kit
03-19-2012, 10:32 AM
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7375
Here is a basic folding brake I made up from some old chain link fencing steel posts that came free. Not pretty but it works well.
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7378
It is basicly three lenghts of angle, each braced with it's own opposite, the bottom two are back to back with their verticals extending downwards in the middle, these are hinged along their centre line, the right hand one of these in the picture folds upwards to form the bend in the sheet.
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7380
Here is the top section, note how the vertical lengths of angle are cut and welded with height reduced and a laid back rake to them, there is a section of card inserted to show the position the sheet fits in (yep I didn't have any metal laying around!!!) this is nessasary to get clearence back over the top for a second bend in the same direction as the first.
The vertical bolt has a 10mmm thread and is the sheet hold down / release, there is a semi captive bolt in the frame for it that can move in a slot,the horizontal bolt is a back stop that holds the top rails position when the vertical bolt is loosened it dictates the exact position of the leading edge for the bend. So the top rail can move back and forwards a little in relation to the base rails to adjust the point of contact for the bend.
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7376
So sheet in, tighten down the vertical bolt. (by hand).
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7377
Lift up the front section to form the bend. The mechanisum needs to be able to move through more then 90 degrees to account for spring back in the sheet to bend a right angle.
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7378
Getting it to work well is all about the hinges, they have to be strong and positioned in line with each other at the centre line of the bottom two lengths of angle. What I did was to use a 7/8'' male pin and a coresponding over that size female just bored with a 7/8'' drill, so no need for any great engineered tolerances, I notched out the holes for them in the angle basicaly, the idea being the male welds to one side the female to the other, mark the centre spot of the male on the lathe to act as a positionig reference, if you look at the top hinge in the picture, the male, you can see a strip of steel welded to it that extends back to the left, that has a hole in it that had an 8mm nut welded to it, (that was cut off when I'd done)I clamped the far left end of the strip to the angle with a wrench, then screwed a bolt in and out of the 8mm nut to raise or lower the hinge to the right position, same for the female, (the centre hole showing on that is threaded for a grease nipple, ignore that).
This way you can carefully move the brake through it's working range in a clamped only mode and check everything stays parallel and evenly gapped, adjusting as nessasary. Then weld her up.
So there it is, basic no finger brake facitities, they could be made up with a new top arm setup. I built it to take a 48'' sheet, I'm only bending up to 1.5mm sheet, any heavier then that and you'd need more bracing, I welded on two stubs on the rear each roughly 1/3rd of the length along to bolt it to a frame rather then giving it it's own legs that way she stands on end taking up little space when not in use.
Here is a basic folding brake I made up from some old chain link fencing steel posts that came free. Not pretty but it works well.
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7378
It is basicly three lenghts of angle, each braced with it's own opposite, the bottom two are back to back with their verticals extending downwards in the middle, these are hinged along their centre line, the right hand one of these in the picture folds upwards to form the bend in the sheet.
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7380
Here is the top section, note how the vertical lengths of angle are cut and welded with height reduced and a laid back rake to them, there is a section of card inserted to show the position the sheet fits in (yep I didn't have any metal laying around!!!) this is nessasary to get clearence back over the top for a second bend in the same direction as the first.
The vertical bolt has a 10mmm thread and is the sheet hold down / release, there is a semi captive bolt in the frame for it that can move in a slot,the horizontal bolt is a back stop that holds the top rails position when the vertical bolt is loosened it dictates the exact position of the leading edge for the bend. So the top rail can move back and forwards a little in relation to the base rails to adjust the point of contact for the bend.
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7376
So sheet in, tighten down the vertical bolt. (by hand).
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7377
Lift up the front section to form the bend. The mechanisum needs to be able to move through more then 90 degrees to account for spring back in the sheet to bend a right angle.
http://www.metalmeet.com/forum/picture.php?albumid=14&pictureid=7378
Getting it to work well is all about the hinges, they have to be strong and positioned in line with each other at the centre line of the bottom two lengths of angle. What I did was to use a 7/8'' male pin and a coresponding over that size female just bored with a 7/8'' drill, so no need for any great engineered tolerances, I notched out the holes for them in the angle basicaly, the idea being the male welds to one side the female to the other, mark the centre spot of the male on the lathe to act as a positionig reference, if you look at the top hinge in the picture, the male, you can see a strip of steel welded to it that extends back to the left, that has a hole in it that had an 8mm nut welded to it, (that was cut off when I'd done)I clamped the far left end of the strip to the angle with a wrench, then screwed a bolt in and out of the 8mm nut to raise or lower the hinge to the right position, same for the female, (the centre hole showing on that is threaded for a grease nipple, ignore that).
This way you can carefully move the brake through it's working range in a clamped only mode and check everything stays parallel and evenly gapped, adjusting as nessasary. Then weld her up.
So there it is, basic no finger brake facitities, they could be made up with a new top arm setup. I built it to take a 48'' sheet, I'm only bending up to 1.5mm sheet, any heavier then that and you'd need more bracing, I welded on two stubs on the rear each roughly 1/3rd of the length along to bolt it to a frame rather then giving it it's own legs that way she stands on end taking up little space when not in use.