Tweet
Are hub bars, like Larkin etc, cut from rolled plated or extruded bar?If they are cut from rolled plate, is there a granular structure to be concerned about when cutting the sheet to begin manufacture?In other words, should the sheet be cut across, or along, or at an angle, or does it matter?Any metallurgists out there?Hoges
-
-
Hm,A good call, like grain in a block of timber - are you cutting cross grain or along?Most of the granular structure is invisible to the eye, it usually needs a microscope.But now that I have a hub bar made from sawn up plate, you've got me thinking - will report back.Cheers,Nick.
-
I know that if you cut beef along the grain, it'll like chew'n ya old boot.(:Ignorance is bliss............but only till you realise you were.You can always get the answer you want, if you ask enough experts.
Comment
-
Birdy,You´ve given me an idea. Maybe meat and aluminium are more alike than we all think.I think it´s a meatollogist I´m looking for.Hoges
Comment
-
Comment
-
Aluminum Fittings.....All aluminum fittings are machined from certified aircraft-quality materials of the proper alloy, with the grain of the metal always properly oriented. One manufacturer in the US has it right.Aussie Paul.[
]www.firebirdgyros.com
Comment
-
Hoges,The answer to your question when cutting a hub bar from rolled sheet there is grain and the bar must be cut along the grain. Darryl
Comment
-
Paul and Daryl,Thanks for the input.Yes, but which way does the grain go in a sheet of 1¨ thick (or so)6061 t6, or 2024 t3 aluminium for arguments sake? That was the original problem I was trying to answer. Is the grain longitudinal, cross, diagonal or doesn´t it matter? I can´t seem to get a clear answer, even from the aluminium supplier.Hoges
Comment
-
-
ScottIn all the sheet and plate (Aluminium or steel) that I have ever seen the grain runs longnitudally (the same way as the writing that identifies it). Bends should be across the grainDarylDaryl Patterson
Comment
-
that is what I've come to believe as well ... Daryl Extruded alum is the same way is it not ?thanks...Bob....." Momm'a alwayse told me , Son the impossable is only a little bit Harder... and ya know I do believe She was RIGHT ! "
Comment
-
Hi All,Yes, I spoke to a friend of mine who has worked extensively with rolled sheet materials, and his considered opinion is that you´re all correct. The grain appears to run with the longitudinal run of the sheet. But this is an opinion, not fact. Would anyone like to be suspended at 5,000 feet by a consesus opinion rotating at 350 rpm? I´m sure most of us have, actually.Hands up, all those who know which way their hub bar was cut from the sheet? Hoges
Comment
-
Hands up all those that have Hub-Bars cut from sheet Aluminium. all the bestPete Barsden
Comment
-
Pete,I know I have one, just made by Jack Allen.It has been cut from 1" thick plate, hopefully along the grain, I'm yet to get confirmation of this from Jack, though I think with his experience he would have specified this requirement. As I have posted before in relation to the working of metals, the cut, most likely made with a band saw will have generated faults into the grain from the side of the cut and these can extend up to 1mm deep, so instead of having a 65mm x 25mm hub bar I have to think of it as a 63mm x 23mm hub bar. This does not perturb me unduly as the prior bar is 65 x 19 extruded, and if you think of it, it could well be a 63 x 17 bar. Why did I have this bar made up? I wanted to increase my rotor diameter by as much as I could using the existing rotor blades, Jack would not use the 3/4 extruded to do it, he was insistent on using the 1" and then he would only go to 4' long with it.How strong is it? To give you an idea we had to acquire a new jack for Jack to bend it, to set the coning angle. It supposedly is capacity rated to 1.8 tonnes (1800 kg), setting the bend in as close to the teeter bar as possible with an 18" offset we were struggling to get the jack to bend the bar, given that the gyro might weigh about 300 kg all up I think it will be strong enough for the machine, but fatigue is another issue.. rigorous inspection routines will prevail - every 50 hrs for a damn good visual.Cheers,Nick.
Comment
-
One for plate, next hand.Pete Barsden
Comment
Comment