![]() ![]() A lot of good info there and I had not seen those links. real tube will ring whereas pipe will clunk. you can tell extruded from formed by hitting it with a piece of metal. pipe is when you take pressed metal and you roll it around and weld a seam. Now china/taiwan has changed how tubing is made and what they call tubing, i call pipe. Yours (and the other guys) cranks could be from another factory or could be a early production. its small enough to place two of them together. I place your cranks in the 90s category because of how small the pinch bolt housing is. lots of info can be found on how profile cranks are made and flights (as well as most of not all tubular cranks) are made pretty much the same way. but i do have experience in this field and I do know how profile cranks are made and its how i explained the process- they use extruded tubing and not formed sheet thats wrapped around and welded. ive never seen how flights were made with my own eyes either (especially back in the late 80s). let me be the first to say I am not linn kastan and i do not know linn kastan, ive never worked for linn kastan or even spoke to the man before. Promise.not picking on.just wanting fact based intellectual discussionįirst off i said maybe and i can EASILY be mistaken. the extrusion section starts around slide 60 or so. This is a great slide show showing several ways you make shapes from a metal ingot. its how you make tubes (like 4130 sanko tubing), forks and tons of other things. Hardened dowel/die into a piece of steel to extrude its shape. most manufacturing of tubular shapes is done with a press by way of some kind of extrusion. I can promise you they are not made like that. ive made (meaning CAD drawn) tons of things and ive worked in the manufacturing (really design) industry for many years (though not any more)īut unless you cut one of these crank arms in half, you do not know if the arm is wrapped around a form and welded or not (like how technique cranks are made for example) To 'no wrap' at some point but its an incorrect description of what you clearly see as something that is either completely wrapped completely around a boss or only partially wrapped around a boss.Īctually, i have seen the extrusion process on literally hundreds of things. our old info threads are gone(due to the reference section being changed) this phrase was shortened No wrap means what exactly? 'no wrap around' is whats said in the image. and before you say it, theyĪre also described by how many pinch bolts it has as well as if it even has pinch bolts. When describing redline cranks everyone goes by the pedal boss and whether or not it completely wraps around it or only wraps around half of it. full wrap means it completely wraps around the pedal boss (or spline boss) Promise.not picking on.just wanting fact based intellectual discussion.ġ/2 wrap means it wraps around 1/2 the boss (no matter if its the pedal boss or the spline boss). How do you know they are really early 1990s? I actually found mine on a 1987 factory racer Cycle Craft that seemed 100% late '80s virtually "survivor". I find mine in the reference section under 1980's, and other places I have found them have said 1980s. Everywhere I find completely no wrap it says 1990+. Lastly, you say my cranks are first version of early '90s. Lots of weld filler, then ground down smooth. Similar with the spindle bolt bosses.I believe the pieces is welded on the end, and then extension tabs top/bottom on the are bent around. I believe the pedal boss wrap around is created by extending two tabs one off the top, one off the bottom sheet, put the pedal boss in there and hammer the tabs down around it.weld across the seam and then grind smooth as if there never was a seam. ![]() That does not leave you with 3-D socket shapes on each end. Can you substantiate that? You've seen the process? I mean you have to think about how the arm gets there, and originally cranks started out as flat sheets and were folded over into a box. Secondly, you stated that the full wrap has the spline/pedal boss socket inserted into a whole in the crank arm. Or maybe there is a complete failure to really have a convention here because if his were "1/2 wrapped" then there is no such thing as "no wrap". "Half wrap" = 1 end full wrapped, the other end no wrap. You see even the infamous "flight timeline" calls them no wrap. They are are "no wrap Redline Flights 1990-1996". "yours are 1/2 wrapped at both ends." IMO, they are no wrapped. Not to pick on you, but there are several things you've said that I beg to differ on: Yours also has the 90s bb setup wereas, troys setup shows the eariler 80s bb design. your are 90s 1/2 wrap cranks but i say they also have 1/2 wrap 90s cranks. if you look closely you can see their cranks are 1/2 wrapped at the pedal boss but is full wrap at the spline boss. ![]()
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