Extending threads on threaded fork
 

Is this a pretty easy/cheap thing for an LBS to do?

I'm looking to get a replacement fork for my 1" headtubed bike, but I'm having a heckuva time finding one with the right length of steer tube and threading.

It's not generally a big job unless the steer tube has chrome on it. Use a piloted die if at all possible to keep the threads on axis.

Park and Hozan both make 1 inch x 24tpi cutting dies with a tool to cut/chase more threads on a threaded steerer. I bought a nice replacement Tange Prestige CrMo fork from one shop and needed a few cm threaded and he did that for free because I bought the fork there. I don't know how much other shops might charge. But just to throw something else into the mix, have you looked at going threadless?

I've replaced fork with both threaded and threadless, and found that going threadless, with, say, a low-cost, Ritchey 1" threadless headset will only cost about $20, and you can get a low cost 1 inch steerer fork, (e.g. for rigid front MTB/Hybrids, the Dimension 1-inch threadless steer fork is quite affordable). Then get a 1 1/8" threadless stem plus buy a 1-inch to 1 1/8th inch shim that is long enough for the stem stack height. Cut the steerer to the proper length for your preferred extension, and get some 1 inch headset stack spacers. Punch the right sized star nut into the steerer and install, and you should have a nicer setup that is easier to adjust and even maintain when you're on the road.

My problem was that with my weight/size, the top threads on the fork were constantly wearing and popping and the headset would get loose because that top headset lock nut isn't exactly got a lot of thread races on it. Threadless solves this problem by virtue of a superior clamping design that doesn't budge and grips the steerer tube, orthogonal to the bearing pressure/preload exerted by the starnut/headset cap and spacers. Just a thought.

I cut threads down, several inches on my Touring bike fork.. ,
It's got a stack of the brake housing hanger, spacers, one I brazed an old bell on it,
and locknuts..

needed a bit of welding on the headtube, in Ireland, so I had my own headset press
handy, then.

Yes it can be done and it's not a terribly difficult job for a properly equipped LBS to EXTEND existing threads. (not to thread a threadless steerer). However, consider gyozadude's recommendation to go threadless. A new headset, fork and stem are the main components you will require and, as noted, both installation and adjustment are easier and there is some weight savings.

+1 for going thread-less. I got a Ritchey 1" threadless carbon fork from Excel Sports in Boulder to put on my old-school Dean Ti road frame. I already had a relatively new Chris King GripNut headset on the bike, so just needed to move the crown race (aka "baseplate") from the old, threaded fork to the new, threadless one, the $40 Chris King threadless conversion kit, some 1" spacers, the aforementioned shim to adapt a 1-1/8" stem to the 1" steer-tube and I was set. Quick job, even with cutting the steer tube on the new fork. I really like the fork and the conversion shaved 6-8 ounces off the bike to boot!

I'll be another for supporting threadless. I used to think there was not a difference, but now I'm amazed at how much a threadless system stiffens the front end. On my '89 aluminum Trek I can visibly bend and twist the bars with my hands in the drops, just standing over the bike. It is much more difficult to do on my '84 steel Trek with a 1" threadless system (newer carbon fork), using the same pair of handlebars.