Making a brake line flaring die, need help figuring how

[great white]

You may have seen my brake line thread, or maybe not.

In a nutshell, I'm planning to make some brake line flaring dies.

But the problem is i can't quite figure out how to do it.

The dies are fairly simple, they look like so:



It's the square block items.

As you can see, it's a hole through the block and then the block is split so you can place the line between them, then it's clamped together and you use a ram to form the flare aginst the 45 degree angle you see at the entrance to the through hole..

The problem I'm having is how to make them.

For example: make one for a 3/16 od line. First thought was to drill/ream a 3/16 through hole and then split the block in half.

Except, I will loose somewhere around 1/16 to 1/8 from the saw so the hole will no longer be 3/16 round. I'll loose (for arguments sake) 1/8 off one of the hole dimensions, meaning it can be 3/16 in one plan but reduced to as much as 1/16 in the plane 90 degrees to the 3/16 portion. That's not going to work because when you clamp them down on the line, it will crush in in one dimension. Not good for vehicle brakes.

I thought maybe make two identical blocks and then split each one offset the blade width. But that means I have to get two items identical in dimension and the cut has to be very precise to make the two halves mate. Off a little bit and it may crush the line or not hold it strong enough.

So I'm at a little bit of a loss to figure out the best (and most efficient) way to build these things.

Suggestions?

 

[FOMOGO]

Cut the block in half, then mill to proper depth with a 3/16 ball mill. Still think you would be way ahead of the game buying that $230 set in the other post. Maybe put in some extra hours at work, or a small handyman job for someone. A day, or two's work would pay for it, instead of spending weeks building something that may, or may not work. Mike

 

[markba633csi]

Yes you would want to split them first, then do the machining while they are clamped together- they need to be hardened and tempered though
otherwise they will wear really fast
I say buy them also
-M

 

[great white]

Cut the block in half, then mill to proper depth with a 3/16 ball mill. Still think you would be way ahead of the game buying that $230 set in the other post. Maybe put in some extra hours at work, or a small handyman job for someone. A day, or two's work would pay for it, instead of spending weeks building something that may, or may not work. Mike

Retired and on disability. I'm not hurting for cash, but i can't throw it around a lot either...

 

[great white]

Man, why didn’t I think to split it and then do the milling/drilling operations?

Everyone who knows me thinks I’m so smart, yet I missed an obvious answer like that….

 

[mattthemuppet2]

another set of eyes is all it takes sometimes

 

[aliva]

Why would you want to make this. They are readily available at any automotive outlet. Remember they have to be double flared.

 

[pontiac428]

To make a forming die, you will need to calculate the springback so that you can make the die correctly to produce results that are on dimension. It might also be wise to machine the whole die and mandrel with a draft taper so the return stroke doesn't require the mandrel to be reefed out of the form with a tractor. I'm not a betting man, but I think that if you measured everything carefully from the pattern die, you'll see what I mean.

 

[great white]

Why would you want to make this. They are readily available at any automotive outlet. Remember they have to be double flared.

see post number 4....like everyone else right now, money is tight, have lots of stock lying around.

I’ve been building brake and hydraulic lines for ground vehicles and aerospace for the better part of 40 years so yeah, I know they're double flared. Now that I’m retired, I don’t have access to all the “Gucci kit” I used to have at work.
There are even some on the car that are bubble flared so thats another consideration...

 

[great white]

Ah, figured out the best way to go here. came across a set of 3/16 die and anvil pieces:




40 bucks CAD gets that to my door. so the precision parts are coming already made. Now all I have to make is the mechanism to press the two together. It's a simple machine, looks like this:



Should be a doodle to build that part.

the majority of the brake lines are 3/16, so this will do most all of the lines. The few other sizes I can do with the conventional "cheapie" style flare tool. The cheapie will hold up fine for the few flares i will need to make with it.