I think 31mm may eat too much of the 50mm flange...I have a few hardened pins I picked up for similar purposes. Might be persuaded to part with some to help a project.
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So I make that about 14 tons per pin for 3/4". So 56 tons for 4....plenty of margin there for a 20 ton press.
Seadog
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Everyone on the forum has, haven't they?I have a few hardened pins I picked up for similar purposes. Might be persuaded to part with some to help a project.
I haven't!!!!!Everyone on the forum has, haven't they?
Screwdriver
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Yes please!
I think they're a little too big in diameter for my 50mm flanges on the channel.Would you like some?
Thanks though!
Screwdriver
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Might be an idea to hang around a local car garage. They often throw out very useable stock including axle shafts.
slim_boy_fat
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E T
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The jack in the picture is an old 8 ton double acting Weber jack my neighbour gave to me some time ago. Total travel something like 260mm of the top of my head
A couple of weeks ago I replaced that with a Chinese 50 ton single cylinder one with 150mm of travel. Chinese tons probably, so maybe between 30 and 40 in real live.
Screwdriver
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As long as you explain why you're loitering.
Well, tbh, it's for the coil springs...
E T
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Maybe you're right.
I just copied something I saw on some presses on the Internet. When I build it I didn't put that bracing in the horizontal channel.
Later I decided it might be a good idea to strengthen them a bit because it's only 80mm channel and 1m long.
E T
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I picked up a fairly big air over hydraulic cylinder a couple of weeks ago for only €10 with the plan to see if I can plumb that into the jack.
For only €10 I couldn't resist it.
Screwdriver
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If you give it some thought, it will be fine whichever way you decide. My take on that style of bracing is that you just need to be sure you know why you're doing it. I don't think it necessarily automatically makes things better. Plus of course, people often want to stick a pin right through the web of the channel, so even a few uprights "boxing" it in in a just few places might be preferable.
E T
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My thought by this form of bracing was that it transferred some of the forces on the thinnest outer edge of the top flange to the thick part of the bottom flange. Don't know if that's true. Anyway the channel is definitely stiffer with this bracing in.
Can't put my head around it why it would make things worse, but calculating forces and stresses is not my line of work.
I just muck about with metal as a hobby.
I think the angled bracing is the right way to do it, transferring any loads on the outer edge at the top to the inside 90 on the bottom
with two pieces back to back and welded together at the ends it'll take a hell of a lot of bend/twist them - it should resist bending/twisting better than if it was braced in as box section?
also you're keeping the load in towards the center of the press, which is better at the pin end, more shear force vs bending
with two pieces back to back and welded together at the ends it'll take a hell of a lot of bend/twist them - it should resist bending/twisting better than if it was braced in as box section?
also you're keeping the load in towards the center of the press, which is better at the pin end, more shear force vs bending
Screwdriver
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I don't "know" but my gut feeling was** if the object of the bracing is to prevent distortion at the edge then having a longer "lever" down to that corner (instead of the shorter length of the flat web of the beam) would give that force greater leverage. Plus my concern was that any welding might introduce stress, weakness and stress risers right at that "pivoting" corner.
That "may" be true for similar, non identical designs where typically I see holes in the bed/beams for inserting pins. Quite exactly how the final design is implemented is critically important to the sudden realisation I may be talking nonsense!
**was. I am rapidly forming the opinion that there isn't that much of a downside and that such bracing can only ever increase strength. I still think there may be better ways to deal with it but I am equally happy to hear from better minds than mine.
If you imagine putting box section in a vice corner to corner and then the same but with a triangle piece.... The box section is much easier to distort/squash than the triangle
I think it's all a bit if a mute point because whatever people do will be many times stronger than needed... But it's good to think about it and not just copy existing designs
I think it's all a bit if a mute point because whatever people do will be many times stronger than needed... But it's good to think about it and not just copy existing designs
KemppiFrog
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Couple of thoughts:
While some structures might be strong enought, eliminating flex matters. If you are trying crack a tight fit, it needs to be good and rigid.
On pins, my local tractor shop has boxes of bolts in all sizes, all 8:8 and sold by weight. Very cheap.
(Glad to see Xmas is not interfereing with shed time)
Have a good one!
KF
While some structures might be strong enought, eliminating flex matters. If you are trying crack a tight fit, it needs to be good and rigid.
On pins, my local tractor shop has boxes of bolts in all sizes, all 8:8 and sold by weight. Very cheap.
(Glad to see Xmas is not interfereing with shed time
)Have a good one!
KF
