How to cut damaged pan brake fingers

[engineeringtech]

Hello!

We have an old 24" Diacro brand pan brake with clamping fingers of various widths. The machine was abused quite badly before we purchased it. My guess is someone bent hard wire. That has left the jaws dinged up (one of our American expressions) . And someone then took a file across the front of some of the fingers to try and even them up. Now when the fingers are mounted in the machine, they all do not stick out the same distance, and the bend line is not straight or smooth. Was wondering what my best approach would be to correct this.

I'd like to run a radius cutter along the tips, but I don't know for certain what radius the factory had on them. Something less than 1/32" or .8 mm. And because they're so dinged up, I'm not sure they would take the radius unless I first thinned down the tips by recutting the angle of the fingers.

I have no grinder, but the metal is soft enough for my Bridgeport mill. But due to a problem with the mill, I can't angle the head. So I'm going to have to angle the parts while holding them in the vise. I'm wondering if I should make some sort of fixture to hold all the fingers on the machine table and cut them all at once.

Any thoughts on this?

[alanstepney]

As you obviously know, the best machine for this job would be a surface grinder.
As you dont have one, the basic dimensions could be milled, but, they will, or should be hard, and you will need a very fine feed to avoid leaving marks on the fingers.

I would make a simple jig to ensure all are to the same angle and height.
It doesnt need to be complicated, two pins in a piece of plate to support the fingers at the correct angle, and clamp said plate inside a machine vice, so that the fingers rest on the pins + bottom of vice.
Then lightly skim until all fingers are the same height.
Then it is just (?) a matter of the radius at the tips of the fingers.
The minimum radius you would want is half the thickness of the thinnest metal you bend.
So, assuming that is 22 swg, around 10 thou radius, or in other words, enough to stop it having sharp corners that would leave marks in the bent metal (especially if it is a soft material.)
If you only want gentle rather than sharp bends, then it could with advantage be, say 15 or 20 thou radius.

How to do it?
I would definately grind it. Jury-rig some type of grinder in the mill, and form the grinding wheel to the required radius.
How you do the jury-rig will depend upon what you have available to you, but it doesnt need to be complex or pretty just to do one job.

[redmog]

Curiosity has got the better of me.

What are 'Pan Brake Fingers' ??

[jasonb]

they are the metal plates that push the metal into a corisponding "v" on a metal brake press (folder), have a look at the following pic, they are the shiny bits held on with cap screws

www.warco.co.uk/productimages/pictures/ThMain_007032.jpg

this will give a better idea of shape

www.warco.co.uk/productimages/pictures/ThMain_008986.4.jpg

Jason

[redmog]

Thanks Jason.

[steam4ian]

G'day

Try my favourite tool, an angle grinder.

Regards,
Ian