RCCrawler Forums

rik · 09-12-2011, 06:40 PM

Was searching around and didn't find much. So, is there a formula for making bends? i.e., I know what length my straight link is. But would now like to make a bent version of said link and still keep the same length of the straight one. Everytime I make bent links I over shoot the overall length by 1/4 - 1/2 inch. Then cut as needed. I'd like to make one cut, then bend and be done with it. I checked the machinist handbook but it gave these ridiculous equations. Just wondering if there is an easier way. Thanks in advance.

tom@vp · 09-12-2011, 06:56 PM

the correct formula is called k factor, but unless your using properly controlled bending equipment your results will vary.

http://en.wikipedia.org/wiki/K-facto...al%29#K-factor

Desert Rc · 09-12-2011, 06:57 PM

Formula=practice

AX10wannabe · 09-12-2011, 07:09 PM

usually i make a drawing of the piece i want to bend (chassis rail or something) then i take a piece of string and form it to the drawing then stretch string out measure onto your tube or rod and thats the right length... or at least close to it.

SMR 510RR · 09-12-2011, 08:33 PM

Search for bending 101, its a good write up over on pirate 4x4. It will get you to the point that you can bend just about anything in one axis.

The basics are as follows:

Bend a test piece of the material you will be using with your bender, mark where the tube lines up with the 0 mark of your bender
Layout the piece on a sheet of paper
Use the test piece to mark the start of the bend
Measure the length of all sides of the piece you are bending and add a little extra just to be sure you have enough
Start bending working your way from the center out

Its easy, when you start doing complex bends it gets a little more complicated.

Postclanker · 09-12-2011, 08:56 PM

Quote:

Originally Posted by AX10wannabe

usually i make a drawing of the piece i want to bend (chassis rail or something) then i take a piece of string and form it to the drawing then stretch string out measure onto your tube or rod and thats the right length... or at least close to it.

there you go....man, I'm pretty good with math...but that formula was brutal...

Postclanker · 09-12-2011, 08:59 PM

I didn't see SMR's until after I posted mine....but that's a good idea too..

might even get some tubing and give it a try

BigSki · 09-12-2011, 09:07 PM

I believe there are some reference charts in the 'machinerys Handbook' for bending allowance, different types of materials 'grow' on outside bends. There are many variables involved with calculating a bending allowance.

The cheap and easy way is to use graph paper and draw out what you want to bend, then use the lines in the graph to make a straight line measurement.

SMR 510RR · 09-12-2011, 10:09 PM

Quote:

Originally Posted by Postclanker

I didn't see SMR's until after I posted mine....but that's a good idea too..

might even get some tubing and give it a try

Trust me, it works very well. There is no formula that will compensate for the difference in materials, this definitely will. Different tube and solid rod will bend differently in the same bender, its hard to compensate for that.

I have used this method to successfully bend different hoops to match width very closely. I almost feel like a 1:1 would be easier because you could compensate for 1/8" of variation very easily. With 1:10 scale that would be 1/80" hard to get that precise.

Nothing will help more than bending and then bending some more. Learn your bender, no matter what bender you are using bought or made at home you need to learn how it will bend.

bob1961 · 09-13-2011, 05:44 AM

trail and error with the small benders we use....since i got back into R/C's with a crawler "the tigress" and now scalers, i have been bending brake line for 3 years now....as said starting in the middle and work your way to the ends has been a good formula....single bend bent links are the easiest to make compaired to making frames....i find it easier to have a longer length then needed and cut both ends, less wasted time starting with a new piece of tube and less waste....you can't add to what you have cause you started with less then you thought, you can always shorten what you started with

.........bob

....

rik · 09-13-2011, 05:06 PM

thanks for the tips guys. just what i was looking for. much appreciated.

squatch71 · 09-16-2011, 11:22 PM

to get the basics pick up a "Uglys" hand book...its a electricians bible...has lots of formulas and how to do stuff.*

*wiring is not a hobby, hire a professional before you burn your house down.

