|
|
Post by andrewsleigh on May 4, 2011 23:18:20 GMT
I feel a bit silly asking this, because its going to be all so simple to you experienced folk.
I am wanting to get the cab (half cab) laser cut for my MJ bagnall, from 2mm mild steel. but need to allow for bending to 90 degrees
Iv looked at most of the explanations and calculators online, but what gets me is the inside radius they ask for.
where does this comes from?
it seems silly because if you knew the inside radius, you could jsut do the maths and work out the arc for what the other radius would be.
Andy
|
|
|
|
Post by Deleted on May 5, 2011 4:42:17 GMT
Hi Andy There is a piece of software on the web ( can't find it this morning) that will calculate this for you once you've entered the details such as material, thickness and angle. Perhaps someone else here knows the URL and will post details as I'm sure it would help others, the program did far more than calculate this. I'll try to find it myself again later , I used to have on my PC until the hard drive failed...  Pete |
|
|
|
Post by albert on May 5, 2011 7:05:56 GMT
Hello Andy,
I would get a piece the metal cut to about 1in by 1/2in square off the ends and measure the length-- bend it to the radius required and then measure the 2 sides and add them together and subtract the 2 from each other and you have a differance dimension.
Well thats what i would do??
Albert.
|
|
|
|
Post by AndrewP on May 5, 2011 13:26:00 GMT
Andy, There is a bending allowance calculator in Alan J. Munday's Model Engineers' Utilities downloadable from here but that still needs the inside radius I admit. Lots of other good stuff though. Cheers, Andy |
|
|
|
Post by RGR 60130 on May 5, 2011 15:49:44 GMT
Andy,
Is it just a sharp right angle bend you are making? In that case I suspect the inside bend radius would be taken as zero.
Reg
|
|
|
|
Post by Deleted on May 5, 2011 16:22:27 GMT
Thanks AndrewP, that's the site I was trying to refind....  Pete |
|
|
|
Post by daveburrage on May 5, 2011 17:08:26 GMT
The inside radius is ideally specified on the part drawing. If not. it is whatever the rad of your bend tool is. If it is a sharp edge it is practically zero. Ideally it is a minimum of 1.5 to 2 x the material thickness. For calculation purposes the radius of the neutral axis of the bend is inside rad + 1/3 of plate thickness.
regards
Dave Burrage
|
|
|
|
Post by fostergp6nhp on May 5, 2011 20:44:48 GMT
Bending allowances are in the Zeus book.
|
|
|
|
Post by andrewsleigh on May 5, 2011 21:17:03 GMT
Thank Chaps. im sure il work it out now.
il see what the box and pan folder at college is like.
|
|
|
|
Post by andrewsleigh on May 5, 2011 21:19:08 GMT
Andy, There is a bending allowance calculator in Alan J. Munday's Model Engineers' Utilities downloadable from here but that still needs the inside radius I admit. Lots of other good stuff though. Cheers, Andy Thanks for the link. i tried to install it but it didnt want to work  oh well |
|
|
|
Post by andrewsleigh on May 5, 2011 21:21:23 GMT
Bending allowances are in the Zeus book. I dont have one  |
|
|
|
Post by Jo on May 6, 2011 10:49:33 GMT
Hi Andrew,
Looking up my Zeus table: For bending 2mm (15 SWG) the smallest (possible without cracking) inside radius is 5/64" for which the bending allowance is 0.19", if you increase the bend radius to 3/32" the allowance goes up to 0.204".
Jo
|
|
|
|
Post by andrewsleigh on May 6, 2011 13:45:58 GMT
Thanks Jo
Thats helpful, as i want a tight radius.and i guess thats what a box and pan folder gives.
|
|
oh well
