as the tap, since the broken tap is evidently nearly impossible to remove. Maybe I have a knack for tapping or I just got lucky, but I had no problems with the tap whatsoever. I used plenty of oil (you can buy oil specifically for cutting, but I used some "Liquid wrench" oil my Dad had around, and I think any light machine oil would work -- I've even seen some websites claim vegetable oil works) and got into a nice "half turn in, quarter turn back" rhythm. (According to the Internet, the quarter turn back is necessary to loosen the metal shavings and the tap will break if you don't do it frequently.) My father suspects breaking the tap is a bigger problem when you tap steel, rather than the softer aluminum the Boye tips are made from. (I wonder if the tips tendency to rotate in the vise if the tap encountered resistance also helped.) I went ahead and tapped a few more connectors, both pairs of 2s, and sizes 3-10 and 13 of my Boye set. I didn't tap the 10.5s or 11s because I rarely use those sizes and was heartily sick of tapping -- I can always go back and do them later if I need them. I only did the 13s because I don't have the Options 13 tips.
One problem I had was that I found that after tapping the needle tip, I had to thread the tap back into the tip by hand (not using the vise or the wrench) several times before the cable would screw all the way to the bottom smoothly. Some tips only needed this treatment once or twice, some needed it several more times, a few I put pack in the vise and tapped again. I don't know why this was. In the case of the ones I had to re-tap, I suspect I just didn't go in far enough the first time. I think that the metal shavings from the tapping process may have also had something to do with it: after screwing the tap back in by hand, the tap usually bought a lot of metal shavings with it when I took it out. I wonder if the holes weren't just getting too clogged with the metal shavings for the cables to screw in easily and screwing the tap in by hand helped clean the hole out.
My Boyes don't seem to match up with my Knitpicks cables as perfectly as the Knitpicks tips do, but they match up close enough for government work. The issue is that the Boye tips taper a bit more at the cable end than the Knitpicks ones. I'm guessing that if it turns out to be a problem I can use my Dremel tool to take the very end off the Boye tips, but I'm not going to try that unless and until the difference bugs me:
One of these days I want to order a second set of the Boye 3 tips (the Hobby Lobby near my parents didn't have any and I don't have Hobby Lobby near me) and tap those, too.
One of the things CalamityKat wanted to do with her conversions was to fill in sizes that neither Needlemaster nor Options come in. I was interested to read on her blog that the Knitpicks fixed 2s and 3s aren't the same size as the Boye 2s and 3s: The Boye 2 is 2.75mm, the KP 2 is 3.00mm, the Boye 3 is 3.125mm, and the KP 3 is 3.25 mm. Then, of course, there's the big hole between US 10.5s (6.5mm) and US 11s (8mm) that could stand to be filled. I'm of two minds about both these gaps in the Boyepicks set. I'm a wee bit skeptical that the 0.125mm difference between the KP 2, Boye 3, and KP 3 is really that important -- but on the other hand, I've been wrong before (a lot). I suppose it could be useful for fiddling with gauge and it falls in a part of the size range that I actually use. The gap between 6.5mm and 8mm is huge, but as I said, I'm a loose knitter and I can't think when I've used needles bigger than 10 for something where gauge actually mattered.
At any rate, it may not matter. Tapping Needlemaser tips, which already have holes in them, turns out to be easy. Drilling holes in needle tips that don't have holes already may be more problematic. It's not the drill bits -- drill bits that size cost less than $1 and I bought the appropriate sizes when I ordered the taps just because I could. It's a matter of getting the hole to go perfectly straight into something that's not very much bigger than the hole itself is. I don't know if the holes that the cables of the fixed Knitpicks needles fit into are deep enough to provide a sufficient guide when drilling by hand, and a drill press would have to be very precise to drill down into those KP 2s. (I actually wonder if drilling them without a press using the cable holes to guide the drill bit might work better than using a press.) I might be better off just buying a set of the fixed KP 2s and 3s and not trying to convert. Although, the small fixed Knitpicks needles ARE cheap... and my father does own a drill press...
So, that's my Boyepicks adventure. I'm pleased to report that tapping your Boye tips is a reasonable DIY project for anyone who has a bit of patience and owns a vise: the tapping is a bit tedious but not difficult once you get the hang of it. I suggest doing it someplace with a TV or some nice music (both of which my father's workbench sadly lacks). You'll also need some oil, a tap wrench (I got a T-style wrench) and a 3-56 plug tap (maybe a bottoming tap, too, but you really seem to only need the plug tap.) The place I got mine has a $25 minimum order. That was OK for me since I was buying the die and die wrench (which are still pretty cheap, but quite a bit more than the tap and tap wrench were). However, the die turned out not to be useful, and you're not going to hit $25 just on the taps unless you happen to need some other hand tools. :-)
A Google search suggests that the same company sells the tap I bought through the Amazon marketplace, as well as a wrench that I *think* would work, though it's a more expensive model than the wrench I bought. I don't know but it's possible the minimum order doesn't apply when you shop from them through Amazon (in which case I wish I'd discovered that before, hee.) It's worth asking, at any rate. I suspect a little Googling will turn up other options. Note that you probably want to look specifically for hand taps, not machine taps, and apparently DON'T want a "spiral point tap" which shouldn't be used to tap blind holes like the Boye tips.
I'm afraid I meant that to be concise and helpful, and instead it turned out to be long and rambling (though I hope still helpful).
(Crossposted to the Knitter's Review forums. My understanding is that's OK since KR isn't a LJ community. Just thought I'd let you know so that if you've read it there, you don't need to read it again here!)