Bending a radius on sheet/plate brass

I am making a custom strike plate (for the hole where the latch from a doorknob goes). However, the one part I am not sure of is the slight curved radius for the inside part where the latch first contacts to retract it. What is the best way to put this radiused bend in a very short part of the metal. I will be working with either .090 or .125 and the part to be bent will be 3-1/2 long I am trying to achieve a smooth perhaps 3/8 radius to the tune of about 30 degrees. Actual radius and degree is not exactly critical, just the appearance of the finished product.

I am not opposed to adding new tools to my tool box. But only if necessary :)

Thanks in advance

Reply to
Absinthe
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Do you have a decent vice? Fit it with some soft brass or aluminum in the jaws so as not to mark your strike plate, then torch the bend line and gently push to the bend you want?

Reply to
Wayne Lundberg

*Don't heat brass to work it*. It's hot short and breaks. If you do heat the material, you'll soften it permanently. Brass is typically provided in various stages of work hardened condition (half hard, for example), which you rely on for strength and rigidity. Any heating renders it soft and possibly worthless for your application. Do all your bends cold, without heating the part. If you have access to an arbor press, it's fairly easy to machine a small set of aluminum plates to act as a die, which would make the necessary offset. You may even be able to do it in a large vise with the same plates.

Harold

Reply to
Harold and Susan Vordos

Harold --

Thanks, glad I read that before I tried torching it. :)

I don't know what an arbor press is, so I guess I don't have one. :) But I do have a vise. I have a metal one, a wooden jawed one, and a plastic one with rubber faces for the jaws.

Can you explain a bit more about what you mean with the plates to be used as a die? I am assuming that you are talking of perhaps one concave and one convex matching? Could they be made of wood since the brass is to be .090 or .125?

Reply to
Absinthe

If you have a sheetmetal bender that handles that material, you just need to make up a radiused mandrel for it. Since you are doing brass and not that wide, the lighter models of benders may work well.

-- Why isn't there an Ozone Hole at the NORTH Pole?

Reply to
Bob May

I would,before you mill the hole, start with a much longer tab. You have a t shape, the verticle part of the letter 'T' being the part you will cut off. Hold the top of the T in a vise, soft jaws, with one jaw radiused the way you want. Bend it over the radius. cut th eextra off and mill the hole. I think don't mill the hole first because it may stretch out of the vise

Reply to
yourname

Yeah, a male and female of the shape you expect. The strike would have a small amount of spring back, but that shouldn't be a problem for you. If it is, make the die somewhat exaggerated.

Could they be made of wood since the brass is to be .090 or

Absolutely, especially something like oak or hickory, a hard and tough wood should work great, and won't mar the material. If you can start the bend in the small area where you expect the bend, and not the entire length of the strike, it should be fairly easy to bend, even using a vise. Might be interesting to hear how it turns out, so let us know.

Harold

Reply to
Harold and Susan Vordos

"Absinthe" wrote: (clip) What is the best way to put this radiused bend in a very short part of the metal. (clip) ^^^^^^^^^^^^^ Start with a piece of brass somewhat larger than you need for the final pattern. Holding one edge in the vise (possibly with jaw extensions) bend the piece by hand, to produce the curvature that looks good to you. Then, lay out the shape on the curved piece, and cut it out.

Reply to
Leo Lichtman

Respects to other posters who have offered precision approaches. A strikerplate just needs a bit of curvature. I've made several of them by grabbing the brass in a vise with a bit of roundstock of slightly less than desired radius behind it and then driving the brass round the bend with a block of hardwood and a hammer. Hint: you don't need a big hammer and you don't have to get it done with one blow.

Another approach is to make a mandrel out of hardwood with the curvature shaped on a beltsander. Then grab the brass and mandrel in a vise and hammerbend it with another piece of hardwood the width of the plate used as a drift.

It works best if you bend it first, then cut off excess on the tag end of the bend and file it to shape and finish. Don't make the rectangular hole until you've bent the radius.

After a minute at the wheel it'll look nicer than any strikerplate at the store.

Reply to
Don Foreman

Well, I just did it. I clamped it in the vise with some wood to protect it from the jaws and with another block of wood and a 4 lb drilling hammer beat the hell out of it :) The simple fact that it was .090 created the radius I needed in the short area of the bend.

Thanks for all your suggestions.

The client was thrilled!

Reply to
Absinthe

Chuckle! All that worrying for nothing.

Good job!

Harold

Reply to
Harold and Susan Vordos

Isn't that always the way. It is the stuff you dwell on that turns out to be nothing, and the thing you never thought of that bites you in the @$$. :)

Reply to
Absinthe

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