Building some Brake Parts

[2muchstuff]

If those plates are 3/8" thick then Danosb is correct in saying you will need a 80 to 100 ton press to get the job done. From the picture I was assuming a plate thickness of 1/4" and just bending alone.

Danosb,

What is pictured in the ebay auction is a punch for 16 guage sheet. It would not work for anything heavier, unless you would want to jam it up or crash it. The thicker the material that you want to punch the greater the clearance between the punch and the die must be.

[DanOSB]

Originally Posted by Geof Yes, I dug out one I had made a few months ago and was going to take photographs. Energystuff: Do you want to see it? Based on my experience doing all four bends in the same die may need something like 80 to 100 tons. I was doing a similar but smaller offset bend in 1-1/2 by 3/16 cold rolled bar and needed around 30 tons. The bottom line is that it would be possible to build something up to bend some samples if a big enough press is available. For large scale production you go to the experts and get a proper die made.

I am energyforce's friend we would definately like to see what you made! definately!! thanks!!!!

[Geof]

I have loaded up some pictures. First one shows the die and a bent piece. The offset on the part depends on the starting length and the position of the stop on the left of the die. The way the top die comes down the slope and is forced against the stop along with the stock means the bends are consistent. With this two step approach it is not possible to do a very short offset but the same simple design can be made longer to do both bends of the offset. One nice thing about an offset like this is the spring back is equal on both bends so your ends are parallel even if the angle of the offset part is not quite accurate

[One of Many]

Originally Posted by 2muchstuff If those plates are 3/8" thick then Danosb is correct in saying you will need a 80 to 100 ton press to get the job done. From the picture I was assuming a plate thickness of 1/4" and just bending alone. Danosb, What is pictured in the ebay auction is a punch for 16 guage sheet. It would not work for anything heavier, unless you would want to jam it up or crash it. The thicker the material that you want to punch the greater the clearance between the punch and the die must be.

More specifically, the thicker the material, the wider the Vee die should be to keep tonnage realistic. This type of die could work given the proper dimensions. After all, this is bending, not punching.

If the standard lower die used on 3/8" is 3". The tonnage per foot is about 25-30 tons. Since this actual bend is about 6" in length adding the two ears, I would estimate it below the 20 ton range IF it were bent to a 90 deg bend. Since it is only a 45......it should not take all of that. Of course you will need to multiply that load times 2 for the suggested die forming 2 bends x 6" at 45 degrees.

The worst part about this is trying to keep the bend radius small. Looking at the part I think I see some coining on the inside radius. If anything, it is evidence of some serious tonnage developed to make the bends tight. Whether that is a product of narrow dies is to be determined.

Taking into account the bend length, the material thickness and the actual distance between the 2 bend lines. We could alter the 2 Vee die widths below the standard 3". The tonnage will increase, but one must ask if it is realistic for the strength in the dies themselves. The physical size of the supporting material in the dies set can compensate for this to some degree. The surface hardness of the dies will need to handle this increase too. Be very cautious HT'ing bending dies to a point that removes ductility. If they don't bend when over stressed, they shatter. How fast can you get out of the way? If possible, flame or case harden. At minimum, keep through hardened dies heavy or below 55Rc.

Another point to make in the die set. It appears that there would be a conflict with the bolt flange. That portion of the dies may need clearance.

Regardless of what approach these bends are done with. There can be some alignment issues between the 2 ears on the same plane? In a production environment, repeatability could be achieved once a pattern was obvious. Not so easy with low quantity runs below 10 and crude tooling? It would compound the problems with separate dies or an attempt to get away with one die set and bend each individually. Not impossible, but not very productive to say the least.

You can use this tonnage calculator to get an estimate in what it will take to bend a given thickness of material over a given Vee Die width. Play with the Vee die width to get an idea of what happens as it gets narrow. Remember that this is for a 90 degree single bend. No....I don't think 2 x 45degree bends will equate to the same tonnage.

Bend Load calculator

Most commercial plate bending dies are made to handle around 40 tons per foot of bending length capacity. That is only 3.3 tons per inch. Please keep these tonnages issues in mind to avoid a potentially dangerous condition!

DC