making kerf cuts to bend a radius

[sctattooer 10+ year member]

When making cuts to bend a radius, obviously the closer the cuts are to each other, the tighter the bend. Is there a way of calculating this based on the radius of the bend?

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[ngsm13 5,000+ posts]

AIDS.

nG

 

[sctattooer 10+ year member]

Geez, man, sorry to hear that. You sure it's not just HIV?

 

[Pioneer~Saturn 5,000+ posts]

Yep //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Take the circumference of the outside of the MDF board and the circumference of the inside of the MDF board in the bend (assuming the bend is a quarter of a circle, finding the circumference of the circle theyd be a part of) and devide them both by four and see what the difference is between the two (this is how much material needs to be cut away)....then see how much length of the board youre using for the bend and see how many blade-widths (minimum) it'd take to make the bend and devide the space on the board by that and mark them evenly spaced //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif...I kinda lost myself...but I think that's about how it goes //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[mugen08 10+ year member]

Yep //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Take the circumference of the outside of the MDF board and the circumference of the inside of the MDF board in the bend (assuming the bend is a quarter of a circle, finding the circumference of the circle theyd be a part of) and devide them both by four and see what the difference is between the two (this is how much material needs to be cut away)....then see how much length of the board youre using for the bend and see how many blade-widths (minimum) it'd take to make the bend and devide the space on the board by that and mark them evenly spaced //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif...I kinda lost myself...but I think that's about how it goes //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[sctattooer 10+ year member]

That almost makes sense, but I swear I felt the wax fly out of my ears as I read it.

I'll give it a try. Seems like once I have the amount of material to be removed, I divide that by 0.125 (thickness of the blade), then by the amount of board needed to make the radius, (which would equal the outside radius measurement) and I should come up with the spacing measurement. Thanks!

 

[Pioneer~Saturn 5,000+ posts]

Yep //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[ughhibye 10+ year member]

i take the inside diameter of the bend and divide by 13. has not failed me yet.

basically you want 13 cuts,

 

[nathanh 10+ year member]

um... might not be a pro.. but i gotta ask.. whats the radius for?! lol my experiance is that all you need a cut that reduces the mdf down to 3/8ths of an inch every 5/8th of a inch. logically, you want enough curfs to let the boad not only bend, but to do so evenly. if you need more bend... yellow glue and laminate 3, 1/4 inch mdf.

 

[nathanh 10+ year member]

oh and make sure you use a square to guide the cuts. otherwise shit gets ugly. be making a downward spiral if youre not careful

 

[Pioneer~Saturn 5,000+ posts]

um... might not be a pro.. but i gotta ask.. whats the radius for?! lol my experiance is that all you need a cut that reduces the mdf down to 3/8ths of an inch every 5/8th of a inch. logically, you want enough curfs to let the boad not only bend, but to do so evenly. if you need more bend... yellow glue and laminate 3, 1/4 inch mdf.

If you were asking me 'whats the radius for?'...it's so you can figure a circumference of the bend...so you can make a calc on how much material needs to be cut away in order to make the bend //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif