So before we get onto the subject of babies faces, robins and fire I should explain .....
I have a couple of thru axle forks that I would like to replace the (1x) quick release and (1x) bolt up axle with something more secure.
My go to would be the DT Swiss RWS axle.
They used to make an off the peg axle that was the right spec 15mm x 125mm but sadly they are no longer available and I cannot source one through the UK distributor.
Sooooooooo I was looking at a spare DT Swiss RWS boost axle that I have. The wall thickness of the axle itself looks to be consistent along its length. Extending the thread further down the axle and then lopping off the end would appear to be possible without compromising the strength - continuous wall thickness etc but IANAE.
Soooooooo
Possible, it would appear.
Safe, I don't see why not.
Thoughts?
Pretty easy to do if you have a lathe and a tap, should be very doable by hand if you're careful. It's aluminium so will tap easily, still worth getting some tapping fluid. It's a standard M15x1.5 thread according to dtswiss
The die will be expensive though as not a common size. Could be single point cut on a lathe.
You're assuming that it's a cut thread not a rolled thread.
Check the outer diameter of the axle where there is no thread. Is it 15mm diameter?
If it is - you can cut away and follow Murray's plan.
If it is NOT (it may be slightly less like 14.5 to 14.8mm) then you have a rolled thread and cutting won't give you a full thread form and hence it will be a weak thread/joint when fitted to the bike.
I shortened a 5mm rws front qr.
I can confirm it is a rolled thread and tapping it meant I was undersizing the thread as per above.
Didn't fail, but in hindsight, the front wheel of my road bike was probably not the ideal place to do this.
I did it for a trailer axle for my old Trek Ebike. Couldn’t find the right length so got a longer one and used a small tap & die set to extend the thread. Worked fine.
Why would the RWS be more secure? The bolt up would surely be more secure?