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Post by Lagger on Jul 17, 2017 13:58:03 GMT -6
A quick question to those of you out there that have done the VTX headlamp mod. I'm looking at fabricating a mounting bracket, I know that Foreman has a bracket made by BAB and that looks good. I'm thinking of making up a bracket that also incorporates the fixing points for the turn signals (since the original bracket is missing on my bike). I'm contemplating either making one from 4mm steel (difficult to bend accurately with my limited resources) or making one from cast aluminium using the lost wax process (easier for me to make from lumps of ally I have kicking around, I just need to fabricate a foundry of some sorts which is quite simple). The question is, if people out there have made one from steel how does it perform? I thinking about whether the headlamp will shake at all on a steel bracket, that's the principle reason I'm thinking that a cast or milled aluminium mount would be better, potentially more stable.
Any experience out there to share?
Thanks
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Post by Streak07 on Jul 17, 2017 16:31:59 GMT -6
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Post by Streak07 on Jul 17, 2017 16:40:21 GMT -6
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Post by Lagger on Jul 17, 2017 23:33:25 GMT -6
Thanks Buddy. I know steel is far stronger but for me there were two possible down sides - working it is a lot harder and I was worried about the "springyness" it might have - a shaky headlight is really annoying. I noticed that BAB make a mount from billet which I might model something from. I'm decided against going for cast as it would likely be too brittle unless really thick. Your RF post is helpful, I think that rather than try to bend and fold steel I'll use various cuts and weld together. Thanks for the link!
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Post by Lagger on Jul 17, 2017 23:34:28 GMT -6
Nice! Just what I need to do this little job
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Post by Lagger on Jul 17, 2017 23:37:46 GMT -6
@streak - do you still use the original turn signal bracket on your set up?
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Post by Lagger on Jul 17, 2017 23:56:30 GMT -6
@streak - never mind, just read your post about using double sided tape for the indicators.
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Post by Streak07 on Jul 18, 2017 8:31:42 GMT -6
Nice! Just what I need to do this little job The "springyness" is purely dependent on the thickness. Since you're talking cast aluminum no it wouldn't be springy but it would be more brittle and likely to have porosity issues. There's a tradeoff there. I've seen the garage casting setups and while neat there's a process to remove impurities which is marginal due to the cheap aluminum being used and relatively low temp. It would need to be much thicker than billet due to the risk of porosity and lower strength. I used 1/8" plate steel. Easy enough to cut with common garage tools and very rigid. If you were cantilevering it with a 1"x1/8" and a foot long piece with a light mounted on the end then yes it wouldn't be rigid but nothing would be because of the shape. Do the same thing with the same thickness aluminum and it would be drooping down 4 inches. That's why any bracket or frame should be angle iron, or C-channel, or boxed frame. It's necessary for rigidity. In an I-beam the majority of the load is taken by the vertical piece but the top and bottom is critical to prevent torsional flex and failure. As soon as it's even slightly out of the perfectly vertical position it can no longer handle any load and will distort to failure in structural situations. A down and dirty structures lesson, just don't make me do calculations cause I got a C-. I used tape versus a welded tab because I always planned to replace the signals with something smaller. That never really happened but the tape works fine going on 7 years now.
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Post by Lagger on Jul 18, 2017 8:47:13 GMT -6
Nice! Just what I need to do this little job The "springyness" is purely dependent on the thickness. Since you're talking cast aluminum no it wouldn't be springy but it would be more brittle and likely to have porosity issues. There's a tradeoff there. I've seen the garage casting setups and while neat there's a process to remove impurities which is marginal due to the cheap aluminum being used and relatively low temp. It would need to be much thicker than billet due to the risk of porosity and lower strength. I used 1/8" plate steel. Easy enough to cut with common garage tools and very rigid. If you were cantilevering it with a 1"x1/8" and a foot long piece with a light mounted on the end then yes it wouldn't be rigid but nothing would be because of the shape. Do the same thing with the same thickness aluminum and it would be drooping down 4 inches. That's why any bracket or frame should be angle iron, or C-channel, or boxed frame. It's necessary for rigidity. In an I-beam the majority of the load is taken by the vertical piece but the top and bottom is critical to prevent torsional flex and failure. As soon as it's even slightly out of the perfectly vertical position it can no longer handle any load and will distort to failure in structural situations. A down and dirty structures lesson, just don't make me do calculations cause I got a C-. I used tape versus a welded tab because I always planned to replace the signals with something smaller. That never really happened but the tape works fine going on 7 years now. Thanks Streak! I've done a reasonable amount of fabrication stuff in the past (longish time ago now) and well understand how to get rigidity by shape. I agree with you regarding "springyness" being largely a factor of thickness but material type plays a role too (stainless steel for example is much more rigid than the same thickness of mild steel but it's also a bitch to work with). Basic garage casting set-ups wouldn't be great but I was planning something a little more sophisticated and using higher grade aluminium. Having given it some thought I'm going to keep it nice and simple and fab something from 4mm steel - I'll probably zip-cup-and-weld to get nice clean radii on the curves - I'm planning to make a step on my bracket since (in my view) the VTX lamp looks better being mounted very slightly lower than the standard Meanie set-up. This is just a personal opinion of course, each to his own! Your tape idea is great, nice elegant and simple and effective, sounds like an ideal solution. Cheers :-)
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