K-factor and bend allowances
K-factor and bend allowances
(OP)
I am designing a box out of 16 gage sheetmetal with several right-angled bends and flanges. I am needing information on the K-factor and bend allowance formulas.
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K-factor and bend allowances
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K-factor and bend allowancesK-factor and bend allowances(OP)
I am designing a box out of 16 gage sheetmetal with several right-angled bends and flanges. I am needing information on the K-factor and bend allowance formulas.
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RE: K-factor and bend allowances
Hope this helps.
RE: K-factor and bend allowances
RE: K-factor and bend allowances
RE: K-factor and bend allowances
One of the companies that I worked for chose their die by multiplying the material thickness by 8 times. This gave us the die width to use. Then we had a chart that told us which bend allowance to use depending on whether it was stainless steel, aluminum, or mild steel. All we used there was air bending.
Another company I worked for multiplied the material thickness by 6 to give us the die width. We used strictly coining, but air bending when absolutely required. We used the same formula for bend allownaces regardless of the material being used. The charts there used a different formula and k-factor for computing the bend allowances.
Then you get into deep discussions about the difference between bend allowances and bend deductions.
After all is said and done, the best way is to cut a small blank, maybe 4" by 6". Debur it to have accurate dimensions. Measure the 4" width with calipers, and write each dimension on the corresponding side. Form it at 2". You now have 2 legs roughtly 2"+ material thickness apiece. Again use calipers to to measure the legs. Add the length of the 2 legs. Subtract the length you wrote down from the combined formed length. Do the same for the other side. You now have the bend deduction for that material thickness using that die width and that punch radius.
Here is a link for an incredible FREE little program that helps you calculate bend deductions and even lets you reverse engineer the k-factor like my long winded explanation above.
http://www.massey.ac.nz/~odiegel/bendworks/
Flores
RE: K-factor and bend allowances
If your interested I have a spreadsheet I've developed to do just what smcadman described in the last post.
RE: K-factor and bend allowances
I would be very interested in your speardsheet you have developed on K-factors. Do you need my e-mail address?
RE: K-factor and bend allowances
"When the inside bend radius is 2x the material thickness or GREATER, the bend allowance is equal to the inside radius plus 1/2 the thickness"
"When the inside bend radius is LESS than 2x the material thickness, the bend allowance is equal to the inside radius plus 1/3 the thickness."
This works well with most sheet metal and tubing. Some materials have a tendency to elongate slightly more or less than others.
RE: K-factor and bend allowances
RE: K-factor and bend allowances
Here it is mckinley@tanamerica.com.
RE: K-factor and bend allowances
htaed@comcast.net
RE: K-factor and bend allowances
Wanna Tip? FAQ731-376
"Probable impossibilities are to be preferred to improbable possibilities."
RE: K-factor and bend allowances
Any help much appreciated.
RE: K-factor and bend allowances
BA= 2 pi x (inside radius + half thickness) x angle of bend in degrees / 360, as a formula 2 x 22/7 x (R + T/2) x A/360 if you are working on outside radius formula becomes 2 x 22/7 x (R - T/2) x A/360.
Works exceptionally well when completing repairs where a doubler must exactly fit a Z section on the corners.
In your application K = R+T.
Grue
www.metalbashatorium.com
RE: K-factor and bend allowances
http://www.massey.ac.nz/~odiegel/bendworks/bending.pdf
Flores