03-21-2015, 07:09 PM
Well, although the last skip-dive wasn't one of the best, it provided a piece of pipe with sturdy flanges, beats dragging quarter-ton hydraulic accumulators out on my own...
Anyway, I *need* a fixed steady for my lathe, it's quite short between centres when I want to cut longer parts, if my welding's up to the job this is what I hope will materialise out of thin air - well, thick steel... Sadly not cast iron, so it may sing a bit :(
The bolts-for-scale in the Crap-O-CAD are M12 x 75, so approximately 1/2" x 3", centre hole is a touch over 200mm/8" (just slightly bigger than I can swing over the cross-slide, perhaps and inch or so), weight is, errr... just about liftable! Can't weigh much more than a 10" steel Pratt-Burnerd 4-jaw, can it? The ring section is about 50mm/2" x 45mm/1-3/4" but there will be three 1" threaded holes through it for the steady fingers...
I saw an interesting video by a shade-tree machinist where he was impressed with the fingers on a big fixed steady - inside the screw-down right-hand thread caps were left-hand threaded rods which pushed the fingers out, so f'rinstance a 10tpi in the cap also pushed down a 12 tpi l/h screw into the moving finger - giving I guess about 6tpi of movement? I may have to try that... but with roller bearings in various sizes and bronze/brass pads that can interchange?
As the pipe flanges already have nicely matched holes, I thought after bevelling the weld lines I'd bolt 'em together then weld the two flanges tgether and the hinge bosses plus locking bosses on in some kiind of jig (lowly stick welder), then cut the two halves apart through two of the holes, which could have a pair of dowel pins to help repeatably locate everything square once in use...
I'm sure there's something there that can't/won't/shouldn't work, Constructive Criticism always welcome! Tell me why I'm an idiot! Tell me how to improve it! I won't be starting for a few weeks, so plenty of time to Get It Right...
Anyway, I *need* a fixed steady for my lathe, it's quite short between centres when I want to cut longer parts, if my welding's up to the job this is what I hope will materialise out of thin air - well, thick steel... Sadly not cast iron, so it may sing a bit :(
The bolts-for-scale in the Crap-O-CAD are M12 x 75, so approximately 1/2" x 3", centre hole is a touch over 200mm/8" (just slightly bigger than I can swing over the cross-slide, perhaps and inch or so), weight is, errr... just about liftable! Can't weigh much more than a 10" steel Pratt-Burnerd 4-jaw, can it? The ring section is about 50mm/2" x 45mm/1-3/4" but there will be three 1" threaded holes through it for the steady fingers...
I saw an interesting video by a shade-tree machinist where he was impressed with the fingers on a big fixed steady - inside the screw-down right-hand thread caps were left-hand threaded rods which pushed the fingers out, so f'rinstance a 10tpi in the cap also pushed down a 12 tpi l/h screw into the moving finger - giving I guess about 6tpi of movement? I may have to try that... but with roller bearings in various sizes and bronze/brass pads that can interchange?
As the pipe flanges already have nicely matched holes, I thought after bevelling the weld lines I'd bolt 'em together then weld the two flanges tgether and the hinge bosses plus locking bosses on in some kiind of jig (lowly stick welder), then cut the two halves apart through two of the holes, which could have a pair of dowel pins to help repeatably locate everything square once in use...
I'm sure there's something there that can't/won't/shouldn't work, Constructive Criticism always welcome! Tell me why I'm an idiot! Tell me how to improve it! I won't be starting for a few weeks, so plenty of time to Get It Right...
Rules are for the obedience of fools, and the guidance of wise men...
(Douglas Bader)
(Douglas Bader)