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Thread: Cutting titanium!?!?!

  1. #1

    Cutting titanium!?!?!

    So I got titanium handrims this time around on my new TRA because my aluminum ones have been turning my hands black for years.

    But the handrims are spaced too wide for me. I need to move them to the closer setting. They already have the holes drilled in just about the perfect place for me, but it sure looks like once I move them to a more inside position the excess tab will be sticking out far enough out the other side that they will get in the way. Maybe even rub against my side guards.

    I already have to do some cutting on the caster forks of my brand new wheelchair, but I'm 95% sure those are aluminum, and it's just a little bit I have to cut off.

    It seems like a pretty big pain in the ass if I have to cut/grind twelve mounting tabs for the handrims... and looking online it seems like in addition to throwing crazy sparks everywhere while you're doing it, it's fairly easy to overheat the titanium and cause it to discolor.

    You think there's some kind of shop that's used to working with titanium that I could take my handrims to... and that I could trust to not screw up the $400 handrims I somehow talked the insurance company into covering?

    Who works with titanium? Maybe some really high end bicycle manufacturers... though someone told me aluminum has proved superior so people aren't bothering with it much. Any other kinds of shops you all can think of that might be comfortable working with titanium?

  2. #2
    Just a comment or two. Recently my husband put my "back-up" wheels on my chair so we can take my wheels to the bike shop for new tires and tubes. The b-u wheels have coated push rims and are in the wide position. Probably because they are coated they are closer to the rim and I can just barely get my thumb through that space (to give you an idea how close).
    I note that if my rims were attached to the close position there seems to be room for them to NOT go past the rim of the wheel and create trouble like you noted about 'rubbing against my side guards'.

    Have you measured exactly where the end of the push rim tab would sit if you have them mounted in the close position (first hole from the rim itself)?
    Sorry, I guess I'm biased as I'm totally uncomfortable with the idea of cutting that wonderful titanium.

  3. #3
    I would first check to see if they're actually titanium, they might be aluminum.

  4. #4
    Quote Originally Posted by Rustyjames View Post
    I would first check to see if they're actually titanium, they might be aluminum.
    The handrims themseles are definitely titanium, the surface is a matte/brushed color that one couldn’t achieve with aluminum.

    i don’t know enough about welding I guess, I just assume that it would be more difficult to weld aluminum tabs to a titanium hand rim than the cost savings would justify.

  5. #5
    Senior Member Oddity's Avatar
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    My new wheels have untrimmed short tab mounting. They don't/barely (mm) extend past the end of the wheel. Stock Spinergy aluminum though. You know me. I'd just use the cut off wheel. Sparks are cool and "heat anodized" titanium looks awesome IMO. I've heat anodized some Ti pocket knife handle scales just for the look. It's like an awesome color case hardening on steel. IMO any of that wouldn't extend but ~ a cm (if that) from the cutting point. If you cut them at the edge of the long tab hole, not through the entire tab, it's less to cut than the forks. With the hole, it's half cut at that spot already. Grind edges with a drum sander attachment for clean them up/smooth off the remains of the hole.

    Side Note: I was sorely disappointed that Spinergy charged extra for "short tabs" but didn't trim the tabs. That's the ONLY part of mounting short tab that warrants an upcharge, IMO. Which hole you put a screw in isn't a cost generator.

  6. #6
    Quote Originally Posted by funklab View Post
    The handrims themseles are definitely titanium, the surface is a matte/brushed color that one couldn’t achieve with aluminum.

    i don’t know enough about welding I guess, I just assume that it would be more difficult to weld aluminum tabs to a titanium hand rim than the cost savings would justify.
    I was thinking the spacers are another material, like aluminum.

  7. #7
    Quote Originally Posted by Oddity View Post
    My new wheels have untrimmed short tab mounting. They don't/barely (mm) extend past the end of the wheel. Stock Spinergy aluminum though. You know me. I'd just use the cut off wheel. Sparks are cool and "heat anodized" titanium looks awesome IMO. I've heat anodized some Ti pocket knife handle scales just for the look. It's like an awesome color case hardening on steel. IMO any of that wouldn't extend but ~ a cm (if that) from the cutting point. If you cut them at the edge of the long tab hole, not through the entire tab, it's less to cut than the forks. With the hole, it's half cut at that spot already. Grind edges with a drum sander attachment for clean them up/smooth off the remains of the hole.

    Side Note: I was sorely disappointed that Spinergy charged extra for "short tabs" but didn't trim the tabs. That's the ONLY part of mounting short tab that warrants an upcharge, IMO. Which hole you put a screw in isn't a cost generator.
    Is that really what they upcharge for?

    I was looking at getting some cheaper aluminum handrims while I'm working on the Ti ones (and also so while I'm getting used to loading the new chair in the car, if I drop it I won't ruin the really nice finish on my Ti handrims.

    sportaid charges and extra $20 for "short tabs", even when you're just buying the handrims on their own. Does this mean that the only thing they change is putting smaller clear plastic guards on the tabs? I mean they're not even installing them at all.

  8. #8
    Quote Originally Posted by Rustyjames View Post
    I was thinking the spacers are another material, like aluminum.

    I'm honestly not sure. I know next to zero about welding aluminum to titanium. If it's pretty easy to do, I'd bet there's a good chance they used aluminum.

  9. #9
    There's no welding aluminum to titanium.

  10. #10
    The long tab holes will definitely extend beyond the Spinergy rim. This can be seen by looking at the location of the short tab holes on the rim side of the wheels. That offset is for you to determine if is too much.

    Cutting seems to be not such an issue. This old thread has several members discussing experience cutting titanium:
    http://sci.rutgers.edu/forum/showthr...tting-titanium

    Too bad that with tab mounts those Marathons have to be removed and remounted to do this.
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

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