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Bender Project

How long is the follower, I'm guessing it has to be at least as long as the arc of the bend. Forgive my ignorance. I bend a LOT of rigid conduit at work, up to 4" trade size, on a big hydraulic Greenlee 881 table bender. I am imagining the follower is similar. I have never used a tubing bender before. It seems that a horizontal mill might work better. I guess I just need to find a pic of this piece were talking about.
 
Nah, it's only about 4" long and all it does is keep the feed-in side of the tube from kicking out as the tube is pulled around the die. The tube slides along the "follower" which is stationary (and doesn't really follow ;)). Also, many of them only have 2 hardened contact shoes, each about 1.5"-2" long (depending on size, maybe as small as 1" long). In the 2 piece designs, the one closest to the die is also on a ~5* angle leading into the die. This also helps to limit spring back.

And yeah, a horizontal with a cob or standard mill cutter (or stack of cutters) of the appropriate diameter would do fine, but you need to get an almost mirror finish on them before heat treat, polish after.
 
Ha, I was just there checking things out. This piece, right:

http://www.jd2.com/images/M3B/die_3.jpg

Seems like you could bore a block of material, say 3" cube to the apprpriate ID to match the tube OD, then saw it in half. Geez, polishing, treating and hardening...hmmmm.....

Anyone have an EDM, or access to one? (I'm looking your way rdn2blazer. . .)
 
Forgive me for not clarifying earlier. I was leaning more towards the lathe being used to machine the actual dies, not the folllowers.
 
I may have a need to bend thicker stuff put me on your list. I just need the thicker arms though as I already have a bender
 
you only need a mill to do the followers, that is how I did mine out of 4340 steel. as far as the dies, even if you have the swing to turn the desired diameter (bend radius) the hard part is the actual radius for the tube of the die. you would have to have a radius attachment to profile the radius. a form tool can only be so big before you start running into too much surface contact then you get mad chatter. I dont care how slow or how much cutting oil or fluid you use you will get chatter. then at some point something will break. for a radius that big (1 3/4, 2.0 rad.) you have to have a rad. attachment.

even a 1.0 wide carbide tool bit obviously is still too small for a radius like that. even if you did a 1 3/4 partial radius on a 1.0 wide tool bit which is a huge tool bit you are obviously only creating a small portion of the rad. you would have to have a form tool for the center, right side, and left side to complete the entire radius. and all three would have way too much surface contact.

only two ways are cnc turning to turn the rad and a rad attach. on a conv. lathe. I made a 1 1/2 die once just to try to make one just as I decribed with form tools. I used a piece of cast iron just to try it. steel is harder ofcourse. I got it made but it was tough. I know it would be impossable in steel.

the follower blocks, you just use a endmill the size you want and rough vertically to the correct depth. I used my aluminum blocks as a model to copy from to make the steel one out of. this one is a 2.0 block, endmill is 2.0 dia. vertical roughing is more efficieant then side milling anyways. the strength of a tool is linear down its length. with side loading you get deflection. ofcourse that is the way endmills have been used for decades. but new techneques have been and are being used. even programming softwears are being developed to use vertical roughing instead of side roughing.

DSCN0821.JPG

DSCN0818.JPG
 
I can show you pics of form tools if your not sure what that is.
 
Metal Supermarket closed for inventory today. Hopefully tomorrow I can get some steel prices. Do we want 1/2" or 5/8" frame parts?
 
I'd prefer 5/8" since I'll hopefully be rigging a full hydro system and be bending thicker stuff some day. 1/2" will do fine if that's the general concensus though.
 
Wow, that end mill likely cost more than the entire bender frame or a set of 2" dies. :D
 
gauder said:
Custom Chevy
cbbr
blazinzuk
Click to expand...

I'd go for one. :D

I've already started building one like the Pro-tools HMP200/Blind Chicken racing version. Just in case I dont like that style, I would like to have a proven design to fall back on.

Z
 
there is a surplus machine supply company here that sells good used endmills for cheap. we have an account with them. we usually buy new but we have bought stuff from them before. there called Cal-Aero Supply in Paramount Ca. call them to see if they have any good used endmills for the follower blocks.
 
by all means... tell them what we want to do...
make it a ck5 project and spread the love... Ill be the sap that buys all the stuff at full bore list for reverse engineering...

If we can build model 4s for us... that would be the schiznit
 
Ok, school me, what's so advantageous about a model 4?

EDIT: Upon further review, it looks ridiculously easy to setup and bend with, dare I ask how much it would cost to reproduce it gauder?

Also, time is kinda of the essence in my case, so the sooner the ball gets rolling the better.
 
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rdn2blazer said:
there is a surplus machine supply company here that sells good used endmills for cheap. we have an account with them. we usually buy new but we have bought stuff from them before. there called Cal-Aero Supply in Paramount Ca. call them to see if they have any good used endmills for the follower blocks.
Click to expand...
Sounds kinda like one of the guys I met locally. He gets all the end mills (among other things) from local CNC shops that have been sharpened out of tollerance for CNC use. Solid carbide cutters, HSS, Cobalt, all sorts of things for pennies on the dollar, and most are freshly sharpened (except for roughers which often have a chip or two).
 
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