09-12-2011, 06:40 PM	#1
rik RCC Addict Join Date: Oct 2009 Location: In the mancave... Posts: 1,038	bending formula? Was searching around and didn't find much. So, is there a formula for making bends? i.e., I know what length my straight link is. But would now like to make a bent version of said link and still keep the same length of the straight one. Everytime I make bent links I over shoot the overall length by 1/4 - 1/2 inch. Then cut as needed. I'd like to make one cut, then bend and be done with it. I checked the machinist handbook but it gave these ridiculous equations. Just wondering if there is an easier way. Thanks in advance.

09-12-2011, 06:56 PM	#2
tom@vp I joined the Band! Join Date: Jun 2008 Location: Sacramento Posts: 1,303	the correct formula is called k factor, but unless your using properly controlled bending equipment your results will vary. http://en.wikipedia.org/wiki/K-facto...al%29#K-factor Last edited by tom@vp; 09-13-2011 at 09:19 AM.

09-12-2011, 08:33 PM	#5
SMR 510RR I wanna be Dave Join Date: Dec 2009 Location: San Francisco Posts: 2,236	Search for bending 101, its a good write up over on pirate 4x4. It will get you to the point that you can bend just about anything in one axis. The basics are as follows: Bend a test piece of the material you will be using with your bender, mark where the tube lines up with the 0 mark of your bender Layout the piece on a sheet of paper Use the test piece to mark the start of the bend Measure the length of all sides of the piece you are bending and add a little extra just to be sure you have enough Start bending working your way from the center out Its easy, when you start doing complex bends it gets a little more complicated.

09-12-2011, 06:57 PM	#3
Desert Rc I wanna be Dave Join Date: Nov 2008 Location: Chillin in Utardia Posts: 2,561	Formula=practice

09-12-2011, 07:09 PM	#4
AX10wannabe RCC Addict Join Date: Jun 2009 Location: Salmon Arm BC Posts: 1,777	usually i make a drawing of the piece i want to bend (chassis rail or something) then i take a piece of string and form it to the drawing then stretch string out measure onto your tube or rod and thats the right length... or at least close to it.

09-12-2011, 08:59 PM	#7
Postclanker I wanna be Dave Join Date: May 2011 Location: Lost in Oregon Posts: 4,450	I didn't see SMR's until after I posted mine....but that's a good idea too.. might even get some tubing and give it a try

09-12-2011, 09:07 PM	#8
BigSki I wanna be Dave Join Date: May 2008 Location: Baltimore Posts: 4,442	I believe there are some reference charts in the 'machinerys Handbook' for bending allowance, different types of materials 'grow' on outside bends. There are many variables involved with calculating a bending allowance. The cheap and easy way is to use graph paper and draw out what you want to bend, then use the lines in the graph to make a straight line measurement.

09-13-2011, 05:44 AM	#10
bob1961 I wanna be Dave Join Date: Mar 2008 Location: Wayne county. PA Posts: 2,507	trail and error with the small benders we use....since i got back into R/C's with a crawler "the tigress" and now scalers, i have been bending brake line for 3 years now....as said starting in the middle and work your way to the ends has been a good formula....single bend bent links are the easiest to make compaired to making frames....i find it easier to have a longer length then needed and cut both ends, less wasted time starting with a new piece of tube and less waste....you can't add to what you have cause you started with less then you thought, you can always shorten what you started with .........bob ....

09-13-2011, 05:06 PM	#11
rik RCC Addict Join Date: Oct 2009 Location: In the mancave... Posts: 1,038	thanks for the tips guys. just what i was looking for. much appreciated.

09-16-2011, 11:22 PM	#12
squatch71 I wanna be Dave Join Date: Sep 2008 Location: four o six Posts: 2,101	to get the basics pick up a "Uglys" hand book...its a electricians bible...has lots of formulas and how to do stuff.* *wiring is not a hobby, hire a professional before you burn your house down.

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